comments

Reviewed-on: #13

.gitignore

@@ -6,4 +6,11 @@ iso_root
 *.iso
 *.gch
 */*.gch
-*/*/*.gch
+*/*/*.gch
+.gdb_history
+symbols.map
+symbols.S
+*.log
+build/
+compile_commands.json
+.cache/

Makefile

@@ -1,11 +1,21 @@
-SOURCES = src/mem/heap/kheap.c src/mem/paging/vmm.c src/mem/paging/paging.c src/mem/paging/pmm.c src/string/string.c src/io/kbd/ps2.c src/io/serial/serial.c src/io/term/printf.c src/io/term/term.c src/idt/idt.c src/mem/gdt/gdt.c src/mem/misc/utils.c src/time/timer.c src/kmain.c
+SOURCES = src/sched/spinlock.c src/debug/misc.c src/io/term/flanterm_backends/fb.c src/io/term/flanterm.c src/debug/panic.c src/debug/stacktrace.c src/boot/boot.c src/sched/scheduler.c src/sched/process.c src/mem/heap/kheap.c src/mem/paging/vmm.c src/mem/paging/paging.c src/mem/paging/pmm.c src/string/string.c src/io/kbd/ps2.c src/io/serial/serial.c src/io/term/term.c src/idt/idt.c src/mem/gdt/gdt.c src/mem/misc/utils.c src/time/timer.c src/kmain.c
+
+CC_FLAGS=-Wall -Wextra -std=gnu99 -nostdlib -ffreestanding -fno-stack-protector -fno-omit-frame-pointer -fno-stack-check -fno-PIC -ffunction-sections -fdata-sections -mcmodel=kernel
+CC_PROBLEMATIC_FLAGS=-Wno-unused-parameter -Wno-unused-variable
+
+.PHONY: build build-iso debug debug2 run clean
 
 build:
-	rm -f *.o
+	mkdir -p build
-	x86_64-elf-gcc -g -c -Isrc $(SOURCES) -Wall -Wextra -std=gnu99 -nostdlib -ffreestanding -fno-stack-protector -fno-omit-frame-pointer -fno-stack-check -fno-PIC -ffunction-sections -fdata-sections -mcmodel=kernel
+	rm -f *.o build/*.o
-	objcopy -O elf64-x86-64 -B i386 -I binary zap-light16.psf zap-light16.o
+	x86_64-elf-gcc -g -c -Isrc $(SOURCES) $(CC_PROBLEMATIC_FLAGS) $(CC_FLAGS)
-	nasm -f elf64 src/idt/idt.S -o idt_stub.o
+	mv *.o build/
-	x86_64-elf-ld -o pepperk -T linker.ld *.o
+	nasm -f elf64 src/idt/idt.S -o build/idt_stub.o
+	x86_64-elf-ld -o pepperk -T linker.ld build/*.o
+	nm -n pepperk | awk '$$2 ~ /[TtDdBbRr]/ {print $$1, $$3}' > symbols.map
+	python3 symbols.py
+	nasm -f elf64 symbols.S -o build/symbols.o
+	x86_64-elf-ld -o pepperk -T linker.ld build/*.o
 
 limine/limine:
 	rm -rf limine
@@ -30,11 +40,15 @@ build-iso: limine/limine build
 	./limine/limine bios-install pepper.iso
 
 debug:
-	qemu-system-x86_64 -drive file=pepper.iso -s -S -d int -no-reboot -no-shutdown &
+	/usr/bin/qemu-system-x86_64 -drive file=pepper.iso -s -S -d int -D qemu.log -no-reboot -no-shutdown &
 	gdb pepperk --command=debug.gdb
 
+debug2:
+	/usr/bin/qemu-system-x86_64 -drive file=pepper.iso -s -S -d int -no-reboot -no-shutdown &
+	pwndbg pepperk --command=debug.gdb
+
 run: build-iso
-	qemu-system-x86_64 -cdrom pepper.iso -serial stdio
+	/usr/bin/qemu-system-x86_64 -cdrom pepper.iso -serial stdio
 
 clean:
-	rm -rf *.o pepperk iso_root pepper.iso limine
+	rm -rf *.o symbols.map symbols.S pepperk iso_root pepper.iso limine build/*.o

README.md

@@ -2,7 +2,13 @@
 
 ## Trying the kernel
 
-First install the dependencies: `sudo apt install xorriso make qemu-system`
+First install the dependencies: `sudo apt install python3 xorriso make qemu-system`
+
+Also, you have to get an x86_64 toolchain for compilation. The easiest way to do that on most systems is to install it from Homebrew:
+
+```
+brew install x86_64-elf-gcc
+```
 
 Then, to compile the kernel and make an ISO image file: `make build-iso`
 To run it with QEMU, `make run`
@@ -11,18 +17,25 @@ To run it with QEMU, `make run`
 
 The basics that I'm targeting are:
 
-- Fix terminal driver (backspace issues, scrolling) OR add Flanterm or equivalent
+### Basic utility of what we call a "kernel"
-- Implement paging / see what Limine does at boot with memory management
+
-- Implement tasks, and task switching
+- Implement tasks, and task switching + context switching and spinlock acquire/release
 - Load an executable
-- Scheduler (round-robin using the PIT timer interrupt)
+- Filesystem (TAR for read-only initfs, then maybe read-write using FAT12/16/32 or easier fs) w/ VFS layer
-- Filesystem (TAR for read-only initfs, then maybe read-write using FAT12/16/32
+- Getting to userspace (ring 3 switching, syscall interface)
-- Getting to userspace (syscalls)
 - Porting musl libc or equivalent
 
-In the future, maybe?
+### Scalability/maintenance/expansion features
 
-- SMP support
+- Documentation
+- SOME error handling in functions
+- Unit tests
+- Good error codes (like Linux kernel: ENOMEM, ENOENT, ...)
+
+### Optional features
+
+In the future, maybe?
+- SMP support (Limine provides functionality to make this easier)
 - Parsing the ACPI tables and using them for something
 - Replacing the PIT timer with APIC
 
@@ -32,8 +45,10 @@ PepperOS wouldn't be possible without the following freely-licensed software:
 
 - the [Limine](https://codeberg.org/Limine/Limine) portable bootloader
 - Marco Paland's freestanding [printf implementation](https://github.com/mpaland)
-- the [ZAP](https://www.zap.org.au/projects/console-fonts-zap/) PSF console fonts
+- Mintuski's [Flanterm](https://codeberg.org/Mintsuki/Flanterm) terminal emulator
 
 ...and without these amazing resources:
 
 - the [OSDev](https://osdev.org) wiki & forums
+- Intel 64 and IA-32 Architectures Software Developer's Manual
+- Documentation for the [GNU Compiler Collection](https://gcc.gnu.org/onlinedocs/gcc/)

debug.gdb

@@ -1,3 +1,7 @@
 target remote localhost:1234
 set disassembly-flavor intel
-display/8i $rip
+display/4i $rip
+
+# Trying to debug that flanterm page fault
+
+# b plot_char_unscaled_uncanvas if $rdi == 0 || $rsi == 0 || $rdx == 0 || $r10 == 0

docs/STYLE.md

@@ -0,0 +1,93 @@
+# Pepper kernel coding style
+
+This document describes the coding style for the Pepper kernel. It is used as a guideline across all source files.
+
+## Indentation
+
+Indentations should be 4 characters long.
+
+## Line length
+
+Lines should not be more than 100 characters long. Exceptions is made for printing strings.
+
+## Variables
+
+Variables should be declared at most once per line.
+
+## Braces
+
+Non-function statement blocks should have an opening brace last on the line, and a closing brace first. Exception is made for `else`, `else if` statements and the like:
+
+```c
+if (something) {
+    do_something();
+} else if (something_else) {
+    do_something_else();
+}
+```
+
+Having no braces for a single statement structure is fine.
+
+Functions should have their opening brace on a separate line, and the same goes for the closing brace:
+
+```c
+void function()
+{
+    do_something();
+}
+```
+
+## Spaces
+
+Use a space after `if, switch, case, for, do, while` keywords, but not for `sizeof, typeof, alignof, __attribute__` and the like.
+
+For pointers, the asterisk should always be placed adjacent to the type name, like `char* str;`.
+
+## Naming
+
+Functions should be named with whole words, beginning with the corresponding name of the module in the kernel (the parent folder). Words should be spaced with underscores, like so:
+
+```c
+serial_init(void* ptr, char* str, int foo);
+```
+
+Constants should be named in all caps, separated by underscores:
+
+```c
+#define MAX_HEAP_SIZE 0x1000
+```
+
+Global variables need to have descriptive names. Local variables can be kept short (especially for loop counters).
+
+## Typedefs
+
+Structures should not be `typedef`'d. However using `typedef` for an enumeration is fine.
+
+## Functions
+
+Functions should be short, simple, and only do one thing.
+
+Function prototypes should include parameter names and their data types.
+
+## Commenting
+
+Comments should describe what a function does and why, not how it does it. The preferred way of commenting functions is the following:
+
+```c
+/*
+ * function_name - Function brief description
+ * @arg1: Argument 1 description
+ * @arg2: Argument 2 description
+ *
+ * A longer description can be featured here, explaining more
+ * in detail what the function does and why it does it.
+ */
+```
+
+## Kernel messages
+
+When printing kernel messages with the `DEBUG` macro, they should start with a capital letter.
+
+### Resources
+
+Some of the elements here are inspired by the [Linux kernel coding style](https://www.kernel.org/doc/html/v4.10/process/coding-style.html).

src/boot/boot.c

@@ -0,0 +1,42 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Limine requests for boot
+ * @description
+ * The kernel makes a few requests to the Limine bootloader
+ * in order to get precious information about the system.
+ * We get a framebuffer, a memory map, the address of the
+ * kernel in memory, and the Higher Half Direct Map offset.
+ * @license GPL-3.0-only
+ */
+
+#include <limine.h>
+
+__attribute__((used, section(".limine_requests")))
+volatile struct limine_framebuffer_request framebuffer_request = {
+	.id = LIMINE_FRAMEBUFFER_REQUEST,
+	.revision = 0
+};
+
+__attribute__((used, section(".limine_requests")))
+volatile struct limine_memmap_request memmap_request = {
+	.id = LIMINE_MEMMAP_REQUEST,
+	.revision = 0
+};
+
+__attribute__((used, section(".limine_requests")))
+volatile struct limine_hhdm_request hhdm_request = {
+	.id = LIMINE_HHDM_REQUEST,
+	.revision = 0
+};
+
+__attribute__((used, section(".limine_requests")))
+volatile struct limine_kernel_address_request kerneladdr_request = {
+	.id = LIMINE_KERNEL_ADDRESS_REQUEST,
+	.revision = 0
+};
+
+__attribute__((used, section(".limine_requests_start")))
+volatile LIMINE_REQUESTS_START_MARKER;
+
+__attribute__((used, section(".limine_requests_end")))
+volatile LIMINE_REQUESTS_END_MARKER;

src/config.h

@@ -0,0 +1,45 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   PepperOS configuration file
+ * @license GPL-3.0-only
+ */
+
+#ifndef CONFIG_H
+#define CONFIG_H
+
+/* version */
+#define PEPPEROS_VERSION_MAJOR "0"
+#define PEPPEROS_VERSION_MINOR "0"
+#define PEPPEROS_VERSION_PATCH "58"
+#define PEPPEROS_SPLASH "\x1b[38;5;196mPepperOS\x1b[0m version "PEPPEROS_VERSION_MAJOR"."PEPPEROS_VERSION_MINOR"."PEPPEROS_VERSION_PATCH"\n"
+
+/* process */
+#define PROCESS_NAME_MAX 64
+#define PROCESS_STACK_SIZE 0x10000 // 64kb
+#define PROCESS_BASE 0x400000
+#define PROCESS_STACK_BASE 0x1000000
+
+/* sched */
+// 1 tick = 1 ms => quantum = 10ms
+#define SCHEDULER_QUANTUM 10
+
+/* kernel */
+#define KERNEL_BASE 0xFFFFFFFF80000000ULL
+// 2 MB should be enough (as of now, the whole kernel ELF is around 75kb)
+#define KERNEL_SIZE 0x200000
+#define KERNEL_STACK_SIZE 65536
+#define KERNEL_IDT_ENTRIES 33
+
+/* paging */
+#define PAGING_MAX_PHYS 0x100000000
+
+/* heap */
+#define KHEAP_SIZE (32*1024*1024)
+
+/* term */
+#define TERM_HISTORY_MAX_LINES 256
+
+/* time */
+#define TIMER_FREQUENCY 1000
+
+#endif

src/debug/misc.c

@@ -0,0 +1,79 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Miscellaneous debug features
+ * @license GPL-3.0-only
+ */
+
+#include <kernel.h>
+#include "limine.h"
+#include "string/string.h"
+#include <stddef.h>
+
+extern struct boot_context boot_ctx;
+
+/*
+ * memmap_display - displays a memory map
+ * @response: Limine memory map response
+ *
+ * Displays the memory map we get from Limine
+ * to see different regions, their sizes, and
+ * how the memory is laid out at handoff.
+ */
+void memmap_display(struct limine_memmap_response* response)
+{
+	DEBUG("Got memory map from Limine: revision %u, %u entries", response->revision, response->entry_count);
+
+	for (size_t i=0; i<response->entry_count; i++) {
+		struct limine_memmap_entry* entry = response->entries[i];
+		char type[32] = {0};
+		switch(entry->type) {
+			case LIMINE_MEMMAP_USABLE:
+				strcpy(type, "USABLE");
+				break;
+			case LIMINE_MEMMAP_RESERVED:
+				strcpy(type, "RESERVED");
+				break;
+			case LIMINE_MEMMAP_ACPI_RECLAIMABLE:
+				strcpy(type, "ACPI_RECLAIMABLE");
+				break;
+			case LIMINE_MEMMAP_ACPI_NVS:
+				strcpy(type, "ACPI_NVS");
+				break;
+			case LIMINE_MEMMAP_BAD_MEMORY:
+				strcpy(type, "BAD_MEMORY");
+				break;
+			case LIMINE_MEMMAP_BOOTLOADER_RECLAIMABLE:
+				strcpy(type, "BOOTLOADER_RECLAIMABLE");
+				break;
+			case LIMINE_MEMMAP_KERNEL_AND_MODULES:
+				strcpy(type, "KERNEL_AND_MODULES");
+				break;
+			case LIMINE_MEMMAP_FRAMEBUFFER:
+				strcpy(type, "FRAMEBUFFER");
+				break;
+			default:
+				strcpy(type, "UNKNOWN");
+				break;
+		}
+		DEBUG("Entry %02u: [0x%016x | %016u bytes] - %s", i, entry->base, entry->length, type);
+	}
+}
+
+/*
+ * hhdm_display - displays the HHDM offset
+ * @hhdm: Limine HHDM offset response
+ */
+void hhdm_display(struct limine_hhdm_response* hhdm)
+{
+	DEBUG("Got HHDM revision=%u offset=0x%p", hhdm->revision, hhdm->offset);
+}
+
+/*
+ * boot_mem_display - displays all memory info
+ */
+void boot_mem_display()
+{
+	memmap_display(boot_ctx.mmap);
+	hhdm_display(boot_ctx.hhdm);
+	DEBUG("Kernel is at phys_base=0x%p virt_base=0x%p", boot_ctx.kaddr->physical_base, boot_ctx.kaddr->virtual_base);
+}

src/debug/panic.c

@@ -0,0 +1,92 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Kernel panic
+ * @license GPL-3.0-only
+ */
+
+#include <stddef.h>
+#include "idt/idt.h"
+#include "io/serial/serial.h"
+#include "kernel.h"
+
+extern struct init_status init;
+extern int panic_count;
+
+/*
+ * reaf_rflags - provide easy reading of the RFLAGS register
+ * @rflags: RFLAGS register value
+ */
+void read_rflags(uint64_t rflags)
+{
+	DEBUG("\x1b[38;5;226m%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\x1b[38;5;231m",
+		CHECK_BIT(rflags, 0) ? "CF " : "", /*carry flag*/
+		CHECK_BIT(rflags, 2) ? "PF " : "", /*parity flag*/
+		CHECK_BIT(rflags, 4) ? "AF " : "", /*auxiliary carry flag*/
+		CHECK_BIT(rflags, 6) ? "ZF " : "", /*zero flag*/
+		CHECK_BIT(rflags, 7) ? "SF " : "", /*sign flag*/
+		CHECK_BIT(rflags, 8) ? "TF " : "", /*trap flag*/
+		CHECK_BIT(rflags, 9) ? "IF " : "", /*interrupt enable flag*/
+		CHECK_BIT(rflags, 10) ? "DF " : "", /*direction flag*/
+		CHECK_BIT(rflags, 11) ? "OF " : "", /*overflow flag*/
+		(CHECK_BIT(rflags, 12) && CHECK_BIT(rflags, 13)) ? "IOPL3 " : "IOPL0 ", /*io privilege lvl*/
+		CHECK_BIT(rflags, 14) ? "NT " : "", /*nested task*/
+		CHECK_BIT(rflags, 16) ? "RF " : "", /*resume flag*/
+		CHECK_BIT(rflags, 17) ? "VM " : "", /*virtual 8086 mode*/
+		CHECK_BIT(rflags, 18) ? "AC " : "", /*alignment check/access control*/
+		CHECK_BIT(rflags, 19) ? "VIF " : "", /*virtual interrupt flag*/
+		CHECK_BIT(rflags, 20) ? "VIP " : "", /*virtual interrupt pending*/
+		CHECK_BIT(rflags, 21) ? "ID " : ""); /*id flag*/
+
+	if (init.terminal) {
+		printf("\x1b[38;5;226m%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s\x1b[38;5;231m\r\n",
+			CHECK_BIT(rflags, 0) ? "CF " : "",
+			CHECK_BIT(rflags, 2) ? "PF " : "",
+			CHECK_BIT(rflags, 4) ? "AF " : "",
+			CHECK_BIT(rflags, 6) ? "ZF " : "",
+			CHECK_BIT(rflags, 7) ? "SF " : "",
+			CHECK_BIT(rflags, 8) ? "TF " : "",
+			CHECK_BIT(rflags, 9) ? "IF " : "",
+			CHECK_BIT(rflags, 10) ? "DF " : "",
+			CHECK_BIT(rflags, 11) ? "OF " : "",
+			(CHECK_BIT(rflags, 12) && CHECK_BIT(rflags, 13)) ? "IOPL3 " : "IOPL0 ",
+			CHECK_BIT(rflags, 14) ? "NT " : "",
+			CHECK_BIT(rflags, 16) ? "RF " : "",
+			CHECK_BIT(rflags, 17) ? "VM " : "",
+			CHECK_BIT(rflags, 18) ? "AC " : "",
+			CHECK_BIT(rflags, 19) ? "VIF " : "",
+			CHECK_BIT(rflags, 20) ? "VIP " : "",
+			CHECK_BIT(rflags, 21) ? "ID " : "");
+	}
+}
+
+/*
+ * panic - Kernel panic
+ * @ctx: CPU context (optional)
+ * @str: Error message 
+ *
+ * Ends execution of the kernel in case of an unrecoverable error.
+ * Will display to terminal if it is initialized, otherwise serial only.
+ * Can be called with or without a CPU context.
+ */
+void panic(struct cpu_status_t* ctx, const char* str)
+{
+	CLEAR_INTERRUPTS;
+	panic_count += 1;
+	if (ctx == NULL) {
+		printf("\r\n\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[48;5;232m Something went horribly wrong! (no cpu ctx)");
+		printf("\r\n%s\r\n\x1b[38;5;231m\x1b[0m", str);
+		debug_stack_trace(100);
+		hcf();
+	}
+
+	printf("\r\n\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[48;5;232mat rip=%p\r\nSomething went horribly wrong! (%s) vect=0x%.2x errcode=0x%x\n\rrax=%p rbx=%p rcx=%p rdx=%p\n\rrsi=%p rdi=%p  r8=%p  r9=%p\n\rr10=%p r11=%p r12=%p r13=%p\n\rr14=%p r15=%p\n\n\rflags=%p ",
+	ctx->iret_rip,
+	str,
+	ctx->vector_number, ctx->error_code, ctx->rax, ctx->rbx, ctx->rcx, ctx->rdx, ctx->rsi, ctx->rdi,
+	ctx->r8, ctx->r9, ctx->r10, ctx->r11, ctx->r12, ctx->r13, ctx->r14, ctx->r15, ctx->iret_flags);
+
+	read_rflags(ctx->iret_flags);
+	debug_stack_trace(100);
+	
+	hcf();
+}

src/debug/stacktrace.c

@@ -0,0 +1,96 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Stack trace tools
+ * @license GPL-3.0-only
+ */
+
+#include <stdint.h>
+#include "kernel.h"
+#include <stddef.h>
+
+extern struct init_status init;
+
+/*
+ * debug_stack_trace - Prints the stack trace
+ * @max_frames: Maximum amount of stack frames to walk
+ *
+ * Walks back the stack and gets all return values (RIP)
+ * and prints them to the DEBUG interface.
+ */
+void debug_stack_trace(unsigned int max_frames)
+{
+    printf("\r\n\x1b[48;5;232m\x1b[38;5;231m*** begin stack trace ***\r\n");
+
+    // Thanks GCC :)
+    uintptr_t* rbp = (uintptr_t*)__builtin_frame_address(0);
+
+    for (unsigned int frame=0; frame<max_frames && rbp != NULL; frame++) {
+        // Return address, 1 word above saved rbp
+        uintptr_t rip = rbp[1];
+        uintptr_t offset = 0;
+        const char* name = debug_find_symbol(rip, &offset);
+        printf("[%u] <0x%p> (%s+0x%x)\r\n", frame, (void*)rip, name, offset);
+
+        uintptr_t* next_rbp = (uintptr_t*)rbp[0];
+
+        // Invalid rbp or we're at the end
+        if (next_rbp <= rbp || next_rbp == NULL) {
+            break;
+        }
+
+        rbp = next_rbp;
+    }
+
+    printf("*** end stack trace ***\r\n[end Kernel panic]\r\nHalting system...\x1b[0m");
+}
+
+typedef struct {
+    uint64_t addr;
+    const char *name;
+} __attribute__((packed)) kernel_symbol_t;
+
+__attribute__((weak)) extern kernel_symbol_t symbol_table[];
+__attribute__((weak)) extern uint64_t symbol_count;
+
+/*
+ * debug_find_symbol - Finds the symbol name associated to an address
+ * @rip:    Pointer to executable code
+ * @offset: Out pointer to reference the offset in the found function, if any
+ *
+ * Return:
+ * <symbol name> - symbol name
+ * "???"         - no symbol table found
+ * "unknown"     - symbol table found, but address isn't in the table
+ */
+const char* debug_find_symbol(uintptr_t rip, uintptr_t* offset)
+{
+    if (!symbol_table || symbol_count == 0) {
+        if (offset) *offset = 0;
+        return "???";
+    }
+
+    int low = 0, high = (int)symbol_count - 1;
+    int best = -1;
+
+    while (low <= high) {
+        int mid = (low + high) / 2;
+        if (symbol_table[mid].addr <= rip) {
+            best = mid;
+            low = mid + 1;
+        } else {
+            high = mid - 1;
+        }
+    }
+
+    if (best != -1) {
+        if (offset) {
+            *offset = rip - symbol_table[best].addr;
+        }
+        return symbol_table[best].name;
+    }
+
+    if (offset) {
+        *offset = 0;
+    }
+    return "unknown";
+}

src/idt/idt.S

@@ -1,4 +1,8 @@
-; Assembly stub for the IDT
+;
+;  @author  xamidev <xamidev@riseup.net>
+;  @brief   Stub for Interrupt Descriptor Table handlers
+;  @license GPL-3.0-only
+;
 
 bits 64
 
@@ -147,12 +151,13 @@ vector_7_handler:
 align 16
 vector_8_handler:
     ; No error code, we only push vector number
-    push qword 1
+    push qword 8
     jmp interrupt_stub
 
 ; Coprocessor Segment Overrun
 align 16
 vector_9_handler:
+    push qword 0
     push qword 9
     jmp interrupt_stub
 

src/idt/idt.c

@@ -1,3 +1,9 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Interrupt Descriptor Table setup and dispatching
+ * @license GPL-3.0-only
+ */
+
 #include "idt.h"
 #include <stdint.h>
 #include <stddef.h>
@@ -5,6 +11,9 @@
 #include "io/kbd/ps2.h"
 #include <kernel.h>
 #include <stdbool.h>
+#include "sched/scheduler.h"
+#include "config.h"
+#include "sched/process.h"
 
 struct interrupt_descriptor idt[256];
 struct idtr idt_reg;
@@ -13,8 +22,14 @@ struct idtr idt_reg;
 extern char vector_0_handler[];
 
 // Timer ticks
-extern uint64_t ticks;
+extern volatile uint64_t ticks;
 
+/*
+ * idt_set_entry - Sets an Interrupt Descriptor Table entry
+ * @vector:  Vector number in the IDT
+ * @handler: Pointer to the executable Interrupt Service Routine
+ * @dpl:     Desired privilege level
+ */
 void idt_set_entry(uint8_t vector, void* handler, uint8_t dpl)
 {
     uint64_t handler_addr = (uint64_t)handler;
@@ -33,6 +48,10 @@ void idt_set_entry(uint8_t vector, void* handler, uint8_t dpl)
     entry->ist = 0;
 }
 
+/*
+ * idt_load - Loads the Interrupt Descriptor Table
+ * @idt_addr: Address to the IDT
+ */
 void idt_load(void* idt_addr)
 {
     // "limit" = "size" = Size of the IDT - 1 byte = (16*256)-1 = 0xFFF
@@ -41,12 +60,15 @@ void idt_load(void* idt_addr)
     asm volatile("lidt %0" :: "m"(idt_reg));
 }
 
+/*
+ * idt_init - Initializes the Interrupt Descriptor Table
+ *
+ * Sets all IDT entries and their corresponding service routines,
+ * then loads it.
+ */
 void idt_init()
 {
-    // We set 256 entries, but we have only the first few stubs.
+    for (size_t i=0; i<=KERNEL_IDT_ENTRIES; i++) {
-    // Undefined behavior?
-    for (size_t i=0; i<256; i++)
-    {
         // Each vector handler is 16-byte aligned, so <vector_no>*16 = address of that handler
         idt_set_entry(i, vector_0_handler + (i*16), 0);
     }
@@ -54,6 +76,15 @@ void idt_init()
     DEBUG("IDT initialized");
 }
 
+/*
+ * read_cr2 - Reads the CR2 register
+ *
+ * This function is useful because it gets the address
+ * that the CPU tried to access in the case of a #PF.
+ *
+ * Return:
+ * %val - CR2 register value
+ */
 static inline uint64_t read_cr2(void)
 {
     uint64_t val;
@@ -61,6 +92,15 @@ static inline uint64_t read_cr2(void)
     return val;
 }
 
+/*
+ * page_fault_handler - Handler for #PF
+ * @ctx: CPU context
+ *
+ * Shows detail about a #PF, especially what instruction (RIP)
+ * caused it, and what address access (CR2) caused it.
+ * Also displays an interpretation of the thrown error code.
+ * Then halts the system. We could implement demand paging later.
+ */
 static void page_fault_handler(struct cpu_status_t* ctx)
 {
     // It could be used to remap pages etc. to fix the fault, but right now what I'm more
@@ -79,13 +119,16 @@ static void page_fault_handler(struct cpu_status_t* ctx)
     CHECK_BIT(ctx->error_code, 7) ? " SGX_VIOLATION" : "",
     cr2);
 
-    /* if (CHECK_BIT(ctx->error_code, 0))
+    panic(ctx, "page fault");
-    {
-        panic(ctx);
-    } */
-    panic(ctx);
 }
 
+/*
+ * gp_fault_handler - Handler for #GP
+ * @ctx: CPU context
+ *
+ * Shows detail about a General Protection Fault,
+ * and what may have caused it. Halts the system.
+ */
 static void gp_fault_handler(struct cpu_status_t* ctx)
 {
     DEBUG("\x1b[38;5;231mGeneral Protection Fault at rip=0x%p, err=%u (%s)\x1b[0m",
@@ -94,8 +137,7 @@ static void gp_fault_handler(struct cpu_status_t* ctx)
     (ctx->error_code == 0) ? "NOT_SEGMENT_RELATED" : "SEGMENT_RELATED");
 
     // Segment-related
-    if (ctx->error_code != 0)
+    if (ctx->error_code != 0) {
-    {
         bool is_external = CHECK_BIT(ctx->error_code, 0);
         // is it IDT, GDT, LDT?
         uint8_t table = ctx->error_code & 0x6; // 0b110 (isolate table)
@@ -109,97 +151,121 @@ static void gp_fault_handler(struct cpu_status_t* ctx)
         index);
     }
 
-    panic(ctx);
+    panic(ctx, "gp fault");
 }
 
+// DEBUG
+void kbdproc_main(void* arg)
+{
+    printf("Key pressed/released.\r\n");
+}
+
+/*
+ * interrupt_dispatch - Interrupt dispatcher
+ * @context: CPU context
+ *
+ * This function is where all interrupt routines go, after they passed
+ * through their corresponding vector handler in the IDT assembly stub.
+ * It catches all exceptions.
+ *
+ * Return:
+ * <context> - CPU context after interrupt
+ */
 struct cpu_status_t* interrupt_dispatch(struct cpu_status_t* context)
 {
-    switch(context->vector_number)
+    if (context == NULL) {
-    {
+        panic(NULL, "Interrupt dispatch recieved NULL context!");
+    }
+
+    switch(context->vector_number) {
         case 0:
-            DEBUG("Divide Error!");
+            panic(context, "Divide Error");
             break;
         case 1:
-            DEBUG("Debug Exception!");
+            panic(context, "Debug Exception");
             break;
         case 2:
-            DEBUG("NMI Interrupt!");
+            panic(context, "NMI Interrupt");
             break;
         case 3:
-            DEBUG("Breakpoint Interrupt!");
+            panic(context, "Breakpoint Interrupt");
             break;
         case 4:
-            DEBUG("Overflow Trap!");
+            panic(context, "Overflow Trap");
             break;
         case 5:
-            DEBUG("BOUND Range Exceeded!");
+            panic(context, "BOUND Range Exceeded");
             break;
         case 6:
-            DEBUG("Invalid Opcode!");
+            panic(context, "Invalid Opcode");
             break;
         case 7:
-            DEBUG("Device Not Available!");
+            panic(context, "Device Not Available");
             break;
         case 8:
-            DEBUG("Double Fault!");
+            panic(context, "Double Fault");
             break;
         case 9:
-            DEBUG("Coprocessor Segment Overrun!");
+            panic(context, "Coprocessor Segment Overrun");
             break;
         case 10:
-            DEBUG("Invalid TSS!");
+            panic(context, "Invalid TSS");
             break;
         case 11:
-            DEBUG("Segment Not Present!");
+            panic(context, "Segment Not Present");
             break;
         case 12:
-            DEBUG("Stack-Segment Fault!");
+            panic(context, "Stack-Segment Fault");
             break;
         case 13:
             gp_fault_handler(context);
             break;
         case 14:
-            // Better debugging for page faults...
             page_fault_handler(context);
             break;
         case 15:
-            DEBUG("Intel Reserved Interrupt! (Achievement unlocked: How Did We Get Here?)");
+            panic(context, "Intel Reserved Interrupt (Achievement unlocked: How Did We Get Here?)");
             break;
         case 16:
-            DEBUG("x87 Floating-Point Error!");
+            panic(context, "x87 Floating-Point Error");
             break;
         case 17:
-            DEBUG("Alignment Check Fault!");
+            panic(context, "Alignment Check Fault");
             break;
         case 18:
-            DEBUG("Machine Check!");
+            panic(context, "Machine Check");
             break;
         case 19:
-            DEBUG("SIMD Floating-Point Exception!");
+            panic(context, "SIMD Floating-Point Exception");
             break;
         case 20:
-            DEBUG("Virtualization Exception!");
+            panic(context, "Virtualization Exception");
             break;
         case 21:
-            DEBUG("Control Protection Exception!");
+            panic(context, "Control Protection Exception");
             break;
 
-        case 32:
+        case 32: // Timer Interrupt
-            //DEBUG("Timer Interrupt");
             ticks++;
             // Send an EOI so that we can continue having interrupts
             outb(0x20, 0x20);
+
+            if (ticks % SCHEDULER_QUANTUM == 0) {
+                return scheduler_schedule(context);
+            }
+
             break;
 
-        case 33:
+        case 33: // Keyboard Interrupt
-            DEBUG("Keyboard Interrupt");
             keyboard_handler();
+            process_create("keyboard-initiated", kbdproc_main, NULL); // DEBUG
+            outb(0x20, 0x20);
             break;
 
         default:
-            DEBUG("Unexpected interrupt");
+            DEBUG("Unexpected Interrupt");
             break;
     }
 
     return context;
-}
+}

src/idt/idt.h

@@ -1,12 +1,17 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Interrupt Descriptor Table setup and dispatching
+ * @license GPL-3.0-only
+ */
+
 #ifndef IDT_H
 #define IDT_H
 
 #include <stdint.h>
 
-void idt_init();
+void idt_init(void);
 
-struct interrupt_descriptor
+struct interrupt_descriptor {
-{
     uint16_t address_low;
     uint16_t selector;
     uint8_t ist;
@@ -16,8 +21,7 @@ struct interrupt_descriptor
     uint32_t reserved;
 } __attribute__((packed));
 
-struct idtr 
+struct idtr {
-{
     uint16_t limit;
     uint64_t base;
 } __attribute__((packed));
@@ -25,8 +29,7 @@ struct idtr
 // All general-purpose registers (except rsp) as stored on the stack,
 // plus the values we pushed (vector number, error code) and the iret frame
 // In reverse order because the stack grows downwards.
-struct cpu_status_t
+struct cpu_status_t {
-{
     uint64_t r15;
     uint64_t r14;
     uint64_t r13;
@@ -36,7 +39,6 @@ struct cpu_status_t
     uint64_t r9;
     uint64_t r8;
     uint64_t rbp;
-    //uint64_t rsp;
     uint64_t rdi;
     uint64_t rsi;
     uint64_t rdx;

src/io/kbd/ps2.c

@@ -1,10 +1,15 @@
-// PS/2 Keyboard support
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   PS/2 Keyboard driver
+ * @license GPL-3.0-only
+ */
 
 #include "io/serial/serial.h"
 #include "ps2.h"
 #include <stdint.h>
 #include "io/term/term.h"
 #include <kernel.h>
+#include <stddef.h>
 
 // The key status bitfield will be used to see if ALT, CONTROL, or SHIFT is pressed
 uint8_t key_status = 0b00000000;
@@ -13,6 +18,8 @@ uint8_t key_status = 0b00000000;
 unsigned char* keymap;
 unsigned char* keymap_shifted;
 
+extern struct init_status init;
+
 unsigned char kbdus[128] =
 {
     0,  27, '1', '2', '3', '4', '5', '6', '7', '8',	/* 9 */
@@ -150,16 +157,22 @@ unsigned char kbdfr_shifted[128] =
     0
 };
 
+/*
+ * keyboard_handler - Keyboard event handler
+ *
+ * Is called from the interrupt dispatcher.
+ * When a key is pressed or released, we get a scancode, and
+ * it is then translated to an ASCII character.
+ * Left Shift, Ctrl, and Alt keys are also taken into consideration. 
+ */
 void keyboard_handler()
 {
     unsigned char scancode = inb(0x60);
 
     // Key release (bit 7 set)
-    if (scancode & 0x80)
+    if (scancode & 0x80) {
-    {
         unsigned char code = scancode & 0x7F;
-        switch (code)
+        switch (code) {
-        {
             // Clear the corresponding bit if corresponding key is released
             case LEFT_SHIFT_PRESSED:
             case RIGHT_SHIFT_PRESSED:
@@ -172,16 +185,10 @@ void keyboard_handler()
                 key_status &= ~ALT_PRESSED_BIT;
                 break;
         }
-
-        // Send EOI
-        outb(0x20, 0x20);
         return;
-    }
+    } else {
-    else
-    {
         // Key press
-        switch (scancode)
+        switch (scancode) {
-        {
             // Set bits for corresponding special key press
             case LEFT_SHIFT_PRESSED:
             case RIGHT_SHIFT_PRESSED:
@@ -196,29 +203,36 @@ void keyboard_handler()
 
             default:
             {
-                // Should we get a SHIFTED char or a regular one?
+                // Avoiding buffer overflow from extended keys lol
-                unsigned char c = (key_status & SHIFT_PRESSED_BIT) ? keymap_shifted[scancode] : keymap[scancode];
+                if (scancode < 128) {
+                    // Should we get a SHIFTED char or a regular one?
+                    unsigned char c = (key_status & SHIFT_PRESSED_BIT) ? keymap_shifted[scancode] : keymap[scancode];
 
-                if (c)
+                    if (c) {
-                {
+                        if (c == '\n') {
-                    // Should probably have a keyboard buffer here... instead of this
+                            _putchar('\r');
-                    putchar(c);
+                        }
+                        // Should probably have a keyboard buffer here... instead of this
+                        _putchar(c);
+                    }
                 }
             }
         }
     }
-
-    // End of Interrupt (to master PIC)
-    outb(0x20, 0x20);
 }
 
+/*
+ * keyboard_init - Keyboard initialization
+ * @layout: Desired layout
+ *
+ * Prepares the PS/2 keyboard to recieve input.
+ */
 void keyboard_init(unsigned char layout)
 {
     // Here we might go and select PS/2, USB, or other... (once we implement multiple keyboard protocols)
 
     // Keyboard layout selection
-    switch (layout)
+    switch (layout) {
-    {
         case US:
             keymap = kbdus;
             keymap_shifted = kbdus_shifted;
@@ -229,14 +243,20 @@ void keyboard_init(unsigned char layout)
             break;
         
         default:
-            skputs("Unsupported layout.");
+            panic(NULL, "Unsupported keyboard layout");
             return;
     }
 
+    // Flush keyboard buffer
+    while (inb(0x64) & 1) {
+        inb(0x60);
+    }
+
     // Unmask IRQ1
     uint8_t mask = inb(0x21);
     mask &= ~(1 << 1);
     outb(0x21, mask);
 
     DEBUG("PS/2 Keyboard initialized");
+    init.keyboard = true;
 }

src/io/kbd/ps2.h

@@ -1,21 +1,25 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   PS/2 Keyboard driver
+ * @license GPL-3.0-only
+ */
+
 #ifndef PS2_H
 #define PS2_H
 
-void keyboard_handler();
+void keyboard_handler(void);
 
 #define SHIFT_PRESSED_BIT 0b00000001
 #define ALT_PRESSED_BIT   0b00000010
 #define CTRL_PRESSED_BIT  0b00000100
 
-enum SpecialKeys
+enum SpecialKeys {
-{
     SHIFT = 255,
     ALT = 254,
     CTRL = 253
 };
 
-enum SpecialScancodes
+enum SpecialScancodes {
-{
     LEFT_SHIFT_PRESSED = 0x2A,
     LEFT_SHIFT_RELEASED = 0xAA,
     RIGHT_SHIFT_PRESSED = 0x36,
@@ -26,8 +30,7 @@ enum SpecialScancodes
     ALT_RELEASED = 0xB8  
 };
 
-enum KeyboardLayout
+enum KeyboardLayout {
-{
     US,
     FR  
 };

src/io/serial/serial.c

@@ -1,11 +1,33 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Debug serial driver
+ * @license GPL-3.0-only
+ */
+ 
 #include <kernel.h>
 #include "serial.h"
 
+extern struct init_status init;
+
+/*
+ * outb - Writes a byte to a CPU port
+ * @port: CPU port to write to
+ * @data: Byte to write
+ *
+ * Writes a single byte to the serial interface.
+ */
 void outb(int port, unsigned char data)
 {
     __asm__ __volatile__("outb %%al, %%dx" :: "a" (data),"d" (port));
 }
 
+/*
+ * inb - Gets a byte in through a CPU port
+ * @port: The CPU port to get a byte from
+ *
+ * Return:
+ * <data> - byte got from port
+ */
 unsigned char inb(int port)
 {
     unsigned char data = 0;
@@ -13,9 +35,13 @@ unsigned char inb(int port)
     return data;
 }
 
-// COM1
+/*
-#define PORT 0x3F8
+ * serial_init - Initializes serial interface
-
+ * 
+ * Return:
+ * %-EIO - Input/output error
+ * %0    - Success
+ */
 int serial_init()
 {
     outb(PORT + 1, 0x00);      // Disable all interrupts
@@ -28,36 +54,52 @@ int serial_init()
     outb(PORT + 4, 0x1E);    // Set in loopback mode, test the serial chip
     outb(PORT + 0, 0xAE);    // Test serial chip (send byte 0xAE and check if serial returns same byte)
 
-    if (inb(PORT) != 0xAE)
+    if (inb(PORT) != 0xAE) {
-    {
         return -EIO;
     }
 
     // Set normal operation mode
     outb(PORT + 4, 0x0F);
 
-    DEBUG("serial initialized");
+    DEBUG("*** Welcome to PepperOS! ***");
+    init.serial = true;
     return 0;
 }
 
+/*
+ * is_transmit_empty - Check if the serial transmit register is empty
+ *
+ * Return: Non-zero if the transmit register is empty and a new
+ * byte can be written to the serial port, 0 otherwise.
+ */
 static int is_transmit_empty()
 {
     return inb(PORT + 5) & 0x20;
 }
 
-// Serial kernel putchar
+/*
+ * skputc - Serial kernel putchar
+ * @c: character to write
+ *
+ * Writes a single character to the serial interface.
+ */
 void skputc(char c)
 {
+    // TODO: Spinlock here (serial access)
     while (!is_transmit_empty()); // wait for free spot
     outb(PORT, c);
 }
 
-// Serial kernel putstring
+/*
+ * skputs - Serial kernel puts
+ * @str: Message to write
+ *
+ * Writes a non-formatted string to serial output.
+ */
 void skputs(const char* str)
 {
     unsigned int i=0;
-    while (str[i])
+    while (str[i]) {
-    {
         skputc(str[i]);
         i++;
     }

src/io/serial/serial.h

@@ -1,10 +1,19 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Debug serial driver
+ * @license GPL-3.0-only
+ */
+
 #ifndef SERIAL_H
 #define SERIAL_H
 
+// COM1
+#define PORT 0x3F8
+
 void outb(int port, unsigned char data);
 unsigned char inb(int port);
 
-int serial_init();
+int serial_init(void);
 void skputs(const char* str);
 void skputc(char c);
 

src/io/term/flanterm.h

@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/* Copyright (C) 2022-2026 Mintsuki and contributors.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef FLANTERM_H
+#define FLANTERM_H 1
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define FLANTERM_CB_DEC 10
+#define FLANTERM_CB_BELL 20
+#define FLANTERM_CB_PRIVATE_ID 30
+#define FLANTERM_CB_STATUS_REPORT 40
+#define FLANTERM_CB_POS_REPORT 50
+#define FLANTERM_CB_KBD_LEDS 60
+#define FLANTERM_CB_MODE 70
+#define FLANTERM_CB_LINUX 80
+#define FLANTERM_CB_OSC 90
+
+#ifdef FLANTERM_IN_FLANTERM
+
+#include "flanterm_private.h"
+
+#else
+
+struct flanterm_context;
+
+#endif
+
+void flanterm_write(struct flanterm_context *ctx, const char *buf, size_t count);
+void flanterm_flush(struct flanterm_context *ctx);
+void flanterm_full_refresh(struct flanterm_context *ctx);
+void flanterm_deinit(struct flanterm_context *ctx, void (*_free)(void *ptr, size_t size));
+
+void flanterm_get_dimensions(struct flanterm_context *ctx, size_t *cols, size_t *rows);
+void flanterm_set_autoflush(struct flanterm_context *ctx, bool state);
+void flanterm_set_callback(struct flanterm_context *ctx, void (*callback)(struct flanterm_context *, uint64_t, uint64_t, uint64_t, uint64_t));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/io/term/flanterm_backends/fb.h

@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/* Copyright (C) 2022-2026 Mintsuki and contributors.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef FLANTERM_FB_H
+#define FLANTERM_FB_H 1
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "../flanterm.h"
+
+#ifdef FLANTERM_IN_FLANTERM
+
+#include "fb_private.h"
+
+#endif
+
+#define FLANTERM_FB_ROTATE_0 0
+#define FLANTERM_FB_ROTATE_90 1
+#define FLANTERM_FB_ROTATE_180 2
+#define FLANTERM_FB_ROTATE_270 3
+
+struct flanterm_context *flanterm_fb_init(
+    /* If _malloc and _free are nulled, use the bump allocated instance (1 use only). */
+    void *(*_malloc)(size_t size),
+    void (*_free)(void *ptr, size_t size),
+    uint32_t *framebuffer, size_t width, size_t height, size_t pitch,
+    uint8_t red_mask_size, uint8_t red_mask_shift,
+    uint8_t green_mask_size, uint8_t green_mask_shift,
+    uint8_t blue_mask_size, uint8_t blue_mask_shift,
+    uint32_t *canvas, /* If nulled, no canvas. */
+    uint32_t *ansi_colours, uint32_t *ansi_bright_colours, /* If nulled, default. */
+    uint32_t *default_bg, uint32_t *default_fg, /* If nulled, default. */
+    uint32_t *default_bg_bright, uint32_t *default_fg_bright, /* If nulled, default. */
+    /* If font is null, use default font and font_width and font_height ignored. */
+    void *font, size_t font_width, size_t font_height, size_t font_spacing,
+    /* If scale_x and scale_y are 0, automatically scale font based on resolution. */
+    size_t font_scale_x, size_t font_scale_y,
+    size_t margin,
+    /* One of FLANTERM_FB_ROTATE_* values. */
+    int rotation
+);
+
+void flanterm_fb_set_flush_callback(struct flanterm_context *ctx, void (*flush_callback)(volatile void *address, size_t length));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/io/term/flanterm_backends/fb_private.h

@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/* Copyright (C) 2022-2026 Mintsuki and contributors.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef FLANTERM_FB_PRIVATE_H
+#define FLANTERM_FB_PRIVATE_H 1
+
+#ifndef FLANTERM_IN_FLANTERM
+#error "Do not use fb_private.h. Use interfaces defined in fb.h only."
+#endif
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define FLANTERM_FB_FONT_GLYPHS 256
+
+struct flanterm_fb_char {
+    uint32_t c;
+    uint32_t fg;
+    uint32_t bg;
+};
+
+struct flanterm_fb_queue_item {
+    size_t x, y;
+    struct flanterm_fb_char c;
+};
+
+struct flanterm_fb_context {
+    struct flanterm_context term;
+
+    void (*plot_char)(struct flanterm_context *ctx, struct flanterm_fb_char *c, size_t x, size_t y);
+    void (*flush_callback)(volatile void *address, size_t length);
+
+    size_t font_width;
+    size_t font_height;
+    size_t glyph_width;
+    size_t glyph_height;
+
+    size_t font_scale_x;
+    size_t font_scale_y;
+
+    size_t offset_x, offset_y;
+
+    volatile uint32_t *framebuffer;
+    size_t pitch;
+    size_t width;
+    size_t height;
+    size_t phys_height;
+    size_t bpp;
+
+    uint8_t red_mask_size, red_mask_shift;
+    uint8_t green_mask_size, green_mask_shift;
+    uint8_t blue_mask_size, blue_mask_shift;
+
+    int rotation;
+
+    size_t font_bits_size;
+    uint8_t *font_bits;
+    size_t font_bool_size;
+    bool *font_bool;
+
+    uint32_t ansi_colours[8];
+    uint32_t ansi_bright_colours[8];
+    uint32_t default_fg, default_bg;
+    uint32_t default_fg_bright, default_bg_bright;
+
+    size_t canvas_size;
+    uint32_t *canvas;
+
+    size_t grid_size;
+    size_t queue_size;
+    size_t map_size;
+
+    struct flanterm_fb_char *grid;
+
+    struct flanterm_fb_queue_item *queue;
+    size_t queue_i;
+
+    struct flanterm_fb_queue_item **map;
+
+    uint32_t text_fg;
+    uint32_t text_bg;
+    size_t cursor_x;
+    size_t cursor_y;
+
+    uint32_t saved_state_text_fg;
+    uint32_t saved_state_text_bg;
+    size_t saved_state_cursor_x;
+    size_t saved_state_cursor_y;
+
+    size_t old_cursor_x;
+    size_t old_cursor_y;
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/io/term/flanterm_private.h

@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/* Copyright (C) 2022-2026 Mintsuki and contributors.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef FLANTERM_PRIVATE_H
+#define FLANTERM_PRIVATE_H 1
+
+#ifndef FLANTERM_IN_FLANTERM
+#error "Do not use flanterm_private.h. Use interfaces defined in flanterm.h only."
+#endif
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define FLANTERM_MAX_ESC_VALUES 16
+
+struct flanterm_context {
+    /* internal use */
+
+    size_t tab_size;
+    bool autoflush;
+    bool cursor_enabled;
+    bool scroll_enabled;
+    bool wrap_enabled;
+    bool origin_mode;
+    bool control_sequence;
+    bool escape;
+    bool osc;
+    bool osc_escape;
+    size_t osc_buf_i;
+    uint8_t osc_buf[256];
+    bool rrr;
+    bool discard_next;
+    bool bold;
+    bool bg_bold;
+    bool reverse_video;
+    bool dec_private;
+    bool insert_mode;
+    bool csi_unhandled;
+    uint64_t code_point;
+    size_t unicode_remaining;
+    uint8_t g_select;
+    uint8_t charsets[2];
+    size_t current_charset;
+    size_t escape_offset;
+    size_t esc_values_i;
+    size_t saved_cursor_x;
+    size_t saved_cursor_y;
+    size_t current_primary;
+    size_t current_bg;
+    size_t scroll_top_margin;
+    size_t scroll_bottom_margin;
+    uint32_t esc_values[FLANTERM_MAX_ESC_VALUES];
+    uint8_t last_printed_char;
+    bool last_was_graphic;
+    bool saved_state_bold;
+    bool saved_state_bg_bold;
+    bool saved_state_reverse_video;
+    bool saved_state_origin_mode;
+    bool saved_state_wrap_enabled;
+    size_t saved_state_current_charset;
+    uint8_t saved_state_charsets[2];
+    size_t saved_state_current_primary;
+    size_t saved_state_current_bg;
+
+    /* to be set by backend */
+
+    size_t rows, cols;
+
+    void (*raw_putchar)(struct flanterm_context *, uint8_t c);
+    void (*clear)(struct flanterm_context *, bool move);
+    void (*set_cursor_pos)(struct flanterm_context *, size_t x, size_t y);
+    void (*get_cursor_pos)(struct flanterm_context *, size_t *x, size_t *y);
+    void (*set_text_fg)(struct flanterm_context *, size_t fg);
+    void (*set_text_bg)(struct flanterm_context *, size_t bg);
+    void (*set_text_fg_bright)(struct flanterm_context *, size_t fg);
+    void (*set_text_bg_bright)(struct flanterm_context *, size_t bg);
+    void (*set_text_fg_rgb)(struct flanterm_context *, uint32_t fg);
+    void (*set_text_bg_rgb)(struct flanterm_context *, uint32_t bg);
+    void (*set_text_fg_default)(struct flanterm_context *);
+    void (*set_text_bg_default)(struct flanterm_context *);
+    void (*set_text_fg_default_bright)(struct flanterm_context *);
+    void (*set_text_bg_default_bright)(struct flanterm_context *);
+    void (*move_character)(struct flanterm_context *, size_t new_x, size_t new_y, size_t old_x, size_t old_y);
+    void (*scroll)(struct flanterm_context *);
+    void (*revscroll)(struct flanterm_context *);
+    void (*swap_palette)(struct flanterm_context *);
+    void (*save_state)(struct flanterm_context *);
+    void (*restore_state)(struct flanterm_context *);
+    void (*double_buffer_flush)(struct flanterm_context *);
+    void (*full_refresh)(struct flanterm_context *);
+    void (*deinit)(struct flanterm_context *, void (*)(void *, size_t));
+
+    /* to be set by client */
+
+    void (*callback)(struct flanterm_context *, uint64_t, uint64_t, uint64_t, uint64_t);
+};
+
+void flanterm_context_reinit(struct flanterm_context *ctx);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

src/io/term/printf.c

@@ -1,914 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-// \author (c) Marco Paland (info@paland.com)
-//             2014-2019, PALANDesign Hannover, Germany
-//
-// \license The MIT License (MIT)
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-// \brief Tiny printf, sprintf and (v)snprintf implementation, optimized for speed on
-//        embedded systems with a very limited resources. These routines are thread
-//        safe and reentrant!
-//        Use this instead of the bloated standard/newlib printf cause these use
-//        malloc for printf (and may not be thread safe).
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#include <stdbool.h>
-#include <stdint.h>
-
-#include "printf.h"
-
-
-// define this globally (e.g. gcc -DPRINTF_INCLUDE_CONFIG_H ...) to include the
-// printf_config.h header file
-// default: undefined
-#ifdef PRINTF_INCLUDE_CONFIG_H
-#include "printf_config.h"
-#endif
-
-
-// 'ntoa' conversion buffer size, this must be big enough to hold one converted
-// numeric number including padded zeros (dynamically created on stack)
-// default: 32 byte
-#ifndef PRINTF_NTOA_BUFFER_SIZE
-#define PRINTF_NTOA_BUFFER_SIZE    32U
-#endif
-
-// 'ftoa' conversion buffer size, this must be big enough to hold one converted
-// float number including padded zeros (dynamically created on stack)
-// default: 32 byte
-#ifndef PRINTF_FTOA_BUFFER_SIZE
-#define PRINTF_FTOA_BUFFER_SIZE    32U
-#endif
-
-// support for the floating point type (%f)
-// default: activated
-#ifndef PRINTF_DISABLE_SUPPORT_FLOAT
-#define PRINTF_SUPPORT_FLOAT
-#endif
-
-// support for exponential floating point notation (%e/%g)
-// default: activated
-#ifndef PRINTF_DISABLE_SUPPORT_EXPONENTIAL
-#define PRINTF_SUPPORT_EXPONENTIAL
-#endif
-
-// define the default floating point precision
-// default: 6 digits
-#ifndef PRINTF_DEFAULT_FLOAT_PRECISION
-#define PRINTF_DEFAULT_FLOAT_PRECISION  6U
-#endif
-
-// define the largest float suitable to print with %f
-// default: 1e9
-#ifndef PRINTF_MAX_FLOAT
-#define PRINTF_MAX_FLOAT  1e9
-#endif
-
-// support for the long long types (%llu or %p)
-// default: activated
-#ifndef PRINTF_DISABLE_SUPPORT_LONG_LONG
-#define PRINTF_SUPPORT_LONG_LONG
-#endif
-
-// support for the ptrdiff_t type (%t)
-// ptrdiff_t is normally defined in <stddef.h> as long or long long type
-// default: activated
-#ifndef PRINTF_DISABLE_SUPPORT_PTRDIFF_T
-#define PRINTF_SUPPORT_PTRDIFF_T
-#endif
-
-///////////////////////////////////////////////////////////////////////////////
-
-// internal flag definitions
-#define FLAGS_ZEROPAD   (1U <<  0U)
-#define FLAGS_LEFT      (1U <<  1U)
-#define FLAGS_PLUS      (1U <<  2U)
-#define FLAGS_SPACE     (1U <<  3U)
-#define FLAGS_HASH      (1U <<  4U)
-#define FLAGS_UPPERCASE (1U <<  5U)
-#define FLAGS_CHAR      (1U <<  6U)
-#define FLAGS_SHORT     (1U <<  7U)
-#define FLAGS_LONG      (1U <<  8U)
-#define FLAGS_LONG_LONG (1U <<  9U)
-#define FLAGS_PRECISION (1U << 10U)
-#define FLAGS_ADAPT_EXP (1U << 11U)
-
-
-// import float.h for DBL_MAX
-#if defined(PRINTF_SUPPORT_FLOAT)
-#include <float.h>
-#endif
-
-
-// output function type
-typedef void (*out_fct_type)(char character, void* buffer, size_t idx, size_t maxlen);
-
-
-// wrapper (used as buffer) for output function type
-typedef struct {
-  void  (*fct)(char character, void* arg);
-  void* arg;
-} out_fct_wrap_type;
-
-
-// internal buffer output
-static inline void _out_buffer(char character, void* buffer, size_t idx, size_t maxlen)
-{
-  if (idx < maxlen) {
-    ((char*)buffer)[idx] = character;
-  }
-}
-
-
-// internal null output
-static inline void _out_null(char character, void* buffer, size_t idx, size_t maxlen)
-{
-  (void)character; (void)buffer; (void)idx; (void)maxlen;
-}
-
-
-// internal _putchar wrapper
-static inline void _out_char(char character, void* buffer, size_t idx, size_t maxlen)
-{
-  (void)buffer; (void)idx; (void)maxlen;
-  if (character) {
-    _putchar(character);
-  }
-}
-
-
-// internal output function wrapper
-static inline void _out_fct(char character, void* buffer, size_t idx, size_t maxlen)
-{
-  (void)idx; (void)maxlen;
-  if (character) {
-    // buffer is the output fct pointer
-    ((out_fct_wrap_type*)buffer)->fct(character, ((out_fct_wrap_type*)buffer)->arg);
-  }
-}
-
-
-// internal secure strlen
-// \return The length of the string (excluding the terminating 0) limited by 'maxsize'
-static inline unsigned int _strnlen_s(const char* str, size_t maxsize)
-{
-  const char* s;
-  for (s = str; *s && maxsize--; ++s);
-  return (unsigned int)(s - str);
-}
-
-
-// internal test if char is a digit (0-9)
-// \return true if char is a digit
-static inline bool _is_digit(char ch)
-{
-  return (ch >= '0') && (ch <= '9');
-}
-
-
-// internal ASCII string to unsigned int conversion
-static unsigned int _atoi(const char** str)
-{
-  unsigned int i = 0U;
-  while (_is_digit(**str)) {
-    i = i * 10U + (unsigned int)(*((*str)++) - '0');
-  }
-  return i;
-}
-
-
-// output the specified string in reverse, taking care of any zero-padding
-static size_t _out_rev(out_fct_type out, char* buffer, size_t idx, size_t maxlen, const char* buf, size_t len, unsigned int width, unsigned int flags)
-{
-  const size_t start_idx = idx;
-
-  // pad spaces up to given width
-  if (!(flags & FLAGS_LEFT) && !(flags & FLAGS_ZEROPAD)) {
-    for (size_t i = len; i < width; i++) {
-      out(' ', buffer, idx++, maxlen);
-    }
-  }
-
-  // reverse string
-  while (len) {
-    out(buf[--len], buffer, idx++, maxlen);
-  }
-
-  // append pad spaces up to given width
-  if (flags & FLAGS_LEFT) {
-    while (idx - start_idx < width) {
-      out(' ', buffer, idx++, maxlen);
-    }
-  }
-
-  return idx;
-}
-
-
-// internal itoa format
-static size_t _ntoa_format(out_fct_type out, char* buffer, size_t idx, size_t maxlen, char* buf, size_t len, bool negative, unsigned int base, unsigned int prec, unsigned int width, unsigned int flags)
-{
-  // pad leading zeros
-  if (!(flags & FLAGS_LEFT)) {
-    if (width && (flags & FLAGS_ZEROPAD) && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) {
-      width--;
-    }
-    while ((len < prec) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
-      buf[len++] = '0';
-    }
-    while ((flags & FLAGS_ZEROPAD) && (len < width) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
-      buf[len++] = '0';
-    }
-  }
-
-  // handle hash
-  if (flags & FLAGS_HASH) {
-    if (!(flags & FLAGS_PRECISION) && len && ((len == prec) || (len == width))) {
-      len--;
-      if (len && (base == 16U)) {
-        len--;
-      }
-    }
-    if ((base == 16U) && !(flags & FLAGS_UPPERCASE) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
-      buf[len++] = 'x';
-    }
-    else if ((base == 16U) && (flags & FLAGS_UPPERCASE) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
-      buf[len++] = 'X';
-    }
-    else if ((base == 2U) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
-      buf[len++] = 'b';
-    }
-    if (len < PRINTF_NTOA_BUFFER_SIZE) {
-      buf[len++] = '0';
-    }
-  }
-
-  if (len < PRINTF_NTOA_BUFFER_SIZE) {
-    if (negative) {
-      buf[len++] = '-';
-    }
-    else if (flags & FLAGS_PLUS) {
-      buf[len++] = '+';  // ignore the space if the '+' exists
-    }
-    else if (flags & FLAGS_SPACE) {
-      buf[len++] = ' ';
-    }
-  }
-
-  return _out_rev(out, buffer, idx, maxlen, buf, len, width, flags);
-}
-
-
-// internal itoa for 'long' type
-static size_t _ntoa_long(out_fct_type out, char* buffer, size_t idx, size_t maxlen, unsigned long value, bool negative, unsigned long base, unsigned int prec, unsigned int width, unsigned int flags)
-{
-  char buf[PRINTF_NTOA_BUFFER_SIZE];
-  size_t len = 0U;
-
-  // no hash for 0 values
-  if (!value) {
-    flags &= ~FLAGS_HASH;
-  }
-
-  // write if precision != 0 and value is != 0
-  if (!(flags & FLAGS_PRECISION) || value) {
-    do {
-      const char digit = (char)(value % base);
-      buf[len++] = digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10;
-      value /= base;
-    } while (value && (len < PRINTF_NTOA_BUFFER_SIZE));
-  }
-
-  return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative, (unsigned int)base, prec, width, flags);
-}
-
-
-// internal itoa for 'long long' type
-#if defined(PRINTF_SUPPORT_LONG_LONG)
-static size_t _ntoa_long_long(out_fct_type out, char* buffer, size_t idx, size_t maxlen, unsigned long long value, bool negative, unsigned long long base, unsigned int prec, unsigned int width, unsigned int flags)
-{
-  char buf[PRINTF_NTOA_BUFFER_SIZE];
-  size_t len = 0U;
-
-  // no hash for 0 values
-  if (!value) {
-    flags &= ~FLAGS_HASH;
-  }
-
-  // write if precision != 0 and value is != 0
-  if (!(flags & FLAGS_PRECISION) || value) {
-    do {
-      const char digit = (char)(value % base);
-      buf[len++] = digit < 10 ? '0' + digit : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10;
-      value /= base;
-    } while (value && (len < PRINTF_NTOA_BUFFER_SIZE));
-  }
-
-  return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative, (unsigned int)base, prec, width, flags);
-}
-#endif  // PRINTF_SUPPORT_LONG_LONG
-
-
-#if defined(PRINTF_SUPPORT_FLOAT)
-
-#if defined(PRINTF_SUPPORT_EXPONENTIAL)
-// forward declaration so that _ftoa can switch to exp notation for values > PRINTF_MAX_FLOAT
-static size_t _etoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double value, unsigned int prec, unsigned int width, unsigned int flags);
-#endif
-
-
-// internal ftoa for fixed decimal floating point
-static size_t _ftoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double value, unsigned int prec, unsigned int width, unsigned int flags)
-{
-  char buf[PRINTF_FTOA_BUFFER_SIZE];
-  size_t len  = 0U;
-  double diff = 0.0;
-
-  // powers of 10
-  static const double pow10[] = { 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000 };
-
-  // test for special values
-  if (value != value)
-    return _out_rev(out, buffer, idx, maxlen, "nan", 3, width, flags);
-  if (value < -DBL_MAX)
-    return _out_rev(out, buffer, idx, maxlen, "fni-", 4, width, flags);
-  if (value > DBL_MAX)
-    return _out_rev(out, buffer, idx, maxlen, (flags & FLAGS_PLUS) ? "fni+" : "fni", (flags & FLAGS_PLUS) ? 4U : 3U, width, flags);
-
-  // test for very large values
-  // standard printf behavior is to print EVERY whole number digit -- which could be 100s of characters overflowing your buffers == bad
-  if ((value > PRINTF_MAX_FLOAT) || (value < -PRINTF_MAX_FLOAT)) {
-#if defined(PRINTF_SUPPORT_EXPONENTIAL)
-    return _etoa(out, buffer, idx, maxlen, value, prec, width, flags);
-#else
-    return 0U;
-#endif
-  }
-
-  // test for negative
-  bool negative = false;
-  if (value < 0) {
-    negative = true;
-    value = 0 - value;
-  }
-
-  // set default precision, if not set explicitly
-  if (!(flags & FLAGS_PRECISION)) {
-    prec = PRINTF_DEFAULT_FLOAT_PRECISION;
-  }
-  // limit precision to 9, cause a prec >= 10 can lead to overflow errors
-  while ((len < PRINTF_FTOA_BUFFER_SIZE) && (prec > 9U)) {
-    buf[len++] = '0';
-    prec--;
-  }
-
-  int whole = (int)value;
-  double tmp = (value - whole) * pow10[prec];
-  unsigned long frac = (unsigned long)tmp;
-  diff = tmp - frac;
-
-  if (diff > 0.5) {
-    ++frac;
-    // handle rollover, e.g. case 0.99 with prec 1 is 1.0
-    if (frac >= pow10[prec]) {
-      frac = 0;
-      ++whole;
-    }
-  }
-  else if (diff < 0.5) {
-  }
-  else if ((frac == 0U) || (frac & 1U)) {
-    // if halfway, round up if odd OR if last digit is 0
-    ++frac;
-  }
-
-  if (prec == 0U) {
-    diff = value - (double)whole;
-    if ((!(diff < 0.5) || (diff > 0.5)) && (whole & 1)) {
-      // exactly 0.5 and ODD, then round up
-      // 1.5 -> 2, but 2.5 -> 2
-      ++whole;
-    }
-  }
-  else {
-    unsigned int count = prec;
-    // now do fractional part, as an unsigned number
-    while (len < PRINTF_FTOA_BUFFER_SIZE) {
-      --count;
-      buf[len++] = (char)(48U + (frac % 10U));
-      if (!(frac /= 10U)) {
-        break;
-      }
-    }
-    // add extra 0s
-    while ((len < PRINTF_FTOA_BUFFER_SIZE) && (count-- > 0U)) {
-      buf[len++] = '0';
-    }
-    if (len < PRINTF_FTOA_BUFFER_SIZE) {
-      // add decimal
-      buf[len++] = '.';
-    }
-  }
-
-  // do whole part, number is reversed
-  while (len < PRINTF_FTOA_BUFFER_SIZE) {
-    buf[len++] = (char)(48 + (whole % 10));
-    if (!(whole /= 10)) {
-      break;
-    }
-  }
-
-  // pad leading zeros
-  if (!(flags & FLAGS_LEFT) && (flags & FLAGS_ZEROPAD)) {
-    if (width && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) {
-      width--;
-    }
-    while ((len < width) && (len < PRINTF_FTOA_BUFFER_SIZE)) {
-      buf[len++] = '0';
-    }
-  }
-
-  if (len < PRINTF_FTOA_BUFFER_SIZE) {
-    if (negative) {
-      buf[len++] = '-';
-    }
-    else if (flags & FLAGS_PLUS) {
-      buf[len++] = '+';  // ignore the space if the '+' exists
-    }
-    else if (flags & FLAGS_SPACE) {
-      buf[len++] = ' ';
-    }
-  }
-
-  return _out_rev(out, buffer, idx, maxlen, buf, len, width, flags);
-}
-
-
-#if defined(PRINTF_SUPPORT_EXPONENTIAL)
-// internal ftoa variant for exponential floating-point type, contributed by Martijn Jasperse <m.jasperse@gmail.com>
-static size_t _etoa(out_fct_type out, char* buffer, size_t idx, size_t maxlen, double value, unsigned int prec, unsigned int width, unsigned int flags)
-{
-  // check for NaN and special values
-  if ((value != value) || (value > DBL_MAX) || (value < -DBL_MAX)) {
-    return _ftoa(out, buffer, idx, maxlen, value, prec, width, flags);
-  }
-
-  // determine the sign
-  const bool negative = value < 0;
-  if (negative) {
-    value = -value;
-  }
-
-  // default precision
-  if (!(flags & FLAGS_PRECISION)) {
-    prec = PRINTF_DEFAULT_FLOAT_PRECISION;
-  }
-
-  // determine the decimal exponent
-  // based on the algorithm by David Gay (https://www.ampl.com/netlib/fp/dtoa.c)
-  union {
-    uint64_t U;
-    double   F;
-  } conv;
-
-  conv.F = value;
-  int exp2 = (int)((conv.U >> 52U) & 0x07FFU) - 1023;           // effectively log2
-  conv.U = (conv.U & ((1ULL << 52U) - 1U)) | (1023ULL << 52U);  // drop the exponent so conv.F is now in [1,2)
-  // now approximate log10 from the log2 integer part and an expansion of ln around 1.5
-  int expval = (int)(0.1760912590558 + exp2 * 0.301029995663981 + (conv.F - 1.5) * 0.289529654602168);
-  // now we want to compute 10^expval but we want to be sure it won't overflow
-  exp2 = (int)(expval * 3.321928094887362 + 0.5);
-  const double z  = expval * 2.302585092994046 - exp2 * 0.6931471805599453;
-  const double z2 = z * z;
-  conv.U = (uint64_t)(exp2 + 1023) << 52U;
-  // compute exp(z) using continued fractions, see https://en.wikipedia.org/wiki/Exponential_function#Continued_fractions_for_ex
-  conv.F *= 1 + 2 * z / (2 - z + (z2 / (6 + (z2 / (10 + z2 / 14)))));
-  // correct for rounding errors
-  if (value < conv.F) {
-    expval--;
-    conv.F /= 10;
-  }
-
-  // the exponent format is "%+03d" and largest value is "307", so set aside 4-5 characters
-  unsigned int minwidth = ((expval < 100) && (expval > -100)) ? 4U : 5U;
-
-  // in "%g" mode, "prec" is the number of *significant figures* not decimals
-  if (flags & FLAGS_ADAPT_EXP) {
-    // do we want to fall-back to "%f" mode?
-    if ((value >= 1e-4) && (value < 1e6)) {
-      if ((int)prec > expval) {
-        prec = (unsigned)((int)prec - expval - 1);
-      }
-      else {
-        prec = 0;
-      }
-      flags |= FLAGS_PRECISION;   // make sure _ftoa respects precision
-      // no characters in exponent
-      minwidth = 0U;
-      expval   = 0;
-    }
-    else {
-      // we use one sigfig for the whole part
-      if ((prec > 0) && (flags & FLAGS_PRECISION)) {
-        --prec;
-      }
-    }
-  }
-
-  // will everything fit?
-  unsigned int fwidth = width;
-  if (width > minwidth) {
-    // we didn't fall-back so subtract the characters required for the exponent
-    fwidth -= minwidth;
-  } else {
-    // not enough characters, so go back to default sizing
-    fwidth = 0U;
-  }
-  if ((flags & FLAGS_LEFT) && minwidth) {
-    // if we're padding on the right, DON'T pad the floating part
-    fwidth = 0U;
-  }
-
-  // rescale the float value
-  if (expval) {
-    value /= conv.F;
-  }
-
-  // output the floating part
-  const size_t start_idx = idx;
-  idx = _ftoa(out, buffer, idx, maxlen, negative ? -value : value, prec, fwidth, flags & ~FLAGS_ADAPT_EXP);
-
-  // output the exponent part
-  if (minwidth) {
-    // output the exponential symbol
-    out((flags & FLAGS_UPPERCASE) ? 'E' : 'e', buffer, idx++, maxlen);
-    // output the exponent value
-    idx = _ntoa_long(out, buffer, idx, maxlen, (expval < 0) ? -expval : expval, expval < 0, 10, 0, minwidth-1, FLAGS_ZEROPAD | FLAGS_PLUS);
-    // might need to right-pad spaces
-    if (flags & FLAGS_LEFT) {
-      while (idx - start_idx < width) out(' ', buffer, idx++, maxlen);
-    }
-  }
-  return idx;
-}
-#endif  // PRINTF_SUPPORT_EXPONENTIAL
-#endif  // PRINTF_SUPPORT_FLOAT
-
-
-// internal vsnprintf
-static int _vsnprintf(out_fct_type out, char* buffer, const size_t maxlen, const char* format, va_list va)
-{
-  unsigned int flags, width, precision, n;
-  size_t idx = 0U;
-
-  if (!buffer) {
-    // use null output function
-    out = _out_null;
-  }
-
-  while (*format)
-  {
-    // format specifier?  %[flags][width][.precision][length]
-    if (*format != '%') {
-      // no
-      out(*format, buffer, idx++, maxlen);
-      format++;
-      continue;
-    }
-    else {
-      // yes, evaluate it
-      format++;
-    }
-
-    // evaluate flags
-    flags = 0U;
-    do {
-      switch (*format) {
-        case '0': flags |= FLAGS_ZEROPAD; format++; n = 1U; break;
-        case '-': flags |= FLAGS_LEFT;    format++; n = 1U; break;
-        case '+': flags |= FLAGS_PLUS;    format++; n = 1U; break;
-        case ' ': flags |= FLAGS_SPACE;   format++; n = 1U; break;
-        case '#': flags |= FLAGS_HASH;    format++; n = 1U; break;
-        default :                                   n = 0U; break;
-      }
-    } while (n);
-
-    // evaluate width field
-    width = 0U;
-    if (_is_digit(*format)) {
-      width = _atoi(&format);
-    }
-    else if (*format == '*') {
-      const int w = va_arg(va, int);
-      if (w < 0) {
-        flags |= FLAGS_LEFT;    // reverse padding
-        width = (unsigned int)-w;
-      }
-      else {
-        width = (unsigned int)w;
-      }
-      format++;
-    }
-
-    // evaluate precision field
-    precision = 0U;
-    if (*format == '.') {
-      flags |= FLAGS_PRECISION;
-      format++;
-      if (_is_digit(*format)) {
-        precision = _atoi(&format);
-      }
-      else if (*format == '*') {
-        const int prec = (int)va_arg(va, int);
-        precision = prec > 0 ? (unsigned int)prec : 0U;
-        format++;
-      }
-    }
-
-    // evaluate length field
-    switch (*format) {
-      case 'l' :
-        flags |= FLAGS_LONG;
-        format++;
-        if (*format == 'l') {
-          flags |= FLAGS_LONG_LONG;
-          format++;
-        }
-        break;
-      case 'h' :
-        flags |= FLAGS_SHORT;
-        format++;
-        if (*format == 'h') {
-          flags |= FLAGS_CHAR;
-          format++;
-        }
-        break;
-#if defined(PRINTF_SUPPORT_PTRDIFF_T)
-      case 't' :
-        flags |= (sizeof(ptrdiff_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
-        format++;
-        break;
-#endif
-      case 'j' :
-        flags |= (sizeof(intmax_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
-        format++;
-        break;
-      case 'z' :
-        flags |= (sizeof(size_t) == sizeof(long) ? FLAGS_LONG : FLAGS_LONG_LONG);
-        format++;
-        break;
-      default :
-        break;
-    }
-
-    // evaluate specifier
-    switch (*format) {
-      case 'd' :
-      case 'i' :
-      case 'u' :
-      case 'x' :
-      case 'X' :
-      case 'o' :
-      case 'b' : {
-        // set the base
-        unsigned int base;
-        if (*format == 'x' || *format == 'X') {
-          base = 16U;
-        }
-        else if (*format == 'o') {
-          base =  8U;
-        }
-        else if (*format == 'b') {
-          base =  2U;
-        }
-        else {
-          base = 10U;
-          flags &= ~FLAGS_HASH;   // no hash for dec format
-        }
-        // uppercase
-        if (*format == 'X') {
-          flags |= FLAGS_UPPERCASE;
-        }
-
-        // no plus or space flag for u, x, X, o, b
-        if ((*format != 'i') && (*format != 'd')) {
-          flags &= ~(FLAGS_PLUS | FLAGS_SPACE);
-        }
-
-        // ignore '0' flag when precision is given
-        if (flags & FLAGS_PRECISION) {
-          flags &= ~FLAGS_ZEROPAD;
-        }
-
-        // convert the integer
-        if ((*format == 'i') || (*format == 'd')) {
-          // signed
-          if (flags & FLAGS_LONG_LONG) {
-#if defined(PRINTF_SUPPORT_LONG_LONG)
-            const long long value = va_arg(va, long long);
-            idx = _ntoa_long_long(out, buffer, idx, maxlen, (unsigned long long)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags);
-#endif
-          }
-          else if (flags & FLAGS_LONG) {
-            const long value = va_arg(va, long);
-            idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned long)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags);
-          }
-          else {
-            const int value = (flags & FLAGS_CHAR) ? (char)va_arg(va, int) : (flags & FLAGS_SHORT) ? (short int)va_arg(va, int) : va_arg(va, int);
-            idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned int)(value > 0 ? value : 0 - value), value < 0, base, precision, width, flags);
-          }
-        }
-        else {
-          // unsigned
-          if (flags & FLAGS_LONG_LONG) {
-#if defined(PRINTF_SUPPORT_LONG_LONG)
-            idx = _ntoa_long_long(out, buffer, idx, maxlen, va_arg(va, unsigned long long), false, base, precision, width, flags);
-#endif
-          }
-          else if (flags & FLAGS_LONG) {
-            idx = _ntoa_long(out, buffer, idx, maxlen, va_arg(va, unsigned long), false, base, precision, width, flags);
-          }
-          else {
-            const unsigned int value = (flags & FLAGS_CHAR) ? (unsigned char)va_arg(va, unsigned int) : (flags & FLAGS_SHORT) ? (unsigned short int)va_arg(va, unsigned int) : va_arg(va, unsigned int);
-            idx = _ntoa_long(out, buffer, idx, maxlen, value, false, base, precision, width, flags);
-          }
-        }
-        format++;
-        break;
-      }
-#if defined(PRINTF_SUPPORT_FLOAT)
-      case 'f' :
-      case 'F' :
-        if (*format == 'F') flags |= FLAGS_UPPERCASE;
-        idx = _ftoa(out, buffer, idx, maxlen, va_arg(va, double), precision, width, flags);
-        format++;
-        break;
-#if defined(PRINTF_SUPPORT_EXPONENTIAL)
-      case 'e':
-      case 'E':
-      case 'g':
-      case 'G':
-        if ((*format == 'g')||(*format == 'G')) flags |= FLAGS_ADAPT_EXP;
-        if ((*format == 'E')||(*format == 'G')) flags |= FLAGS_UPPERCASE;
-        idx = _etoa(out, buffer, idx, maxlen, va_arg(va, double), precision, width, flags);
-        format++;
-        break;
-#endif  // PRINTF_SUPPORT_EXPONENTIAL
-#endif  // PRINTF_SUPPORT_FLOAT
-      case 'c' : {
-        unsigned int l = 1U;
-        // pre padding
-        if (!(flags & FLAGS_LEFT)) {
-          while (l++ < width) {
-            out(' ', buffer, idx++, maxlen);
-          }
-        }
-        // char output
-        out((char)va_arg(va, int), buffer, idx++, maxlen);
-        // post padding
-        if (flags & FLAGS_LEFT) {
-          while (l++ < width) {
-            out(' ', buffer, idx++, maxlen);
-          }
-        }
-        format++;
-        break;
-      }
-
-      case 's' : {
-        const char* p = va_arg(va, char*);
-        unsigned int l = _strnlen_s(p, precision ? precision : (size_t)-1);
-        // pre padding
-        if (flags & FLAGS_PRECISION) {
-          l = (l < precision ? l : precision);
-        }
-        if (!(flags & FLAGS_LEFT)) {
-          while (l++ < width) {
-            out(' ', buffer, idx++, maxlen);
-          }
-        }
-        // string output
-        while ((*p != 0) && (!(flags & FLAGS_PRECISION) || precision--)) {
-          out(*(p++), buffer, idx++, maxlen);
-        }
-        // post padding
-        if (flags & FLAGS_LEFT) {
-          while (l++ < width) {
-            out(' ', buffer, idx++, maxlen);
-          }
-        }
-        format++;
-        break;
-      }
-
-      case 'p' : {
-        width = sizeof(void*) * 2U;
-        flags |= FLAGS_ZEROPAD | FLAGS_UPPERCASE;
-#if defined(PRINTF_SUPPORT_LONG_LONG)
-        const bool is_ll = sizeof(uintptr_t) == sizeof(long long);
-        if (is_ll) {
-          idx = _ntoa_long_long(out, buffer, idx, maxlen, (uintptr_t)va_arg(va, void*), false, 16U, precision, width, flags);
-        }
-        else {
-#endif
-          idx = _ntoa_long(out, buffer, idx, maxlen, (unsigned long)((uintptr_t)va_arg(va, void*)), false, 16U, precision, width, flags);
-#if defined(PRINTF_SUPPORT_LONG_LONG)
-        }
-#endif
-        format++;
-        break;
-      }
-
-      case '%' :
-        out('%', buffer, idx++, maxlen);
-        format++;
-        break;
-
-      default :
-        out(*format, buffer, idx++, maxlen);
-        format++;
-        break;
-    }
-  }
-
-  // termination
-  out((char)0, buffer, idx < maxlen ? idx : maxlen - 1U, maxlen);
-
-  // return written chars without terminating \0
-  return (int)idx;
-}
-
-
-///////////////////////////////////////////////////////////////////////////////
-
-int printf_(const char* format, ...)
-{
-  va_list va;
-  va_start(va, format);
-  char buffer[1];
-  const int ret = _vsnprintf(_out_char, buffer, (size_t)-1, format, va);
-  va_end(va);
-  return ret;
-}
-
-
-int sprintf_(char* buffer, const char* format, ...)
-{
-  va_list va;
-  va_start(va, format);
-  const int ret = _vsnprintf(_out_buffer, buffer, (size_t)-1, format, va);
-  va_end(va);
-  return ret;
-}
-
-
-int snprintf_(char* buffer, size_t count, const char* format, ...)
-{
-  va_list va;
-  va_start(va, format);
-  const int ret = _vsnprintf(_out_buffer, buffer, count, format, va);
-  va_end(va);
-  return ret;
-}
-
-
-int vprintf_(const char* format, va_list va)
-{
-  char buffer[1];
-  return _vsnprintf(_out_char, buffer, (size_t)-1, format, va);
-}
-
-
-int vsnprintf_(char* buffer, size_t count, const char* format, va_list va)
-{
-  return _vsnprintf(_out_buffer, buffer, count, format, va);
-}
-
-
-int fctprintf(void (*out)(char character, void* arg), void* arg, const char* format, ...)
-{
-  va_list va;
-  va_start(va, format);
-  const out_fct_wrap_type out_fct_wrap = { out, arg };
-  const int ret = _vsnprintf(_out_fct, (char*)(uintptr_t)&out_fct_wrap, (size_t)-1, format, va);
-  va_end(va);
-  return ret;
-}

src/io/term/printf.h

@@ -1,117 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////
-// \author (c) Marco Paland (info@paland.com)
-//             2014-2019, PALANDesign Hannover, Germany
-//
-// \license The MIT License (MIT)
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-// 
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-// 
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-//
-// \brief Tiny printf, sprintf and snprintf implementation, optimized for speed on
-//        embedded systems with a very limited resources.
-//        Use this instead of bloated standard/newlib printf.
-//        These routines are thread safe and reentrant.
-//
-///////////////////////////////////////////////////////////////////////////////
-
-#ifndef _PRINTF_H_
-#define _PRINTF_H_
-
-#include <stdarg.h>
-#include <stddef.h>
-
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-
-/**
- * Output a character to a custom device like UART, used by the printf() function
- * This function is declared here only. You have to write your custom implementation somewhere
- * \param character Character to output
- */
-void _putchar(char character);
-
-
-/**
- * Tiny printf implementation
- * You have to implement _putchar if you use printf()
- * To avoid conflicts with the regular printf() API it is overridden by macro defines
- * and internal underscore-appended functions like printf_() are used
- * \param format A string that specifies the format of the output
- * \return The number of characters that are written into the array, not counting the terminating null character
- */
-#define printf printf_
-int printf_(const char* format, ...);
-
-
-/**
- * Tiny sprintf implementation
- * Due to security reasons (buffer overflow) YOU SHOULD CONSIDER USING (V)SNPRINTF INSTEAD!
- * \param buffer A pointer to the buffer where to store the formatted string. MUST be big enough to store the output!
- * \param format A string that specifies the format of the output
- * \return The number of characters that are WRITTEN into the buffer, not counting the terminating null character
- */
-#define sprintf sprintf_
-int sprintf_(char* buffer, const char* format, ...);
-
-
-/**
- * Tiny snprintf/vsnprintf implementation
- * \param buffer A pointer to the buffer where to store the formatted string
- * \param count The maximum number of characters to store in the buffer, including a terminating null character
- * \param format A string that specifies the format of the output
- * \param va A value identifying a variable arguments list
- * \return The number of characters that COULD have been written into the buffer, not counting the terminating
- *         null character. A value equal or larger than count indicates truncation. Only when the returned value
- *         is non-negative and less than count, the string has been completely written.
- */
-#define snprintf  snprintf_
-#define vsnprintf vsnprintf_
-int  snprintf_(char* buffer, size_t count, const char* format, ...);
-int vsnprintf_(char* buffer, size_t count, const char* format, va_list va);
-
-
-/**
- * Tiny vprintf implementation
- * \param format A string that specifies the format of the output
- * \param va A value identifying a variable arguments list
- * \return The number of characters that are WRITTEN into the buffer, not counting the terminating null character
- */
-#define vprintf vprintf_
-int vprintf_(const char* format, va_list va);
-
-
-/**
- * printf with output function
- * You may use this as dynamic alternative to printf() with its fixed _putchar() output
- * \param out An output function which takes one character and an argument pointer
- * \param arg An argument pointer for user data passed to output function
- * \param format A string that specifies the format of the output
- * \return The number of characters that are sent to the output function, not counting the terminating null character
- */
-int fctprintf(void (*out)(char character, void* arg), void* arg, const char* format, ...);
-
-
-#ifdef __cplusplus
-}
-#endif
-
-
-#endif  // _PRINTF_H_

src/io/term/term.c

@@ -1,3 +1,9 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Framebuffer-based terminal driver
+ * @license GPL-3.0-only
+ */
+
 // Terminal output
 /*
 There are a couple of bugs here and there but for now I don't care too much
@@ -5,204 +11,145 @@ because this shitty implementation will be replaced one day by Flanterm
 (once memory management is okay: paging & kernel malloc)
 */
 
-#include <limine.h>
 #include <stddef.h>
 #include <kernel.h>
 #include "term.h"
-#include "mem/misc/utils.h"
+#include "config.h"
+#include "flanterm.h"
+#include "flanterm_backends/fb.h"
+#include "mem/heap/kheap.h"
+#include "limine.h"
+#include <stdarg.h>
+#include "sched/spinlock.h"
+#include "io/serial/serial.h"
 
-extern struct boot_context boot_ctx;
+#define NANOPRINTF_IMPLEMENTATION
+#include "nanoprintf.h"
 
-// Importing the PSF object file
+extern struct flanterm_context* ft_ctx;
-extern unsigned char _binary_zap_light16_psf_start[];
+extern struct init_status init;
-extern unsigned char _binary_zap_light16_psf_end[];
 
-PSF1_Header* font = (PSF1_Header*)_binary_zap_light16_psf_start;
+struct spinlock_t term_lock = {0};
-uint8_t* glyphs = _binary_zap_light16_psf_start + sizeof(PSF1_Header);
 
-#define FONT_WIDTH 8
+extern int panic_count;
-#define FONT_HEIGHT font->characterSize
 
-
+/*
-
+ * _putchar - Writes a character to terminal (DEPRECATED)
-// Character cursor
+ * @character: character to write
-typedef struct
+ */
-{
-	size_t x;
-	size_t y;
-} Cursor;
-
-static Cursor cursor = {0, 0};
-
-static uint8_t* fb;
-static struct limine_framebuffer* framebuffer;
-
-uint8_t lines_length[MAX_LINES];
-
-static inline size_t term_max_cols(void)
-{
-	return framebuffer->width / FONT_WIDTH;
-}
-
-static inline size_t term_max_lines(void)
-{
-	return framebuffer->height / FONT_HEIGHT;
-}
-
-int term_init()
-{
-	// Get framebuffer address from Limine struct
-	
-	if (!boot_ctx.fb)
-	{
-		return -ENOMEM;
-	}
-
-	framebuffer = boot_ctx.fb;
-	fb = (uint8_t*)framebuffer->address;
-
-	memset(lines_length, 0, sizeof(lines_length));
-
-	DEBUG("terminal initialized, fb=0x%p (width=%u height=%u pitch=%u bpp=%u)", fb, framebuffer->width, framebuffer->height, framebuffer->pitch, framebuffer->bpp);
-	return 0;
-}
-
-// These are marked "static" because we don't wanna expose them all around
-// AKA they should just be seen here (kind of like private functions in cpp)
-static inline void putpixel(size_t x, size_t y, uint32_t color)
-{
-	// Guard so we don't write past fb boundaries
-	if (x >= framebuffer->width || y >= framebuffer->height) return;
-	// Depth isn't part of limine_framebuffer attributes so it will be 4
-	size_t pos = x*4 + y*framebuffer->pitch;
-	fb[pos] = color & 255; // blue channel
-	fb[pos+1] = (color >> 8) & 255; // green
-	fb[pos+2] = (color >> 16) & 255; // blue
-}
-
-static void draw_char(char c, size_t px, size_t py, uint32_t fg, uint32_t bg)
-{
-	// So we cannot write past fb
-	if (px+FONT_WIDTH > framebuffer->width || py+FONT_HEIGHT > framebuffer->height) return;
-
-	uint8_t* glyph = glyphs + ((unsigned char)c * FONT_HEIGHT);
-
-	for (size_t y=0; y<FONT_HEIGHT; y++)
-	{
-		uint8_t row = glyph[y];
-		for (size_t x=0; x<FONT_WIDTH; x++)
-		{
-			uint32_t color = (row & (0x80 >> x)) ? fg : bg;
-			putpixel(px+x, py+y, color);
-		}
-	}
-}
-
-static void erase_char(size_t px, size_t py)
-{
-	if (px+FONT_WIDTH > framebuffer->width || py+FONT_HEIGHT > framebuffer->height) return;
-
-	for (size_t y=0; y<FONT_HEIGHT; y++)
-	{
-		for (size_t x=0; x<FONT_WIDTH; x++)
-		{
-			// Black
-			putpixel(px+x, py+y, 0);
-		}
-	}
-}
-
-void term_scroll()
-{
-	// Erase first text line
-	memset(fb, 255, FONT_HEIGHT*framebuffer->pitch);
-
-	// Move whole framebuffer up by one text line
-	memmove(fb, fb+(FONT_HEIGHT*framebuffer->pitch), (framebuffer->height-FONT_HEIGHT)*framebuffer->pitch);
-
-	// Clear last text line
-	size_t clear_start = (framebuffer->height - FONT_HEIGHT) * framebuffer->pitch;
-	memset(fb + clear_start, 255, FONT_HEIGHT * framebuffer->pitch);
-
-	// Shift line lengths by 1 (for backspace handling)
-	size_t max_lines = term_max_lines();
-	for (size_t i = 1; i < max_lines; i++)
-	{
-		lines_length[i - 1] = lines_length[i];
-	}
-	lines_length[max_lines - 1] = 0;
-}
-
-void putchar(char c)
-{
-	const size_t max_cols = term_max_cols();
-	const size_t max_lines = term_max_lines();
-
-	if (c == '\n') {
-		lines_length[cursor.y] = cursor.x;
-		cursor.x = 0;
-
-		if (cursor.y + 1 >= max_lines)
-		{
-			term_scroll();
-		}
-		else
-		{
-			cursor.y++;
-		}
-		return;
-	}
-
-	if (c == '\b') 
-	{
-		if (cursor.x > 0) 
-		{
-			cursor.x--;
-		}
-		else if (cursor.y > 0)
-		{
-			cursor.y--;
-			cursor.x = lines_length[cursor.y];
-		}
-		else
-		{
-			return;
-		}
-
-		erase_char(cursor.x * FONT_WIDTH, cursor.y * FONT_HEIGHT);
-		return;
-	}
-
-	if (cursor.x >= max_cols) 
-	{
-		cursor.x = 0;
-		if (cursor.y + 1 >= max_lines)
-		{
-			term_scroll();
-		}
-		else
-		{
-			cursor.y++;
-		}
-	}
-
-	draw_char(c, cursor.x * FONT_WIDTH, cursor.y * FONT_HEIGHT, WHITE, BLACK);
-	cursor.x++;
-}
-
-// Overhead that could be avoided, right? (for printf)
 void _putchar(char character)
 {
-	putchar(character);
+	// TODO: Spinlock here (terminal access)
+	flanterm_write(ft_ctx, &character, 1);
 }
 
-// Debug-printing
+/*
+ * internal_putc - Internal putchar function
+ * @c: char to print
+ * @_: (unused, for nanoprintf)
+ *
+ * Prints a character to the terminal if it's ready,
+ * and also to the serial interface if it's ready.
+ */
+void internal_putc(int c, void *_)
+{
+    (void)_;
+    char ch = (char)c;
+
+    if (init.terminal) {
+        if (panic_count == 0) {
+            spinlock_acquire(&term_lock);
+            flanterm_write(ft_ctx, &ch, 1);
+            spinlock_release(&term_lock);
+        } else {
+            flanterm_write(ft_ctx, &ch, 1);
+        }
+    }
+
+    if (init.serial) {
+        if (ch == '\n') {
+            skputc('\r');
+        }
+        skputc(ch);
+    }
+}
+
+/*
+ * printf - Fromatted printing
+ * @fmt: format string
+ * @...: variadic arguments
+ *
+ * Wrapper for nanoprintf
+ *
+ * Return:
+ * <ret> - number of characters sent to the callback
+ */
+int printf(const char* fmt, ...)
+{
+    va_list args;
+    va_start(args, fmt);
+    int ret = npf_vpprintf(internal_putc, NULL, fmt, args);
+    va_end(args);
+    return ret;
+}
+
+/*
+ * kputs - Kernel puts
+ * @str: String to write
+ *
+ * Writes a non-formatted string to terminal
+ */
 void kputs(const char* str)
 {
 	size_t i=0;
-	while (str[i] != 0)
+	while (str[i] != 0) {
-	{
+		_putchar(str[i]);
-		putchar(str[i]);
 		i++;
 	}
+	_putchar('\r');
+}
+
+extern struct flanterm_context* ft_ctx;
+extern struct boot_context boot_ctx;
+
+/*
+ * flanterm_free_wrapper - free() wrapper for Flanterm 
+ * @ptr:  pointer to free
+ * @size: amount of bytes to free
+ *
+ * This function exists solely because the Flanterm initialization
+ * function only accepts a free() function with a size parameter,
+ * and the default one doesn't have it.
+ */
+void flanterm_free_wrapper(void* ptr, size_t size)
+{
+	(void)size;
+	kfree(ptr);
+}
+
+/*
+ * term_init - Video output/terminal initialization
+ *
+ * Uses Flanterm and the framebuffer given by Limine.
+ */
+void term_init()
+{
+	uint32_t bgColor = 0x252525;
+	ft_ctx = flanterm_fb_init(
+        kmalloc,
+        flanterm_free_wrapper,
+        boot_ctx.fb->address, boot_ctx.fb->width, boot_ctx.fb->height, boot_ctx.fb->pitch,
+        boot_ctx.fb->red_mask_size, boot_ctx.fb->red_mask_shift,
+        boot_ctx.fb->green_mask_size, boot_ctx.fb->green_mask_shift,
+        boot_ctx.fb->blue_mask_size, boot_ctx.fb->blue_mask_shift,
+        NULL,
+        NULL, NULL,
+        &bgColor, NULL,
+        NULL, NULL,
+        NULL, 0, 0, 1,
+        0, 0,
+        0,
+        0
+    );
+	init.terminal = true;
 }

src/io/term/term.h

@@ -1,28 +1,15 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Framebuffer-based terminal driver
+ * @license GPL-3.0-only
+ */
+
 #ifndef TERM_H
 #define TERM_H
 
-int term_init();
 void kputs(const char* str);
-void putchar(char c);
+void _putchar(char character);
-
+void term_init(void);
-enum TermColors
+int printf(const char* fmt, ...);
-{
-    BLACK = 0x000000,
-    WHITE = 0xffffff
-};
-
-#define MAX_LINES 256
-
-#define PSF1_FONT_MAGIC 0x0436
-
-typedef struct
-{
-    uint16_t magic;
-    uint8_t fontMode;
-    uint8_t characterSize; // height
-} PSF1_Header;
-
-// debug 
-void term_scroll();
 
 #endif

src/kernel.h

@@ -1,12 +1,13 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Kernel global macros
+ * @license GPL-3.0-only
+ */
+
 #ifndef KERNEL_H
 #define KERNEL_H
 
-#define PEPPEROS_VERSION_MAJOR "0"
+enum ErrorCodes {
-#define PEPPEROS_VERSION_MINOR "0"
-#define PEPPEROS_VERSION_PATCH "1"
-
-enum ErrorCodes
-{
 	ENOMEM,
 	EIO
 };
@@ -15,25 +16,48 @@ enum ErrorCodes
 #define SET_INTERRUPTS __asm__ volatile("sti")
 
 #include "io/serial/serial.h"
-#include "io/term/printf.h"
+#include "io/term/term.h"
 #include "idt/idt.h"
+#include <stdbool.h>
 
-#define DEBUG(log, ...) fctprintf((void*)&skputc, 0, "debug: [%s]: " log "\r\n", __FILE__, ##__VA_ARGS__)
+extern volatile uint64_t ticks;
+#define DEBUG(log, ...) printf("[%8u] debug: <%s>: " log "\r\n", ticks, __func__, ##__VA_ARGS__)
+
+/* #define DEBUG(log, ...) \
+	printf("debug: [%s]: " log "\r\n", __FILE__, ##__VA_ARGS__); \
+	fctprintf((void*)&skputc, 0, "debug: [%s]: " log "\r\n", __FILE__, ##__VA_ARGS__)
+ */
+
+#define DIE_DEBUG(str) printf(str)
 
 #define CHECK_BIT(var,pos) ((var) & (1<<(pos)))
 
 // printf("debug: [%s]: " log "\n", __FILE__, ##__VA_ARGS__);
 
-void panic(struct cpu_status_t* ctx);
+void panic(struct cpu_status_t* ctx, const char* str);
-void hcf();
+void hcf(void);
+void idle(void);
+
+/* debug */
+void debug_stack_trace(unsigned int max_frames);
+const char* debug_find_symbol(uintptr_t rip, uintptr_t* offset);
+void boot_mem_display(void);
+
 #define assert(check) do { if(!(check)) hcf(); } while(0)
 
-struct boot_context
+struct boot_context {
-{
 	struct limine_framebuffer* fb;
 	struct limine_memmap_response* mmap;
 	struct limine_hhdm_response* hhdm;
 	struct limine_kernel_address_response* kaddr;
 };
 
+// Are these modules initialized yet?
+struct init_status {
+	bool terminal;
+	bool serial;
+	bool keyboard;
+	bool timer;
+};
+
 #endif

src/kmain.c

@@ -1,8 +1,14 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   PepperOS kernel entry point
+ * @license GPL-3.0-only
+ */
+
 #include <stdbool.h>
 #include <stddef.h>
 #include <limine.h>
 #include "io/term/term.h"
-#include "io/term/printf.h"
+#include "io/term/term.h"
 #include "io/serial/serial.h"
 #include "mem/gdt/gdt.h"
 #include "mem/misc/utils.h"
@@ -14,115 +20,111 @@
 #include "mem/paging/paging.h"
 #include "mem/paging/vmm.h"
 #include "mem/heap/kheap.h"
+#include "sched/process.h"
+#include "sched/scheduler.h"
+#include "config.h"
+#include "io/term/flanterm.h"
+#include "io/term/flanterm_backends/fb.h"
 
 // Limine version used
 __attribute__((used, section(".limine_requests")))
-static volatile LIMINE_BASE_REVISION(3);
+volatile LIMINE_BASE_REVISION(3);
 
-// Framebuffer request
+int panic_count = 0;
-__attribute__((used, section(".limine_requests")))
-static volatile struct limine_framebuffer_request framebuffer_request = {
-	.id = LIMINE_FRAMEBUFFER_REQUEST,
-	.revision = 0
-};
 
-// Memory map request
+/*
-__attribute__((used, section(".limine_requests")))
+ * hcf - Halt and catch fire
-static volatile struct limine_memmap_request memmap_request = {
+ *
-	.id = LIMINE_MEMMAP_REQUEST,
+ * This function is called only in the case of an unrecoverable
-	.revision = 0
+ * error. It halts interrupts, and stops execution. The machine
-};
+ * will stay in an infinite loop state.
-
+ */
-// Higher Half Direct Map
-__attribute__((used, section(".limine_requests")))
-static volatile struct limine_hhdm_request hhdm_request = {
-	.id = LIMINE_HHDM_REQUEST,
-	.revision = 0
-};
-
-// Executable Address/Kernel Address (find base phys/virt address of kernel)
-__attribute__((used, section(".limine_requests")))
-static volatile struct limine_kernel_address_request kerneladdr_request = {
-	.id = LIMINE_KERNEL_ADDRESS_REQUEST,
-	.revision = 0
-};
-
-__attribute__((used, section(".limine_requests_start")))
-static volatile LIMINE_REQUESTS_START_MARKER;
-
-__attribute__((used, section(".limine_requests_end")))
-static volatile LIMINE_REQUESTS_END_MARKER;
-
-// Panic (should dump registers etc. in the future)
 void hcf()
 {
-	for (;;)
+	CLEAR_INTERRUPTS; for (;;)asm("hlt");
-	{
+}
+
+/*
+ * idle - Make the machine idle
+ *
+ * When there is nothing else to do, this function
+ * gets called. It can be interrupted, so it allows
+ * the scheduler, timer, and keyboard to work.
+ */
+void idle() {SET_INTERRUPTS; for(;;)asm("hlt");}
+
+struct flanterm_context *ft_ctx;
+struct boot_context boot_ctx;
+struct init_status init = {0};
+
+extern volatile struct limine_framebuffer_request framebuffer_request;
+extern volatile struct limine_memmap_request memmap_request;
+extern volatile struct limine_hhdm_request hhdm_request;
+extern volatile struct limine_kernel_address_request kerneladdr_request;
+
+extern struct process_t* processes_list;
+extern struct process_t* current_process;
+struct process_t* idle_proc;
+
+// Never gets executed although pedicel is scheduled?
+void pedicel_main(void* arg)
+{
+	printf("\n\nWelcome to PepperOS! Pedicel speaking.\r\nNothing left to do, let's go idle!");
+}
+
+void idle_main(void* arg)
+{
+	for (;;) {
 		asm("hlt");
 	}
 }
 
-void panic(struct cpu_status_t* ctx)
+extern uintptr_t kheap_start;
-{
-	DEBUG("\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m at rip=%p\nSomething went horribly wrong! vect=0x%.2x errcode=0x%x\nrax=%p rbx=%p rcx=%p rdx=%p\nrsi=%p rdi=%p  r8=%p  r9=%p\nr10=%p r11=%p r12=%p r13=%p\nr14=%p r15=%p\n\nflags=%p\nstack at rbp=%p\nHalting...",
-		ctx->iret_rip,
-		ctx->vector_number, ctx->error_code, ctx->rax, ctx->rbx, ctx->rcx, ctx->rdx, ctx->rsi, ctx->rdi,
-		ctx->r8, ctx->r9, ctx->r10, ctx->r11, ctx->r12, ctx->r13, ctx->r14, ctx->r15, ctx->iret_flags,
-		ctx->rbp);
-	hcf();
-}
 
-const char* splash = "pepperOS version "PEPPEROS_VERSION_MAJOR"."PEPPEROS_VERSION_MINOR"."PEPPEROS_VERSION_PATCH"\n";
+/*
-
+ * kmain - Kernel entry point
-struct boot_context boot_ctx;
+ *
-
+ * This is where execution begins at handoff from Limine.
-// This is our entry point
+ * The function fetches all needed information from the
+ * bootloader, initializes all kernel modules and structures,
+ * and then goes in an idle state.
+ */
 void kmain()
 {
+	CLEAR_INTERRUPTS;
 	if (!LIMINE_BASE_REVISION_SUPPORTED) hcf();
 
+	serial_init();
+	timer_init();
+
 	// Populate boot context
  	boot_ctx.fb = framebuffer_request.response ? framebuffer_request.response->framebuffers[0] : NULL;
 	boot_ctx.mmap = memmap_request.response ? memmap_request.response : NULL;
 	boot_ctx.hhdm = hhdm_request.response ? hhdm_request.response : NULL;
 	boot_ctx.kaddr = kerneladdr_request.response ? kerneladdr_request.response : NULL;
 
-	serial_init();
+	boot_mem_display();
-
+	pmm_init(boot_ctx);
-	memmap_display(boot_ctx.mmap);
-	hhdm_display(boot_ctx.hhdm);
-	DEBUG("kernel: phys_base=0x%p virt_base=0x%p", boot_ctx.kaddr->physical_base, boot_ctx.kaddr->virtual_base);
-
-	CLEAR_INTERRUPTS;
-	gdt_init();
-	idt_init();
-	timer_init();
-	SET_INTERRUPTS;
-
-	pmm_init(boot_ctx.mmap, boot_ctx.hhdm);
 
 	// Remap kernel , HHDM and framebuffer
-	paging_init(boot_ctx.kaddr, boot_ctx.fb);
+	paging_init(boot_ctx);
-	
 	kheap_init();
 
-	void* ptr = kmalloc(10); DEBUG("(KMALLOC TEST) Allocated 10 bytes at 0x%p", ptr);
-	void* ptr2 = kmalloc(200); DEBUG("(KMALLOC TEST) Allocated 200 bytes at 0x%p", ptr2);
-	kfree(ptr);
-	void* ptr3 = kmalloc(5); DEBUG("(KMALLOC TEST) Allocated 5 bytes at 0x%p", ptr3);
-
-	vmm_init();
-
 	keyboard_init(FR);
 
 	term_init();
-	kputs(splash);
 
-	for (int i=0; i<10; i++)
+	gdt_init();
-	{
+	idt_init();
-		printf("testing, attention please %d\n", i);
+	
-	}
+	process_init();
-	// term_scroll(); 
+	idle_proc = process_create("idle", (void*)idle_main, 0);
+	struct process_t* pedicel = process_create("pedicel", (void*)pedicel_main, 0);
 
-	hcf();
+	process_display_list(processes_list);
+
+	scheduler_init();
+
+	kputs(PEPPEROS_SPLASH);
+	idle();
 }

src/mem/gdt/gdt.c

@@ -1,3 +1,9 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Global Descriptor Table (for legacy reasons)
+ * @license GPL-3.0-only
+ */
+
 #include "gdt.h"
 #include <stdint.h>
 #include "io/serial/serial.h"
@@ -8,11 +14,20 @@
 uint64_t gdt_entries[NUM_GDT_ENTRIES];
 struct GDTR gdtr;
 
+/*
+ * gdt_load - Loads Global Descriptor Table
+ */
 static void gdt_load()
 {
     asm("lgdt %0" : : "m"(gdtr));
 }
 
+/*
+ * gdt_flush - Flushes the Global Descriptor Table
+ *
+ * This function loads new Segment Selectors to make
+ * the GDT changes take effect
+ */
 static void gdt_flush()
 {
     // Here, 0x8 is the kernel code selector
@@ -36,6 +51,15 @@ static void gdt_flush()
     );
 }
 
+/*
+ * gdt_init - Global Descriptor Table initialization 
+ *
+ * This function loads a new GDT in the CPU.
+ * It contains a null descriptor, kernel code and data
+ * segments, and user code and data segments.
+ * However, we do not use segmentation to manage memory on
+ * 64-bit x86, as it's deprecated. Instead, we use paging. 
+ */
 void gdt_init()
 {
     // Null descriptor (required)

src/mem/gdt/gdt.h

@@ -1,3 +1,9 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Global Descriptor Table (for legacy reasons)
+ * @license GPL-3.0-only
+ */
+
 #ifndef GDT_H
 #define GDT_H
 
@@ -15,12 +21,11 @@
 #define USER_CODE_SEGMENT 0x18
 #define USER_DATA_SEGMENT 0x20
 
-struct GDTR 
+struct GDTR {
-{
     uint16_t limit;
     uint64_t address;
 } __attribute__((packed));
 
-void gdt_init();
+void gdt_init(void);
 
 #endif

src/mem/heap/kheap.c

@@ -1,8 +1,16 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Kernel heap
+ * @license GPL-3.0-only
+ */
+
 #include "kheap.h"
 #include "mem/paging/paging.h"
 #include "mem/paging/pmm.h"
 #include <stddef.h>
 #include <kernel.h>
+#include "sched/process.h"
+#include "config.h"
 
 extern uint64_t kernel_phys_base;
 extern uint64_t kernel_virt_base;
@@ -15,54 +23,77 @@ static uintptr_t end;
 // Kernel root table (level 4)
 extern uint64_t *kernel_pml4;
 
-static void kheap_map_page()
+/*
-{
+ * kheap_init - Kernel heap initialization
-    uintptr_t phys = pmm_alloc();
+ *
-    paging_map_page(kernel_pml4, end, phys, PTE_PRESENT | PTE_WRITABLE | PTE_NOEXEC);
+ * This function physically allocates and maps enough pages
-    end += PAGE_SIZE;
+ * of memory for KHEAP_SIZE, which is defined in config.h.
-    DEBUG("Mapped first kheap page");
+ *
-}
+ * It then creates one big heap block, which will be the
-
+ * base for a linked list.
+ */
 void kheap_init()
 {
     kheap_start = ALIGN_UP(kernel_virt_base + KERNEL_SIZE, PAGE_SIZE);
-    end = kheap_start;
+    
+    size_t heap_pages = ALIGN_UP(KHEAP_SIZE, PAGE_SIZE) / PAGE_SIZE;
+    DEBUG("Mapping %d kernel heap pages at 0x%p", heap_pages, kheap_start);
 
-    // At least 1 page must be mapped for it to work
+    uintptr_t current_addr = kheap_start;
-    kheap_map_page();
+
+    // Map/alloc enough pages for heap (KHEAP_SIZE)
+    for (size_t i=0; i<heap_pages; i++) {
+        uintptr_t phys = pmm_alloc();
+        if (phys == 0) {
+            panic(NULL, "Not enough memory available to initialize kernel heap.");
+        }
+
+        paging_map_page(kernel_pml4, current_addr, phys, PTE_PRESENT | PTE_WRITABLE);
+        current_addr += PAGE_SIZE;
+    }
+
+    end = current_addr;
 
     // Give linked list head its properties
     head = (struct heap_block_t*)kheap_start;
-    head->size = PAGE_SIZE - sizeof(struct heap_block_t);
+    head->size = (end-kheap_start) - sizeof(struct heap_block_t);
     head->free = true;
     head->next = NULL;
-    DEBUG("kheap initialized, head=0x%p, size=%u", head, head->size);
+    DEBUG("Kernel heap initialized, head=0x%p, size=%u bytes", head, head->size);
 }
 
+/*
+ * kmalloc - Kernel memory allocation
+ * @size: number of bytes to allocate
+ *
+ * Looks for a big enough free block and marks it
+ * as taken. Each block of memory is preceded by
+ * the linked list header.
+ *
+ * Return:
+ * <ptr> - Pointer to at least <size> bytes of usable memory
+ * NULL  - No more memory, or no valid size given
+ */
 void* kmalloc(size_t size)
 {
     // No size, no memory allocated!
     if (!size) return NULL;
+    size = ALIGN(size);
 
     struct heap_block_t* curr = head;
 
-    while (curr)
+    while (curr) {
-    {
         // Is block free and big enough for us?
-        if (curr->free && curr->size >= size)
+        if (curr->free && curr->size >= size) {
-        {
             // We split the block if it is big enough
-            if (curr->size > size + sizeof(struct heap_block_t))
+            if (curr->size >= size + sizeof(struct heap_block_t) + 16) {
-            {
+                struct heap_block_t* split = (struct heap_block_t*)((uintptr_t)curr + sizeof(struct heap_block_t) + size);
-                struct heap_block_t* new_block = (struct heap_block_t*)((uintptr_t)curr + sizeof(struct heap_block_t) + size);
+                
-                // We have to subtract the size of our block struct
+                split->size = curr->size - size - sizeof(struct heap_block_t);
-                new_block->size = curr->size - size - sizeof(struct heap_block_t);
+                split->free = true;
-                new_block->free = true;
+                split->next = curr->next;
-
-                // Then we chain up the block in the list
-                new_block->next = curr->next;
-                curr->next = new_block;
 
+                curr->next = split;
                 curr->size = size;
             }
 
@@ -74,27 +105,22 @@ void* kmalloc(size_t size)
         curr = curr->next;
     }
 
-    // If we're hear it means we didn't have enough memory
+    // No growing. If we're here it means the initial pool
-    // for the block allocation. So we will allocate more..
+    // wasn't sufficient. Too bad.
-    uintptr_t old_end = end;
+    DEBUG("Kernel heap is OUT OF MEMORY!");
-    kheap_map_page();
+    // if we were terrorists maybe we should panic
-
+    // or just wait for others to free stuff?
-    struct heap_block_t* block = (struct heap_block_t*)old_end;
+    return NULL;
-    block->size = PAGE_SIZE - sizeof(struct heap_block_t);
-    block->free = false;
-    block->next = NULL;
-
-    // Put the block at the end of the list
-    curr = head;
-    while (curr->next)
-    {
-        curr = curr->next;
-    }
-    curr->next = block;
-
-    return (void*)((uintptr_t)block + sizeof(struct heap_block_t));
 }
 
+/*
+ * kfree - Kernel memory freeing
+ * @ptr: pointer to memory region to free
+ *
+ * Marks the memory block beginning at <ptr>
+ * as free. Also merges adjacent free blocks
+ * to lessen fragmentation.
+ */
 void kfree(void* ptr)
 {
     // Nothing to free
@@ -103,4 +129,32 @@ void kfree(void* ptr)
     // Set it free!
     struct heap_block_t* block = (struct heap_block_t*)((uintptr_t)ptr - sizeof(struct heap_block_t));
     block->free = true;
+
+    // merge adjacent free blocks (coalescing)
+    struct heap_block_t* curr = head;
+    while (curr && curr->next) {
+        if (curr->free && curr->next->free) {
+            curr->size += sizeof(*curr) + curr->next->size;
+            curr->next = curr->next->next;
+            continue;
+        }
+        curr = curr->next;
+    }
+}
+
+/*
+ * kalloc_stack - Stack memory allocation
+ *
+ * Allocates a memory region of at least PROCESS_STACK_SIZE,
+ * to be used as a stack for a process. The pointer returned
+ * points to the end of the region, as the stack grows downwards.
+ *
+ * Return:
+ * <ptr> - Pointer to a region after at least PROCESS_STACK_SIZE bytes of usable memory
+ * NULL  - No more memory
+ */
+void* kalloc_stack()
+{
+    uint8_t* ptr = kmalloc(PROCESS_STACK_SIZE); // As it's out of kmalloc, stack is already mapped into kernel space
+    return ptr ? ptr+PROCESS_STACK_SIZE : NULL;
 }

src/mem/heap/kheap.h

@@ -1,3 +1,9 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Kernel heap
+ * @license GPL-3.0-only
+ */
+
 #ifndef KHEAP_H
 #define KHEAP_H
 
@@ -6,21 +12,21 @@
 // When the kernel heap is ready, we can alloc our VM object linked list
 // and then continue working on the VMM.
 
-// 16MB should be enough for some linked lists
-#define KHEAP_SIZE (16*1024*1024)
-
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
 
-struct heap_block_t
+struct heap_block_t {
-{
     size_t size;
-    bool free;
+    bool free; // 1byte
+    uint8_t reserved[7]; // (7+1 = 8 bytes)
     struct heap_block_t* next;
-};
+} __attribute__((aligned(16)));
 
-void kheap_init();
+void kheap_init(void);
 void* kmalloc(size_t size);
 void kfree(void* ptr);
+void* kalloc_stack(void);
+void kheap_map_page(void);
 
 #endif

src/mem/misc/utils.c

@@ -1,3 +1,9 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Common memory utilities
+ * @license GPL-3.0-only
+ */
+
 #include <stddef.h>
 #include <stdint.h>
 #include <limine.h>
@@ -10,113 +16,107 @@
 // We use the "restrict" keyword on pointers so that the compiler knows it can
 // do more optimization on them (and as it's a much used function, it's good to
 // be able to do that)
+
+/*
+ * memcpy - Copy memory from one place to another
+ * @dest: pointer to the destination region
+ * @src:  pointer to the source region
+ * @n:    amount of bytes to copy
+ *
+ * This function copies n bytes of memory from
+ * src to dest.
+ *
+ * Return:
+ * <dest> - Pointer to destination region
+ */
 void* memcpy(void* restrict dest, const void* restrict src, size_t n)
 {
 	uint8_t* restrict pdest = (uint8_t* restrict)dest;
 	const uint8_t* restrict psrc = (const uint8_t* restrict)src;
 
-	for (size_t i=0; i<n; i++)
+	for (size_t i=0; i<n; i++) {
-	{
 		pdest[i] = psrc[i];
 	}
 
 	return dest;
 }
 
+/*
+ * memset - Sets a memory region to given byte
+ * @s:    pointer to memory region
+ * @c:    byte to be written
+ * @n:    amount of bytes to write
+ *
+ * This function writes n times the byte c
+ * to the memory region pointed to by s.
+ *
+ * Return:
+ * <s> - Pointer to memory region
+ */
 void* memset(void* s, int c, size_t n)
 {
 	uint8_t* p = (uint8_t*)s;
 
-	for (size_t i=0; i<n; i++)
+	for (size_t i=0; i<n; i++) {
-	{
 		p[i] = (uint8_t)c;
 	}
 
 	return s;
 }
 
+/*
+ * memmove - Move memory from one place to another
+ * @dest: pointer to the destination region
+ * @src:  pointer to the source region
+ * @n:    amount of bytes to move
+ *
+ * This function moves n bytes of memory from
+ * src to dest.
+ *
+ * Return:
+ * <dest> - Pointer to destination region
+ */
 void* memmove(void *dest, const void* src, size_t n)
 {
 	uint8_t* pdest = (uint8_t*)dest;
 	const uint8_t* psrc = (uint8_t*)src;
 
-	if (src > dest)
+	if (src > dest) {
-	{
+		for (size_t i=0; i<n; i++) {
-		for (size_t i=0; i<n; i++)
-		{
 			pdest[i] = psrc[i];
 		}
-	} else if (src < dest) 
+	} else if (src < dest) {
-	{
+		for (size_t i=n; i>0; i--) {
-		for (size_t i=n; i>0; i--)
-		{
 			pdest[i-1] = psrc[i-1];
 		}
 	}
 	return dest;	
 }
 
+/*
+ * memcmp - Compare two memory regions
+ * @s1:   pointer to the first region
+ * @s2:   pointer to the second region
+ * @n:    amount of bytes to compare
+ *
+ * This function compares n bytes of memory
+ * bewteen regions pointed to by s1 and s2.
+ *
+ * Return:
+ * %0     - if s1 and s2 are equal 
+ * %-1    - if s1 is smaller than s2
+ * %1     - if s1 is greater than s2
+ */
 int memcmp(const void* s1, const void* s2, size_t n)
 {
 	const uint8_t* p1 = (const uint8_t*)s1;
 	const uint8_t* p2 = (const uint8_t*)s2;
 
-	for (size_t i=0; i<n; i++)
+	for (size_t i=0; i<n; i++) {
-	{
+		if (p1[i] != p2[i]) {
-		if (p1[i] != p2[i])
-		{
 			return p1[i] < p2[i] ? -1 : 1;
 		}
 	}
 
 	return 0;
-}
-
-// Display the memmap so we see how the memory is laid out at handoff
-void memmap_display(struct limine_memmap_response* response)
-{
-	DEBUG("Got memory map from Limine: revision %u, %u entries", response->revision, response->entry_count);
-
-	for (size_t i=0; i<response->entry_count; i++)
-	{
-		struct limine_memmap_entry* entry = response->entries[i];
-		char type[32] = {0};
-		switch(entry->type)
-		{
-			case LIMINE_MEMMAP_USABLE:
-				strcpy(type, "USABLE");
-				break;
-			case LIMINE_MEMMAP_RESERVED:
-				strcpy(type, "RESERVED");
-				break;
-			case LIMINE_MEMMAP_ACPI_RECLAIMABLE:
-				strcpy(type, "ACPI_RECLAIMABLE");
-				break;
-			case LIMINE_MEMMAP_ACPI_NVS:
-				strcpy(type, "ACPI_NVS");
-				break;
-			case LIMINE_MEMMAP_BAD_MEMORY:
-				strcpy(type, "BAD_MEMORY");
-				break;
-			case LIMINE_MEMMAP_BOOTLOADER_RECLAIMABLE:
-				strcpy(type, "BOOTLOADER_RECLAIMABLE");
-				break;
-			case LIMINE_MEMMAP_KERNEL_AND_MODULES:
-				strcpy(type, "KERNEL_AND_MODULES");
-				break;
-			case LIMINE_MEMMAP_FRAMEBUFFER:
-				strcpy(type, "FRAMEBUFFER");
-				break;
-			default:
-				strcpy(type, "UNKNOWN");
-				break;
-		}
-		DEBUG("entry %02u: [0x%016x | %016u bytes] - %s", i, entry->base, entry->length, type);
-	}
-}
-
-// Display the HHDM
-void hhdm_display(struct limine_hhdm_response* hhdm)
-{
-	DEBUG("Got HHDM revision=%u offset=0x%p", hhdm->revision, hhdm->offset);
 }

src/mem/misc/utils.h

@@ -1,3 +1,9 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Common memory utilities
+ * @license GPL-3.0-only
+ */
+
 #ifndef MEM_UTILS_H
 #define MEM_UTILS_H
 
@@ -8,6 +14,7 @@ void* memset(void* s, int c, size_t n);
 void* memmove(void *dest, const void* src, size_t n);
 int memcmp(const void* s1, const void* s2, size_t n);
 
+// DEBUG
 void memmap_display(struct limine_memmap_response* response);
 void hhdm_display(struct limine_hhdm_response* hhdm);
 

src/mem/paging/paging.c

@@ -1,8 +1,15 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   x64 4-level paging implementation
+ * @license GPL-3.0-only
+ */
+
 #include "paging.h"
 #include "pmm.h"
 #include <kernel.h>
 #include <stddef.h>
 #include <limine.h>
+#include "config.h"
 
 /*
 Paging on x86 uses four different page table levels:
@@ -17,23 +24,46 @@ If we use 1GB huge pages: PML4 -> PDPT -> 1gb pages
 4KB (regular size): PML4 -> PDPT -> PD -> PT -> 4kb pages
 */
 
-static inline void load_cr3(uint64_t value) {
+/*
+ * load_cr3 - Load a new value into the CR3 register
+ * @value: the value to load
+ *
+ * This function is used to load the physical address
+ * of the root page table (PML4), to switch the paging
+ * structures the CPU sees and uses.
+ */
+void load_cr3(uint64_t value) {
     asm volatile ("mov %0, %%cr3" :: "r"(value) : "memory");
 }
 
-// To flush TLB
+/*
+ * invlpg - Invalidates a Translation Lookaside Buffer entry
+ * @addr: page memory address
+ *
+ * This function is used to flush at least the TLB entrie(s)
+ * for the page that contains the <addr> address.
+ */
 static inline void invlpg(void *addr)
 {
     asm volatile("invlpg (%0)" :: "r"(addr) : "memory");
 }
 
-// Allocates a 512-entry 64bit page table/directory/whatever (zeroed)
+/*
+ * alloc_page_table - Page table allocation
+ *
+ * This function allocates enough memory for a 512-entry
+ * 64-bit page table, for any level (PML4/3/2).
+ *
+ * Memory allocated here is zeroed.
+ *
+ * Return:
+ * <virt> - Pointer to allocated page table
+ */
 static uint64_t* alloc_page_table()
 {
     uint64_t* virt = (uint64_t*)PHYS_TO_VIRT(pmm_alloc());
 
-    for (size_t i=0; i<512; i++)
+    for (size_t i=0; i<512; i++) {
-    {
         virt[i] = 0;
     }
     return virt;
@@ -43,10 +73,19 @@ static uint64_t* alloc_page_table()
 __attribute__((aligned(4096)))
 uint64_t *kernel_pml4;
 
-// Map a page, taking virt and phys address. This will go through the paging structures
+/*
-// beginning at the given root table, translate the virtual address in indexes in
+ * paging_map_page - Mapping a memory page
-// page table/directories, and then mapping the correct page table entry with the
+ * @root_table: Address of the PML4
-// given physical address + flags
+ * @virt:       Virtual address
+ * @phys:       Physical address
+ * @flags:      Flags to set on page
+ *
+ * This function maps the physical address <phys> to the virtual
+ * address <virt>, using the paging structures beginning at
+ * <root_table>. <flags> can be set according to the PTE_FLAGS enum.
+ *
+ * If a page table/directory entry is not present yet, it creates it.
+ */
 void paging_map_page(uint64_t* root_table, uint64_t virt, uint64_t phys, uint64_t flags)
 {
     virt = PAGE_ALIGN_DOWN(virt);
@@ -63,33 +102,27 @@ void paging_map_page(uint64_t* root_table, uint64_t virt, uint64_t phys, uint64_
     // PML4
     // If the entry at index is not present, allocate enough space for it
     // then populate the entry with correct addr + flags
-    if (!(root_table[pml4_i] & PTE_PRESENT))
+    if (!(root_table[pml4_i] & PTE_PRESENT)) {
-    {
         pdpt = alloc_page_table();
         root_table[pml4_i] = VIRT_TO_PHYS(pdpt) | PTE_PRESENT | PTE_WRITABLE;
-    }
+    } else {
-    else {
+        pdpt = (uint64_t *)PHYS_TO_VIRT(root_table[pml4_i] & PTE_ADDR_MASK);
-        pdpt = (uint64_t *)PHYS_TO_VIRT(root_table[pml4_i] & ~0xFFFULL);
     }
 
     // PDPT: same here
-    if (!(pdpt[pdpt_i] & PTE_PRESENT))
+    if (!(pdpt[pdpt_i] & PTE_PRESENT)) {
-    {
         pd = alloc_page_table();
         pdpt[pdpt_i] = VIRT_TO_PHYS(pd) | PTE_PRESENT | PTE_WRITABLE;
-    } 
+    } else {
-    else {
+        pd = (uint64_t *)PHYS_TO_VIRT(pdpt[pdpt_i] & PTE_ADDR_MASK);
-        pd = (uint64_t *)PHYS_TO_VIRT(pdpt[pdpt_i] & ~0xFFFULL);
     }
 
     // PD: and here
-    if (!(pd[pd_i] & PTE_PRESENT))
+    if (!(pd[pd_i] & PTE_PRESENT)) {
-    {
         pt = alloc_page_table();
         pd[pd_i] = VIRT_TO_PHYS(pt) | PTE_PRESENT | PTE_WRITABLE;
-    }
+    } else {
-    else {
+        pt = (uint64_t *)PHYS_TO_VIRT(pd[pd_i] & PTE_ADDR_MASK);
-        pt = (uint64_t *)PHYS_TO_VIRT(pd[pd_i] & ~0xFFFULL);
     }
 
     // PT: finally, populate the page table entry
@@ -102,37 +135,62 @@ void paging_map_page(uint64_t* root_table, uint64_t virt, uint64_t phys, uint64_
 uint64_t kernel_phys_base;
 uint64_t kernel_virt_base;
 
-void paging_init(struct limine_kernel_address_response* kaddr, struct limine_framebuffer* fb)
+/*
+ * paging_init - Paging initialization
+ * @boot_ctx: Boot context structure
+ *
+ * This function initializes new paging structures, to replace
+ * the ones given by the bootloader.
+ *
+ * It maps the kernel, the HHDM space, and the framebuffer.
+ */
+void paging_init(struct boot_context boot_ctx)
 {
     // We should map the kernel, GDT, IDT, stack, framebuffer.
     // Optionally we could map ACPI tables (we can find them in the Limine memmap)
 
-    kernel_phys_base = kaddr->physical_base;
+    kernel_phys_base = boot_ctx.kaddr->physical_base;
-    kernel_virt_base = kaddr->virtual_base;
+    kernel_virt_base = boot_ctx.kaddr->virtual_base;
+    struct limine_framebuffer* fb = boot_ctx.fb;
 
     DEBUG("Kernel lives at virt=0x%p phys=0x%p", kernel_virt_base, kernel_phys_base);
 
     kernel_pml4 = alloc_page_table();
-
+    
     // for debug
     uint64_t page_count = 0;
 
-    // HHDM map first 1 GB using given offset
+    // Find max physical address from limine memmap
-    for (uint64_t i=0; i<0x40000000; i += PAGE_SIZE)
+    uint64_t max_phys = 0;
-    {
+    for (uint64_t i=0; i<boot_ctx.mmap->entry_count; i++) {
-        //paging_kmap_page(i+hhdm_off, i, PTE_WRITABLE);
+        struct limine_memmap_entry* entry = boot_ctx.mmap->entries[i];
-        paging_map_page(kernel_pml4, i+hhdm_off, i, PTE_WRITABLE);
+        if (entry->length == 0) {
+            continue;
+        }
+        uint64_t top = entry->base + entry->length;
+        if (top > max_phys) {
+            max_phys = top;
+        }
+    }
+
+    // 4GB
+    if (max_phys > PAGING_MAX_PHYS) {
+        DEBUG("WARNING: max_phys capped to 4GB (%x) (from max_phys=%p)", PAGING_MAX_PHYS, max_phys);
+        max_phys = PAGING_MAX_PHYS;
+    }
+
+    // HHDM map up to max_phys or PAGING_MAX_PHYS, whichever is smaller, using given offset
+    for (uint64_t i=0; i<max_phys; i += PAGE_SIZE) {
+        paging_map_page(kernel_pml4, i+hhdm_off, i, PTE_WRITABLE | PTE_PRESENT);
         page_count++;
     }
-    DEBUG("Mapped %u pages for first 1GB (HHDM)", page_count); page_count = 0;
+    DEBUG("Mapped %u pages up to 0x%p (HHDM)", page_count, max_phys); page_count = 0;
 
     // Map the kernel (according to virt/phys_base given by Limine)
     // SOME DAY when we want a safer kernel we should map .text as Read/Exec
     // .rodata as Read and .data as Read/Write
     // For now who gives a shit, let's RWX all kernel
-    for (uint64_t i = 0; i < KERNEL_SIZE; i += PAGE_SIZE)
+    for (uint64_t i = 0; i < KERNEL_SIZE; i += PAGE_SIZE) {
-    {
-        //paging_kmap_page(kernel_virt_base+i, kernel_phys_base+i, PTE_WRITABLE);
         paging_map_page(kernel_pml4, kernel_virt_base+i, kernel_phys_base+i, PTE_WRITABLE);
         page_count++;
     }
@@ -145,9 +203,7 @@ void paging_init(struct limine_kernel_address_response* kaddr, struct limine_fra
     uint64_t fb_pages = (fb_size + PAGE_SIZE-1)/PAGE_SIZE;
 
     // Map the framebuffer (with cache-disable & write-through)
-    for (uint64_t i=0; i<fb_pages; i++)
+    for (uint64_t i=0; i<fb_pages; i++) {
-    {
-        //paging_kmap_page(fb_virt+i*PAGE_SIZE, fb_phys+i*PAGE_SIZE, PTE_WRITABLE | PTE_PCD | PTE_PWT);
         paging_map_page(kernel_pml4, fb_virt+i*PAGE_SIZE, fb_phys+i*PAGE_SIZE, PTE_WRITABLE | PTE_PCD | PTE_PWT);
         page_count++;
     }
@@ -155,5 +211,5 @@ void paging_init(struct limine_kernel_address_response* kaddr, struct limine_fra
 
     // Finally, we load the physical address of our PML4 (root table) into cr3
     load_cr3(VIRT_TO_PHYS(kernel_pml4));
-    DEBUG("cr3 loaded, we're still alive");
+    DEBUG("Loaded kernel PML4 into CR3");
 }

src/mem/paging/paging.h

@@ -1,24 +1,38 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   x64 4-level paging implementation
+ * @license GPL-3.0-only
+ */
+
 #ifndef PAGING_H
 #define PAGING_H
 
 #define PAGE_SIZE 4096
-#define BITS_PER_ROW 64
 
 #include <stdint.h>
 #include <limine.h>
+#include "mem/heap/kheap.h"
+#include <kernel.h>
 
-void paging_init(struct limine_kernel_address_response* kaddr, struct limine_framebuffer* fb);
+void paging_init(struct boot_context boot_ctx);
 void paging_map_page(uint64_t* root_table, uint64_t virt, uint64_t phys, uint64_t flags);
 
+// To swap root page tables
+void load_cr3(uint64_t value);
+
 extern uint64_t hhdm_off;
 
 #define PHYS_TO_VIRT(x) ((void*)((uintptr_t)(x) + hhdm_off))
 #define VIRT_TO_PHYS(x) ((uintptr_t)(x) - hhdm_off)
 
+#define PTE_ADDR_MASK 0x000FFFFFFFFFF000
 // Stole it
 #define ALIGN_UP(x, align)   (((x) + ((align) - 1)) & ~((align) - 1))
 #define ALIGN_DOWN(x, align) ((x) & ~((align) - 1))
-#define PAGE_ALIGN_DOWN(x) ((x) & ~0xFFFULL)
+#define PAGE_ALIGN_DOWN(x) ((x) & PTE_ADDR_MASK)
+
+#define ALIGN(size) ALIGN_UP(size, 16)
+#define BLOCK_MIN_SIZE (sizeof(struct heap_block_t) + 16)
 
 #define PML4_INDEX(x) (((x) >> 39) & 0x1FF)
 #define PDPT_INDEX(x) (((x) >> 30) & 0x1FF)
@@ -27,18 +41,15 @@ extern uint64_t hhdm_off;
 
 // Page entry special bits
 // Bits set on a parent (directory, table) fall back to their children
-#define PTE_PRESENT     (1ULL << 0)
+enum PTE_FLAGS
-#define PTE_WRITABLE    (1ULL << 1)
+{
-#define PTE_USER        (1ULL << 2)
+    PTE_PRESENT = (1ULL << 0),
-#define PTE_PWT         (1ULL << 3)
+    PTE_WRITABLE = (1ULL << 1),
-#define PTE_PCD         (1ULL << 4)
+    PTE_USER = (1ULL << 2),
-#define PTE_HUGE        (1ULL << 7)
+    PTE_PWT = (1ULL << 3),
-#define PTE_NOEXEC      (1ULL << 63)
+    PTE_PCD = (1ULL << 4),
-
+    PTE_HUGE = (1ULL << 7),
-// Specified in linker.ld
+    PTE_NOEXEC = (1ULL << 63)
-#define KERNEL_BASE 0xFFFFFFFF80000000ULL
+};
-
-// 2 MB should be enough (as of now, the whole kernel ELF is around 75kb)
-#define KERNEL_SIZE 0x200000
 
 #endif

src/mem/paging/pmm.c

@@ -1,4 +1,8 @@
-// OMG here we are. I'm cooked.
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Physical memory manager from freelist
+ * @license GPL-3.0-only
+ */
 
 /*
 pmm - Physical Memory Manager
@@ -20,13 +24,16 @@ First we'll have to discover the physical memory layout,
 and for that we can use a Limine request.
 */
 
-/*
-We will look for the biggest usable physical memory region
-and use this for the bitmap. The reserved memory will be ignored.
-*/
-
 struct limine_memmap_entry* biggest_entry;
 
+/*
+ * pmm_find_biggest_usable_region - Finding the biggest free memory region
+ * @memmap: Limine memory map
+ * @hhdm:   Limine HHDM offset
+ *
+ * This function uses the memory map provided by the bootloader
+ * to find the single biggest free memory region we can use.
+ */
 static void pmm_find_biggest_usable_region(struct limine_memmap_response* memmap, struct limine_hhdm_response* hhdm)
 {
     // Max length of a usable memory region
@@ -34,12 +41,10 @@ static void pmm_find_biggest_usable_region(struct limine_memmap_response* memmap
     uint64_t offset = hhdm->offset;
 
     DEBUG("Usable Memory:");
-    for (size_t i=0; i<memmap->entry_count; i++)
+    for (size_t i=0; i<memmap->entry_count; i++) {
-    {
         struct limine_memmap_entry* entry = memmap->entries[i];
 
-        if (entry->type == LIMINE_MEMMAP_USABLE)
+        if (entry->type == LIMINE_MEMMAP_USABLE) {
-        {
             DEBUG("0x%p-0x%p mapped at 0x%p-0x%p", entry->base, entry->base+entry->length,
                         entry->base+offset, entry->base+entry->length+offset);
             if (entry->length > length_max)
@@ -60,20 +65,40 @@ uint64_t hhdm_off;
 
 static uintptr_t g_freelist = 0;
 
+/*
+ * pmm_alloc - Allocate a physical page
+ *
+ * This function allocates a single physical page (frame)
+ * 
+ * Return:
+ * <addr> - Address for the allocated page
+ */
 uintptr_t pmm_alloc()
 {
-    if (!g_freelist) return 0;
+    if (!g_freelist) {
+		panic(NULL, "PMM is out of memory!");		
+	}
     uintptr_t addr = g_freelist;
     g_freelist = *(uintptr_t*) PHYS_TO_VIRT(g_freelist);
     return addr;
 }
 
+/*
+ * pmm_free - Frees a memory page
+ * @addr: Address to the page
+ */
 void pmm_free(uintptr_t addr)
 {
     *(uintptr_t*) PHYS_TO_VIRT(addr) = g_freelist;
     g_freelist = addr;
 }
 
+/*
+ * pmm_init_freelist - PMM freelist initialization
+ *
+ * This function marks the biggest memory region as
+ * free, so we can use it in pmm_alloc.
+ */
 static void pmm_init_freelist()
 {
     // We simply call pmm_free() on each page that is marked USABLE
@@ -82,22 +107,26 @@ static void pmm_init_freelist()
     uint64_t end = ALIGN_DOWN(biggest_entry->base + biggest_entry->length, PAGE_SIZE);
 
     uint64_t page_count=0;
-    for (uint64_t addr = base; addr < end; addr += PAGE_SIZE)
+    for (uint64_t addr = base; addr < end; addr += PAGE_SIZE) {
-    {
         pmm_free(addr);
-        //DEBUG("page %u lives at phys 0x%p (virt 0x%p)", page_count, addr, PHYS_TO_VIRT(addr));
         page_count++;
     }
     DEBUG("%u frames in freelist, available for use (%u bytes)", page_count, page_count*PAGE_SIZE);
 }
 
-void pmm_init(struct limine_memmap_response* memmap, struct limine_hhdm_response* hhdm)
+/*
+ * pmm_init - Physical memory manager initialization
+ * @boot_ctx: Boot context structure
+ *
+ * This function prepares the PMM for use.
+ * The PMM works with a freelist.
+ */
+void pmm_init(struct boot_context boot_ctx)
 {
-    hhdm_off = hhdm->offset;
+    hhdm_off = boot_ctx.hhdm->offset;
-    pmm_find_biggest_usable_region(memmap, hhdm);
+    pmm_find_biggest_usable_region(boot_ctx.mmap, boot_ctx.hhdm);
-    //pmm_allocate_bitmap(hhdm); too complicated for my small brain
+
-    
     // Now we have biggest USABLE region,
     // so to populate the free list we just iterate through it
     pmm_init_freelist();
-}
+}

src/mem/paging/pmm.h

@@ -1,10 +1,17 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Physical memory manager from freelist
+ * @license GPL-3.0-only
+ */
+
 #ifndef PAGING_PMM_H
 #define PAGING_PMM_H
 
 #include <limine.h>
+#include <kernel.h>
 
-void pmm_init(struct limine_memmap_response* memmap, struct limine_hhdm_response* hhdm);
+void pmm_init(struct boot_context boot_ctx);
 void pmm_free(uintptr_t addr);
-uintptr_t pmm_alloc();
+uintptr_t pmm_alloc(void);
 
 #endif

src/mem/paging/vmm.c

@@ -1,3 +1,9 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Virtual memory manager
+ * @license GPL-3.0-only
+ */
+
 /*
 The VMM (virtual memory manager) will have two roles:
 - mapping pages
@@ -18,6 +24,14 @@ void* vmm_pt_root = 0;
 // Linked list head for virtual memory objects
 struct vm_object* vm_objs = NULL;
 
+/*
+ * Will have to be rewritten and expanded,
+ * to prepare for userspace.
+ * The platform-agnostic flags will be removed
+ * because as long as the kernel is x86 only,
+ * we don't need over complication.
+ * Plus I don't plan to port to other architectures
+*/
 
 uint64_t convert_x86_vm_flags(size_t flags)
 {
@@ -62,5 +76,6 @@ void vmm_setup_pt_root()
 
 void vmm_init()
 {
-    vmm_setup_pt_root();
+    // NO U
+    //vmm_setup_pt_root();
 }

src/mem/paging/vmm.h

@@ -1,3 +1,9 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Virtual memory manager
+ * @license GPL-3.0-only
+ */
+
 #ifndef VMM_H
 #define VMM_H
 
@@ -10,8 +16,7 @@ Flags here aren't x86 flags, they are platform-agnostic
 kernel-defined flags.
 */
 
-struct vm_object
+struct vm_object {
-{
     uintptr_t base;
     size_t length;
     size_t flags;
@@ -24,6 +29,6 @@ struct vm_object
 #define VM_FLAG_EXEC (1 << 1)
 #define VM_FLAG_USER (1 << 2)
 
-void vmm_init();
+void vmm_init(void);
 
 #endif

src/sched/process.c

@@ -0,0 +1,199 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Process linked list implementation
+ * @license GPL-3.0-only
+ */
+
+#include <stddef.h>
+#include "process.h"
+#include "mem/heap/kheap.h"
+#include "kernel.h"
+#include "string/string.h"
+#include "mem/gdt/gdt.h"
+#include "config.h"
+#include "io/serial/serial.h"
+
+#include "io/term/flanterm.h"
+extern struct flanterm_context* ft_ctx;
+
+struct process_t* processes_list;
+struct process_t* current_process;
+
+extern uint64_t *kernel_pml4;
+
+size_t next_free_pid = 0;
+
+/*
+ * process_init - Initializes process list
+ */
+void process_init()
+{
+    processes_list = NULL;
+    current_process = NULL;
+}
+
+/*
+ * process_display_list - Debug function to display processes
+ * @processes_list: head of the process linked list
+ *
+ * This function prints the linked list of processes
+ * to the DEBUG output.
+ */
+void process_display_list(struct process_t* processes_list)
+{
+    int process_view_id = 0;
+    struct process_t* tmp = processes_list;
+    while (tmp != NULL) {
+        DEBUG("{%d: %p} -> ", process_view_id, tmp);
+        tmp = tmp->next;
+        process_view_id++;
+    }
+    DEBUG("NULL");
+}
+
+/*
+ * process_create - Create a process
+ * @name:     name of the process
+ * @function: beginning of process executable code
+ * @arg:      (optional) argument provided to process
+ *
+ * This function creates a process, gives it all
+ * necessary context and a stack, and adds the
+ * process to the linked list.
+ *
+ * Return:
+ * <proc> - pointer to created process
+ */
+struct process_t* process_create(char* name, void(*function)(void*), void* arg)
+{
+    CLEAR_INTERRUPTS;
+    struct process_t* proc = (struct process_t*)kmalloc(sizeof(struct process_t));
+    struct cpu_status_t* ctx = (struct cpu_status_t*)kmalloc(sizeof(struct cpu_status_t));
+
+    // No more memory?
+    if (!proc) return NULL;
+    if (!ctx) return NULL;
+
+    strncpy(proc->name, name, PROCESS_NAME_MAX);
+    proc->pid = next_free_pid++;
+    proc->status = READY;
+
+    uint64_t* stack_top = (uint64_t*)kalloc_stack();
+    // push return address to the stack so when "ret" hits we jmp to exit instead of idk what
+    // stack grows DOWNWARDS!!
+    *(--stack_top) = (uint64_t)process_exit;
+
+    proc->context = ctx;
+    proc->context->iret_ss = KERNEL_DATA_SEGMENT; // process will live in kernel mode
+    proc->context->iret_rsp = (uint64_t)stack_top;
+    proc->context->iret_flags = 0x202; //bit 2 and 9 set (Interrupt Flag)
+    proc->context->iret_cs = KERNEL_CODE_SEGMENT;
+    proc->context->iret_rip = (uint64_t)function; // beginning of executable code
+    proc->context->rdi = (uint64_t)arg; // 1st arg is in rdi (as per x64 calling convention)
+    proc->context->rbp = 0; 
+
+    // Kernel PML4 as it already maps code/stack (when switching to userland we'll have to change that)
+    proc->root_page_table = kernel_pml4;
+
+    proc->next = 0;
+
+    process_add(&processes_list, proc);
+
+    SET_INTERRUPTS;
+    return proc;
+}
+
+/*
+ * process_add - Add a process to the end of the linked list
+ * @processes_list: pointer to the head of the linked list
+ * @process:        process to add at the end of the linked list
+ */
+void process_add(struct process_t** processes_list, struct process_t* process)
+{
+    if (!process) return;
+    process->next = NULL;
+
+    if (*processes_list == NULL) {
+        // List is empty
+        *processes_list = process;
+        return;
+    }
+
+    struct process_t* tmp = *processes_list;
+    while (tmp->next != NULL) {
+        tmp = tmp->next;
+    }
+    // We're at last process before NULL
+    tmp->next = process;
+}
+
+/*
+ * process_delete - Delete a process from the linked list
+ * @processes_list: pointer to head of linked list
+ * @process:        the process to delete from the list
+ */
+void process_delete(struct process_t** processes_list, struct process_t* process)
+{
+    if (!processes_list || !*processes_list || !process) return;
+
+    if (*processes_list == process) {
+        // process to delete is at head
+        *processes_list = process->next;
+        process->next = NULL;
+        kfree(process);
+        return;
+    }
+
+    struct process_t* tmp = *processes_list;
+    while (tmp->next && tmp->next != process) {
+        tmp = tmp->next;
+    }
+
+    if (tmp->next == NULL) {
+        // Didn't find the process
+        return;
+    }
+
+    // We're at process before the one we want to delete
+    tmp->next = process->next;
+    process->next = NULL;
+    kfree(process);
+}
+
+/*
+ * process_get_next - Get the next process (unused)
+ * @process: pointer to process
+ *
+ * Return:
+ * <process->next> - process right after the one specified
+ */
+struct process_t* process_get_next(struct process_t* process)
+{
+    if (!process) return NULL;
+    return process->next;
+}
+
+/*
+ * process_exit - Exit from a process
+ *
+ * This function is pushed to all process stacks, as a last
+ * return address. Once the process is done executing, it 
+ * ends up here.
+ *
+ * Process is marked as DEAD, and then execution loops.
+ * Next time the scheduler sees the process, it will
+ * automatically delete it from the linked list.
+ */
+void process_exit()
+{
+    DEBUG("Exiting from process '%s'", current_process->name);
+    CLEAR_INTERRUPTS;
+    if (current_process) {
+        current_process->status = DEAD;
+    }
+    SET_INTERRUPTS;
+    
+    for (;;) {
+        asm("hlt");
+    }
+}

src/sched/process.h

@@ -0,0 +1,39 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Process definition
+ * @license GPL-3.0-only
+ */
+
+#ifndef PROCESS_H
+#define PROCESS_H
+
+#include <stddef.h>
+#include "config.h"
+#include <stdint.h>
+
+typedef enum {
+    READY,
+    RUNNING,
+    DEAD
+} status_t;
+
+struct process_t {
+    size_t pid;
+    char name[PROCESS_NAME_MAX];
+
+    status_t status;
+    struct cpu_status_t* context;
+	void* root_page_table; // Process PML4 (should contain kernel PML4 in higher half [256-511]
+    struct process_t* next;
+};
+
+void process_init(void);
+struct process_t* process_create(char* name, void(*function)(void*), void* arg);
+void process_add(struct process_t** processes_list, struct process_t* process);
+void process_delete(struct process_t** processes_list, struct process_t* process);
+struct process_t* process_get_next(struct process_t* process);
+void process_exit(void);
+
+void process_display_list(struct process_t* processes_list);
+
+#endif

src/sched/scheduler.c

@@ -0,0 +1,78 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Round-robin scheduler
+ * @license GPL-3.0-only
+ */
+
+#include "kernel.h"
+#include "process.h"
+#include "mem/paging/paging.h"
+#include <stdint.h>
+#include "io/serial/serial.h"
+
+extern struct process_t* processes_list;
+extern struct process_t* current_process;
+extern struct process_t* idle_proc;
+
+/*
+ * scheduler_init - Choose the first process
+ */
+void scheduler_init()
+{
+    current_process = processes_list;
+}
+
+/*
+ * scheduler_schedule - Main scheduling routine
+ * @context: CPU context of previous process
+ *
+ * Chooses the next process that we should run.
+ * The routine is executed every SCHEDULER_QUANTUM ticks.
+ *
+ * Return:
+ * <context> - CPU context for next process
+ */
+struct cpu_status_t* scheduler_schedule(struct cpu_status_t* context)
+{
+    if (context == NULL) {
+        panic(NULL, "Scheduler called with NULL context"); 
+    }
+
+    if (current_process == NULL) {
+        // If no more processes, then set IDLE as the current process, that's it.
+        current_process = idle_proc;
+    }
+
+    if (current_process == idle_proc && current_process->next == NULL)
+    {
+        return idle_proc->context;
+    }
+
+    current_process->context = context;
+    //current_process->status = READY;
+
+    for (;;) {
+        struct process_t* prev_process = current_process;
+        if (current_process->next != NULL) {
+            current_process = current_process->next;
+        } else {
+            current_process = processes_list;
+        }
+        
+        if (current_process != NULL && current_process->status == DEAD) {
+            process_delete(&prev_process, current_process);
+            current_process = NULL;
+            return idle_proc->context;
+        } else {
+            current_process->status = RUNNING;
+            break;
+        }
+    }
+
+    DEBUG("current_process={pid=%u, name='%s', root_page_table[virt]=%p}", current_process->pid, current_process->name, current_process->root_page_table);
+
+    load_cr3(VIRT_TO_PHYS((uint64_t)current_process->root_page_table));
+    DEBUG("Loaded process PML4 into CR3");
+
+    return current_process->context;
+}

src/sched/scheduler.h

@@ -0,0 +1,13 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Round-robin scheduler
+ * @license GPL-3.0-only
+ */
+
+#ifndef SCHEDULER_H
+#define SCHEDULER_H
+
+struct cpu_status_t* scheduler_schedule(struct cpu_status_t* context);
+void scheduler_init(void);
+
+#endif

src/sched/spinlock.c

@@ -0,0 +1,44 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Spinlock implementation
+ * @license GPL-3.0-only
+ */
+
+#include <stdatomic.h>
+#include <stdbool.h>
+#include "kernel.h"
+#include "spinlock.h"
+
+/*
+ * spinlock_acquire - Lock a lock
+ * @lock: pointer to desired spinlock
+ *
+ * Saves the RFLAGS register, then acquires a lock.
+ * Pause instruction is used to ease the CPU.
+ */
+void spinlock_acquire(struct spinlock_t* lock)
+{
+    uint64_t rflags;
+    asm volatile("pushfq ; pop %0 ; cli" : "=rm"(rflags) : : "memory");
+
+    while (__atomic_test_and_set(&lock->locked, __ATOMIC_ACQUIRE)) {
+        __builtin_ia32_pause();
+    }
+
+    lock->rflags = rflags;
+}
+
+/*
+ * spinlock_release - Unlock a lock
+ * @lock: pointer to desired spinlock
+ *
+ * Gets saved RFLAGS register from the lock and
+ * unlocks it (clears locked state).
+ * RFLAGS is then restored.
+ */
+void spinlock_release(struct spinlock_t* lock)
+{
+    uint64_t rflags = lock->rflags;
+    __atomic_clear(&lock->locked, __ATOMIC_RELEASE);
+    asm volatile("push %0 ; popfq" : : "rm"(rflags) : "memory");
+}

src/sched/spinlock.h

@@ -0,0 +1,22 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Spinlock implementation
+ * @license GPL-3.0-only
+ */
+
+#ifndef SPINLOCK_H
+#define SPINLOCK_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+struct spinlock_t
+{
+    bool locked;
+    uint64_t rflags;
+};
+
+void spinlock_acquire(struct spinlock_t* lock);
+void spinlock_release(struct spinlock_t* lock);
+
+#endif

src/string/string.c

@@ -1,6 +1,72 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   String manipulation utilities
+ * @license GPL-3.0-only
+ */
+
+#include <stddef.h>
+
+/*
+ * strcpy - copy a NULL-terminated string
+ * @dest: destination buffer where the string is copied
+ * @src:  source string to copy from
+ *
+ * Copies the string pointed to by @src (including the terminating
+ * NULL byte) into the buffer pointed to by @dest.
+ *
+ * Return: pointer to the destination string (@dest)
+ */
 char* strcpy(char *dest, const char *src)
 {
     char *temp = dest;
     while((*dest++ = *src++));
     return temp;
+}
+
+/*
+ * strcat - append a NUL-terminated string
+ * @dest: destination buffer containing the initial string
+ * @src:  source string to append
+ *
+ * Appends the string pointed to by @src to the end of the string
+ * pointed to by @dest. The terminating NUL byte in @dest is
+ * overwritten and a new terminating NUL byte is added.
+ *
+ * The destination buffer must be large enough to hold the result.
+ *
+ * Taken from: https://stackoverflow.com/questions/2488563/strcat-implementation
+ *
+ * Return: pointer to the destination string (@dest)
+ */
+char *strcat(char *dest, const char *src)
+{
+    size_t i,j;
+    for (i = 0; dest[i] != '\0'; i++);
+
+    for (j = 0; src[j] != '\0'; j++)
+        dest[i+j] = src[j];
+    
+    dest[i+j] = '\0';
+    return dest;
+}
+
+/*
+ * strncpy - copy a string with length limit
+ * @dst: destination buffer
+ * @src: source string
+ * @n:   maximum number of bytes to copy
+ *
+ * Copies up to @n bytes from @src to @dst. Copying stops early if a
+ * NULL byte is encountered in @src. If @src is shorter than @n, the
+ * remaining bytes in @dst are left unchanged in this implementation.
+ *
+ * Note: This differs slightly from the standard strncpy behavior,
+ * which pads the remaining bytes with NULL.
+ *
+ * Taken from: https://stackoverflow.com/questions/14159625/implementation-of-strncpy
+ */
+void strncpy(char* dst, const char* src, size_t n)
+{
+   size_t i = 0;
+   while(i++ != n && (*dst++ = *src++));
 }

src/string/string.h

@@ -1,6 +1,16 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   String manipulation functions
+ * @license GPL-3.0-only
+ */
+
 #ifndef STRING_H
 #define STRING_H
 
+#include <stddef.h>
+
 char *strcpy(char *dest, const char *src);
+char *strcat(char *dest, const char *src);
+void strncpy(char* dst, const char* src, size_t n);
 
 #endif

src/time/timer.c

@@ -1,6 +1,13 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   Programmable Interval Timer init and enabling
+ * @license GPL-3.0-only
+ */
+
 #include <stdint.h>
 #include "io/serial/serial.h"
 #include <kernel.h>
+#include "config.h"
 
 /*
 For now, the timer module will be using the PIC.
@@ -12,6 +19,15 @@ interested in multi-core functionnality like SMP)
 
 volatile uint64_t ticks = 0;
 
+extern struct init_status init;
+
+/*
+ * pic_remap - Remap the Programmable Interrupt Controller
+ *
+ * By default, interrupts are mapped at the wrong place.
+ * This function remaps interrupt numbers so interrupts
+ * don't conflict with each other. 
+ */
 void pic_remap()
 {
     uint8_t master_mask = inb(0x21);
@@ -39,6 +55,12 @@ void pic_remap()
     outb(0xA1, slave_mask);
 }
 
+/*
+ * pic_enable - Enable the Programmable Interrupt Controller
+ *
+ * This function enables IRQ0 and IRQ1, which correspond to
+ * the timer and keyboard interrupts, respectively.
+ */
 void pic_enable()
 {
     // Enabling IRQ0 (unmasking it) but not the others
@@ -49,12 +71,15 @@ void pic_enable()
 }
 
 /*
-Base frequency = 1.193182 MHz
+ * pit_init - Initialization of the Programmable Interval Timer
-1 tick per ms (divide by 1000) = roughly 1193 Hz
+ *
-*/
+ * The PIT is the simplest timer we can get working on x86.
+ * It has a base frequency of 1.193182 MHz.
+ * A custom frequency can be set using TIMER_FREQUENCY macro.
+ */
 void pit_init()
 {
-    uint32_t frequency = 1000; // 1 kHz
+    uint32_t frequency = TIMER_FREQUENCY;
     uint32_t divisor = 1193182 / frequency;
 
     // Set PIT to mode 3, channel 0
@@ -65,17 +90,25 @@ void pit_init()
     outb(0x40, (divisor >> 8) & 0xFF);
 }
 
-// Wait n ticks
+/*
-// Given that there's a tick every 1ms, wait n milliseconds
+ * timer_wait - Wait for X ticks
+ *
+ * By default, the timer frequency is 1000Hz, meaning
+ * ticks are equal to milliseconds.
+ */
 void timer_wait(uint64_t wait_ticks)
 {
     uint64_t then = ticks + wait_ticks;
-    while (ticks < then)
+    while (ticks < then) {
-    {
         asm("hlt");
     };
 }
 
+/*
+ * timer_init - Initialization of the timer
+ *
+ * This function wakes the PIT.
+ */
 void timer_init()
 {
     // Remapping the PIC, because at startup it conflicts with
@@ -85,4 +118,5 @@ void timer_init()
     pic_enable();
     pit_init();
     DEBUG("PIT initialized");
+    init.timer = true;
 }

src/time/timer.h

@@ -1,7 +1,13 @@
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   PIT functions
+ * @license GPL-3.0-only
+ */
+
 #ifndef TIMER_H
 #define TIMER_H
 
-void timer_init();
+void timer_init(void);
 void timer_wait(unsigned int wait_ticks);
 
 #endif

symbols.py

@@ -0,0 +1,33 @@
+# Make assembly file from ELF symbols map
+# Then link it to kernel so it's aware of symbol names
+# then we can use that for the stack trace.
+
+print("Extracting symbols from map file to assembly...")
+
+with open("symbols.map", "r") as f:
+    lines = f.readlines()
+
+    symbols = []
+    for line in lines:
+        parts = line.split()
+        # output is formed like "address name"
+        symbols.append((parts[0], parts[1]))
+
+with open("symbols.S", "w") as f:
+    f.write("section .rodata\n")
+    f.write("global symbol_table\n")
+    f.write("global symbol_count\n")
+    f.write("symbol_table:\n")
+
+    for i, (addr, name) in enumerate(symbols):
+        f.write(f"    dq 0x{addr}\n")
+        f.write(f"    dq sym_name_{i}\n")
+
+    f.write("\nsymbol_count: dq " + str(len(symbols)) + "\n\n")
+
+    for i, (addr, name) in enumerate(symbols):
+        # escaping quotes
+        safe_name = name.replace('"', '\\"')
+        f.write(f'sym_name_{i}: db "{safe_name}", 0\n')
+
+print("Done!")