First commit: add folder structure, make process, kernel main function, base for framebuffer driver

README.md

@@ -0,0 +1,3 @@
+# blankos32
+
+WIP (framebuffer driver)

bochslog.txt

@@ -0,0 +1,275 @@
+00000000000i[      ] Bochs x86 Emulator 2.7
+00000000000i[      ]   Built from SVN snapshot on August  1, 2021
+00000000000i[      ]   Timestamp: Sun Aug  1 10:07:00 CEST 2021
+00000000000i[      ] System configuration
+00000000000i[      ]   processors: 1 (cores=1, HT threads=1)
+00000000000i[      ]   A20 line support: yes
+00000000000i[      ] IPS is set to 1000000
+00000000000i[      ] CPU configuration
+00000000000i[      ]   SMP support: yes, quantum=16
+00000000000i[      ]   level: 6
+00000000000i[      ]   APIC support: xapic
+00000000000i[      ]   FPU support: yes
+00000000000i[      ]   MMX support: yes
+00000000000i[      ]   3dnow! support: yes
+00000000000i[      ]   SEP support: yes
+00000000000i[      ]   SIMD support: sse2
+00000000000i[      ]   XSAVE support: no 
+00000000000i[      ]   AES support: no
+00000000000i[      ]   SHA support: no
+00000000000i[      ]   MOVBE support: no
+00000000000i[      ]   ADX support: no
+00000000000i[      ]   x86-64 support: yes
+00000000000i[      ]   1G paging support: no
+00000000000i[      ]   MWAIT support: yes
+00000000000i[      ]   VMX support: 1
+00000000000i[      ]   SVM support: no
+00000000000i[      ] Optimization configuration
+00000000000i[      ]   RepeatSpeedups support: yes
+00000000000i[      ]   Fast function calls: yes
+00000000000i[      ]   Handlers Chaining speedups: no
+00000000000i[      ] Devices configuration
+00000000000i[      ]   PCI support: i440FX i430FX i440BX
+00000000000i[      ]   Network devices support: NE2000 E1000
+00000000000i[      ]   Sound support: SB16 ES1370
+00000000000i[      ]   USB support: UHCI OHCI EHCI xHCI
+00000000000i[      ]   VGA extension support: vbe cirrus voodoo
+00000000000i[IMG   ] Disk image modules
+00000000000i[IMG   ]   flat concat sparse dll growing undoable volatile vpc
+00000000000i[IMG   ]   vmware3 vmware4 vbox vvfat
+00000000000i[NETCTL] Networking modules
+00000000000i[NETCTL]   null vde vnet linux socket tuntap slirp
+00000000000i[SNDCTL] Sound drivers
+00000000000i[SNDCTL]   dummy oss file alsa sdl
+00000000000i[USBCTL] Pluggable USB devices
+00000000000i[USBCTL]   mouse tablet keypad keyboard floppy disk cdrom printer
+00000000000i[USBCTL]   hub
+00000000000i[MEM0  ] allocated memory at 0x7f1f95ddd010. after alignment, vector=0x7f1f95dde000
+00000000000i[MEM0  ] 32.00MB
+00000000000i[MEM0  ] mem block size = 0x00020000, blocks=256
+00000000000i[MEM0  ] rom at 0xffff0000/65536 ('/usr/share/bochs/BIOS-bochs-legacy')
+00000000000i[CPU0  ] WARNING: 3DNow! is not implemented yet !
+00000000000i[DEV   ] will paste characters every 100 iodev timer ticks
+00000000000i[      ] lt_dlhandle is 0x55a4d7248350
+00000000000i[PLUGIN] loaded plugin libbx_soundalsa.so
+00000000000i[WAVOUT] ALSA: opened default PCM output device
+00000000000i[WAVOUT] changed sample rate to 44101
+00000000000i[      ] lt_dlhandle is 0x55a4d79fe0f0
+00000000000i[PLUGIN] loaded plugin libbx_pci.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7248430
+00000000000i[PLUGIN] loaded plugin libbx_pci2isa.so
+00000000000i[      ] lt_dlhandle is 0x55a4d71c65f0
+00000000000i[PLUGIN] loaded plugin libbx_usb_uhci.so
+00000000000i[      ] lt_dlhandle is 0x55a4d72628f0
+00000000000i[PLUGIN] loaded plugin libbx_acpi.so
+00000000000i[      ] lt_dlhandle is 0x55a4d71c59f0
+00000000000i[PLUGIN] loaded plugin libbx_hpet.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7a088a0
+00000000000i[PLUGIN] loaded plugin libbx_cmos.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7a090b0
+00000000000i[PLUGIN] loaded plugin libbx_dma.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7a09a20
+00000000000i[PLUGIN] loaded plugin libbx_pic.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7a0a1e0
+00000000000i[PLUGIN] loaded plugin libbx_pit.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7a0ac00
+00000000000i[PLUGIN] loaded plugin libbx_vga.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7a2c240
+00000000000i[PLUGIN] loaded plugin libbx_floppy.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7a2ca80
+00000000000i[PLUGIN] loaded plugin libbx_ioapic.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7a2d290
+00000000000i[PLUGIN] loaded plugin libbx_keyboard.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7a2db90
+00000000000i[PLUGIN] loaded plugin libbx_harddrv.so
+00000000000i[      ] lt_dlhandle is 0x55a4d7a2fc60
+00000000000i[PLUGIN] loaded plugin libbx_pci_ide.so
+00000000000i[PLUGIN] init_dev of 'pci' plugin device by virtual method
+00000000000i[DEV   ] i440FX PMC present at device 0, function 0
+00000000000i[PLUGIN] init_dev of 'pci2isa' plugin device by virtual method
+00000000000i[DEV   ] PIIX3 PCI-to-ISA bridge present at device 1, function 0
+00000000000i[PLUGIN] init_dev of 'cmos' plugin device by virtual method
+00000000000i[CMOS  ] Using local time for initial clock
+00000000000i[CMOS  ] Setting initial clock to: Sat May 18 22:03:59 2024 (time0=1716062639)
+00000000000i[PLUGIN] init_dev of 'dma' plugin device by virtual method
+00000000000i[DMA   ] channel 4 used by cascade
+00000000000i[PLUGIN] init_dev of 'pic' plugin device by virtual method
+00000000000i[PLUGIN] init_dev of 'pit' plugin device by virtual method
+00000000000i[PIT   ] PIT using realtime synchronisation method
+00000000000i[PLUGIN] init_dev of 'vga' plugin device by virtual method
+00000000000i[MEM0  ] Register memory access handlers: 0x0000000a0000 - 0x0000000bffff
+00000000000i[VGA   ] interval=200000, mode=realtime
+00000000000i[VGA   ] VSYNC using realtime mode
+00000000000i[MEM0  ] Register memory access handlers: 0x0000e0000000 - 0x0000e0ffffff
+00000000000i[BXVGA ] VBE Bochs Display Extension Enabled
+00000000000i[MEM0  ] rom at 0xc0000/38400 ('/usr/share/bochs/VGABIOS-lgpl-latest')
+00000000000i[PLUGIN] init_dev of 'floppy' plugin device by virtual method
+00000000000i[DMA   ] channel 2 used by Floppy Drive
+00000000000i[FLOPPY] Using boot sequence cdrom, none, none
+00000000000i[FLOPPY] Floppy boot signature check is enabled
+00000000000i[PLUGIN] init_dev of 'acpi' plugin device by virtual method
+00000000000i[DEV   ] ACPI Controller present at device 1, function 3
+00000000000i[PLUGIN] init_dev of 'hpet' plugin device by virtual method
+00000000000i[HPET  ] initializing HPET
+00000000000i[MEM0  ] Register memory access handlers: 0x0000fed00000 - 0x0000fed003ff
+00000000000i[PLUGIN] init_dev of 'ioapic' plugin device by virtual method
+00000000000i[IOAPIC] initializing I/O APIC
+00000000000i[MEM0  ] Register memory access handlers: 0x0000fec00000 - 0x0000fec00fff
+00000000000i[IOAPIC] IOAPIC enabled (base address = 0xfec00000)
+00000000000i[PLUGIN] init_dev of 'keyboard' plugin device by virtual method
+00000000000i[PLUGIN] init_dev of 'harddrv' plugin device by virtual method
+00000000000i[HD    ] CD on ata0-0: 'os.iso'
+00000000000i[CD1   ] load cdrom with path='os.iso'
+00000000000i[CD1   ] Opening image file as a cd.
+00000000000i[HD    ] Media present in CD-ROM drive
+00000000000i[HD    ] Capacity is 237 sectors (0.46 MB)
+00000000000i[PLUGIN] init_dev of 'pci_ide' plugin device by virtual method
+00000000000i[DEV   ] PIIX3 PCI IDE controller present at device 1, function 1
+00000000000i[PLUGIN] init_dev of 'unmapped' plugin device by virtual method
+00000000000i[PLUGIN] init_dev of 'speaker' plugin device by virtual method
+00000000000i[PCSPK ] Using lowlevel sound support for output
+00000000000i[PLUGIN] init_dev of 'iodebug' plugin device by virtual method
+00000000000i[PLUGIN] init_dev of 'parallel' plugin device by virtual method
+00000000000i[PAR   ] parallel port 1 at 0x0378 irq 7
+00000000000i[PLUGIN] init_dev of 'biosdev' plugin device by virtual method
+00000000000i[PLUGIN] init_dev of 'serial' plugin device by virtual method
+00000000000i[SER   ] com1 at 0x03f8 irq 4 (mode: null)
+00000000000i[PLUGIN] init_dev of 'extfpuirq' plugin device by virtual method
+00000000000i[PLUGIN] init_dev of 'gameport' plugin device by virtual method
+00000000000i[PLUGIN] init_dev of 'usb_uhci' plugin device by virtual method
+00000000000i[DEV   ] USB UHCI present at device 1, function 2
+00000000000i[UHCI  ] USB UHCI initialized
+00000000000i[PLUGIN] register state of 'pci' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'pci2isa' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'cmos' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'dma' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'pic' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'pit' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'vga' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'floppy' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'unmapped' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'speaker' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'iodebug' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'parallel' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'biosdev' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'serial' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'extfpuirq' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'gameport' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'usb_uhci' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'acpi' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'hpet' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'ioapic' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'keyboard' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'harddrv' plugin device by virtual method
+00000000000i[PLUGIN] register state of 'pci_ide' plugin device by virtual method
+00000000000i[SYS   ] bx_pc_system_c::Reset(HARDWARE) called
+00000000000i[CPU0  ] cpu hardware reset
+00000000000i[APIC0 ] allocate APIC id=0 (MMIO enabled) to 0x0000fee00000
+00000000000i[CPU0  ] CPU[0] is the bootstrap processor
+00000000000i[CPU0  ] CPUID[0x00000000]: 00000005 68747541 444d4163 69746e65
+00000000000i[CPU0  ] CPUID[0x00000001]: 00000633 00010800 00002028 17cbfbff
+00000000000i[CPU0  ] CPUID[0x00000002]: 00000000 00000000 00000000 00000000
+00000000000i[CPU0  ] CPUID[0x00000003]: 00000000 00000000 00000000 00000000
+00000000000i[CPU0  ] CPUID[0x00000004]: 00000000 00000000 00000000 00000000
+00000000000i[CPU0  ] CPUID[0x00000005]: 00000040 00000040 00000003 00000020
+00000000000i[CPU0  ] CPUID[0x80000000]: 80000008 68747541 444d4163 69746e65
+00000000000i[CPU0  ] CPUID[0x80000001]: 00000633 00000000 00000101 ebd3f3ff
+00000000000i[CPU0  ] CPUID[0x80000002]: 20444d41 6c687441 74286e6f 7020296d
+00000000000i[CPU0  ] CPUID[0x80000003]: 65636f72 726f7373 00000000 00000000
+00000000000i[CPU0  ] CPUID[0x80000004]: 00000000 00000000 00000000 00000000
+00000000000i[CPU0  ] CPUID[0x80000005]: 01ff01ff 01ff01ff 40020140 40020140
+00000000000i[CPU0  ] CPUID[0x80000006]: 00000000 42004200 02008140 00000000
+00000000000i[CPU0  ] CPUID[0x80000007]: 00000000 00000000 00000000 00000000
+00000000000i[CPU0  ] CPUID[0x80000008]: 00003028 00000000 00000000 00000000
+00000000000i[CPU0  ] CPU Features supported:
+00000000000i[CPU0  ] 		x87
+00000000000i[CPU0  ] 		486ni
+00000000000i[CPU0  ] 		pentium_ni
+00000000000i[CPU0  ] 		p6ni
+00000000000i[CPU0  ] 		mmx
+00000000000i[CPU0  ] 		3dnow!
+00000000000i[CPU0  ] 		debugext
+00000000000i[CPU0  ] 		vme
+00000000000i[CPU0  ] 		pse
+00000000000i[CPU0  ] 		pae
+00000000000i[CPU0  ] 		pge
+00000000000i[CPU0  ] 		pse36
+00000000000i[CPU0  ] 		mtrr
+00000000000i[CPU0  ] 		pat
+00000000000i[CPU0  ] 		sysenter_sysexit
+00000000000i[CPU0  ] 		clflush
+00000000000i[CPU0  ] 		sse
+00000000000i[CPU0  ] 		sse2
+00000000000i[CPU0  ] 		mwait
+00000000000i[CPU0  ] 		vmx
+00000000000i[CPU0  ] 		longmode
+00000000000i[CPU0  ] 		lm_lahf_sahf
+00000000000i[CPU0  ] 		nx
+00000000000i[CPU0  ] 		cmpxhg16b
+00000000000i[CPU0  ] 		rdtscp
+00000000000i[CPU0  ] 		ffxsr
+00000000000i[CPU0  ] 		xapic
+00000000000i[PLUGIN] reset of 'pci' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'pci2isa' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'cmos' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'dma' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'pic' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'pit' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'vga' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'floppy' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'acpi' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'hpet' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'ioapic' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'keyboard' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'harddrv' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'pci_ide' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'unmapped' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'speaker' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'iodebug' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'parallel' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'biosdev' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'serial' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'extfpuirq' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'gameport' plugin device by virtual method
+00000000000i[PLUGIN] reset of 'usb_uhci' plugin device by virtual method
+00000000000i[      ] set SIGINT handler to bx_debug_ctrlc_handler
+00000004662i[BIOS  ] $Revision: 14314 $ $Date: 2021-07-14 18:10:19 +0200 (Mi, 14. Jul 2021) $
+00000317288i[KBD   ] reset-disable command received
+00000318445i[PIDE  ] BAR #4: i/o base address = 0xc000
+00000318672i[UHCI  ] BAR #4: i/o base address = 0xc100
+00000324507i[P2ISA ] PCI IRQ routing: PIRQD# set to 0x0b
+00000324523i[P2ISA ] write: ELCR2 = 0x08
+00000324543i[UHCI  ] new IRQ line = 11
+00000324608i[P2ISA ] PCI IRQ routing: PIRQA# set to 0x0a
+00000324624i[P2ISA ] write: ELCR2 = 0x0c
+00000324644i[ACPI  ] new IRQ line = 10
+00000442944i[VBIOS ] VGABios $Id: vgabios.c 288 2021-05-28 19:05:28Z vruppert $
+00000443015i[BXVGA ] VBE known Display Interface b0c0
+00000443047i[BXVGA ] VBE known Display Interface b0c5
+00000445690i[VBIOS ] VBE Bios $Id: vbe.c 292 2021-06-03 12:24:22Z vruppert $
+00004097860i[BIOS  ] IDE time out
+00808587967i[BIOS  ] Booting from 07c0:0000
+00808683351i[BIOS  ] int13_harddisk: function 41, unmapped device for ELDL=80
+00808687022i[BIOS  ] int13_harddisk: function 08, unmapped device for ELDL=80
+00808690693i[BIOS  ] *** int 15h function AX=00c0, BX=0000 not yet supported!
+01119585462i[      ] Ctrl-C detected in signal handler.
+01119585463i[      ] dbg: Quit
+01119585463i[CPU0  ] CPU is in protected mode (active)
+01119585463i[CPU0  ] CS.mode = 32 bit
+01119585463i[CPU0  ] SS.mode = 32 bit
+01119585463i[CPU0  ] EFER   = 0x00000000
+01119585463i[CPU0  ] | EAX=0000002a  EBX=0002cd80  ECX=00000008  EDX=00000028
+01119585463i[CPU0  ] | ESP=00067ecc  EBP=00067ee0  ESI=0002ced8  EDI=0002ced9
+01119585463i[CPU0  ] | IOPL=0 id vip vif ac vm rf nt of df if tf sf zf af pf cf
+01119585463i[CPU0  ] | SEG sltr(index|ti|rpl)     base    limit G D
+01119585463i[CPU0  ] |  CS:0008( 0001| 0|  0) 00000000 ffffffff 1 1
+01119585463i[CPU0  ] |  DS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
+01119585463i[CPU0  ] |  SS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
+01119585463i[CPU0  ] |  ES:0010( 0002| 0|  0) 00000000 ffffffff 1 1
+01119585463i[CPU0  ] |  FS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
+01119585463i[CPU0  ] |  GS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
+01119585463i[CPU0  ] | EIP=00100147 (00100147)
+01119585463i[CPU0  ] | CR0=0x60000011 CR2=0x00000000
+01119585463i[CPU0  ] | CR3=0x00000000 CR4=0x00000000
+01119585463i[CMOS  ] Last time is 1716063758 (Sat May 18 22:22:38 2024)
+01119585463i[SIM   ] quit_sim called with exit code 0

bochsrc.txt

@@ -0,0 +1,9 @@
+megs:            32
+display_library: sdl2 
+romimage:        file=/usr/share/bochs/BIOS-bochs-legacy
+vgaromimage:     file=/usr/share/bochs/VGABIOS-lgpl-latest
+ata0-master:     type=cdrom, path=os.iso, status=inserted
+boot:            cdrom
+log:             bochslog.txt
+clock:           sync=realtime, time0=local
+cpu:             count=1, ips=1000000

io.h

@@ -0,0 +1,6 @@
+#ifndef INCLUDE_IO_H
+#define INCLUDE_IO_H
+
+void outb(unsigned short port, unsigned char data);
+
+#endif

io.s

@@ -0,0 +1,7 @@
+global outb
+
+outb:
+  mov al, [esp + 8]
+  mov dx, [esp + 4]
+  out dx, al
+  ret

iso/boot/grub/menu.lst

@@ -0,0 +1,5 @@
+default=0
+timeout=0
+
+title os
+kernel /boot/kernel.elf

kmain.c

@@ -0,0 +1,7 @@
+#include "stdio.h"
+
+int kmain(int retvalue)
+{
+  putchar(0, 'A', FB_GREEN, FB_DARK_GREY);
+  return retvalue;
+}

link.ld

@@ -0,0 +1,30 @@
+ENTRY(loader)
+
+SECTIONS {
+  /* Address to load at; 1MB */
+
+  . = 0x00100000;
+
+  /* Align relevant sections at 4KB  */
+
+  .text ALIGN (0x1000) :
+  {
+    *(.text)
+  }
+
+  .rodata ALIGN (0x1000) :
+  {
+    *(.rodata*)
+  }
+
+  .data ALIGN (0x1000) :
+  {
+    *(.data)
+  }
+
+  .bss ALIGN (0x1000) :
+  {
+    *(COMMON)
+    *(.bss)
+  }
+}

loader.s

@@ -0,0 +1,28 @@
+global loader
+
+MAGIC_NUMBER      equ 0x1BADB002   ; multiboot magic 
+FLAGS             equ 0x0 
+CHECKSUM          equ -MAGIC_NUMBER
+KERNEL_STACK_SIZE equ 4096
+
+section .text:
+align 4
+  dd MAGIC_NUMBER
+  dd FLAGS
+  dd CHECKSUM
+
+extern kmain
+
+loader:
+  ; mov eax, 0xCAFEBABE
+  push dword 42
+  call kmain
+
+.loop:
+  jmp .loop
+
+section .bss
+align 4 
+kernel_stack:
+  resb KERNEL_STACK_SIZE
+  mov esp, kernel_stack + KERNEL_STACK_SIZE

makefile

@@ -0,0 +1,35 @@
+OBJECTS = loader.o kmain.o stdio.o io.o 
+CC = gcc
+CFLAGS = -m32 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -Wall -Wextra -c
+LDFLAGS = -T link.ld -melf_i386
+AS = nasm
+ASFLAGS = -f elf
+
+all: kernel.elf
+
+kernel.elf: $(OBJECTS)
+	ld $(LDFLAGS) $(OBJECTS) -o kernel.elf
+
+os.iso: kernel.elf
+	cp kernel.elf iso/boot/kernel.elf
+	genisoimage -R                              \
+							-b boot/grub/stage2_eltorito    \
+							-no-emul-boot                   \
+							-boot-load-size 4               \
+							-A os                           \
+							-input-charset utf8             \
+							-quiet                          \
+							-boot-info-table                \
+							-o os.iso                       \
+							iso
+
+run: os.iso
+	bochs -f bochsrc.txt -q 
+
+%.o: %.c 
+	$(CC) $(CFLAGS) $< -o $@
+%.o: %.s 
+	$(AS) $(ASFLAGS) $< -o $@
+
+clean:
+	rm -rf *.o kernel.elf os.iso

stdio.c

@@ -0,0 +1,23 @@
+#include "io.h"
+#include "stdio.h"
+
+char* fb = (char *) 0x000B8000;
+
+void move_cursor(unsigned short pos)
+{
+  outb(FB_CMD_PORT, FB_HIGH_BYTE_CMD);
+  outb(FB_DATA_PORT, ((pos >> 8) & 0x00FF));
+  outb(FB_CMD_PORT, FB_LOW_BYTE_CMD);
+  outb(FB_DATA_PORT, pos & 0x00FF);
+}
+
+void putchar(unsigned int i, char c, unsigned char fg, unsigned char bg)
+{
+  fb[i] = c;
+  fb [i+1] = ((fg & 0x0F) << 4 | (bg & 0x0F));
+}
+
+int write(char *buf, unsigned int len)
+{
+  return 42;
+}

stdio.h

@@ -0,0 +1,16 @@
+#ifndef INCLUDE_STDIO_H
+#define INCLUDE_STDIO_H
+
+#define FB_GREEN      2
+#define FB_DARK_GREY  8
+
+#define FB_CMD_PORT       0x3D4
+#define FB_DATA_PORT      0x3D5
+#define FB_HIGH_BYTE_CMD  14
+#define FB_LOW_BYTE_CMD   15
+
+void move_cursor(unsigned short pos);
+void putchar(unsigned int i, char c, unsigned char fg, unsigned char bg);
+int write(char *buf, unsigned int len);
+
+#endif