Makefile

@@ -1,5 +1,5 @@
-USER_PROGRAMS := pedicel.raw apex.raw
+USER_PROGRAMS := pedicel.raw apex.raw doom.raw
-USER_FILES := wow.txt
+USER_FILES := wow.txt doom1.wad
 
 BUILDDIR := build
 ELFFILE := pepperk

user/Makefile

@@ -1,18 +1,28 @@
 CC := x86_64-elf-gcc
 CC_FLAGS := -ffreestanding -nostdlib -fno-pic -mno-red-zone -Ilibc
+DOOM_CC_FLAGS := $(CC_FLAGS) -std=gnu11
 
 LD := x86_64-elf-ld
 
 BUILDDIR := ../build
 LIBDIR := libc
 
-all: pedicel apex
+all: pedicel apex doom
 
+.PHONY: pedicel
 pedicel:
 	nasm -f bin pedicel.S -o $(BUILDDIR)/pedicel.raw
 
+.PHONY: apex
 apex:
 	$(CC) $(CC_FLAGS) -c apex.c -o $(BUILDDIR)/apex.o
 	nasm -f elf64 $(LIBDIR)/crt0.S -o $(BUILDDIR)/crt0.o
 	$(LD) -T $(LIBDIR)/linker.ld $(BUILDDIR)/crt0.o $(BUILDDIR)/apex.o -o $(BUILDDIR)/apex.elf
 	objcopy -O binary $(BUILDDIR)/apex.elf $(BUILDDIR)/apex.raw
+
+.PHONY: doom
+doom:
+	$(CC) $(DOOM_CC_FLAGS) -c doom.c -o $(BUILDDIR)/doom.o
+	nasm -f elf64 $(LIBDIR)/crt0.S -o $(BUILDDIR)/crt0.o
+	$(LD) -T $(LIBDIR)/linker.ld $(BUILDDIR)/crt0.o $(BUILDDIR)/doom.o -o $(BUILDDIR)/doom.elf
+	objcopy -O binary $(BUILDDIR)/doom.elf $(BUILDDIR)/doom.raw

user/doom.c

@@ -0,0 +1,147 @@
+#define DOOM_IMPLEMENTATION 
+#include "PureDOOM.h"
+#include <syscall.h>
+#include <stdint.h>
+
+//We use a separate heap because malloc is not yet available in userspace.
+#define DOOM_HEAP_START ((unsigned char*)0x00500000)
+#define DOOM_HEAP_SIZE  (24 * 1024 * 1024) //24mb
+
+static unsigned char* doom_heap_curr = DOOM_HEAP_START;
+static unsigned char* doom_heap_end = DOOM_HEAP_START + DOOM_HEAP_SIZE;
+
+// The following functions are wrappers for system calls made for
+// compatibility with puredoom's function signatures
+static int doom_cstr_len(const char* str)
+{
+    int len = 0;
+    while (str && str[len]) len++;
+    return len;
+}
+
+static void doom_print_cb(const char* str)
+{
+    int len = doom_cstr_len(str);
+    if (len > 0) {
+        write(1, str, len);
+    }
+}
+
+static void* doom_open_cb(const char* filename, const char* mode)
+{
+    (void)mode; // open doesn't support flags/mode (yet)
+    int fd = open(filename, 0);
+    if (fd < 0) return 0;
+    return (void*)(intptr_t)(fd);
+}
+
+static void doom_close_cb(void* handle)
+{
+    int fd = (int)(intptr_t)handle;
+    if (fd >= 0) {
+        close(fd);
+    }
+}
+
+static int doom_read_cb(void* handle, void* buf, int count)
+{
+    int fd = (int)(intptr_t)handle;
+    if (fd < 0) return -1;
+    return read(fd, (char*)buf, count);
+}
+
+static int doom_write_cb(void* handle, const void* buf, int count)
+{
+    int fd = (int)(intptr_t)handle;
+    if (fd < 0) return -1;
+    return (int)write(fd, (const char*)buf, count);
+}
+
+static int doom_seek_cb(void* handle, int offset, doom_seek_t origin)
+{
+    int fd = (int)(intptr_t)handle;
+    if (fd < 0) return -1;
+    return seek(fd, offset, (int)origin);
+}
+
+static int doom_tell_cb(void* handle)
+{
+    int fd = (int)(intptr_t)handle;
+    if (fd < 0) return -1;
+    return tell(fd);
+}
+
+static int doom_eof_cb(void* handle)
+{
+    int fd = (int)(intptr_t)handle;
+    if (fd < 0) return 1;
+    return eof(fd);
+}
+
+// Bump allocator (bump ptr until we're out of heap memory)
+static void* doom_malloc_cb(int size)
+{
+    if (size <= 0) return 0;
+
+    uintptr_t curr = (uintptr_t)doom_heap_curr;
+
+    // 16-byte align allocated blocks
+    curr = (curr + 15ULL) & ~15ULL;
+
+    if (curr + (uintptr_t)size > (uintptr_t)doom_heap_end) {
+        return 0;
+    }
+
+    doom_heap_curr = (unsigned char*)(curr + (uintptr_t)size);
+    return (void*)curr;
+}
+
+// No free
+static void doom_free_cb(void* ptr)
+{
+    (void)ptr;
+}
+
+static void doom_exit_cb(int code)
+{
+    exit(code);
+}
+
+// To get path for the WAD file
+static char* doom_getenv_cb(const char* var)
+{
+    static char home[] = "/";
+    static char waddir[] = "/";
+
+    if (!var) return 0;
+    if (doom_strcmp(var, "HOME") == 0) return home;
+    if (doom_strcmp(var, "DOOMWADDIR") == 0) return waddir;
+    return 0;
+}
+
+int main()
+{
+    char* argv[2] = {"doom", 0};
+
+    // Override default implementations
+    doom_set_print(doom_print_cb);
+    doom_set_malloc(doom_malloc_cb, doom_free_cb);
+    doom_set_file_io(doom_open_cb,
+                     doom_close_cb,
+                     doom_read_cb,
+                     doom_write_cb,
+                     doom_seek_cb,
+                     doom_tell_cb,
+                     doom_eof_cb);
+    doom_set_exit(doom_exit_cb);
+    doom_set_getenv(doom_getenv_cb);
+
+    doom_init(1, argv, 0);
+
+    while (true)
+    {
+        doom_force_update();
+        const uint8_t* framebuffer = doom_get_framebuffer(4);
+        draw(framebuffer, 320, 200, 4);
+    }
+}