Merge pull request 'Doom port' (#21) from doomed into main

Reviewed-on: https://git.furtest.fr/pepper-org/pepperOS/pulls/21

Makefile

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

docs/SYSCALLS.md

@@ -2,16 +2,14 @@
 
 The following table contains all of the system calls supported by PepperOS, as well as their arguments. The explanation for what every system call does is available as a comment above each function in corresponding files in the `src/syscall` folder.
 
-Name | Number (%rax) | arg0 (%rdi) | arg1 (%rsi) | arg2 (%rdx) |
-|---|---|---|---|---|
-| sys_read | 0 | unsigned int fd | char* buf | size_t count |
-| sys_write | 1 | unsigned int fd | const char* buf | size_t count |
-| sys_open | 2 | const char* filename | int flags | |
-| sys_close | 3 | unsigned int fd | | |
-
-| sys_lseek | 8 | unsigned int fd | int offset | int whence |
-| sys_tell | 9 | unsigned int fd |
-| sys_eof | 10 | unsigned int fd |
+Name | Number (%rax) | arg0 (%rdi) | arg1 (%rsi) | arg2 (%rdx) | arg3 (%r10) |
+|---|---|---|---|---|---|
+| sys_read | 0 | unsigned int fd | char* buf | size_t count | |
+| sys_write | 1 | unsigned int fd | const char* buf | size_t count | |
+| sys_open | 2 | const char* filename | int flags | | |
+| sys_close | 3 | unsigned int fd | | | |
+| sys_lseek | 8 | unsigned int fd | int offset | int whence | |
+| sys_tell | 9 | unsigned int fd | | | |
+| sys_eof | 10 | unsigned int fd | | | |
 | sys_draw | 11 | const uint8_t* src | int width | int height | int channels |
-
-| sys_exit | 60 | int error_code | | |
+| sys_exit | 60 | int error_code | | | |

src/syscall/syscall.c

@@ -18,15 +18,15 @@
 
 extern struct process* current_process;
 
+int sys_read(unsigned int fd, char* buf, size_t count);
+int sys_write(unsigned int fd, const char* buf, size_t count);
 int sys_open(const char* filename, int flags);
 int sys_close(unsigned int fd);
 int sys_lseek(unsigned int fd, int offset, int whence);
 int sys_tell(unsigned int fd); // needed by doom, therefore TOP PRIORITY
 int sys_eof(unsigned int fd); // same
-int sys_read(unsigned int fd, char* buf, size_t count);
-int sys_write(unsigned int fd, const char* buf, size_t count);
-int sys_exit(int error_code);
 int sys_draw(const uint8_t* src, int width, int height, int channels);
+int sys_exit(int error_code);
 
 /*
  * syscall_handler - System call dispatcher

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
+	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);
+    }
+}

user/libc/syscall.h

@@ -1,21 +1,79 @@
-#pragma once
+/*
+ * @author  xamidev <xamidev@riseup.net>
+ * @brief   System call wrappers for userspace
+ * @license GPL-3.0-only
+ */
 
-// 3 because 3 arguments to the call, get it??
+#pragma once
+// TODO: replace all ifndef/define/endif by pragma once..
+
+#include <stddef.h>
+#include <stdint.h>
+
+// 3-args syscall
 static inline long syscall3(long n, long a, long b, long c) {
     long ret;
 
     __asm__ volatile (
         "int $0x80"
         : "=a"(ret)
-        : "a"(n), "D"(a), "S"(b), "d"(c)
+        : "a"(n), "D"(a), "S"(b), "d"(c) // a = rax, D = rdi, S = rsi, d = rdx
         : "memory"
     );
 
     return ret;
 }
 
-static inline void write(int fd, const char* buf, long len) {
-    syscall3(1, fd, (long)buf, len);
+// 4-args syscall
+static inline long syscall4(long n, long a, long b, long c, long d) {
+    long ret;
+    register long r10 __asm__("r10") = d;
+
+    __asm__ volatile (
+        "int $0x80"
+        : "=a"(ret)
+        : "a"(n), "D"(a), "S"(b), "d"(c), "r"(r10)
+        : "memory"
+    );
+
+    return ret;
+}
+
+// Single-arg syscall
+static inline long syscall1(long n, long a) {
+    return syscall3(n, a, 0, 0);
+}
+
+static inline int write(int fd, const char* buf, long len) {
+    return (int)syscall3(1, fd, (long)buf, len);
+}
+
+static inline int read(int fd, char* buf, long len) {
+    return (int)syscall3(0, fd, (long)buf, len);
+}
+
+static inline int open(const char* path, int flags) {
+    return (int)syscall3(2, (long)path, flags, 0);
+}
+
+static inline int close(unsigned int fd) {
+    return (int)syscall3(3, fd, 0, 0);
+}
+
+static inline int seek(int fd, int offset, int whence) {
+    return (int)syscall3(8, fd, offset, whence);
+}
+
+static inline int tell(unsigned int fd) {
+    return (int)syscall1(9, fd);
+}
+
+static inline int eof(unsigned int fd) {
+    return (int)syscall1(10, fd);
+}
+
+static inline int draw(const unsigned char* buf, int width, int height, int channels) {
+    return (int)syscall4(11, (long)buf, width, height, channels);
 }
 
 static inline void exit(int code) {