VBE attempt 1

2 files changed, 145 insertions, 30 deletions

diff --git a/src/boot.asm b/src/boot.asm
index cbf57d6..c88f08c 100644
--- a/src/boot.asm
+++ b/src/boot.asm
@@ -1,20 +1,37 @@
 ;> The Multiboot header must be contained completely within the first 8192 bytes of the OS 
 ;> image, and must be longword (32-bit) aligned.
 MULTIBOOT_ALIGN_TO_PAGE:   equ 1 << 0
-MULTIBOOT_MEMORY_DESCRIBE: equ 1 << 2
+MULTIBOOT_MEMORY_DESCRIBE: equ 1 << 1
+MULTIBOOT_VIDEO_MODE:      equ 1 << 2
 MULTIBOOT_MAGIC:           equ 0x1BADB002
-MULTIBOOT_FLAGS:           equ (MULTIBOOT_ALIGN_TO_PAGE | MULTIBOOT_MEMORY_DESCRIBE)
+MULTIBOOT_FLAGS:           equ (MULTIBOOT_ALIGN_TO_PAGE | MULTIBOOT_MEMORY_DESCRIBE | MULTIBOOT_VIDEO_MODE)
 MULTIBOOT_CHECKSUM:        equ -(MULTIBOOT_MAGIC + MULTIBOOT_FLAGS)
-section .multiboot_header
+MULTIBOOT_VIDEO_TYPE:      equ 0
+MULTIBOOT_GODS_WIDTH:      equ 640
+MULTIBOOT_GODS_HEIGHT:     equ 480
+MULTIBOOT_VIDEO_BPP:       equ 16
+
+; We don't set flags[16] because we assemble to ELF32 so header_addr, etc is useless to us
+; (at least at the moment).
+UNUSED_BYTES_COUNT: equ 5*4
+section .multiboot_header:
+; I guess multiboot 2 requires a length field and we might migrate to that in the future.
+multiboot_header_start:
 align 4
     dd MULTIBOOT_MAGIC
     dd MULTIBOOT_FLAGS
     dd MULTIBOOT_CHECKSUM
+    times UNUSED_BYTES_COUNT db 0
+    dd MULTIBOOT_VIDEO_TYPE
+    dd MULTIBOOT_GODS_WIDTH
+    dd MULTIBOOT_GODS_HEIGHT
+    dd MULTIBOOT_VIDEO_BPP
+multiboot_header_end:
 
 STACK_SIZE: equ (1 << 14)
 section .bss
 align 16
-stack_bottom:
+stack_bottom: ; ("haha bottom" somewhere in there??)
     resb STACK_SIZE
 stack_top:
 
diff --git a/src/kernel.c b/src/kernel.c
index 1459f73..917c07e 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -1,36 +1,134 @@
 #include <stddef.h>
 #include <stdint.h>
+#include <stdbool.h>
 
-#define WIDTH 80
-#define HEIGHT 25
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned int u32;
+typedef unsigned long long u64;
 
-#define BLACK 0
-#define BLUE 1
-#define GREEN 2
-#define RED 4
-#define MAGENTA 13
-#define WHITE 15
+#ifndef asm
+#define asm __asm__ volatile
+#endif
 
-int strlen(char* s) {
-  int n = 0;
-  char* s_ptr = s;
-  while (*(s_ptr++)) { 
-    n++;
-  }
-  return n;
+struct __attribute__((packed)) multiboot_info
+{
+  /* Multiboot info version number */
+  u32 flags;
+
+  /* Available memory from BIOS */
+  u32 mem_lower;
+  u32 mem_upper;
+
+  /* "root" partition */
+  u32 boot_device;
+
+  /* Kernel command line */
+  u32 cmdline;
+
+  /* Boot-Module list */
+  u32 mods_count;
+  u32 mods_addr;
+
+//   union
+//   {
+//     multiboot_aout_symbol_table_t aout_sym;
+//     multiboot_elf_section_header_table_t elf_sec;
+//   } u;
+  u32 unused_1;
+  u32 unused_2;
+  u32 unused_3;
+  u32 unused_4;
+
+  /* Memory Mapping buffer */
+  u32 mmap_length;
+  u32 mmap_addr;
+
+  /* Drive Info buffer */
+  u32 drives_length;
+  u32 drives_addr;
+
+  /* ROM configuration table */
+  u32 config_table;
+
+  /* Boot Loader Name */
+  u32 boot_loader_name;
+
+  /* APM table */
+  u32 apm_table;
+
+  /* Video */
+  u32 vbe_control_info;
+  u32 vbe_mode_info;
+  u16 vbe_mode;
+  u16 vbe_interface_seg;
+  u16 vbe_interface_off;
+  u16 vbe_interface_len;
+
+  u64 framebuffer_addr;
+  u32 framebuffer_pitch;
+  u32 framebuffer_width;
+  u32 framebuffer_height;
+  u8 framebuffer_bpp;
+#define MULTIBOOT_FRAMEBUFFER_TYPE_INDEXED 0
+#define MULTIBOOT_FRAMEBUFFER_TYPE_RGB     1
+#define MULTIBOOT_FRAMEBUFFER_TYPE_EGA_TEXT     2
+  u8 framebuffer_type;
+  union
+  {
+    struct
+    {
+      u32 framebuffer_palette_addr;
+      u16 framebuffer_palette_num_colors;
+    };
+    struct
+    {
+      u8 framebuffer_red_field_position;
+      u8 framebuffer_red_mask_size;
+      u8 framebuffer_green_field_position;
+      u8 framebuffer_green_mask_size;
+      u8 framebuffer_blue_field_position;
+      u8 framebuffer_blue_mask_size;
+    };
+  };
+};
+typedef struct multiboot_info multiboot_info_t;
+
+u8 inportb(u16 port) {
+    u8 r;
+    asm("inb %1, %0" : "=a" (r) : "dN" (port));
+    return r;
+}
+
+void outportb(u16 port, u8 data) {
+    asm("outb %1, %0" : : "dN" (port), "a" (data));
+}
+
+// TODO: Why won't this work? void macaroni_panic(char* msg) {
+void macaroni_panic() {
+    // we'll do something with msg later.
+    while(true){ asm("nop\n\t"); }
+}
+
+void macaroni_assert(bool condition) {
+    if (condition) {
+        return;
+    }
+    macaroni_panic();
 }
 
 void cmain(void) {
-  uint16_t* vgamem = (uint16_t*) 0xB8000;
-  uint16_t vgacolors[6] = {WHITE | RED << 4, WHITE | GREEN << 4, WHITE | BLUE << 4, BLACK | RED << 4, BLACK | GREEN << 4, BLACK | BLUE << 4};
-  char* s = "Hello world!";
-  int i,j,k;
-  for (k = 0; k >= 0; ++k) {
-    k = (k % 5);
-    j = 0;
-    while (j < 100000000) { j++; } // Since we don't have an interrupt descriptor table we can't use the PIC; this emulates "sleeping"
-    for (i = 0; i < WIDTH*HEIGHT; i++) {
-      vgamem[i] = s[i % strlen(s)] | vgacolors[(i+k) % 6] << 8;
+    u32 magic_response = 0x1;
+    multiboot_info_t* p_multiboot_info;
+    asm("\t movl %%eax,%0" : "=r"(magic_response));
+    asm("\t movl %%ebx,%0" : "=r"(p_multiboot_info));
+
+    void *fb = (void *) (unsigned long) p_multiboot_info->framebuffer_addr;
+    u8* pixel = fb;
+    for (int i = 0; i < 10000; i++) {
+        *(pixel + i) = i * 2;
     }
-  }
+
+    macaroni_assert(magic_response == 0x2BADB002);
+    //asm("int $0x13");
 }
\ No newline at end of file