#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>

typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;
typedef unsigned long long u64;

#ifndef asm
#define asm __asm__ volatile
#endif

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));
}

void macaroni_panic(char* msg) {
    // we'll do something with msg later.
    while(true){ asm("nop\n\t"); }
}

void macaroni_assert(bool condition) {
    if (condition) {
        return;
    }
    macaroni_panic("thisisatest");
}

void cmain(void) {
    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");
}