;Copyright 2019 Benji Dial

;Permission to use, copy, modify, and/or distribute this
;software for any purpose with or without fee is hereby
;granted, provided that the above copyright notice and this
;permission notice appear in all copies.

;THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS
;ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
;IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
;EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
;INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
;RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
;ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
;ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
;OF THIS SOFTWARE.

extern main

section .mb_header
dd 0xe852_50d6;magic
dd 0x0000_0000;architecture - i386
dd mb_end - $$;length
dd 0x17adaf2a - mb_end + $$;check

;tags
dw 0x0001;info request
dw 0x0000;flags
dd mb_end - $$ - 16
dd 5;boot device
dd 6;memory map

mb_end:

section .text
bits 32
global _start
_start:
  mov dword [info_pointer], ebx
  mov esp, stack
  call main
  mov edx, eax

  mov eax, 0x4720_4720
  mov ebx, 0x000b_8000
  mov ecx, 0x000b_8fa0
clear_screen_loop:
  mov dword [ebx], eax
  add ebx, 4
  test ebx, ecx
  jne clear_screen_loop

  mov dword [0x000b_8000], 0x4772_4745
  mov dword [0x000b_8004], 0x476f_4772
  mov dword [0x000b_8008], 0x4720_4772

  mov ebx, 0x000b_8020
  mov ecx, 0x000b_800a
error_number_loop:
  mov al, dl
  and al, 0x07
  or al, 0x30
  mov byte [ebx], al
  sub ebx, 2
  shr edx, 3
  test ebx, ecx
  jne error_number_loop

  cli
halt:
  hlt
  jmp halt

section .bss
global info_pointer
info_pointer resd 1
resb 0x1000 - $ + $$
stack: