; kb.asm
PUBLIC _keyboardPressed
PUBLIC _keyboardHandler


.386
.model flat,c

.DATA

_keyboardPressed db 0

.CODE

_keyboardHandler:
  cli
  push eax
  push ebx

  in al, 0x60
  mov bl, al

  ; acknowledge keyboard
  in al, 0x61
  mov ah, al
  or al, 0x80
  out 0x61, al
  xchg ah, al
  out 0x61, al

  and bl,0x80
  jne _keyboardHandler_notKeydown

  mov [_keyboardPressed], 1
_keyboardHandler_notKeydown:
  ; acknowledge interrupt
  mov al, 0x20
  out 0x20, al

  pop ebx
  pop eax
  sti
  iretd ; needed for 32 bit protected mode