input.asm

; input.asm: Input-handling routines

%ifndef INPUT_ASM
%define INPUT_ASM

%include 'std/stdio.asm'

%define KEY_ESC 0x01
%define KEY_UP 0x48
%define KEY_LEFT 0x4b
%define KEY_RIGHT 0x4d
%define KEY_DOWN 0x50

; Processes the keys in the keyboardState buffer.
; - Cursor keys (up, down, left, right): Adjust player position.
; - Esc key: set is_running to false (game will be exited)
process_keys:
  cmp byte [keyboardState+KEY_ESC], 1
  jne .testUp
  mov byte [is_running], 0
  .testUp:
    cmp byte [keyboardState+KEY_UP], 1
    jne .testDown
    dec word [player_y]
  .testDown:
    cmp byte [keyboardState+KEY_DOWN], 1
    jne .testLeft
    inc word [player_y]
  .testLeft:
    cmp byte [keyboardState+KEY_LEFT], 1
    jne .testRight
    dec word [player_x]
  .testRight:
    cmp byte [keyboardState+KEY_RIGHT], 1
    jne .done
    inc word [player_x]
  .done:
    ret

%endif ; INPUT_ASM