ASMINPUT.ASM

gistfile1.asm

; The implementation of INPUT.H for the BIOS

BITS 16

global initmouse
global getmouseinfo

initmouse:
	mov ax, 00h
	int 33h

	cmp ax, 0ffffh
	je success
	int 20h
success:
	ret

getmouseinfo:
	push bp
	mov sp, bp

	mov ax, 03h
	int 33h
	
	shr cx, 01h                 ; cx is doubled in 320x300, correct
	
	mov ax, bx
	and ax, 01h
	cmp ax, ax
	jnz mlefttrue
	mov word [bp], 00h          ; mouse->left = 0
	jmp mleftfalse
mlefttrue:
	mov word [bp], 01h          ; mouse->left = 1
mleftfalse:

	mov ax, bx
	and ax, 02h
	cmp ax, ax
	jnz mrighttrue
	mov word [bp + 2], 00h      ; mouse->right = 0
	jmp mrightfalse
mrighttrue:
	mov word [bp + 2], 01h      ; mouse->right = 1
mrightfalse:

	mov word [bp + 4], cx       ; mouse->x = cx
	mov word [bp + 6], dx       ; mouse->y = dx
	pop bp
	ret