Eigenmath-fx/tex/disp.src

;;
;;  setPixel() function.
;;  Sets the color of a pixel on the screen.
;;

	.global _setPixel

_setPixel:
	mov.l #127,r1
	cmp/hi r1,r4
	bt end
	mov.l #63,r1
	cmp/hi r1,r5
	bt end
	mov r4,r0
	shll2 r5
	shll2 r5
	mov #-3,r1
	shld r1,r4
	add r4,r7
	add r5,r7
	mov.b @r7,r1
	mov #7,r2
	and r0,r2
	neg r2,r2
	mov.l #128,r3
	shld r2,r3
	tst r6,r6
	bt white
black:
	or r3,r1
	rts
	mov.b r1,@r7
white:
	not r3,r3
	and r3,r1
	rts
	mov.b r1,@r7
end:
	rts
	nop

	.end