Smoke - palette

gistfile1.asm

setup_palette:

	mov	cx, 255			; 256 colour indicies to set
	
next_colour_idx:
	mov	al, 255			; setup al so that we're setting
	sub	al, cl			; colour indicies from low to high
	
	mov	dx, 3c7h		; this port selects the colour index
					; that we'll set r,g,b for
	out	dx, al
	
	mov	dx, 3c9h		; this port sets the r,g,b components
						; for the selected index
							
	shr	al, 2			; rgb intensities are in range of 0..63
					; so, divide by 4 to adjust
							
	out	dx, al			; set the red
	out	dx, al			; set the green
	out	dx, al			; set the blue

	dec	cx			; move onto the next colour
	jnz	next_colour_idx
	
	ret