Nightshade: Routine at D255

D255: Step Down Left In List

Used by the routine at DrawCell. Moves the position of the strips down eight pixels and left sixteen pixels, and moves on to the next strip in the list.
StepDownLeftInList	D255	LD DE,$0008	Set the step down to eight.
This entry point is used by the routine at StepUpLeftInList. Move on to the next strip in the list, and move the position by the step (in DE) and left sixteen pixels.
StepLeftInList	D258	INC IY	Move on to the next strip in the list.
	D25A	INC IY	Move on to the next strip in the list.
	D25C	LD HL,($BBB8)	Add the step to the Y position of the strips.
	D25F	ADD HL,DE
	D260	LD ($BBB8),HL
	D263	LD HL,($BBB6)	Subtract sixteen from the X position of the strips.
	D266	LD DE,$FFF0
	D269	ADD HL,DE
	D26A	LD ($BBB6),HL
	D26D	RET	Return.