pokecrystal-board/engine/gfx/place_graphic.asm

PlaceGraphic:
; Fill wBoxAlignment-aligned box width b height c
; with iterating tile starting from hGraphicStartTile at hl.

	ld de, SCREEN_WIDTH

	ld a, [wBoxAlignment]
	and a
	jr nz, .right

	ldh a, [hGraphicStartTile]
.x1
	push bc
	push hl

.y1
	ld [hl], a
	add hl, de
	inc a
	dec c
	jr nz, .y1

	pop hl
	inc hl
	pop bc
	dec b
	jr nz, .x1
	ret

.right
; Right-aligned.
	push bc
	ld b, 0
	dec c
	add hl, bc
	pop bc

	ldh a, [hGraphicStartTile]
.x2
	push bc
	push hl

.y2
	ld [hl], a
	add hl, de
	inc a
	dec c
	jr nz, .y2

	pop hl
	dec hl
	pop bc
	dec b
	jr nz, .x2
	ret