asm4c.s

.export _UnRLE

; not sure this is an appropriate place for these:
.segment "ZEROPAGE"
	RLE_LOW:	.res 1
	RLE_HIGH:	.res 1
	RLE_TAG:	.res 1
	RLE_BYTE:	.res 1

.segment "CODE"

_UnRLE:
	tay
	stx <RLE_HIGH
	lda #0
	sta <RLE_LOW

	lda (RLE_LOW),y
	sta <RLE_TAG
	iny
	bne @1
	inc <RLE_HIGH
@1:
	lda (RLE_LOW),y
	iny
	bne @11
	inc <RLE_HIGH
@11:
	cmp <RLE_TAG
	beq @2
	sta $2007
	sta <RLE_BYTE
	bne @1
@2:
	lda (RLE_LOW),y
	beq @4
	iny
	bne @21
	inc <RLE_HIGH
@21:
	tax
	lda <RLE_BYTE
@3:
	sta $2007
	dex
	bne @3
	beq @1
@4:
	rts