* = $c000

; disintegratinator
; 32b intro 2024-10-26
; by oxidisedbraincells
; run using SYS 49152

; originally wanted this to increment all non-spaces 256 times
; but it would stop incrementing on every space so it just kinda deleted everything
; still that just makes it an even cooler effect though


; maybe i don't need to initialise these three to zero
;ldx #$00
;ldy #$00

; unused zeropage space $FB and $FC is used to store the address of screen RAM being written to
;stx $FB


incrementingloop
	lda #$03 ; gets incremented to 4 on first run of increment256characters
	sta $FC

	incrementpage
	; first increment the page of memory we're writing to
	inc $FC

	spacecheck
		lda ($FB),y
		cmp #32 ; space
		beq LOOPEND ; don't increment if character is space
	
		;lda ($FB),y
		clc
		adc #1
		sta ($FB),y ; unfortunately INC has no indirect addressing mode so we have to use this stuff

		LOOPEND
		iny
		bne spacecheck ; do this increment-or-skip process 256 times; a full page of memory
	
	lda $FC
	cmp #$07 ; if we've done page 07 already we've finished incrementing
	bne incrementpage

	inx
	bne incrementingloop ; do it 256 times; guarantees that the screen is cleared totally

rts ; back to BASIC