Makes a trippy diagonal line pattern on the VCS

atari_diag_lines.a

; use with 8bitworkshop's VCS IDE
; http://8bitworkshop.com/?platform=vcs
	processor 6502
	
; Include files for Atari 2600 constants and handy macro routines
	include "vcs.h"
	include "macro.h"
	
	org  $f000

Start   sei		; disable interrupts
        cld		; disable BCD math mode
	ldx  #$ff	; init stack pointer to $FF (grows upward)
	txs		; ... transfer X register to S register (stack pointer)

	lda  #$00
        ldy  #$00
Loop
        ;load value into A ($30 is deep red on NTSC)
        sty COLUBK
        ldx #61
Loop2 	Dex
        sty COLUBK
        sta COLUBK
        Bpl Loop2
        INY
        Bne Loop

        org $fffc
        .word Start
        .word Start