processor 6502
        include "vcs.h"
        include "macro.h"
        include "xmacro.h"

	seg.u Variables
        org $80

Temp		byte
LoopCount	byte

THREE_COPIES    equ %011

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

	seg Code
	org $f000

Start
	CLEAN_START

NextFrame
	VERTICAL_SYNC

	TIMER_SETUP 37
        lda #64
        sta LoopCount	; scanline counter
        lda #$ff
        sta COLUBK	; background color
        lda #$22
        sta COLUP0	; show how players alternate
        lda #$12
        sta COLUP1	; by having different colors
        lda #THREE_COPIES
        sta NUSIZ0
        sta NUSIZ1	; both players have 3 copies
        sta WSYNC
        SLEEP 20
        sta RESP0	; position 1st player
        sta RESP1	; ...and 2nd player
        lda #$10
        sta HMP1	; 1 pixel to the left
        sta WSYNC
        sta HMOVE	; apply HMOVE
        sta HMCLR
        lda #1
        sta VDELP0	; we need the VDEL registers
        sta VDELP1	; so we can do our 4-store trick
        TIMER_WAIT

	TIMER_SETUP 192

	SLEEP 40	; start near end of scanline
BigLoop
	ldy LoopCount	; counts backwards
        lda Bitmap0,y	; load B0 (1st sprite byte)
        sta GRP0	; B0 -> [GRP0]
        lda Bitmap1,y	; load B1 -> A
        sta GRP1	; B1 -> [GRP1], B0 -> GRP0
        sta WSYNC	; sync to next scanline
        lda Bitmap2,y	; load B2 -> A
        sta GRP0	; B2 -> [GRP0], B1 -> GRP1
        lda Bitmap5,y	; load B5 -> A
        sta Temp	; B5 -> temp
        ldx Bitmap4,y	; load B4 -> X
        lda Bitmap3,y	; load B3 -> A
        ldy Temp	; load B5 -> Y
        sta GRP1	; B3 -> [GRP1]; B2 -> GRP0
        stx GRP0	; B4 -> [GRP0]; B3 -> GRP1
        sty GRP1	; B5 -> [GRP1]; B4 -> GRP0
        sta GRP0	; ?? -> [GRP0]; B5 -> GRP1
        dec LoopCount	; go to next line
	bpl BigLoop	; repeat until < 0

        TIMER_WAIT

	TIMER_SETUP 30
        TIMER_WAIT
        jmp NextFrame

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Bitmap data, six columns

	align $100	; ensure we start on a page boundary
Bitmap0
	hex 00
	hex 00000000000000000000000000000000
	hex 00000000000000000000000000000001
	hex 01010205040402040404040404040404
	hex 040404060203000107df7f1f0f000000
Bitmap1
	hex 00
	hex 0000073f1f0303000000000000010704
	hex 0808101010101412120a0a1e75c38000
	hex 0000076260e0e0e0c0c0e0e0c0c00000
	hex 00000000408170feffffffffc7030000
Bitmap2
	hex 00
	hex 007ffffcf0e0c0404040404020bb7608
	hex 000402020809094f494949fa07010000
	hex 00000000006070f0f0f0c0e0e0e0e0e0
	hex 400000000010a06010e0e0f1ffff7f00
Bitmap3
	hex 00
	hex 3effff07010000000000302159878184
	hex 848efeffffff9f0f0e9c7c0402c12010
	hex 08040207050000000002020104070f0f
	hex 0f070703030707070f1f7efcf8f0c000
Bitmap4
	hex 00
	hex 00f0f0fffff0404040404080641e02c3
	hex 4242c3e2e2f4fcfc787838787cfa3131
	hex 6102021cf840c04042a022c14080c4c3
	hex c0c0c0c0808090900010180c04243800
Bitmap5
	hex 00
	hex 000000fcfefc1c0c040402020202040c
	hex f800e01804040402020101010111e192
	hex dc700000000000000000000080808000
	hex 00000000000000000000000000000000

; Epilogue
	org $fffc
        .word Start
        .word Start