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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 #$00
sta COLUBK ; background color
lda #$D6
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
lda #%11110000
sta PF0
lda #%11101010
sta PF1
lda #%01010101
sta PF2
lda #$02
sta COLUPF
lda #%00000001
sta CTRLPF ; reflect playfield
sta WSYNC
SLEEP 20
sta RESP0 ; position 1st player
sta RESP1 ; ...and 2nd player
lda #$10
sta HMP1 ; 1 pixel to the left
sta WSYNC
sta HMOVE ; apply HMOVE
sta HMCLR
lda #0
sta VDELP0 ; we need the VDEL registers
sta VDELP1 ; so we can do our 4-store trick
TIMER_WAIT
TIMER_SETUP 192
lda #%10101010
sta GRP0 ; B0 -> [GRP0]
lda #00
sta GRP1 ; B1 -> [GRP1], B0 -> GRP0
lda #$ff
;sta NUSIZ0
EMR1 equ %00110011
EMR2 equ %00110011
EMR3 equ %00110011
EMR4 equ %11001100
EMR5 equ %11001100
SLEEP 30 ; start near end of scanline
sta WSYNC ; sync to next scanline
BigLoop
ldy LoopCount ; counts backwards
sta WSYNC
lda #0
sta GRP0 ; B0 -> [GRP0]
SLEEP 22
sta RESP0 ; sync to next scanline
sta WSYNC
lda #EMR1
sta GRP0 ; B0 -> [GRP0]
ldx #EMR5
ldy #EMR2
lda #EMR3
sleep 22
sty GRP0
; SLEEP 18
sta GRP0
sta RESP0 ; sync to next scanline
lda #EMR4
sta GRP0
sleep 3
stx GRP0
dec LoopCount ; go to next line
bpl BigLoop ; repeat until < 0
lda #0
sta GRP0
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
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