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Assembler Atari 2600.asm
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Assembler Atari 2600.asm
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; A "Hello, World!" which illustrates an Atari 2600 programming
; introduction talk (slides at http://slideshare.net/chesterbr).
;
; This is free software (see license below). Build it with DASM
; (http://dasm-dillon.sourceforge.net/), by running:
;
; dasm hello.asm -ohello.bin -f3
;
PROCESSOR 6502
INCLUDE "vcs.h"
ORG $F000
StartFrame:
lda #%00000010
sta VSYNC
REPEAT 3
sta WSYNC
REPEND
lda #0
sta VSYNC
PreparePlayfield:
lda #$00
sta ENABL
sta ENAM0
sta ENAM1
sta GRP0
sta GRP1
sta COLUBK
sta PF0
sta PF2
lda #$FF
sta COLUPF
lda #$00
sta CTRLPF
ldx #0
REPEAT 37
sta WSYNC
REPEND
lda #0
sta VBLANK
Scanline:
cpx #174
bcs ScanlineEnd
txa
lsr
tay
lda Phrase,y
sta PF1
ScanlineEnd:
sta WSYNC
inx
cpx #191
bne Scanline
Overscan:
lda #%01000010
sta VBLANK
REPEAT 30
sta WSYNC
REPEND
jmp StartFrame
Phrase:
.BYTE %00000000
.BYTE %01000010
.BYTE %01111110
.BYTE %01000010
.BYTE %01000010
.BYTE %01000010
.BYTE %00000000
.BYTE %00000000
.BYTE %01111110
.BYTE %01000000
.BYTE %01111100
.BYTE %01000000
.BYTE %01000000
.BYTE %01111110
.BYTE %00000000
.BYTE %00000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01111110
.BYTE %00000000
.BYTE %00000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01111110
.BYTE %00000000
.BYTE %00000000
.BYTE %00111100
.BYTE %01000010
.BYTE %01000010
.BYTE %01000010
.BYTE %01000010
.BYTE %00111100
.BYTE %00000000
.BYTE %00000000
.BYTE %00000000
.BYTE %00000000
.BYTE %00000000
.BYTE %00000000
.BYTE %00000000
.BYTE %00000000
.BYTE %00000000
.BYTE %00000000
.BYTE %01000010
.BYTE %01000010
.BYTE %01000010
.BYTE %01000010
.BYTE %01011010
.BYTE %00100100
.BYTE %00000000
.BYTE %00000000
.BYTE %00111100
.BYTE %01000010
.BYTE %01000010
.BYTE %01000010
.BYTE %01000010
.BYTE %00111100
.BYTE %00000000
.BYTE %00000000
.BYTE %01111100
.BYTE %01000010
.BYTE %01000010
.BYTE %01111100
.BYTE %01000100
.BYTE %01000010
.BYTE %00000000
.BYTE %00000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01000000
.BYTE %01111110
.BYTE %00000000
.BYTE %00000000
.BYTE %01111000
.BYTE %01000100
.BYTE %01000010
.BYTE %01000010
.BYTE %01000100
.BYTE %01111000
.BYTE %00000000)
ORG $FFFA
.WORD StartFrame
.WORD StartFrame
.WORD StartFrame
END
;
; Copyright 2011-2013 Carlos Duarte do Nascimento (Chester). All rights reserved.
;
; Redistribution and use in source and binary forms, with or without modification, are
; permitted provided that the following conditions are met:
;
; 1. Redistributions of source code must retain the above copyright notice, this list of
; conditions and the following disclaimer.
;
; 2. Redistributions in binary form must reproduce the above copyright notice, this list
; of conditions and the following disclaimer in the documentation and/or other materials
; provided with the distribution.
;
; THIS SOFTWARE IS PROVIDED BY CHESTER ''AS IS'' AND ANY EXPRESS OR IMPLIED
; WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
; FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR
; CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
; CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
; SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
; ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
; ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
;
; The views and conclusions contained in the software and documentation are those of the
; authors and should not be interpreted as representing official policies, either expressed
; or implied, of Chester.
;