The document discusses programming the Atari VCS, highlighting its limited resources such as 128 bytes of RAM and a basic 6507 CPU. It provides assembly code examples for designing a playfield and emphasizes the intellectual challenge and educational value of working with such constraints. The author suggests that overcoming these limitations can lead to creativity in game design.

1. Programming the Atari VCS for Fun
Paul Dixon @lordelph paul@elphin.com
http://github.com/lordelph/2600intro

2. An XBox it Ain’t!
128 bytes
of RAM
remember
these?
6507 CPU
0.5 MIPS
160 x 192
pixels.
Hmmm….

4. So let’s make something!

5. PFData0
.byte #%00000000
.byte #%01010000
.byte #%01010000
.byte #%01010000
.byte #%01110000
.byte #%01010000
.byte #%01010000
.byte #%01010000
.byte #%00000000
Design a playfield…

6. ScanLoop
STA WSYNC
; load our playfield data
LDA PFData0,X
STA PF0
LDA PFData1,X
STA PF1
LDA PFData2,X
STA PF2
DEX
BNE MorePlayfield
LDX #18 ;reset playfield counter
MorePlayfield
DEY ; decrement scanline counter
BNE ScanLoop ; next scan line
This loader uses 26
cycles per
scanline. We only
have 22 cycles
before the TV
starts displaying
the line! OMFG!

8. Why do this to yourself?
• It’s a fun intellectual challenge
• Great introduction to assembler
• Serves to remind you how wasteful
something like this is
$ext=array_pop(
explode(‘.’, $filename)
);

9. “You can’t have art
without resistance in
the materials”
Paul Dixon @lordelph paul@elphin.com
http://github.com/lordelph/2600intro
William Morris