[stella] The FAQ as it stands

["Mark Graybill" <saundby@xxxxxxxxxxxx>]

OK, here's the FAQ as I've got it so far. I've added a bit, shifted some around, rewritten bits and shifted other parts into a dummy variable until I get farther along.

 

What you won't see is some of the material that was posted back when this got started back in May of 2000, but I've clipped a bunch of this stuff into the pure hash version of the file and I'll be editing it in during my next session with the FAQ, I expect. You won't see it here, but it will be in soon. If there were any suggestions in the archives for what ought to go into the FAQ that are outside that time frame, I probably haven't seen them yet so you may want to point me to them.

 

There's also not much actual programming info, but that's also going to start with the next session.

 

The next session will probably come next week, my weekend is pretty full already. I was lucky to have some down time to put into this today.

 

Enjoy,

 

Mark G.

The Stella Mailing List FAQ

Updated October, 2002 by Mark Graybill

1. The Stella Mailing List
	1.1 What is the Stella Mailing List?
	1.2 How do I get on the list?
	1.3 Where are the list archives?
	1.4 What are the posting guidelines?
	1.5 Who is "Stella?"
	1.6 How do I get the FAQ?
	1.7 How do I submit to the FAQ?
	1.8 Where did the FAQ come from?

2. Getting Started
	2.1 Are the 2600 and 7800 difficult to program?
	2.2 What do I need to get started?
	2.3 What experience do I need?
	2.4 What books are there on 6502 programming?
	2.5 Where can I find info on the internet?
	2.5.1 Where is info specific to 2600/7800 programming on the internet?
	2.5.2 Where is general info about the 2600 and 7800 on the internet?
	2.5.3 Where is more general 6502 programming and tech info on the internet?

3.0 System Hardware Overview
	3.1 What are the Atari 2600 VCS and Atari 7800?
	3.2 What CPU does the Atari 2600 VCS use?
	3.3 What CPU does the Atari 7800 ProSystem use?
	3.4 What graphics chip does the 2600 use?
		3.4.1 What software features does the TIA have?
		3.4.2 What are the registers in the TIA and their functions?
	3.5 What graphics chip does the 7800 use?
	3.6 What I/O chip does the VCS use?
	3.7 What I/O chip does the 7800 use?
	3.8 What sound chip does the VCS use?
	3.9 What sound chip does the 7800 use?

4.0 Programming Tools
	4.1 How do I test code? (The Emulator)
	4.2 Where do I get coding info? (The Documentation)
	4.3 How can I read other peoples' code? (The Disassembler)
	4.4 How do I compile my own code? (The Cross-Assembler)
	4.5 How do I make programming go faster? (Programming Environment)
	4.6 How do I get my code to the 2600 hardware?
		4.6.1 The Starpath Supercharger
		4.6.2 The CuttleCart
		4.6.3 RAM/Flash Cartridges
		4.6.4 ZIF Cartridges
		4.6.5 Cartridge Manufacture
	4.7 How do I get my code to the 7800 hardware?

5.0 Basic Programming for the Atari 2600
	5.1 Where can I find programming tutorials?
	5.1 How do I start? (The Kernel)
	5.2 Program Structure
	5.3 How do I put something on the screen?
		5.3.1 The Background
		5.3.2 The Playfield
		5.3.3 The Players
		5.3.4 The Missiles
		5.3.5 The Ball
	5.4 How do I talk to the game controllers?
		5.4.1 The Fire Buttons
		5.4.2 The Joysticks
		5.4.3 The Paddles
		5.4.4 The Driving Controllers
		5.4.5 The Keypads
	5.5 How do I make it _do_ something?
		5.5.1 Vertical Positioning and Movement
		5.5.2 Horizontal Positioning and Movement
		5.5.3 Collision Detection
	5.6 How do I make sounds?
		5.6.1 Noise
		5.6.2 Music
	5.7 How do I provide score and status displays?
		5.7.1 The Divided Display
		5.7.2 Score Displays
		5.7.3 Status Displays
6.0 Basic Programming for the Atari 7800

7.0 Advanced Routines for the Atari 2600
	7.1 How do I display more than two players?
	7.2 How can the two halves of the playfield be different?
	7.3 How can I use six digit displays?
	7.4 How do I get more than 4K of ROM?
	7.5 How do I get more than 128 bytes of RAM?
	7.6 How do I display text?

8.0 Advanced Routines for the Atari 7800

9.0 Common Errors and Gotchas

10.0 The Zen of VCS Development
	10.1 What sort of masochist does this, anyway?
	10.2 How do I port Quake III and Unreal Tournament to the VCS?
	10.3 Is it true what they say about the VCS programmer groupies?
	10.4 Is this a great way for me to make my first million?
	10.5 Why should I post my code, what will the list do for me?
	10.6 Won't somebody steal my amazing secret algorithm?

11.0 Sharing and Selling Your Work
	11.1 How can I sell my work?
	11.2 How can I market my work?
	11.3 How many people will actually buy this stuff?
	11.4 What will people pay for this stuff?
	11.5 What are the major events I should know about?



1. The Stella Mailing List

1.1 What is the Stella Mailing List?

The Stella Mailing List is a meeting place for programmers of the Atari 2600 VCS and Atari 7800 ProSystem game consoles. It is used to share code, programming tips and techniques, and other information related to programming these systems. The list has also been peripherally involved with the development of some new hardware for the Atari video game systems.

The list started in 1996 as a special interest group for the Starpath Supercharger CD project. Since 1996, the Stella List has evolved into the primary clearing-house for game development for the Atari 2600 and 7800.

Stella List members represent programmers who work collectively to solve 
technical problems, and also observers who offer game design advice and 
playtesting.  It provides a place for peer review and collaboration, as well as assistance and guidance for struggling new programmers of these systems.


1.2 How do I get on the list?

Go to:
http://www.biglist.com/lists/stella/


1.3 Where are the list archives?

Go to:
http://www.biglist.com/lists/stella/archives/


1.4 What are the posting guidelines?

Other than the standard netiquette, see:
http://www.biglist.com/lists/stella/info.shtml

In general, posting of program binaries and source is encouraged. Since these programs tend to be small (compared to the software used by current systems), this does not pose a problem for most people's email systems.


1.5 Who is "Stella?"

Stella was the name of a french bicycle owned by Joe Decuir, one of the original Atari 2600 hardware designers.  He chose that name as a password for his time-sharing account he used to develop early kernels such as Video Olympics. Ultimately Jay Miner, another Atari hardware designer, attached it to the Atari 2600 project.


1.6 How do I get the FAQ?

It's a little odd to asnwer the question inside the FAQ, but let's suppose you have an old one and want a new one.

The FAQ has been posted to the Stella ML, so if you haven't received one among the things you've gotten from the ML, you'll want to go to the Stella ML Archives and get it.

You may also find a copy at The Dig!, a spectacular compilation of some of the best bits of the list's archives: http://www.neonghost.com/the-dig/index.html

_Don't_ ask the maintainer (whoever that may be) to email it to you, please.


1.7 How do I submit to the FAQ?

The FAQ has no real maintainer at present. I (Mark Graybill) have contributed to the FAQ, but I'm not really the maintainer. If you have something to add to the FAQ, mention it in a post to the list. Then one of the following may happen:

-I or someone else who've had hands on the FAQ recently and have a copy handy will insert it in the FAQ and post the updated FAQ.

-Someone(s) will comment that the FAQ doesn't really have anybody maintaining it and how would you like the job? And while you're at it, go ahead and insert that bit you've posted.

-You politely regret that you are unable to dedicate the time to be a moderator since you're a programmer, not a writer. But you get the most recent copy of the FAQ and insert your bit, returning it to the communal pool afterward.


1.8 Where did the FAQ come from?

After some back and forth about FAQs in May 1997, David Schweinsberg posted a draft outline proposal for a FAQ specific to the Stella list:
http://www.biglist.com/lists/stella/archives/200005/msg00098.html


2. Getting Started

2.1 Are the 2600 and 7800 difficult to program?

The 2600 is considered one of the most difficult systems to program because of the strict timing required of any program it runs. The design of the 2600 requires the program to perform its activities in synchronization with the drawing of video data on the TV screen. Also, the system resources are very sparse, with very little space for program memory or variable data.

The video image itself is generated "on the fly" by the program, there is no video memory in which the image is stored. Only registers in the video chip store data that is to be displayed, and the values in the registers must be changed whenever the data to be displayed onscreen needs to be changed.

The Atari 7800 has more resources than the 2600, and provides significantly greater capabilities. It has been relatively untapped by programmers, however, due in large part to the encryption/digital signature system that makes its enhancements unavailable to the programmer unless the program includes an appropriate code to unlock these features. The hardware of the system can be modified to remove this protection, but it is not a trivial task.

Recently the encryption system of the 7800 has been removed as a barrier to program development. Programmers can now generate codes to give their programs access to the 7800's enhancements through commonly available tools.

Programming of both systems would be a laborious process, even beyond the problems posed by the systems themselves, if it were not for the availability of good programming tools for both systems. Emulators allow software to be tested on the development system itself, without having to transfer the software to the target system. Disassemblers allow code from existing ROMs to be reviewed for useful programming techniques. Cross-assemblers allow development on current computer systems. And so on. With respect to tools for programmers, things have never been better for programmers of these systems than they are now, and the tools themselves continue to be developed and improved.

2.2 What do I need to get started?

Here are the general steps:

-Join the mailing list, so that you can draw on the experience of the people there as well as share your own experience. 

-Obtain an emulator for the system you are planning on programming that will run on your development system to test your code. 

-Get the basic documentation on the system. 

-Get a cross-assembler for your development system, and a disassembler.

More detail on each of these steps is below.

2.3 What experience do I need?

A good foundation in 6502-family assembly language is very useful.  But since there is very little time in-between frames for the 2600 to "think", you probably 
won't need to learn much about assembly number crunching algorithms.  Most 2600 programming is simple load and store commands to the TIA registers and a careful watch of cycle times.

Otherwise, assembly language experience for other processors will do at a pinch, particularly if the experience is in programming video games on older systems like the Odyssey^2 and the Vectrex. You will find the 6502 series to be rather sparse processors compared to others with more registers and a more orthagonal instruction set, but its simplicity also makes it easy to learn.

The Atari videogame systems are not really the place to start if you don't have prior experience in these areas, though the members of the list will certainly try to help if you're sufficiently determined to try anyway. It is more advisable to start with one of the home computer systems (Apple II, Atari 400/800/XE, BBC, Commodore Pet/Vic-20/C-64/+4/128, etc.) or microprocessor trainers (KIM, AIM-65, etc.) that use a 6502-series CPU, then move to the Atari videogame systems once you've got your feet under you. You can also start with an emulator for one of these systems if you don't want to mess with the actual hardware.

2.4 What books are there on 6502 programming?

Probably the definitive work on 6502 programming is:
Programming the 6502 by Rodnay Saks (Sybex, 1978-, ISBN 0-89588-135-7)

There is also:
6502 Assembly Language Programming by Christopher Lampton (Franklin Watts, 1985, ISBN 0-531-04923-X) which specifically covers programming the Apple, Atari, and Commodore systems based on these processors.

6502 Assembly Language Programming by Lance Leventhal (Osborn/McGraw-Hill, ISBN 0-07-931027-3.)

Other good introductions to 6502 assembly programming can be found in the Commodore VIC-20 and Commodore 64 Programmer's Reference Guides, as well as The Atari Assembler by Inman and Inman (Reston Publishing Company, 1979, ISBN 0-8359-0236-6). The Commodore guides practically contain the 6502 family programmer's guides from Mostek/CSG, the chip's manufacturers. The manual for the Rockwell AIM-65 microprocessor trainer/development board is also very good.

A brief introduction to programming the 6502 can be found in Microprocessors and their Operating Systems by R.C. Holland (Pergamon Press, 1989, ISBN 0-08-037188-X), but there are some errors in the sample code where 16-bit operands are used where 8-bit ones are required.

These are only a few of the many fine books on 6502 programming that have been published. Most 6502 programming books are out of print, but they were once common enough that finding them from vendors of used technical books is not difficult. Searching at powells.com and abebooks.com or similar sites will turn them up.

There are also numerous introductions to 6502 assembly programming that were printed in magazines that covered the systems based on this processor (e.g. Compute, Compute's Gazette.) Many of these are excellent places for beginners.

2.5 Where can I find info on the internet?

There's no way to compile a complete list of all the sites that would be valuable to a 2600/7800 programmer. There are just too many that would fit from too many different points of view. The following lists should be considered as starting points, rather than as comprehensive listings.

2.5.1 Where is information specific to 2600/7800 programming on the internet?

Cyberpunks Website, the founders of the list:
http://www.geocities.com/Hollywood/1698/cyberpunks/

The Stella ML Archives, of course:
http://www.biglist.com/lists/stella/archives/

The Dig! An excavation of the information in the Stella ML archives:
http://www.neonghost.com/the-dig/index.html

Nick Bensema's comprehensive site, a must-see for any VCS programmer:
http://www.io.com/~nickb/atari/

Paul Slocum's page of projects, including music synthesis with the 2600:
http://www.mindspring.com/~paul-slocum/

2.5.2 Where is general info about the 2600 and 7800 on the internet?

A mecca of Atari information:
http://www.atariage.com/

2600 Tech info, and a mega-ROM/Supercharger project called Bankzilla:
http://tripoint.org/kevtris/2600/2600schemo.html


2.5.3 Where is more general 6502 programming and tech info on the internet?

A cornucopia of 6502 information, data sheets, projects, you name it:
http://www.6502.org/

Tech info on the 6502 used in creating arcade machine emulation:
http://www.spies.com/~arcade/simulation/processors/6502/


3.0 System Hardware Overview

3.1 What are the Atari 2600 VCS and Atari 7800? What versions of these systems are there?

For general information on these systems, consult the relevant FAQs for each system. The Atari videogame systems (2600, 5200, 7800) were once all in one document, but the 5200 was split out some time ago as it is a very different sort of system from the 2600 and 7800. The FAQs for the 2600 and the 7800 have recently been split as well, as the information unique to the 7800 has grown.

The hardware information contained in this FAQ focuses on the features from a programming viewpoint.

Atari 2600 FAQ:
http://www.atariage.com/2600/faq/index.html?SystemID=2600

Atari 7800 FAQ:
http://www.atariage.com/7800/faq/index.html?SystemID=7800

3.2 What CPU does the Atari 2600 VCS use?

This system is based on the Mostek/CSG 6507 microprocessor. This is one of the variants of the 6500 series that came in a 28-pin package for use in limited or embedded applications that do not require the features or cost of the 40-pin versions like the 6502.

>From a programmer's point of view it is practically identical to the 6502, it will run software for the 6502, with the only limitation being that instructions that specifically rely on the hardware elements of the 6502 that are not present in the 6507 will not have the same effect. They will not cause an exception if they are used, however.

The 6507 has only 13 address lines, providing an 8K address space. Addresses outside this address space can be used, with the effect that the upper bits are ignored, resulting in the appearance of a "folded" address space.

The 6507 also has no external interrupt hardware, so it is not affected be any external interrupts.

The pinout of the 6507 is as follows, for those of you who debug with a Chip Clip or an oscilloscope probe:

/RESET-| 1      28 |--Phi2
Vss----| 2      27 |--Phi0
RDY----| 3      26 |--R/W
Vcc----| 4      25 |--D7
A0-----| 5      24 |--D6
A1-----| 6      23 |--D5
A2-----| 7      22 |--D4
A3-----| 8      21 |--D3
A4-----| 9      20 |--D2
A5-----| 10     19 |--D1
A6-----| 11     18 |--D0
A7-----| 12     17 |--A12
A8-----| 13     16 |--A11
A9-----| 14     15 |--A10

This CPU was also used in many of the peripherals Atari made for their line of 8-bit computers.

3.3 What CPU does the Atari 7800 ProSystem use?

The ProSystem uses the Mostek/CSG 6502 processor. The version used is the "C" version, which is a standard 6502 that can be clocked at speeds up to 4MHz. It is an NMOS processor, not to be confused with the 65C02, which is a CMOS version of the 6502 with some programming changes, and it is not used in the 7800.

The mention of the less well-known versions of the 6502 processor used in the 2600 and 7800 often brings up questions and confusion about the processor family as a whole. There were several versions of the NMOS 6502 in different speed grades. The original 6502 was a 1MHz processor, the 6502A was functionally identical, but could be clocked up to 2MHz. The 6502B clocked up to 3MHz. And then there was the 6502C as used in the 7800, which goes up to 4MHz.

The 6507 used in the 2600 was one of many 28-pin variants of the 6502. Each of the different versions brought out different pins from among those that had been dropped from the 40-pin package to provide access to different features on the chip for different applications. Some brought out the interrupt line, but not the RDY line, for example, or dropped an address line for both, or for the NMI line. There were variations among the 40-pin versions, too, including versions that provided for separation of data and program memory spaces, added I/O, etc. For further information on the 6502 chip family, visit http://www.6502.org/.

3.4 What graphics chip does the 2600 use?

The chip used to drive the graphics in the 2600 is called the TIA (Television Interface Adapter.) It is a custom chip designed by Jay Miner at Atari for the 2600. It generates the video and audio signals of the 2600. It is controlled through a number of write-only registers that are memory-mapped into the zero page of the 2600.

The TIA directly produces composite color video signals and controls the horizontal timing of the video signal. Vertical timing control is managed by the CPU through software. This means that the software has to send the appropriate signals at the correct times to the TIA to produce a proper video signal. Without these signals, the 2600 will not produce displayable video signals. This is part of what makes programming the 2600 challenging.

3.4.1 What software features does the TIA have?

In addition to video control, the TIA provides 5 movable objects, playfield graphics, and background color control. The five movable objects are two "players", two "missiles", and a "ball". Each of the missiles has functions that relate them to one of the players. The players are displayed using a byte-wide bitmap, the missiles and ball are solid objects that have a width set by writing to the appropriate TIA control registers.

It sounds very limiting to have only 5 movable objects to display, but each object can be reused many times to produce a display that shows more than 5 objects at one time. The TIA specifically provides functions to display a single player/missile combination repeatedly (one, two, or three times per display), but there are also software techniques that can do far more.

The primary limitation to how many objects can be displayed, and how much can be done with those objects, is the time available to the programmer to execute the instructions to reuse the objects as the display is drawn. The timing is such that while it is possible to display as many as 15 (or 14 and 1/2) sprites side-by-side per scanline, there's no time left over to change the bitmap and colors of the individual sprites (so far as anyone can tell at present.)

The playfield is a bit-mapped graphics overlay with a resolution of 40 bits per scanline. It was designed to be used for background elements that are seldom changed, but it can be used far more flexibly to provide active elements of the game.

In the Atari Combat cartridge, the playfield is used to produce the mazes that the tanks are in and the clouds in the aircraft games. In Centipede, the playfield elements are used to produce the mushrooms.

The TIA will detect collisions between the different movable objects, and between the movable objects and the playfield. The collision detection can be used to trigger game effects. The TIA also controls the display priority of the different parts of the display, managing which objects will "cover" the others in the display when they are to be displayed at the same place. Software can control the priorities that the TIA uses.

3.4.2 What are the registers in the TIA and their functions?

3.5 What graphics chip does the 7800 use?

In addition to having the features of the TIA, the 7800 has a chip called the MARIA which is considerably more sophisticated than the TIA.


3.6 What I/O chip does the VCS use?

A 6532 "RIOT" chip is used. This is a version of the 6520/30 VIA (Versatile Interface Adapter) that includes 128 bytes of RAM. It is used to communicate with the console switches, and the game controllers. It also provides a single software controlled timer.

The features of the 6532 are used through a set of memory-mapped registers that allow the control of the chip as well as the reading and writing of data.

3.7 What I/O chip does the 7800 use?

3.8 What sound chip does the VCS use?

The TIA chip is not only a graphics chip but also a rudimentary sound 
chip.  It uses polynomial counters (pseudorandom number generators) and 
various clock dividers to generate different tones and distortions on those 
tones.

These tones do not match up perfectly to the diatonic musical scale.  A 
chart was created to provide relative note values and their actual 
frequency (in hertz). You can see it at The Dig! here:
http://www.neonghost.com/the-dig/dox/sound_chart.txt

3.9 What sound chip does the 7800 use?


4.0 Programming Tools

4.1 How do I test code? (The Emulator)

4.2 Where do I get coding info? (The Documentation)

4.3 How can I read other peoples' code? (The Disassembler)

4.4 How do I compile my own code? (The Cross-Assembler)

4.5 How do I make programming go faster? (Programming Environment)

4.6 How do I get my code to the 2600 hardware?

4.6.1 The Starpath Supercharger

4.6.2 The CuttleCart

4.6.3 RAM/Flash Cartridges

4.6.4 ZIF Cartridges

4.6.5 Cartridge Manufacture
If you have a cart you want made, check out Hozer Video:
http://webpages.charter.net/hozervideo/index.html

You can also make your own, for onesies you can get the basic info from Hozer video:
http://webpages.charter.net/hozervideo/atari/makecart.html

If you want to go into production, you can look into having PC boards manufactured to accept the ROMs, work with a plastic manufacturer to come up with a cart case design and put it into production, and either get the ROMs masked or burn your own. Then you just need to look into assembly services. Make sure you have a stable home life and substantial disposable income before beginning (and enjoy them while they last.)

To get PC (printed circuit) boards manufactured, you can go to any of several companies that do prototype quantities at reasonable rates. Many provide free layout/artwork software for designing your board, tutorials on how to do it, and will provide you with a quote online. Here are a couple:

http://www.pcbexpress.com/
http://www.pcb123.com/

To get the cases made, look in your phone book to find a plastics manufacturer in your area that does prototype work. You'll probably want to work with them face-to-face in designing it to make sure it doe everything you need. Having an assembled PCB along will help.

Semiconductor suppliers and manufacturers will often provide services to program parts for you. An idea: if you use flash components you can assemble the carts, then program whatever program you want into them later if you have your own programmer.

Assembly services can also be obtained locally. Look for electronics manufacturers in the area. Many of them have excess capacity on their production floor that they would be happy to sell you. Their requirements for taking on the work will vary. Some will require specific parts preparation and assembly instructions, others will take loose boxes of parts and a sample assembled board that they can use as a guide to assembling the others.

Now that you've got boxes of assembled carts (never mind the ruined marriage, empty bank account, and lost job), you're ready to get some art drawn up by a graphic artist, and labels and boxes made up by a printer. Then you need to start marketing and selling your carts.


4.7 How do I get my code to the 7800 hardware?



5.0 Basic Programming for the Atari 2600

This section provides information to allow the programmer to make rudimentary use of the 2600. Most programmers will want to develop games that are more sophisticated than these basic routines allow. More advanced techniques are covered below. The information here is not intended to be a complete tutorial, see 5.1 for some of those.

5.1 Where can I find programming tutorials?

[2600 101]

5.1 How do I start? (The Kernel)

5.2 Program Structure

5.3 How do I put something on the screen?

5.3.1 The Background

5.3.2 The Playfield

5.3.3 The Players

5.3.4 The Missiles

5.3.5 The Ball

5.4 How do I talk to the game controllers?

5.4.1 The Fire Buttons

5.4.2 The Joysticks

5.4.3 The Paddles

5.4.4 The Driving Controllers

5.4.5 The Keypads

5.5 How do I make it _do_ something?

5.5.1 Vertical Positioning and Movement

5.5.2 Horizontal Positioning and Movement

5.5.3 Collision Detection

5.6 How do I make sounds?

5.6.1 Noise

5.6.2 Music

5.7 How do I provide score and status displays?

5.7.1 The Divided Display

5.7.2 Score Displays

5.7.3 Status Displays

6.0 Basic Programming for the Atari 7800

7.0 Advanced Routines for the Atari 2600

7.1 How do I display more than two players?

7.2 How can the two halves of the playfield be different?

7.3 How can I use six digit displays?

The six digit display, also known as the six-character-display or the 
six-char is actually not digits or characters per se, but six 
sprites.  These sprites represent player 1 and player 2 cloned into 3 
copies with wide spacing, lined up in such a way that they overlap 
eachother, forming a 48-pixel block which the programmer can use to draw 
graphics.  Typically, cloned sprites must share the same graphics 
data.  However, since the 6507 is free to overwrite graphics registers 
while the scanline is being drawn, a properly timed kernal has just enough 
time to rewrite player copies inbetween the TIA's drawing operation for 
each sprite.

This is typically used in score routines, but can also be used to display 
narrow but higher-resolution blocks of graphics for things like title 
displays, or even moving objects like the drag racers in Dragster.  When 
moving these objects, a very precise time-wasting kernel is employed to 
adjust the positions and rewrite-time of the kernel.  This severely limits 
any sort of playfield manipulations.

7.4 How do I get more than 4K of ROM?

7.5 How do I get more than 128 bytes of RAM?

Since the phase2 (clock) and read/write lines were omitted from the 
cartridge port for cost purposes, RAM on the cartridge can not be supported 
through conventional means.  The Starpath Supercharger, Superchip, and CBS 
Ram Plus all provide elaborate means of providing external RAM to the 2600.

Of these, the Starpath Supercharger is probably the only one hobby gamers 
would likely support, since most who frequent Stellalist own Superchargers 
to use as development stations since game code can be downloaded into them.

7.6 How do I display text?

The 2600 has no hardware fonts or text capabilities.  These must be 
generated in software. Typically players are used to create characters using font bitmaps on the ROM.

8.0 Advanced Routines for the Atari 7800

9.0 Common Errors and Gotchas

10.0 The Zen of VCS Development

10.1 What sort of masochist does this, anyway?

The joy from 2600 programming comes from the challenge.  The challenge is 
in fitting your game into constrained memory.  While you could write a 
large banked ROM game, most people write for 4K because it's easier to 
cannibalize common cartridges (Pac-Man especially) for distribution.  4K 
also fits neatly in the Supercharger for easy debugging.

The challenge also comes in taking an idea for a game and find a way to 
make it happen given the quirks of the 2600 hardware.  The end result 
represents many individual tradeoffs of the programmer which are very 
apparent to the player in how the game looks and feels.  Now to the bad 
programmer, these limitations will get the best of him, but to the good and 
persistent programmer, he can find a middle-ground where everything becomes 
balanced.  Like working within the constraints of a rigid poetic structure 
such as haiku, a programmer's style shows through in the end product far 
more than would be evident from other systems.

Also, remember that far more is expected from games on the PC than any one 
programmer can create within a reasonable span of time.  To write a PC game 
of professional quality is beyond the scope of a hobbyist.  You could write 
a game which played like a fancy 2600 title much faster than writing for 
the 2600, but it would likely be ignored or scoffed by the PC gamer.  The 
2600 provides programmers with an individual creative outlet in which 
simplicity is an inevitability, and therefore criticisms about the art and 
the sound are eliminated.  The coder is free to focus on the core aspects 
of gameplay.  He also knows that there is a small but solid group of people 
who will really appreciate his work.

As far as comparisons with developing for other consoles, it's simply not 
viable to do grass roots development for modern consoles.  Developer 
machines are very expensive.  So some satisfaction can be gained from being 
able to actually have a game distributed in cartridge form for a real 
console system.


10.2 How do I port Quake III and Unreal Tournament to the VCS?

10.3 Is it true what they say about the VCS programmer groupies?

10.4 Is this a great way for me to make my first million?

10.5 Why should I post my code, what will the list do for me?

Game development works best when the programmer periodically shares his 
source code to the list.  This is typically done through attaching a .BIN 
file and a ZIP of the sourcecode (or just inserting it as plaintext into 
the body of the message).  The list (or peers) review the soruce code and 
often find ways for the code to be more efficient.  The less technical play 
around with the assembled BIN file.  They act as beta testers and game 
testers, finding visible bugs and offering advice in how to make the game 
look and play better.

The most critical period for game development is the last 10%.  This can be 
the most frustrating.  You've worked on your game so much you're burned 
out, but people keep on asking for new features and tweaks.  The temptation 
is to just ship it.  But if you know it can be better, and other people on 
the list help out to free up bytes and processor time, then keep whittling 
at it.  It could mean the difference between a good game, and a great one.


10.6 Won't somebody steal my amazing secret algorithm?

Um, assuming you have a way to unlock multi-MIP processing power from within the VCS you may ask yourself how you came about obtaining the skill to find it and get at it. Have you benefitted from the list's assistance or the shared tools in any way? Would you have gotten that benefit if we'd all sat in our own caves and kept our work "secret"?

If you give the same algorithm to 'n' programmers it'll end up being used in a minimum of n-cubed different ways. So even if you share it you probably won't find anyone treading on the toes of your current project. If you're doing a port of Final Fantasy IX with it, that doesn't mean that everyone else will, too. One programmer will make a Frotz interpreter so that we can all play Infocom games on our VCS's, another will use it to make the most amazing Pong variant that's ever seen the light of day. Someone else will turn out a demo that gives onlookers an intuitive understanding of four-dimensional space and a serious headache. Sharing code enriches everyone, and maybe someone else will post a tweaked version of it that trims off those last few machine cycles that have _you_ tearing your hair out.
 
Besides, we'll all see your code once you ROM it, anyway.

11.0 Sharing and Selling Your Work

11.1 How can I sell my work?

11.2 How can I market my work?

11.3 How many people will actually buy this stuff?

11.4 What will people pay for this stuff?

11.5 What are the major events I should know about?

11.6 What are the major projects that have come out of the list?