Rev John

Can I vote "None of the Above" ?

This game was released by Sydney's "Home Entertainment Suppliers" in the plastic box with the instructions on the sleeve. As such I don't think it is particularly rare, at least in Australia. A number of these Home Entertainment Suppliers games (eg Commando, Rampage, Pitfall!, Tomcat, My Golf etc) turn up all the time on ebay and often in their packets. The red bordered version of the cart though does appear to be much rarer.

You're an Aussie? Cool, another PAL Atari is gonna get looked after. It can be hard to find new games and gear cheap but keep an eye on ebay (as dodgy as it can sometimes be) sometimes you see an Atari lot for sale near you, sometimes you get Atari stuff that no one bids for and you can get a good price. As you only have a couple of games try asking around and you might find a mate's folks have an Atari stashed away, or a nearby Atari enthusiast may have a bunch of common spares. I would also recommend using a cotton-bud and some WD40 on the electrical contacts of any carts you get, most carts will work well or even come to life with a bit of attention and you'd be protecting your system too.

Maybe best to ask on the Twin Galaxies forums? (shrugs)

He posted it back in 2006 to Stella (he called it a WIP, but IMO it looks fairly complete). The message is archived here. NOTE: the download link may show up as a .bin file...it's actually a zip. Rename the extension to open if necessary. Thanks Nukey Shay, that's excellent! benbrad - check out the dissassembled code - you can change all the graphics if you want, see how the lives get counted, or have a go at messing around with whatever aspect of the game you like. It's cool. It's the tutorial!

I just did the exercise myself for Ms Pac Man - good stuff to try yourself benbrad to learn about how the 2600 was programmed. FBh can be seen decrementing quite clearly in the debugger, looking at a quick dissassembly I can find DEC FB at 208Fh, I used a hex editor to change 208Fh and 2090h (I see I need to read up about bank switching) to 'NOP' (FAh), and came up with the attached which seems to work nicely. May I ask where I can find the dissassembled Ms Pac Man? Cheers, Rev John [EDIT: PS My first Atari hack! Yay!] MSPACMAN.BIN

There's heaps of material listed at http://www.atariage.com/2600/programming/index.html . I only discovered this a couple of weeks ago myself. I would also recommend looking at some of the dissembled Atari games at http://www.qotile.net/minidig/ . If you use the debugger on PCAEWIN you might be able to see which variable gets decremented when a life is lost. Then look for instructions that change that variable in the code, change to NOPs (No operation) or whatever as needed and re-assemble. Then hope for the best, some games have just one instruction to take away a life, others are more complex.

My thinking is that the programmer wanted to (or had to) put in some way for the game to get back into attract mode, to help prevent an image of the unfinished game being burnt permanently onto the screen. ie to go back into screen saver mode. The code is written to wait a suitably long time (approx 255 x 256 frames / 17 minutes) when someone stops playing and leaves the screen potentially vulnerable. However the 'attractModeTimer' variable never resets during normal play, so it appears to be a bug that the game will eventually reset during normal play when there is no problem of damage to the screen. I'm curious as to whether other Atari games have a similar reset / intervention feature to prevent the screen image from remaing the same during play?

Pardon me if I'm resurrecting an old thread, but this is my first post to AA so I plead ignorance! The resetting problem in Berzerk can occur if someone accrues more than 127 lives, but is more likely to be happening because of the piece of code below (with thanks to Dennis Debro who did the original dissassembly). Essentially Berzerk has an undocumented doomsday clock aka 'attractModeTimer' which increments if the joystick is in the neutral position every 256th frame. When the attractModeTimer rolls past 255 the game resets. I figure this gives the gamer a cumulative total of approx 17 minutes of 'not moving the joystick' time before the game resets. ReadJoystickValues lda #0 sta temp02 lda #127 sta randomNumberMax ; set random number ceiling lda SWCHA ; read the joystick values lsr ; shift player1's values to lower nybbles lsr lsr lsr eor #$0F ; flip the bits so high bit shows movement and #$0F ; mask the upper nybbles bne .setPlayerDirection lda #PLAYER_STAND_ANIM_OFFSET sta playerAnimationIndex sta playerGraphicLSB sta playerMotion ; reset player fractional movement delay lda frameCount ; get current frame count bne CheckForFireButtonPressed ; branch if not rolled over from 255 inc attractModeTimer ; increment attract mode timer bne CheckForFireButtonPressed ; branch if not rolled over from 255 lda gameSelection ; get current game selection jmp SetGameSelection ; make game go into attract mode