Subject: Re: [stella] Megacart Specs From: bwmott@xxxxxxxxxxxx Date: Mon, 13 Apr 1998 10:04:04 -0400 (EDT) |
> At 09.26 12/04/98 -0400, bwmott@xxxxxxxxxxxx wrote: > > >It has some sort of pointer registers in it. The idea is that you set > >the register to point somewhere in the ROM then each time you read > >from the register it automatically increments the pointer to the next > >address. This saves you from having to do that manually. These pointer > >registers also have bounds on them I believe. When the pointer is outside > >the bounds the data read is always zero. > > Do you know how this feature was used in Pitfall 2, besides the background > soundtrack? It's been a while since I looked at the Pitfall 2 code, but I seem to recall that it used these registers for sound as well as graphics. I'm almost positive that it was using them for loading the playfield graphics and I believe it used them for player graphics as well. It seems to me that these registers could be used for just about anything sound, graphics, and colors. Basically the game's kernel could consist of reading from these registers and sticking the values in the correct TIA registers. Then during VBLANK you could setup the pointers for the next frame. I guess for complex games you might reset the pointers several times during a frame. Brad -------------------------------------------------------------------------- Bradford W. Mott (bwmott@xxxxxxx) Computer Science Department http://www4.ncsu.edu/~bwmott/www North Carolina State University -------------------------------------------------------------------------- -- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/stella.html Don't post pirate BINs to Stellalist. Be a programmer, not a pirate. Write the best game, win framed autographs of famous Atari alumni!!
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