I just posted a new version of the BTP2 demo in the homebrew forum here. Amazing what a poor little 6507 can do. Interestingly, this demo doesn't use any undefined opcodes except for the three-cycle NOP, and it probably doesn't need even that (BIT would probably work just as well).
Here's a demo of an RPG kernel which should be quite practical in a 4A50 cart or maybe even the SuperCharger. It would require self-modifying code, but not obscene amounts (256 bytes per row, so 2.25K for a nine-row display); a SuperCharger implimentation would probably be reasonable also.The kernel supports a 9x9 display of 8x16-pixel characters with eight pseudocolors at 30Hz flicker (each character can contain two real colors, and they can be blended if desired). The graphics here aren't th
Haven't posted in awhile, but I've been working on some things.
-1- Paddle fixer. Simple little circuit that should allow paddles to work beautifully even when dirty.
-2- EEPROM enhancement for AA cart.
-3- Ruby Runner
-4- The 4A50 programmer. My current programmer works, but it only runs under DOS (ugh). So I'm working on a version that will connect via serial port and run under Windows (easily adaptable for Linux/Macintosh/whatever).
-5- EEPROM emulation for Z26 (I'll of
Here's a kernel demo which might be useful for the game Archon. For demo purposes it can run as either 3F bankswitching (use the -g11 switch in Z26) or as 4A50. A banking file is included for Cuttle Cart 2 users.
I've just been feeling like doing minikernels lately. I don't know why. Maybe 'cos they offer a nice quick challenge.My latest minikernel was an effort to try doing the Warlords shields and kings all with player sprites, so as to free up missiles for additional fireballs. Turns out I forgot that NUSIZx affects missiles as well as players (grrr...) but the code is still somewhat interesting as it manages a single-line kernel with two 16-pixel-wide kings on the same scan line as two movable shi
Some gamers love paddles. And for some games, they can be the best form of control.Many 2600 programmers hate paddles. They're a pain in the tush to read, since the programmer has to observe, with about a scan line's precision, when the paddle input changes shape.Fortunately, it's possible to ease the requirements for reading paddles considerably if one uses a little trick: although many games reset the paddle timing circuit at the start or end of VSYNC or VBLANK, there is no requirement that
The original "Wormy", written by a young man named Matt Gokey, was a Commodore 64 game (written in BASIC) in which the player would move a snake around the screen to collect all the goodies while avoiding mines (or his tail). Very much like Commodore's VIC-20 game Slither, except that the screen was filled with non-moving goodies and obstacles rather than having randomly-appearing targets. My first real game on the PC (CGA) was a variation called "Wormy II", which smoothly animated the snake's
Here's a rough banking file to run 4A50-format banking on the CC2, along with a little test program. The banking file has a slight bug which this program works around. In particular, the hotspots at $7Fxx don't work unless they are immediately preceded by a read operation which fetches a value $60-$6F (should be $60-$7F). It's possible to work around this this by banking a page full of the value $60 into address $1Exx, and then using "LDA $1EFF,Y" to do the read (with a Y value one higher tha
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