“Now Go Bang!” is named after a source comment in Spacewar!, the first digital video game. It marks the very instance, when a spaceship which has been dragged into the gravitational star starts to explode. What follows, is impressionist pixel-dust floating along the ship’s former trajectory in a sparkling bloom of phosphor activation.
In 1704, a French Domican priest described 30 patterns of tiles, now they are on the PET.
Yesterday, Robin “8-Bit Show And Tell” released a YouTube video, demonstrating an implementation for the Commodore 64 of all the 30 original Truchet tile patterns (made of just 4 standard tiles), as described by Sébastien Truchet in his “Mémoire sur les combinations” in 1704. Since the program was made available in the video discription, I downloaded it and ported it to the PET (any 40-column PETs, that is.)
Here’s the result (reverse-engineered from binary, adapted and re-assembled):
>Emulation: run it online…(press any key to cycle through the 30 patterns)
A proper account of the deplorable life and times of the LIST routine in Commodore BASIC.
In our last installment we had a closer look into the tokenizer routine (also known as CRUNCH) in Commodore BASIC. This time, we follow up on this by closer look into the reverse operation, namely the “LIST” command, which — among other things — has to expand the various BASIC tokens into human readable keywords back again. What could possibly go wrong?
Curious adventures in (Commodore) BASIC tokenizing.
No, this is not about a one-hit-wonder from the charts of 1977, rather, it is about something that could have happened on a Commodore PET around this time. For this installment, it’s all about #BASIC tokenizing, and, as this promises some #6502 fun, we really ought to investigate…
There are times when your 6502 code doesn’t behave, where it steers off of its path into directions, never intended, when it runs away. The new debugging traps for the PET 2001 emulator are meant for exactly those times. And they may be helpful for reverse engineering, as well. Simply put, they are for those “How did we end up here?” moments. And the “Holy electron, Batman, what’s happening?” moments, as well.
WDC and Rockwell related additions to the 6502 instruction set sheet.
Just added Western Design Center (WDC) and Rockwell extensions to the standard instruction set of the 6502 processor to the well-received 6502 Instruction Set page. There’s now an additional view option for the instruction table, as well as new sections providing details on WDC 65C02(S) specifics and Rockwell extensions (linked at the top of the page) for their respective variants of the venerable 6502. Moreover, in order to avoid confusion, the section on “illegal” opcodes is now marked as specific to the original NMOS version.
While WDC’s 65C02 is really the only version of the 6502 still in production, the fact that WDC-datasheets are neither the clearest, nor the most complete, may have contributed to a relative obscurity of the additional instructions and behavioral differences. Maybe, including them in a one-stop documentation will help, just a bit? Or even eight? ;-)
Also, as a minor improvement, the page should be now easier to tab through (lots of tabinidces).
The original line-up of Commodore PET computers at a glance.
While Commodore PETs are quite easily and unmistakably identified by their unique form factor, the basic model evolved quite a bit over the years. Here’s a comprehensive guide to the various models of the original line-up (not including the later series with rounded case and separate keyboard) and their basic features.
