“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.
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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.
It’s that time of the year, again…
This year’s seasonal tribute: a PETSCII animation based on a popular cross-stitch pattern.
Users are kindly requested to imagine that trademark eerily fluttering 1950s UFO sound effect that I find hard to achieve on the PET’s “CB2” sound*.
>Emulation: run it online…
*) In case you were to ask, “What is CB2-sound?”
Well, the PET doesn’t feature sound, at all. But you can hook up a speaker to the output of a serial shift-register, creatively named “CB2”, which may be manipulated to output audible frequencies, sampling sound by a single bit at 1 MHz. This is CB2-sound.
*****
The already tradional PET recreation of an animated screen of the 1982 Christmas Demo for the C64 has also received an update: it now fits into 4K of RAM and allows for easy updates, as the year is now stored in a dedicated variable at the very top of the BASIC program text.
Y to zero to omit the output of the year entirely.)>Emulation: run it online…
The Japanese character ROM and keyboard come to the PET 2001 emulator.
Another update to the PET 2001 emulator, spefically, a tribute to Japan and its importance to home computing history in general, and its role for Commodore in particular.
A new game for the Commodore PET, also, how to detect keyboards on a Commodore PET.
Rumors that I am might be writing a game (or is it a playable joke?) are not entirey unfounded. Also, another (maybe helpful) note on PET keybords and how to detect them.
A curious case of jumper settings for PETs with the dynamic system board.
The curious tale of a PET, two jumpers, and some funny games…
A visual tour.
So a few words on the debugger for the PET 2001 emulator: this is meant to help you around with 6502 machine code on the virtual PET, both for exploring existing software and testing your own code.
Be my guest on a visual tour…
Adventures in MS BASIC (Commodore PET edition).
As it happens, I recently added a debugger to the PET 2001 emulator, with the expressed purpose of facilitating code reverse engineering. To celebrate this, we’ll risk a glimpse into a peculiar bug — or is it a feature? — of the BASIC flavor found on Commodore’s PET computers. Particularly, it’s about BASIC bailing out into a warm start, whenever an empty string is entered by just pressing RETURN on the INPUT prompt.
New 6502 emulator feature: Instruction preview with resolved operands.
A new feature for the 6502 emulator: Now, there’s an instant preview for the effects of the next instruction to be executed, with effective values and operands resolved.
E.g., given the following memory and register content,
$2004: $88 $0044: $04 ;<$2004 $0045: $20 ;>$2004 X: $04
the emulator will show the following preview for the instruction `A1 40` or “LDA ($40,X)”:
A ⇐ $88
resolving the X-indexed addressing and showing the effective value, which will be assigned to the A register (accumulator).
Or, for an ASL instruction, it may show this (depending on the content of A):
A ⇐ C < |10001000| < 0
And, for the instruction `CE 04 20` or “DEC $2004”, it may show:
[2004] ⇐ $88 - 1
Thanks to this preview of the effective values, which will be actually used, complex behavior may be followed more easily and common errors, like forgetting “#” to mark up immediate operands in the assembler (and using zeropage mode instead — the dreaded “LDX $00”), should become pretty obvious.
(I’m not aware, whether there is prior art for this idea or not.)
And, by popular demand, there is now a “RST” button, sending a RESET signal to the emulator.
☛ Try the 6502 emulator.