
Insanity 4004 – Experiments with the world's first microprocessor - userbinator
http://insanity4004.blogspot.com/
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spicybright
For those unaware, this is a 4 bit CPU! I'm assuming everyone moved to 8 bits
after realizing how little you can do with 4.

It would be neat to code some asm for this to do some addition and such to
really feel the limitations on it.

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mjcohen
One of the first computers on the west coast, the SWAC, built in 1950, had a
4-bit op code
([https://en.wikipedia.org/wiki/SWAC_(computer)](https://en.wikipedia.org/wiki/SWAC_\(computer\))).

For a year, it was the fastest computer in the world.

I enjoyed programming it in the early 60's. I even wrote an assembler for it
that ran on the 1401.

It had a 36-bit word - 4-bit op code and 4 8-bit addresses. It had 256 words
of Williams tube memory. It took up a whole room.

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kqr2
How about experiments with the 1-bit microprocessor?

[https://en.wikipedia.org/wiki/Motorola_MC14500B](https://en.wikipedia.org/wiki/Motorola_MC14500B)

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doctorshady
From an engineer I talked to who worked with one of these, apparently you can
use a toggle switch to single step the processor and do all manner of weird
things with it.

That being said, I wonder if you can kluge pulse-density modulation (think:
oversampled, 1-bit audio streams. Popular on a lot of nineties DACs) out of
something like this.

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stevekemp
There are other chips like that which can be single-stepped. The one that I've
driven with a push-button wired to the clock-input would be the Z80.

The z80 is very tolerant to slow clocks, letting you pulse every second or two
to step forwards and watch the data & I/O lines in real-time.

