Douglas Butler wrote:
> If you can still get the parts, it might be fun to build your own
> bit-slice CPU.  Design and build the registers, ALU, instruction
> decoders, etc. yourself.  My friend did this in 1982 as his senior
> project in college.  He used 4 bit bit-slice parts to make a 36 bit CPU.
>  The logic was static so he could single step the clock phases for
> debugging.  I think his max clock speed was about 100kHz.  It could do a
> 36x36 multiply in the blink of an eye - if you didn't blink too fast!

Neat idea - but I think all those parts are made of unobtanium now.
Bit-slice CPUs have certainly gone the way of the dodo. Even a lot of
the MSI TTL stuff that you would have used in a CPU design - ALUs and so
forth - have been discontinued. (You might be able to make replacements
for some of the functions out of PALs.) Bipolar PROMs - another mainstay
of such designs - are history, too, though CMOS parts have gotten fast
enough that they might be able to fill in - or, if not, you could use
SRAM that was loaded from ROM at boot time.

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