On 2019-09-21, Yousuf Khan wrote:
What's your guess? 100 instructions? 50 instructions? 10? Would you
believe just 1 instruction!? And that instruction is implied, you don't
even need an opcode for that! And you're not going to believe what that
one instruction is either! This video explains how it's possible.

https://youtu.be/jRZDnetjGuo

Interesting. In terms of commercially-successful CPUs the most minimal
I've worked with was the DEC PDP-8, which had 8 instructions (3-bit opcode).
However, one of those (OPR) permitted the programmer to combine several
operations into one instruction cycle by setting the appropriate bits.

The PDP-8 was a 12-bit word-oriented machine sold from 1965-1979. Early
models used discrete transistors, the last models were CMOS microprocessors.
There was also a serial model that operated on one bit at a time - slow!!
No stack was employed - subroutines worked via the caller writing the
return address into the first word of the called routine. Fun times!

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Roger Blake (Posts from Google Groups killfiled due to excess spam.)

NSA sedition and treason -- http://www.DeathToNSAthugs.com
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