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Comment by mrintellectual | Hacker News Reader

My vote for worst CPU goes to the iAPX 432 (also not on this list).

Wow, a garbage collector implemented inside of the processor. Chip level support for objects. You can't fault Intel for their ambition here, just their common sense.

And the whole thing is built for a world where everybody is writing code in Ada. I bet some compiler makers were salivating at the prospect of collecting all of those huge license fees from developers.

It was a different time - memory/CPU speed trade-offs were very different - we saw RISC once we were able to move cache on-chip (or very very close) - but at that point CISC made sense and the 432 pushed CISC to the extreme.

IMHO the x86 won out (an d is still with us) because of all the CISCs of its time it was the closest to RISC when memory started to get a lot faster (almost all instructions make at most 1 memory access, few esoteric memory operations etc)

All instructions take at least 1 memory access. All instructions that do memory access need at least 2 memory accesses.

I once encountered a note from one of the people working on iAPX 432, claiming that the core idea of high level cpu wasn't really the issue it tanked, but project mismanagement and horrible design applied which resulted in a chip that would be technologically at home... In 1960s, just done in VLSI - one of the things I recall were issues with actual physical implementation of the memory data paths resulting in horrible IPC

I was looking for this as well. It should be on there for introducing a completely new architecture, costing more, and underperforming contemporary products from Intel's catalog.

When I saw the headline I expected the iAPX to be number one on the list.

Isn't the i860 the inheritor of iAPX 432 design details?

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