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From: mitchalsup@aol.com (MitchAlsup1)
Newsgroups: comp.arch
Subject: Re: My 66000 and High word facility
Date: Sat, 10 Aug 2024 21:12:12 +0000
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On Sat, 10 Aug 2024 18:17:54 +0000, Brett wrote:

>
> My 66000 should look into the z/architecture High Word Facility as that
> would give you another 65% more registers or so. You have the opcode
> space and it is Another nice boost for some customers.
>
> IBM supports Linux, so the compiler support should exist. X86 solved the
> aliasing issue with finer tracking.

x86 (the x is lower case) solved the problem at great cost to various
implementations. The AMD *doze family could not perform forwarding of
these lower or upper portions of registers and its performance suffered.
The high/low stuff makes it very difficult to do forwarding when the
clock cycle is less than 14-gates per cycle.

After x86 grew out of its 8-register only enclave and went with 16
(later
32) GPRs; register pressure went down markedly.
>
> Thanks,
> Brett