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From: Robert Finch <robfi680@gmail.com>
Newsgroups: comp.arch
Subject: Tonights Tradeoff
Date: Fri, 6 Sep 2024 22:27:40 -0400
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Making the scalar register file a subset of the vector register file. 
And renaming only vector elements.

There are eight elements in a vector register and each element is 
128-bits wide. (Corresponding to the size of a GPR). Vector register 
file elements are subject to register renaming to allow the full power 
of the OoO machine to be used to process vectors. The issue is that with 
both the vector and scalar registers present for renaming there are a 
lot of registers to rename. It is desirable to keep the number of 
renamed registers (including vector elements) <= 256 total. So, the 64 
scalar registers are aliased with the first eight vector registers. 
Leaving only 24 truly available vector registers. Hm. There are 1024 
physical registers, so maybe going up to about 300 renamable register 
would not hurt.