Re: My 66000 and High word facility

Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:

Brett <ggtgp@yahoo.com> writes:

The lack of CPU’s with 64 registers is what makes for a market, that 4%
that could benefit have no options to pick from.

 
They had:
 
SPARC: Ok, only 32 GPRs available at a time, but more in hardware
through the Window mechanism.
 
AMD29K: IIRC a 128-register stack and 64 additional registers
 
IA-64: 128 GPRs and 128 FPRs with register stack and rotating register
files to make good use of them.

All antiques no longer available.

The additional registers obviously did not give these architectures a
decisive advantage.
 
When ARM designed A64, when the RISC-V people designed RISC-V, and
when Intel designed APX, each of them had the opportinity to go for 64
GPRs, but they decided not to.  Apparently the benefits do not
outweigh the disadvantages.
 
Where is your 4% number coming from?

The 4% number is poor memory and a guess.
Here is an antique paper on the issue:

https://www.eecs.umich.edu/techreports/cse/00/CSE-TR-434-00.pdf

I used to be able to find better sources, but Google is full of garbage
now.