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From: Michael S <already5chosen@yahoo.com>
Newsgroups: comp.arch
Subject: Re: Keeping other stuff with addresses (was: What is an N-bit
 machine?)
Date: Sat, 30 Nov 2024 19:32:06 +0200
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On Sat, 30 Nov 2024 16:57:56 GMT
anton@mips.complang.tuwien.ac.at (Anton Ertl) wrote:

> Thomas Koenig <tkoenig@netcologne.de> writes:
> >Anton Ertl <anton@mips.complang.tuwien.ac.at> schrieb:  
> >> anton@mips.complang.tuwien.ac.at (Anton Ertl) writes:  
> >>>John Levine <johnl@taugh.com> writes:  
> >>>>These days I'd say the relevant N is the size of arithmetic
> >>>>registers but a lot of marketers appear to disagree with me.  
> >>>
> >>>Which arithmetic registers on an Intel processor?  The 64 bits of a
> >>>GPR?  The 128 bits of an XMM register?  The 256 bits of a YMM
> >>>register?  The 512 bits of a ZMM register?  
> >>
> >> The Cray-1 is even more interesting in that respect.  Is it a
> >> 4096-bit machine?  
> >
> >If you consider the widest arithmetic it is capable of in one piece,
> >it is a 64-bit machine.  
> 
> That's not John Levine's criterion.
> 
> BTW, with your criterion, the Zen5 in the Ryzen AI 370HX is a 256-bit
> machine, while the Zen5 in the Ryzen 9600X is a 512-bit machine.
> According to John Levine's criterion they are both 512-bit machines.
> According to me they are both 64-bit machines.  John Levine's and my
> criteria are architectural, yours is implementation-oriented.
> 
> - anton

John Levine said "arythmetic". Not logic, not move, not swizzle, not
load/store. The widest arythmetic on Intel/AMD is 64 bits for inputs and
128 bits for output (integer multiplication).
On IBM processors, both z and POWER, they have arithmetic instructions
with 128-bit inputs. I think, on POWER some of them are even integer
arithmetic. Not sure about z.