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From: Thomas Koenig <tkoenig@netcologne.de>
Newsgroups: comp.arch
Subject: Re: Calling conventions (particularly 32-bit ARM)
Date: Mon, 13 Jan 2025 21:33:32 -0000 (UTC)
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Stephen Fuld <sfuld@alumni.cmu.edu.invalid> schrieb:
> Has Lapack (and the other old style Fortran numeric 
> code that Waldek mentioned) lost its/their importance as a major user of 
> CPU cycles?

It's less than it used to be in the days when supercomputers
roamed the computer centers, but for these applications where
it matters, it can be significant.

> Or do these subroutines consume so many CPU cycles that the 
> overhead of the large number of parameters is lost in the noise?

If you have many small matrices to multiply, startup overhead
can be quite significant.  Not on a 2000*2000 matrix, though.

> Or is 
> there some other explanation for Mitch not considering their importance?

I think eight arguments, passed by reference in registers, is not
too bad.