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Re: digest algorithm performance

From: Paul Eggert
Subject: Re: digest algorithm performance
Date: Tue, 21 Jun 2005 23:50:50 -0700
User-agent: Gnus/5.1006 (Gnus v5.10.6) Emacs/21.4 (gnu/linux)

One more data point: I tweaked my copy of the coreutils code to use
asms for the "obvious" things, in particular, to use the byte-swapping
instructions on the x86 instead of the complicated expression
involving shifting and masking.

The measured performance went down.

That is, it took more instructions for GCC 4.0.0 to get the data into
the "right" registers and use the byte-swap instruction than for it to
simply do the shifts and masks itself.  A humbling experience....

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