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Message-ID: <4fa335fefab972925ce2eac6500a232a@smtp.hushmail.com>
Date: Mon, 7 Sep 2015 19:38:21 +0200
From: magnum <john.magnum@...hmail.com>
To: john-dev@...ts.openwall.com
Subject: Intrinsics experiment with CPP macros
Solar, all,
https://github.com/magnumripper/JohnTheRipper/issues/1720
A little experiment is currently in the cpp-intrinsics topic branch.
Specifically 51f3fe6 for now.
To the formats, nothing changed. But eg. SIMDmd4body() is now a
function-like macro that will optimize away some branching and make the
actual functions smaller (this could be taken further).
Currently only MD4 & MD5 are done, and more could be done to them. What
is done, is there are now (behind the curtain) two different functions -
one for single (or first) block and another for "reload". Also, the
"flat to interleaved" is moved to a separate function and that is also
hidden by PP macros (optimized away unless needed since SSEi_flags are a
constant).
Boost seems to be 5-10% depending on format. Still, I'm not quite sure
we want to walk this path at all?
One effect of this (version) is we now have two copies of the core
MD4(w, a, b, c, d) function inside simd-intrinsics.c. The good thing
about that is the optimizer may do some good stuff with the beginning of
the "non-reload" version since a, b, c and d are now constants but I'm
not sure the optimizer actually manages to do that with intrinsics (for
plain C or OpenCL I'm pretty sure it does).
Perhaps we can do this in a different (and better) way, or perhaps this
is fine. Or perhaps we should forget about this whole idea, for
easier-to-follow code. I have no opinion yet, I'm just experimenting.
magnum
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