Date: Mon, 28 Nov 2005 06:15:10 +0000 (UTC) From: Bruce Evans <bde@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/lib/msun/src s_cosf.c s_sinf.c Message-ID: <200511280615.jAS6FACG052829@repoman.freebsd.org>
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bde 2005-11-28 06:15:10 UTC
FreeBSD src repository
Modified files:
lib/msun/src s_cosf.c s_sinf.c
Log:
Exploit skew-symmetry to avoid an operation: -sin(x-A) = sin(A-x). This
gives a tiny but hopefully always free optimization in the 2 quadrants
to which it applies. On Athlons, it reduces maximum latency by 4 cycles
in these quadrants but has usually has a smaller effect on total time
(typically ~2 cycles (~5%), but sometimes 8 cycles when the compiler
generates poor code).
Revision Changes Path
1.14 +2 -2 src/lib/msun/src/s_cosf.c
1.14 +2 -2 src/lib/msun/src/s_sinf.c
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