Date: Tue, 22 Feb 2005 11:03:00 -0800 From: Nate Lawson <nate@root.org> To: David Schultz <das@FreeBSD.ORG> Cc: cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/lib/msun/i387 Makefile.inc e_atan2.S e_atan2f.S s_atan.S Message-ID: <421B81E4.6080909@root.org> In-Reply-To: <20050222135251.GB29054@VARK.MIT.EDU> References: <200502211604.j1LG4NNx037623@repoman.freebsd.org> <421B24E2.7050800@portaone.com> <20050222135251.GB29054@VARK.MIT.EDU>
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David Schultz wrote: > By the way, here are some other results for the Pentium 4, all > without SSE. SSE makes things a bit worse, probably because the > x87 and SSE registers are shared, and the Pentium 4 imposes a > large penalty for switching between the two sets. I don't believe this is correct. MMX and x87 use the same register context (hence emms), however the XMM registers (SSE*) are separate. It's possible gcc is generating MMX instructions though with your SSE command line switch. -- Nate
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