Date: Thu, 25 Oct 2001 15:19:35 -0700 From: Luigi Rizzo <rizzo@aciri.org> To: Doug Rabson <dfr@nlsystems.com> Cc: John Baldwin <jhb@FreeBSD.org>, Jonathan Lemon <jlemon@FreeBSD.org>, cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org Subject: Re: cvs commit: src/sys/dev/fxp if_fxp.c Message-ID: <20011025151935.G57392@iguana.aciri.org> In-Reply-To: <20011025231245.K549-100000@salmon.nlsystems.com> References: <20011025143748.C57392@iguana.aciri.org> <20011025231245.K549-100000@salmon.nlsystems.com>
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> > does it mean that integer multiply in the kernel is bad on the ia64 :) > > Not really - its reasonably quick. They just didn't bother to add any > integer multipliers when there were two perfectly good floating point > units going idle. Moving integers in and out of float registers is quick > and easy so it actually makes sense. Divides are done with floating point > too. the point for not having FP in the kernel is not speed, but rather the fact that you do not have to save those registers in a context switch. This could just be an artifact of ancient times where FPU's were separate units... So, i guess the FP registers are saved in the IA64 context switch routines ? luigi To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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