Date: Thu, 15 Jan 2009 12:19:16 -0800 From: Chuck Swiger <cswiger@mac.com> To: Dan Nelson <dnelson@allantgroup.com> Cc: Michael Powell <nightrecon@verizon.net>, freebsd-questions@freebsd.org Subject: Re: kernel configuration Message-ID: <1F87C1DC-A8B3-4FFC-9BA8-AC4F7F38336F@mac.com> In-Reply-To: <20090115193147.GA61100@dan.emsphone.com> References: <496E06D1.2070706@gmail.com> <20090114181522.GB4487@aurora.oekb.co.at> <B4DD918A-6026-4206-9C14-70DCD0028CFB@mac.com> <gknt72$39i$1@ger.gmane.org> <20090115193147.GA61100@dan.emsphone.com>
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On Jan 15, 2009, at 11:31 AM, Dan Nelson wrote: > Actually, those functions are only enabled if the CPU is truly a > 586-class processor. See /sys/i386/isa/npx.c , the npx_attach() > function. There is a test for cpu_class==CPUCLASS_586, while most > modern CPUs are CPUCLASS_686. Thanks for the additional feedback, Dan. I remember some weirdness around things like the VIA C3 "Centaur" processors, which had CMOV feature and claimed to be a 686, but lacked SSE...not that those were an especially common case, but I still have one floating around. I see 686- and SSE2-optimized pagezero routines in support.s, but I don't see equivalents for bzero, bcopy, and copyin/copyout. Is something like generic_bzero() faster on a 686-class CPU than i586_bzero() would be? Regards, -- -Chuck
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