Date: Mon, 5 Jul 1999 08:27:59 +1000 From: Peter Jeremy <jeremyp@gsmx07.alcatel.com.au> To: freebsd-stable@FreeBSD.ORG Subject: Re: MMX Message-ID: <99Jul5.081031est.40334@border.alcanet.com.au> In-Reply-To: <377C84BF.33E147F2@cs.strath.ac.uk>
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Roger Hardiman <roger@cs.strath.ac.uk> wrote: >Here is the almost proper way to determine if a CPU has MMX support. >I say _alomost_ because it uses the CPU-ID instruction. >This instruction is not on 386 machines or some early 486 machines. The Intel 486 manual (that I have at home) includes `official' code for determining what processor (8086 thru pre-CPUID 80486) you are running on. I'd suspect a later version would include testing for the presence of CPUID. I believe the code will run in user-mode. That said, I think the correct approach is a hook to allow a user-mode program to query the kernel (which has already determined what CPU it's running on). I'm not sure whether this should be an extension of an existing syscall, or a sysctl variable. Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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