Date: Tue, 29 Jun 1999 19:29:22 -0700 (PDT) From: Geff Hanoian <boing@kusanagi.boing.com> To: darius@dons.net.au Cc: frodef@acm.org, freebsd-stable@FreeBSD.ORG Subject: RE: MMX Message-ID: <199906300229.TAA06545@kusanagi.boing.com> In-Reply-To: <XFMail.990630103147.darius@dons.net.au>
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On 30 Jun, Daniel J. O'Connor wrote:
>
> On 29-Jun-99 Frode Vatvedt Fjeld wrote:
>> What is the preferred way for my application to determine if the CPU
>> is MMX-capable?
What about taking the code from /usr/src/sys/i386/i386/identcpu.c?
(and which ever defines, etc are necessary). Can users execute such
code without special privledges and after boot time?
-----
static void
do_cpuid(u_int ax, u_int *p)
{
__asm __volatile(
".byte 0x0f, 0xa2;"
"movl %%eax, (%2);"
"movl %%ebx, 4(%2);"
"movl %%ecx, 8(%2);"
"movl %%edx, 12(%2);"
: "=a" (ax)
: "0" (ax), "S" (p)
: "bx", "cx", "dx"
);
}
----
do_cpuid(1, regs);
cpu_id = regs[0]; /* eax */
cpu_feature = regs[3]; /* edx */
----
cpu_feature appears to contain a "feature set".
Geff
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