1dnl  x86 pentium time stamp counter access routine.
2
3dnl  Copyright 1999, 2000, 2003, 2004, 2005 Free Software Foundation, Inc.
4dnl
5dnl  This file is part of the GNU MP Library.
6dnl
7dnl  The GNU MP Library is free software; you can redistribute it and/or
8dnl  modify it under the terms of the GNU Lesser General Public License as
9dnl  published by the Free Software Foundation; either version 3 of the
10dnl  License, or (at your option) any later version.
11dnl
12dnl  The GNU MP Library is distributed in the hope that it will be useful,
13dnl  but WITHOUT ANY WARRANTY; without even the implied warranty of
14dnl  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15dnl  Lesser General Public License for more details.
16dnl
17dnl  You should have received a copy of the GNU Lesser General Public License
18dnl  along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.
19
20
21include(`../config.m4')
22
23
24C void speed_cyclecounter (unsigned p[2]);
25C
26C Get the pentium rdtsc cycle counter, storing the least significant word in
27C p[0] and the most significant in p[1].
28C
29C cpuid is used to serialize execution.  On big measurements this won't be
30C significant but it may help make small single measurements more accurate.
31
32PROLOGUE(speed_cyclecounter)
33
34	C rdi	p
35
36	movq	%rbx, %r10
37	xorl	%eax, %eax
38	cpuid
39	rdtsc
40	movl	%eax, (%rdi)
41	movl	%edx, 4(%rdi)
42	movq	%r10, %rbx
43	ret
44EPILOGUE()
45