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/*************************************************************************
* Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The Sandglass Library. *
* *
* The Sandglass Library is free software; you can redistribute it *
* and/or modify it under the terms of the GNU Lesser General Public *
* License as published by the Free Software Foundation; either version *
* 3 of the License, or (at your option) any later version. *
* *
* The Sandglass Library is distributed in the hope that it will be *
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty *
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
/*
* Return the time stamp counter, and serialize the instruction
*/
.text
/* long sandglass_get_tsc(); */
.globl sandglass_get_tsc
.type sandglass_get_tsc, @function
sandglass_get_tsc:
movq %rbx, %rdi /* Callee-save register, clobbered by cpuid */
xorl %eax, %eax /* Make cpuid do a consistent operation */
cpuid /* Serialize */
rdtsc /* Read time stamp counter */
shlq $32, %rdx
orq %rdx, %rax
movq %rax, %rsi
xorl %eax, %eax
cpuid /* Serialize again */
movq %rsi, %rax
movq %rdi, %rbx
ret
.size sandglass_get_tsc, .-sandglass_get_tsc
/*
* Return the granularity of the TSC
*/
/* unsigned int sandglass_tsc_loops(); */
.globl sandglass_tsc_loops
.type sandglass_tsc_loops, @function
sandglass_tsc_loops:
rdtsc /* Read time stamp counter */
movl %eax, %ecx
.Lrdtsc:
rdtsc /* Read counter again */
subl %ecx, %eax
jz .Lrdtsc /* If we got the same value, try again */
ret
.size sandglass_tsc_loops, .-sandglass_tsc_loops
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