i386_gettimeofday_asm.s [plain text]
/*
* Copyright (c) 2003-2007 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <sys/appleapiopts.h>
#include <machine/cpu_capabilities.h>
#define NSEC_PER_SEC 1000*1000*1000
#define NSEC_PER_USEC 1000
.align 4
.private_extern ___commpage_gettimeofday
___commpage_gettimeofday:
push %ebp
mov %esp,%ebp
push %esi
push %ebx
0:
movl _COMM_PAGE_GTOD_GENERATION,%esi /* get generation (0 if disabled) */
testl %esi,%esi /* disabled? */
jz 4f
call _mach_absolute_time /* get nanotime in %edx:%eax */
sub _COMM_PAGE_GTOD_NS_BASE,%eax
sbb _COMM_PAGE_GTOD_NS_BASE+4,%edx
mov _COMM_PAGE_GTOD_SEC_BASE,%ebx /* load all the data before checking generation */
mov $ NSEC_PER_SEC,%ecx
cmpl _COMM_PAGE_GTOD_GENERATION,%esi /* has time data changed out from under us? */
jne 0b
div %ecx
add %eax,%ebx
mov $ NSEC_PER_USEC,%ecx
mov %edx,%eax
xor %edx,%edx
div %ecx
mov 8(%ebp),%ecx
mov %ebx,(%ecx)
mov %eax,4(%ecx)
xor %eax,%eax
3:
pop %ebx
pop %esi
pop %ebp
ret
4: /* fail */
movl $1,%eax
jmp 3b