pthread_mutex_lock.s [plain text]
/*
* Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
*
* @APPLE_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. 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_LICENSE_HEADER_END@
*/
#include <machine/cpu_capabilities.h>
.text
.align 2
.globl __commpage_pthread_mutex_lock
__commpage_pthread_mutex_lock:
pushl %ebp // set up frame for backtrace
movl %esp,%ebp
pushl %esi
pushl %edi
pushl %ebx
xorl %ebx,%ebx // clear "preemption pending" flag
movl 20(%esp),%edi // %edi == ptr to LVAL/UVAL structure
lea 20(%esp),%esi // %esi == ptr to argument list
movl _COMM_PAGE_SPIN_COUNT, %edx
movl 16(%esi),%ecx // get mask (ie, PTHRW_EBIT etc)
1:
testl 0(%edi),%ecx // is mutex available?
jz 2f // yes, it is available
pause
decl %edx // decrement max spin count
jnz 1b // keep spinning
2:
movl $(_COMM_PAGE_PFZ_MUTEX_LOCK), %ecx
call *%ecx
testl %ebx,%ebx // pending preemption?
jz 3f
pushl %eax // save return value across sysenter
call _preempt
popl %eax
3:
popl %ebx
popl %edi
popl %esi
popl %ebp
ret