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>
#define PTHRW_LVAL 0
#define PTHRW_UVAL 4
.text
.align 2
.globl __commpage_pthread_mutex_lock
__commpage_pthread_mutex_lock:
pushq %rbp // set up frame for backtrace
movq %rsp,%rbp
pushq %rbx
xorl %ebx,%ebx // clear "preemption pending" flag
movl $(_COMM_PAGE_SPIN_COUNT), %eax
1:
testl PTHRW_LVAL(%rdi),%ecx // is mutex available?
jz 2f // yes, it is available
pause
decl %eax // decrement max spin count
jnz 1b // keep spinning
2:
movq $(_COMM_PAGE_PFZ_MUTEX_LOCK), %rcx
call *%rcx
testl %ebx,%ebx // pending preemption?
jz 1f // no
call _preempt
1:
popq %rbx
popq %rbp
ret