[apple/libc.git] / x86_64 / pthreads / pthread_mutex_lock.s

/*
 * 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
Commit	Line	Data
8e029c65 A	1	/*
	2	* Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. Please obtain a copy of the License at
	10	* http://www.opensource.apple.com/apsl/ and read it before using this
	11	* file.
	12	*
	13	* The Original Code and all software distributed under the License are
	14	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	15	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	16	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	17	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	18	* Please see the License for the specific language governing rights and
	19	* limitations under the License.
	20	*
	21	* @APPLE_LICENSE_HEADER_END@
	22	*/
8e029c65	23
224c7076 A	24	#include <machine/cpu_capabilities.h>
224c7076 A	25
1f2f436a A	26	#define PTHRW_LVAL 0
1f2f436a A	27	#define PTHRW_UVAL 4
224c7076 A	28
	29	.text
	30	.align 2
34e8f829 A	31	.globl __commpage_pthread_mutex_lock
34e8f829 A	32	__commpage_pthread_mutex_lock:
1f2f436a A	33	pushq %rbp // set up frame for backtrace
	34	movq %rsp,%rbp
	35	pushq %rbx
	36	xorl %ebx,%ebx // clear "preemption pending" flag
	37	movl $(_COMM_PAGE_SPIN_COUNT), %eax
	38	1:
	39	testl PTHRW_LVAL(%rdi),%ecx // is mutex available?
	40	jz 2f // yes, it is available
	41	pause
	42	decl %eax // decrement max spin count
	43	jnz 1b // keep spinning
	44	2:
	45	movq $(_COMM_PAGE_PFZ_MUTEX_LOCK), %rcx
	46	call *%rcx
	47	testl %ebx,%ebx // pending preemption?
	48	jz 1f // no
	49	call _preempt
	50	1:
	51	popq %rbx
	52	popq %rbp
	53	ret