i386/pthreads/pthread_mutex_lock.s

   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  */
  23
  24 #include <machine/cpu_capabilities.h>
  25 #include <architecture/i386/asm_help.h>
  26
  27         .text
  28         .align  2
  29         .globl  __commpage_pthread_mutex_lock
  30 __commpage_pthread_mutex_lock:
  31         pushl   %ebp                        // set up frame for backtrace
  32         movl    %esp,%ebp
  33         pushl   %esi
  34         pushl   %edi
  35         pushl   %ebx
  36         xorl    %ebx,%ebx                   // clear "preemption pending" flag
  37         movl    20(%esp),%edi               // %edi == ptr to LVAL/UVAL structure
  38         lea     20(%esp),%esi               // %esi == ptr to argument list
  39         movl    _COMM_PAGE_SPIN_COUNT, %edx
  40         movl    16(%esi),%ecx               // get mask (ie, PTHRW_EBIT etc)
  41 1:
  42         testl   0(%edi),%ecx                // is mutex available?
  43         jz      2f                          // yes, it is available
  44         pause
  45         decl    %edx                        // decrement max spin count
  46         jnz     1b                          // keep spinning
  47 2:
  48         EXTERN_TO_REG(_commpage_pfz_base, %ecx)
  49         movl    (%ecx), %ecx
  50         addl    $(_COMM_TEXT_PFZ_MUTEX_LOCK_OFFSET), %ecx
  51         call    *%ecx
  52         testl   %ebx,%ebx                   // pending preemption?
  53         jz      3f
  54         pushl   %eax                        // save return value across sysenter
  55         call    _preempt
  56         popl    %eax
  57 3:
  58         popl    %ebx
  59         popl    %edi
  60         popl    %esi
  61         popl    %ebp
  62         ret