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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 | /* * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_OSREFERENCE_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_LICENSE_OSREFERENCE_HEADER_END@ */ /* * Copyright (c) 1998 Apple Computer, Inc. All rights reserved. * * HISTORY * */ /* Copyright (c) 1992 NeXT Computer, Inc. All rights reserved. * * EventShmemLock.h - Shared memory area locks for use between the * WindowServer and the Event Driver. * * HISTORY * 30 Nov 1992 Ben Fathi (benf@next.com) * Ported to m98k. * * 29 April 1992 Mike Paquette at NeXT * Created. * * Multiprocessor locks used within the shared memory area between the * kernel and event system. These must work in both user and kernel mode. * The locks are defined in an include file so they get exported to the local * include file area. */ #ifndef _IOKIT_IOSHAREDLOCKIMP_H #define _IOKIT_IOSHAREDLOCKIMP_H #include <architecture/ppc/asm_help.h> #ifdef KERNEL #undef END #include <mach/ppc/asm.h> #endif /* * void * ev_lock(p) * register int *p; * * Lock the lock pointed to by p. Spin (possibly forever) until * the lock is available. Test and test and set logic used. */ TEXT #ifndef KERNEL LEAF(_ev_lock) li a6,1 // lock value 8: lwz a7,0(a0) // Get lock word mr. a7,a7 // Is it held? bne-- 8b // Yup... 9: lwarx a7,0,a0 // read the lock mr. a7,a7 // Is it held? bne-- 7f // yes, kill reservation stwcx. a6,0,a0 // try to get the lock bne-- 9b // failed, try again isync blr // got it, return 7: li a7,-4 // Point to a spot in the red zone stwcx. a7,a7,r1 // Kill reservation b 8b // Go wait some more... END(_ev_lock) LEAF(_IOSpinLock) li a6,1 // lock value 8: lwz a7,0(a0) // Get lock word mr. a7,a7 // Is it held? bne-- 8b // Yup... 9: lwarx a7,0,a0 // read the lock mr. a7,a7 // Is it held? bne-- 7f // yes, kill reservation stwcx. a6,0,a0 // try to get the lock bne-- 9b // failed, try again isync blr // got it, return 7: li a7,-4 // Point to a spot in the red zone stwcx. a7,a7,r1 // Kill reservation b 8b // Go wait some more... END(_IOSpinLock) #endif /* * void * spin_unlock(p) * int *p; * * Unlock the lock pointed to by p. */ LEAF(_ev_unlock) sync li a7,0 stw a7,0(a0) blr END(_ev_unlock) LEAF(_IOSpinUnlock) sync li a7,0 stw a7,0(a0) blr END(_IOSpinUnlock) /* * ev_try_lock(p) * int *p; * * Try to lock p. Return TRUE if successful in obtaining lock. */ LEAF(_ev_try_lock) li a6,1 // lock value lwz a7,0(a0) // Get lock word mr. a7,a7 // Is it held? bne-- 6f // Yup... 9: lwarx a7,0,a0 // read the lock mr. a7,a7 // Is it held? bne-- 7f // yes, kill reservation stwcx. a6,0,a0 // try to get the lock bne-- 9b // failed, try again li a0,1 // return TRUE isync blr // got it, return 7: li a7,-4 // Point to a spot in the red zone stwcx. a7,a7,r1 // Kill reservation 6: li a0,0 // return FALSE blr END(_ev_try_lock) LEAF(_IOTrySpinLock) li a6,1 // lock value lwz a7,0(a0) // Get lock word mr. a7,a7 // Is it held? bne-- 6f // Yup... 9: lwarx a7,0,a0 // read the lock mr. a7,a7 // Is it held? bne-- 7f // yes, kill reservation stwcx. a6,0,a0 // try to get the lock bne-- 9b // failed, try again li a0,1 // return TRUE isync blr // got it, return 7: li a7,-4 // Point to a spot in the red zone stwcx. a7,a7,r1 // Kill reservation 6: li a0,0 // return FALSE blr END(_IOTrySpinLock) #endif /* ! _IOKIT_IOSHAREDLOCKIMP_H */ |