arm/sys/OSAtomic-v4.c

   1 /*
   2  * Copyright (c) 2004 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 <libkern/OSAtomic.h>
  25 #include <arm/arch.h>
  26
  27
  28 #if !defined(_ARM_ARCH_6)
  29
  30 /*
  31  * The only atomic operation ARMv4T provides (atomic swap) is not
  32  * sufficient for the general 32-bit arithmetic and compare-and-swap
  33  * operations OSAtomic is supposed to provide.  So we use a global
  34  * spin lock around all operations.
  35  *
  36  * Since we have only a single, in-order, CPU, we do not need
  37  * memory barriers for data.
  38  */
  39
  40 static OSSpinLock _atomic_lock = OS_SPINLOCK_INIT;
  41
  42 int32_t OSAtomicAdd32( int32_t theAmount, int32_t *theValue )
  43 {
  44     int32_t result;
  45
  46     OSSpinLockLock(&_atomic_lock);
  47     result = (*theValue += theAmount);
  48     OSSpinLockUnlock(&_atomic_lock);
  49
  50     return result;
  51 }
  52
  53 int32_t OSAtomicAdd32Barrier( int32_t theAmount, int32_t *theValue )
  54 {
  55     return OSAtomicAdd32(theAmount, theValue);
  56 }
  57
  58 int32_t OSAtomicOr32( uint32_t theMask, uint32_t *theValue )
  59 {
  60     int32_t result;
  61
  62     OSSpinLockLock(&_atomic_lock);
  63     result = (*theValue |= theMask);
  64     OSSpinLockUnlock(&_atomic_lock);
  65
  66     return result;
  67 }
  68
  69 int32_t OSAtomicOr32Barrier( uint32_t theMask, uint32_t *theValue )
  70 {
  71     return OSAtomicOr32(theMask, theValue);
  72 }
  73
  74 int32_t OSAtomicAnd32( uint32_t theMask, uint32_t *theValue )
  75 {
  76     int32_t result;
  77
  78     OSSpinLockLock(&_atomic_lock);
  79     result = (*theValue &= theMask);
  80     OSSpinLockUnlock(&_atomic_lock);
  81
  82     return result;
  83 }
  84
  85 int32_t OSAtomicAnd32Barrier( uint32_t theMask, uint32_t *theValue )
  86 {
  87     return OSAtomicAnd32(theMask, theValue);
  88 }
  89
  90 int32_t OSAtomicXor32( uint32_t theMask, uint32_t *theValue )
  91 {
  92     int32_t result;
  93
  94     OSSpinLockLock(&_atomic_lock);
  95     result = (*theValue ^= theMask);
  96     OSSpinLockUnlock(&_atomic_lock);
  97
  98     return result;
  99 }
 100
 101 int32_t OSAtomicXor32Barrier( uint32_t theMask, uint32_t *theValue )
 102 {
 103     return OSAtomicXor32(theMask, theValue);
 104 }
 105
 106 bool    OSAtomicCompareAndSwap32( int32_t oldValue, int32_t newValue, int32_t *theValue )
 107 {
 108     bool result;
 109
 110     OSSpinLockLock(&_atomic_lock);
 111     result = (*theValue == oldValue);
 112     if (result) *theValue = newValue;
 113     OSSpinLockUnlock(&_atomic_lock);
 114
 115     return result;
 116 }
 117
 118 bool    OSAtomicCompareAndSwap32Barrier( int32_t oldValue, int32_t newValue, int32_t *theValue )
 119 {
 120     return OSAtomicCompareAndSwap32(oldValue, newValue, theValue);
 121 }
 122
 123 bool    OSAtomicTestAndSet( uint32_t n, void *theAddress )
 124 {
 125     char *byteAddress = ((char*)theAddress + (n>>3));
 126     uint32_t byteBit = (0x80>>(n&7));
 127     bool result;
 128
 129     OSSpinLockLock(&_atomic_lock);
 130     result = *byteAddress & byteBit;
 131     *byteAddress |= byteBit;
 132     OSSpinLockUnlock(&_atomic_lock);
 133
 134     return result;
 135 }
 136
 137 bool    OSAtomicTestAndSetBarrier( uint32_t n, void *theAddress )
 138 {
 139     return OSAtomicTestAndSet(n, theAddress);
 140 }
 141
 142 bool    OSAtomicTestAndClear( uint32_t n, void *theAddress )
 143 {
 144     char *byteAddress = ((char*)theAddress + (n>>3));
 145     uint32_t byteBit = (0x80>>(n&7));
 146     bool result;
 147
 148     OSSpinLockLock(&_atomic_lock);
 149     result = *byteAddress & byteBit;
 150     *byteAddress &= (~byteBit);
 151     OSSpinLockUnlock(&_atomic_lock);
 152
 153     return result;
 154 }
 155
 156 bool    OSAtomicTestAndClearBarrier( uint32_t n, void *theAddress )
 157 {
 158     return OSAtomicTestAndClear(n, theAddress);
 159 }
 160
 161 void    OSMemoryBarrier( void )
 162 {
 163     return;
 164 }
 165
 166 #endif /* !defined(_ARM_ARCH_6) */