arm/sys/OSAtomic-v4.c

   1 /*
   2  * Copyright (c) 2004, 2008 Apple 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, volatile 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, volatile int32_t *theValue )
  54 {
  55     return OSAtomicAdd32(theAmount, theValue);
  56 }
  57
  58 int64_t OSAtomicAdd64( int64_t theAmount, volatile int64_t *theValue )
  59 {
  60     int64_t result;
  61
  62     OSSpinLockLock(&_atomic_lock);
  63     result = (*theValue += theAmount);
  64     OSSpinLockUnlock(&_atomic_lock);
  65
  66     return result;
  67 }
  68
  69 int64_t OSAtomicAdd64Barrier( int64_t theAmount, volatile int64_t *theValue )
  70 {
  71     return OSAtomicAdd64(theAmount, theValue);
  72 }
  73
  74 int32_t OSAtomicOr32( uint32_t theMask, volatile 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 OSAtomicOr32Barrier( uint32_t theMask, volatile uint32_t *theValue )
  86 {
  87     return OSAtomicOr32(theMask, theValue);
  88 }
  89
  90 int32_t OSAtomicOr32Orig( uint32_t theMask, volatile uint32_t *theValue )
  91 {
  92     int32_t result;
  93
  94     OSSpinLockLock(&_atomic_lock);
  95     result = *theValue;
  96     *theValue |= theMask;
  97     OSSpinLockUnlock(&_atomic_lock);
  98
  99     return result;
 100 }
 101
 102 int32_t OSAtomicOr32OrigBarrier( uint32_t theMask, volatile uint32_t *theValue )
 103 {
 104     return OSAtomicOr32Orig(theMask, theValue);
 105 }
 106
 107 int32_t OSAtomicAnd32( uint32_t theMask, volatile uint32_t *theValue )
 108 {
 109     int32_t result;
 110
 111     OSSpinLockLock(&_atomic_lock);
 112     result = (*theValue &= theMask);
 113     OSSpinLockUnlock(&_atomic_lock);
 114
 115     return result;
 116 }
 117
 118 int32_t OSAtomicAnd32Barrier( uint32_t theMask, volatile uint32_t *theValue )
 119 {
 120     return OSAtomicAnd32(theMask, theValue);
 121 }
 122
 123 int32_t OSAtomicAnd32Orig( uint32_t theMask, volatile uint32_t *theValue )
 124 {
 125     int32_t result;
 126
 127     OSSpinLockLock(&_atomic_lock);
 128     result = *theValue;
 129     *theValue &= theMask;
 130     OSSpinLockUnlock(&_atomic_lock);
 131
 132     return result;
 133 }
 134
 135 int32_t OSAtomicAnd32OrigBarrier( uint32_t theMask, volatile uint32_t *theValue )
 136 {
 137     return OSAtomicAnd32Orig(theMask, theValue);
 138 }
 139
 140 int32_t OSAtomicXor32( uint32_t theMask, volatile uint32_t *theValue )
 141 {
 142     int32_t result;
 143
 144     OSSpinLockLock(&_atomic_lock);
 145     result = (*theValue ^= theMask);
 146     OSSpinLockUnlock(&_atomic_lock);
 147
 148     return result;
 149 }
 150
 151 int32_t OSAtomicXor32Barrier( uint32_t theMask, volatile uint32_t *theValue )
 152 {
 153     return OSAtomicXor32(theMask, theValue);
 154 }
 155
 156 int32_t OSAtomicXor32Orig( uint32_t theMask, volatile uint32_t *theValue )
 157 {
 158     int32_t result;
 159
 160     OSSpinLockLock(&_atomic_lock);
 161     result = *theValue;
 162     *theValue ^= theMask;
 163     OSSpinLockUnlock(&_atomic_lock);
 164
 165     return result;
 166 }
 167
 168 int32_t OSAtomicXor32OrigBarrier( uint32_t theMask, volatile uint32_t *theValue )
 169 {
 170     return OSAtomicXor32Orig(theMask, theValue);
 171 }
 172
 173 bool    OSAtomicCompareAndSwap32( int32_t oldValue, int32_t newValue, volatile int32_t *theValue )
 174 {
 175     bool result;
 176
 177     OSSpinLockLock(&_atomic_lock);
 178     result = (*theValue == oldValue);
 179     if (result) *theValue = newValue;
 180     OSSpinLockUnlock(&_atomic_lock);
 181
 182     return result;
 183 }
 184
 185 bool    OSAtomicCompareAndSwap32Barrier( int32_t oldValue, int32_t newValue, volatile int32_t *theValue )
 186 {
 187     return OSAtomicCompareAndSwap32(oldValue, newValue, theValue);
 188 }
 189
 190 bool    OSAtomicCompareAndSwap64( int64_t oldValue, int64_t newValue, volatile int64_t *theValue )
 191 {
 192     bool result;
 193
 194     OSSpinLockLock(&_atomic_lock);
 195     result = (*theValue == oldValue);
 196     if (result) *theValue = newValue;
 197     OSSpinLockUnlock(&_atomic_lock);
 198
 199     return result;
 200 }
 201
 202 bool    OSAtomicCompareAndSwap64Barrier( int64_t oldValue, int64_t newValue, volatile int64_t *theValue )
 203 {
 204     return OSAtomicCompareAndSwap64(oldValue, newValue, theValue);
 205 }
 206
 207 bool    OSAtomicTestAndSet( uint32_t n, volatile void *theAddress )
 208 {
 209     char *byteAddress = ((char*)theAddress + (n>>3));
 210     uint32_t byteBit = (0x80>>(n&7));
 211     bool result;
 212
 213     OSSpinLockLock(&_atomic_lock);
 214     result = *byteAddress & byteBit;
 215     *byteAddress |= byteBit;
 216     OSSpinLockUnlock(&_atomic_lock);
 217
 218     return result;
 219 }
 220
 221 bool    OSAtomicTestAndSetBarrier( uint32_t n, volatile void *theAddress )
 222 {
 223     return OSAtomicTestAndSet(n, theAddress);
 224 }
 225
 226 bool    OSAtomicTestAndClear( uint32_t n, volatile void *theAddress )
 227 {
 228     char *byteAddress = ((char*)theAddress + (n>>3));
 229     uint32_t byteBit = (0x80>>(n&7));
 230     bool result;
 231
 232     OSSpinLockLock(&_atomic_lock);
 233     result = *byteAddress & byteBit;
 234     *byteAddress &= (~byteBit);
 235     OSSpinLockUnlock(&_atomic_lock);
 236
 237     return result;
 238 }
 239
 240 bool    OSAtomicTestAndClearBarrier( uint32_t n, volatile void *theAddress )
 241 {
 242     return OSAtomicTestAndClear(n, theAddress);
 243 }
 244
 245 void    OSMemoryBarrier( void )
 246 {
 247     return;
 248 }
 249
 250
 251 bool    OSAtomicCompareAndSwapPtrBarrier( void *__oldValue, void *__newValue, void * volatile *__theValue )
 252 {
 253     return OSAtomicCompareAndSwapPtr(__oldValue, __newValue, __theValue);
 254 }
 255
 256 bool    OSAtomicCompareAndSwapPtr( void *__oldValue, void *__newValue, void * volatile *__theValue )
 257 {
 258     bool result;
 259
 260     OSSpinLockLock(&_atomic_lock);
 261     result = (*__theValue == __oldValue);
 262     if (result) *__theValue = __newValue;
 263     OSSpinLockUnlock(&_atomic_lock);
 264
 265     return result;
 266 }
 267
 268 #endif /* !defined(_ARM_ARCH_6) */