X-Git-Url: https://git.saurik.com/apple/libc.git/blobdiff_plain/0a7506c9bdc0d0d560d4b9c8a3d1089f5db425b9..b5d655f7532a546b54809da387f7467d128a756b:/arm/sys/OSAtomic-v4.c

diff --git a/arm/sys/OSAtomic-v4.c b/arm/sys/OSAtomic-v4.c
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+++ b/arm/sys/OSAtomic-v4.c
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+/*
+ * Copyright (c) 2004 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 <libkern/OSAtomic.h>
+#include <arm/arch.h>
+
+
+#if !defined(_ARM_ARCH_6)
+
+/*
+ * The only atomic operation ARMv4T provides (atomic swap) is not
+ * sufficient for the general 32-bit arithmetic and compare-and-swap
+ * operations OSAtomic is supposed to provide.  So we use a global
+ * spin lock around all operations.
+ *
+ * Since we have only a single, in-order, CPU, we do not need
+ * memory barriers for data.
+ */
+
+static OSSpinLock _atomic_lock = OS_SPINLOCK_INIT;
+
+int32_t	OSAtomicAdd32( int32_t theAmount, int32_t *theValue )
+{
+    int32_t result;
+
+    OSSpinLockLock(&_atomic_lock);
+    result = (*theValue += theAmount);
+    OSSpinLockUnlock(&_atomic_lock);
+
+    return result;
+}
+
+int32_t	OSAtomicAdd32Barrier( int32_t theAmount, int32_t *theValue )
+{
+    return OSAtomicAdd32(theAmount, theValue);
+}
+
+int32_t	OSAtomicOr32( uint32_t theMask, uint32_t *theValue )
+{
+    int32_t result;
+
+    OSSpinLockLock(&_atomic_lock);
+    result = (*theValue |= theMask);
+    OSSpinLockUnlock(&_atomic_lock);
+
+    return result;
+}
+
+int32_t	OSAtomicOr32Barrier( uint32_t theMask, uint32_t *theValue )
+{
+    return OSAtomicOr32(theMask, theValue);
+}
+
+int32_t	OSAtomicAnd32( uint32_t theMask, uint32_t *theValue )
+{
+    int32_t result;
+
+    OSSpinLockLock(&_atomic_lock);
+    result = (*theValue &= theMask);
+    OSSpinLockUnlock(&_atomic_lock);
+
+    return result;
+}
+
+int32_t	OSAtomicAnd32Barrier( uint32_t theMask, uint32_t *theValue )
+{
+    return OSAtomicAnd32(theMask, theValue);
+}
+
+int32_t	OSAtomicXor32( uint32_t theMask, uint32_t *theValue )
+{
+    int32_t result;
+
+    OSSpinLockLock(&_atomic_lock);
+    result = (*theValue ^= theMask);
+    OSSpinLockUnlock(&_atomic_lock);
+
+    return result;
+}
+
+int32_t	OSAtomicXor32Barrier( uint32_t theMask, uint32_t *theValue )
+{
+    return OSAtomicXor32(theMask, theValue);
+}
+
+bool	OSAtomicCompareAndSwap32( int32_t oldValue, int32_t newValue, int32_t *theValue )
+{
+    bool result;
+    
+    OSSpinLockLock(&_atomic_lock);
+    result = (*theValue == oldValue);
+    if (result) *theValue = newValue;
+    OSSpinLockUnlock(&_atomic_lock);
+
+    return result;
+}
+
+bool    OSAtomicCompareAndSwap32Barrier( int32_t oldValue, int32_t newValue, int32_t *theValue )
+{
+    return OSAtomicCompareAndSwap32(oldValue, newValue, theValue);
+}
+
+bool    OSAtomicTestAndSet( uint32_t n, void *theAddress )
+{
+    char *byteAddress = ((char*)theAddress + (n>>3));
+    uint32_t byteBit = (0x80>>(n&7));
+    bool result;
+
+    OSSpinLockLock(&_atomic_lock);
+    result = *byteAddress & byteBit;
+    *byteAddress |= byteBit;
+    OSSpinLockUnlock(&_atomic_lock);
+
+    return result;
+}
+
+bool    OSAtomicTestAndSetBarrier( uint32_t n, void *theAddress )
+{
+    return OSAtomicTestAndSet(n, theAddress);
+}
+
+bool    OSAtomicTestAndClear( uint32_t n, void *theAddress )
+{
+    char *byteAddress = ((char*)theAddress + (n>>3));
+    uint32_t byteBit = (0x80>>(n&7));
+    bool result;
+
+    OSSpinLockLock(&_atomic_lock);
+    result = *byteAddress & byteBit;
+    *byteAddress &= (~byteBit);
+    OSSpinLockUnlock(&_atomic_lock);
+
+    return result;
+}
+
+bool    OSAtomicTestAndClearBarrier( uint32_t n, void *theAddress )
+{
+    return OSAtomicTestAndClear(n, theAddress);
+}
+
+void    OSMemoryBarrier( void )
+{
+    return;
+}
+
+#endif /* !defined(_ARM_ARCH_6) */