OSAtomicOperations.c [plain text]
#include <libkern/OSAtomic.h>
enum {
false = 0,
true = 1
};
#ifndef NULL
#define NULL ((void *)0)
#endif
#if !defined(__i386__) && !defined(__x86_64__)
#undef OSAddAtomic
SInt32
OSAddAtomic(SInt32 amount, volatile SInt32 * value)
{
SInt32 oldValue;
SInt32 newValue;
do {
oldValue = *value;
newValue = oldValue + amount;
} while (!OSCompareAndSwap((UInt32)oldValue,
(UInt32)newValue,
(volatile UInt32 *) value));
return oldValue;
}
#undef OSAddAtomicLong
long
OSAddAtomicLong(long theAmount, volatile long *address)
{
#if __LP64__
#error Unimplemented
#else
return (long)OSAddAtomic((SInt32)theAmount, address);
#endif
}
#undef OSCompareAndSwapPtr
Boolean OSCompareAndSwapPtr(void *oldValue, void *newValue,
void * volatile *address)
{
#if __LP64__
return OSCompareAndSwap64((UInt64)oldValue, (UInt64)newValue,
(volatile UInt64 *)address);
#else
return OSCompareAndSwap((UInt32)oldValue, (UInt32)newValue,
(volatile UInt32 *)address);
#endif
}
#endif
#undef OSIncrementAtomic
SInt32 OSIncrementAtomic(volatile SInt32 * value)
{
return OSAddAtomic(1, value);
}
#undef OSDecrementAtomic
SInt32 OSDecrementAtomic(volatile SInt32 * value)
{
return OSAddAtomic(-1, value);
}
static UInt32 OSBitwiseAtomic(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, volatile UInt32 * value)
{
UInt32 oldValue;
UInt32 newValue;
do {
oldValue = *value;
newValue = ((oldValue & and_mask) | or_mask) ^ xor_mask;
} while (! OSCompareAndSwap(oldValue, newValue, value));
return oldValue;
}
#undef OSBitAndAtomic
UInt32 OSBitAndAtomic(UInt32 mask, volatile UInt32 * value)
{
return OSBitwiseAtomic(mask, 0, 0, value);
}
#undef OSBitOrAtomic
UInt32 OSBitOrAtomic(UInt32 mask, volatile UInt32 * value)
{
return OSBitwiseAtomic((UInt32) -1, mask, 0, value);
}
#undef OSBitXorAtomic
UInt32 OSBitXorAtomic(UInt32 mask, volatile UInt32 * value)
{
return OSBitwiseAtomic((UInt32) -1, 0, mask, value);
}
static Boolean OSCompareAndSwap8(UInt8 oldValue8, UInt8 newValue8, volatile UInt8 * value8)
{
UInt32 mask = 0x000000ff;
UInt32 alignment = (UInt32)((unsigned long) value8) & (sizeof(UInt32) - 1);
UInt32 shiftValues = (24 << 24) | (16 << 16) | (8 << 8);
int shift = (UInt32) *(((UInt8 *) &shiftValues) + alignment);
volatile UInt32 * value32 = (volatile UInt32 *) ((uintptr_t)value8 - alignment);
UInt32 oldValue;
UInt32 newValue;
mask <<= shift;
oldValue = *value32;
oldValue = (oldValue & ~mask) | (oldValue8 << shift);
newValue = (oldValue & ~mask) | (newValue8 << shift);
return OSCompareAndSwap(oldValue, newValue, value32);
}
static Boolean OSTestAndSetClear(UInt32 bit, Boolean wantSet, volatile UInt8 * startAddress)
{
UInt8 mask = 1;
UInt8 oldValue;
UInt8 wantValue;
startAddress += (bit / 8);
mask <<= (7 - (bit % 8));
wantValue = wantSet ? mask : 0;
do {
oldValue = *startAddress;
if ((oldValue & mask) == wantValue) {
break;
}
} while (! OSCompareAndSwap8(oldValue, (oldValue & ~mask) | wantValue, startAddress));
return (oldValue & mask) == wantValue;
}
Boolean OSTestAndSet(UInt32 bit, volatile UInt8 * startAddress)
{
return OSTestAndSetClear(bit, true, startAddress);
}
Boolean OSTestAndClear(UInt32 bit, volatile UInt8 * startAddress)
{
return OSTestAndSetClear(bit, false, startAddress);
}
SInt8 OSIncrementAtomic8(volatile SInt8 * value)
{
return OSAddAtomic8(1, value);
}
SInt8 OSDecrementAtomic8(volatile SInt8 * value)
{
return OSAddAtomic8(-1, value);
}
SInt8 OSAddAtomic8(SInt32 amount, volatile SInt8 * value)
{
SInt8 oldValue;
SInt8 newValue;
do {
oldValue = *value;
newValue = oldValue + amount;
} while (! OSCompareAndSwap8((UInt8) oldValue, (UInt8) newValue, (volatile UInt8 *) value));
return oldValue;
}
static UInt8 OSBitwiseAtomic8(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, volatile UInt8 * value)
{
UInt8 oldValue;
UInt8 newValue;
do {
oldValue = *value;
newValue = ((oldValue & and_mask) | or_mask) ^ xor_mask;
} while (! OSCompareAndSwap8(oldValue, newValue, value));
return oldValue;
}
UInt8 OSBitAndAtomic8(UInt32 mask, volatile UInt8 * value)
{
return OSBitwiseAtomic8(mask, 0, 0, value);
}
UInt8 OSBitOrAtomic8(UInt32 mask, volatile UInt8 * value)
{
return OSBitwiseAtomic8((UInt32) -1, mask, 0, value);
}
UInt8 OSBitXorAtomic8(UInt32 mask, volatile UInt8 * value)
{
return OSBitwiseAtomic8((UInt32) -1, 0, mask, value);
}
static Boolean OSCompareAndSwap16(UInt16 oldValue16, UInt16 newValue16, volatile UInt16 * value16)
{
UInt32 mask = 0x0000ffff;
UInt32 alignment = (UInt32)((unsigned long) value16) & (sizeof(UInt32) - 1);
UInt32 shiftValues = (16 << 24) | (16 << 16);
UInt32 shift = (UInt32) *(((UInt8 *) &shiftValues) + alignment);
volatile UInt32 * value32 = (volatile UInt32 *) (((unsigned long) value16) - alignment);
UInt32 oldValue;
UInt32 newValue;
mask <<= shift;
oldValue = *value32;
oldValue = (oldValue & ~mask) | (oldValue16 << shift);
newValue = (oldValue & ~mask) | (newValue16 << shift);
return OSCompareAndSwap(oldValue, newValue, value32);
}
SInt16 OSIncrementAtomic16(volatile SInt16 * value)
{
return OSAddAtomic16(1, value);
}
SInt16 OSDecrementAtomic16(volatile SInt16 * value)
{
return OSAddAtomic16(-1, value);
}
SInt16 OSAddAtomic16(SInt32 amount, volatile SInt16 * value)
{
SInt16 oldValue;
SInt16 newValue;
do {
oldValue = *value;
newValue = oldValue + amount;
} while (! OSCompareAndSwap16((UInt16) oldValue, (UInt16) newValue, (volatile UInt16 *) value));
return oldValue;
}
static UInt16 OSBitwiseAtomic16(UInt32 and_mask, UInt32 or_mask, UInt32 xor_mask, volatile UInt16 * value)
{
UInt16 oldValue;
UInt16 newValue;
do {
oldValue = *value;
newValue = ((oldValue & and_mask) | or_mask) ^ xor_mask;
} while (! OSCompareAndSwap16(oldValue, newValue, value));
return oldValue;
}
UInt16 OSBitAndAtomic16(UInt32 mask, volatile UInt16 * value)
{
return OSBitwiseAtomic16(mask, 0, 0, value);
}
UInt16 OSBitOrAtomic16(UInt32 mask, volatile UInt16 * value)
{
return OSBitwiseAtomic16((UInt32) -1, mask, 0, value);
}
UInt16 OSBitXorAtomic16(UInt32 mask, volatile UInt16 * value)
{
return OSBitwiseAtomic16((UInt32) -1, 0, mask, value);
}