void SimpleRWLock::LockForRead() {
UINT64 oldVal = itsLock;
while (((oldVal & NoWriterBitMask) == 0) ||
!CAS64(&itsLock, oldVal, oldVal-1)) {
oldVal = itsLock;
}
HT_ASSERT(((oldVal-1) & NoWriterBitMask) != 0);
}
/////////////////////////////////////////////////////////
// EXTERNAL FUNCTIONS
/////////////////////////////////////////////////////////
volatile int64_t atomic_add(volatile int64_t * addr, int64_t dx) {
volatile int64_t v;
for (v = *addr ; CAS64 (addr, v, v+dx) != v; v = *addr) {}
return v ;
}
RetVal LFUObjectApplyOp(LFUObject *l, LFUObjectThreadState *th_state, RetVal (*sfunc)(Object, ArgVal, int), ArgVal arg, int pid) {
RetVal old_val = arg, new_val;
reset_backoff(&th_state->backoff);
do {
old_val = l->val; // val is volatile
new_val = sfunc(old_val, arg, pid);
if (CAS64(&l->val, old_val, new_val) == true)
break;
else backoff_delay(&th_state->backoff);
} while(true);
return old_val;
}
void SimpleRWLock::UnLock() {
UINT64 oldVal = itsLock;
HT_ASSERT(oldVal != Free);
if ((oldVal & NoWriterBitMask) == 0) {
itsLock = Free;
} else {
while (!CAS64(&itsLock, oldVal, oldVal+1)) {
oldVal = itsLock;
HT_ASSERT(oldVal != Free);
HT_ASSERT((oldVal & NoWriterBitMask) != 0);
}
}
}
volatile int64_t CAS(volatile int64_t * addr, int64_t expected_value, int64_t new_value) {
return CAS64(addr, expected_value, new_value);
}
void SimpleRWLock::LockForWrite(UINT64 theThreadId) {
while ((itsLock != Free) || !CAS64(&itsLock, Free, theThreadId)) {
;
}
}
