mingzailao
/
mitsuba
mirror of https://github.com/Quartenia/mitsuba.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

atomic FP addition

metadata
Wenzel Jakob 2011-02-10 17:16:36 +01:00
parent 33e4108319
commit a1da52f589
1 changed files with 27 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
include/mitsuba/core/atomic.h
View File

@ -27,6 +27,8 @@ MTS_NAMESPACE_BEGIN
#include <libkern/OSAtomic.h> #include <libkern/OSAtomic.h>
#endif #endif
/* The following implementations are based on PBRT */
template <typename T> inline bool atomicCompareAndExchangePtr(T **v, T *newValue, T *oldValue) { template <typename T> inline bool atomicCompareAndExchangePtr(T **v, T *newValue, T *oldValue) {
#if defined(WIN32) #if defined(WIN32)
return InterlockedCompareExchangePointer( return InterlockedCompareExchangePointer(
@ -48,6 +50,31 @@ template <typename T> inline bool atomicCompareAndExchangePtr(T **v, T *newValue
#endif #endif
} }
inline bool atomicCompareAndExchange(volatile int32_t *v, int32_t newValue, int32_t oldValue) {
#if defined(WIN32)
return InterlockedCompareExchange(
reint32_terpret_cast<volatile int32_t *>(v), newValue, oldValue) == oldValue;
#else
return __sync_bool_compare_and_swap(v, oldValue, newValue);
#endif
}
inline float atomicAdd(volatile float *val, float delta) {
/* Atomic FP addition from PBRT */
union bits { float f; int32_t i; };
bits oldVal, newVal;
do {
// On IA32/x64, adding a PAUSE instruction in compare/exchange loops
// is recommended to improve performance. (And it does!)
#if (defined(__i386__) || defined(__amd64__))
__asm__ __volatile__ ("pause\n");
#endif
oldVal.f = *val;
newVal.f = oldVal.f + delta;
} while (atomicCompareAndExchange((volatile int32_t *) val, newVal.i, oldVal.i) != oldVal.i);
return newVal.f;
}
MTS_NAMESPACE_END MTS_NAMESPACE_END
#endif /* __ATOMIC_H */ #endif /* __ATOMIC_H */