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Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.

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Implementation used: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/support/win32/support.h?view=markup#l135
This commit is contained in:
Carter Li 2015-02-22 17:43:58 +08:00
parent 2b35c9e8e7
commit 524222f094
1 changed files with 10 additions and 3 deletions
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13
format.h
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@ -56,15 +56,22 @@ inline uint32_t clz(uint32_t x) {
return 31 - r; return 31 - r;
} }
# define FMT_BUILTIN_CLZ(n) fmt::internal::clz(n) # define FMT_BUILTIN_CLZ(n) fmt::internal::clz(n)
# ifdef _WIN64
# pragma intrinsic(_BitScanReverse64)
inline uint32_t clzll(uint64_t n) { inline uint32_t clzll(uint64_t n) {
unsigned long r = 0; unsigned long r = 0;
# ifdef _WIN64
# pragma intrinsic(_BitScanReverse64)
_BitScanReverse64(&r, x); _BitScanReverse64(&r, x);
# else
// Scan the high 32 bits.
if (_BitScanReverse(&r, static_cast<uint32_t>(n >> 32)))
return 63 - (r + 32);
// Scan the low 32 bits.
_BitScanReverse(&r, static_cast<uint32_t>(n));
# endif
return 63 - r; return 63 - r;
} }
# define FMT_BUILTIN_CLZLL(n) fmt::internal::clzll(n) # define FMT_BUILTIN_CLZLL(n) fmt::internal::clzll(n)
# endif
} }
} }
#endif #endif