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Merge pull request #2258 from Niadb/dev

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Added STATIC_BMI2 for compile time detection of BMI2 on MSVC, when enabled various intrinsics are used
This commit is contained in:
Yann Collet
2020-08-04 09:43:59 -07:00
committed by GitHub
parent 60b56e3b5f a8ebc14035
commit 38e38546a4
4 changed files with 47 additions and 15 deletions
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lib/compress/zstd_compress_internal.h
+12 -4
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@@ -498,8 +498,12 @@ static unsigned ZSTD_NbCommonBytes (size_t val)
if (MEM_isLittleEndian()) {
if (MEM_64bits()) {
# if defined(_MSC_VER) && defined(_WIN64)
unsigned long r = 0;
return _BitScanForward64( &r, (U64)val ) ? (unsigned)(r >> 3) : 0;
# if STATIC_BMI2
return _tzcnt_u64(val) >> 3;
# else
unsigned long r = 0;
return _BitScanForward64( &r, (U64)val ) ? (unsigned)(r >> 3) : 0;
# endif
# elif defined(__GNUC__) && (__GNUC__ >= 4)
return (__builtin_ctzll((U64)val) >> 3);
# else
@@ -530,8 +534,12 @@ static unsigned ZSTD_NbCommonBytes (size_t val)
} else { /* Big Endian CPU */
if (MEM_64bits()) {
# if defined(_MSC_VER) && defined(_WIN64)
unsigned long r = 0;
return _BitScanReverse64( &r, val ) ? (unsigned)(r >> 3) : 0;
# if STATIC_BMI2
return _lzcnt_u64(val) >> 3;
# else
unsigned long r = 0;
return _BitScanReverse64(&r, (U64)val) ? (unsigned)(r >> 3) : 0;
# endif
# elif defined(__GNUC__) && (__GNUC__ >= 4)
return (__builtin_clzll(val) >> 3);
# else