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mdbx: микро-оптимизация cmp_reverse().

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This commit is contained in:
Леонид Юрьев (Leonid Yuriev)
2022-12-31 01:30:52 +03:00
parent bcddeaba9f
commit 8519fde741
2 changed files with 86 additions and 8 deletions
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40
src/osal.h
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@@ -890,6 +890,46 @@ MDBX_INTERNAL_VAR MDBX_SetFileIoOverlappedRange mdbx_SetFileIoOverlappedRange;
/*----------------------------------------------------------------------------*/
MDBX_MAYBE_UNUSED MDBX_NOTHROW_PURE_FUNCTION static __always_inline uint64_t
osal_bswap64(uint64_t v) {
#if __GNUC_PREREQ(4, 4) || __CLANG_PREREQ(4, 0) || \
__has_builtin(__builtin_bswap64)
return __builtin_bswap64(v);
#elif defined(_MSC_VER) && !defined(__clang__)
return _byteswap_uint64(v);
#elif defined(__bswap_64)
return __bswap_64(v);
#elif defined(bswap_64)
return bswap_64(v);
#else
return v << 56 | v >> 56 | ((v << 40) & UINT64_C(0x00ff000000000000)) |
((v << 24) & UINT64_C(0x0000ff0000000000)) |
((v << 8) & UINT64_C(0x000000ff00000000)) |
((v >> 8) & UINT64_C(0x00000000ff000000)) |
((v >> 24) & UINT64_C(0x0000000000ff0000)) |
((v >> 40) & UINT64_C(0x000000000000ff00));
#endif
}
MDBX_MAYBE_UNUSED MDBX_NOTHROW_PURE_FUNCTION static __always_inline uint32_t
osal_bswap32(uint32_t v) {
#if __GNUC_PREREQ(4, 4) || __CLANG_PREREQ(4, 0) || \
__has_builtin(__builtin_bswap32)
return __builtin_bswap32(v);
#elif defined(_MSC_VER) && !defined(__clang__)
return _byteswap_ulong(v);
#elif defined(__bswap_32)
return __bswap_32(v);
#elif defined(bswap_32)
return bswap_32(v);
#else
return v << 24 | v >> 24 | ((v << 8) & UINT32_C(0x00ff0000)) |
((v >> 8) & UINT32_C(0x0000ff00));
#endif
}
/*----------------------------------------------------------------------------*/
#if defined(_MSC_VER) && _MSC_VER >= 1900
/* LY: MSVC 2015/2017/2019 has buggy/inconsistent PRIuPTR/PRIxPTR macros
* for internal format-args checker. */