mirror of https://github.com/postgres/postgres
This reverts commitspull/38/headfc6c72747a,109de05cbb,d0b4663c23and711bab1e4d. Somebody will have to try harder before submitting this patch again. I've spent entirely too much time on it already, and the #ifdef maze yet to be written in order for it to build at all got on my nerves. The amount of work needed to get a platform-specific performance improvement that's barely above the noise level is not worth it.
Alvaro Herrera
6 years ago
parent
e89f14e2bb
commit
457aef0f1f
@ -1,186 +0,0 @@ |
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/*------------------------------------------------------------------------ -
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* |
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* pg_bitutils.h |
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* miscellaneous functions for bit-wise operations. |
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* |
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* |
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* Portions Copyright(c) 2019, PostgreSQL Global Development Group |
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* |
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* src/include/port/pg_bitutils.h |
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* |
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*------------------------------------------------------------------------ - |
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*/ |
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#ifndef PG_BITUTILS_H |
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#define PG_BITUTILS_H |
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extern int (*pg_popcount32) (uint32 word); |
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extern int (*pg_popcount64) (uint64 word); |
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extern uint64 pg_popcount(const char *buf, int bytes); |
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/* in pg_bitutils_hwpopcnt.c */ |
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extern int pg_popcount32_hw(uint32 word); |
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extern int pg_popcount64_hw(uint64 word); |
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#ifndef HAVE__BUILTIN_CTZ |
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/*
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* Array marking the position of the right-most set bit for each value of |
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* 1-255. We count the right-most position as the 0th bit, and the |
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* left-most the 7th bit. The 0th index of the array must not be used. |
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*/ |
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static const uint8 rightmost_one_pos[256] = { |
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0, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, |
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4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 |
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}; |
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#endif /* !HAVE__BUILTIN_CTZ */ |
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/*
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* pg_rightmost_one32 |
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* Returns the number of trailing 0-bits in word, starting at the least |
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* significant bit position. word must not be 0. |
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*/ |
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static inline int |
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pg_rightmost_one32(uint32 word) |
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{ |
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int result = 0; |
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Assert(word != 0); |
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#ifdef HAVE__BUILTIN_CTZ |
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result = __builtin_ctz(word); |
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#else |
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while ((word & 255) == 0) |
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{ |
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word >>= 8; |
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result += 8; |
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} |
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result += rightmost_one_pos[word & 255]; |
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#endif /* HAVE__BUILTIN_CTZ */ |
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return result; |
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} |
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/*
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* pg_rightmost_one64 |
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* Returns the number of trailing 0-bits in word, starting at the least |
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* significant bit position. word must not be 0. |
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*/ |
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static inline int |
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pg_rightmost_one64(uint64 word) |
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{ |
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int result = 0; |
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Assert(word != 0); |
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#ifdef HAVE__BUILTIN_CTZ |
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#if defined(HAVE_LONG_INT_64) |
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return __builtin_ctzl(word); |
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#elif defined(HAVE_LONG_LONG_INT_64) |
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return __builtin_ctzll(word); |
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#else |
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#error must have a working 64-bit integer datatype |
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#endif |
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#else /* HAVE__BUILTIN_CTZ */ |
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while ((word & 255) == 0) |
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{ |
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word >>= 8; |
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result += 8; |
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} |
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result += rightmost_one_pos[word & 255]; |
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#endif |
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return result; |
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} |
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#ifndef HAVE__BUILTIN_CLZ |
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/*
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* Array marking the position of the left-most set bit for each value of |
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* 1-255. We count the right-most position as the 0th bit, and the |
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* left-most the 7th bit. The 0th index of the array must not be used. |
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*/ |
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static const uint8 leftmost_one_pos[256] = { |
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0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, |
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4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, |
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5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, |
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5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, |
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6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, |
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6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, |
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6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, |
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6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, |
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, |
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, |
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, |
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, |
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, |
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, |
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, |
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 |
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}; |
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#endif /* !HAVE_BUILTIN_CLZ */ |
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/*
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* pg_leftmost_one32 |
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* Returns the 0-based position of the most significant set bit in word |
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* measured from the least significant bit. word must not be 0. |
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*/ |
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static inline int |
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pg_leftmost_one32(uint32 word) |
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{ |
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#ifdef HAVE__BUILTIN_CLZ |
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Assert(word != 0); |
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return 31 - __builtin_clz(word); |
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#else |
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int shift = 32 - 8; |
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Assert(word != 0); |
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while ((word >> shift) == 0) |
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shift -= 8; |
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return shift + leftmost_one_pos[(word >> shift) & 255]; |
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#endif /* HAVE__BUILTIN_CLZ */ |
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} |
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/*
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* pg_leftmost_one64 |
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* Returns the 0-based position of the most significant set bit in word |
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* measured from the least significant bit. word must not be 0. |
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*/ |
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static inline int |
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pg_leftmost_one64(uint64 word) |
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{ |
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#ifdef HAVE__BUILTIN_CLZ |
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Assert(word != 0); |
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#if defined(HAVE_LONG_INT_64) |
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return 63 - __builtin_clzl(word); |
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#elif defined(HAVE_LONG_LONG_INT_64) |
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return 63 - __builtin_clzll(word); |
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#else |
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#error must have a working 64-bit integer datatype |
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#endif |
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#else /* HAVE__BUILTIN_CLZ */ |
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int shift = 64 - 8; |
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Assert(word != 0); |
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while ((word >> shift) == 0) |
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shift -= 8; |
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return shift + leftmost_one_pos[(word >> shift) & 255]; |
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#endif /* !HAVE__BUIILTIN_CLZ */ |
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} |
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#endif /* PG_BITUTILS_H */ |
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@ -1,219 +0,0 @@ |
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/*-------------------------------------------------------------------------
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* |
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* pg_bitutils.c |
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* miscellaneous functions for bit-wise operations. |
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* |
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* Portions Copyright (c) 2019, PostgreSQL Global Development Group |
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* |
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* IDENTIFICATION |
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* src/port/pg_bitutils.c |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#include "postgres.h" |
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#ifdef HAVE__GET_CPUID |
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#include <cpuid.h> |
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#endif |
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#ifdef HAVE__CPUID |
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#include <intrin.h> |
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#endif |
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#include "port/pg_bitutils.h" |
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#ifdef HAVE__BUILTIN_POPCOUNT |
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static bool pg_popcount_available(void); |
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static int pg_popcount32_choose(uint32 word); |
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static int pg_popcount32_builtin(uint32 word); |
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static int pg_popcount64_choose(uint64 word); |
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static int pg_popcount64_builtin(uint64 word); |
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int (*pg_popcount32) (uint32 word) = pg_popcount32_choose; |
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int (*pg_popcount64) (uint64 word) = pg_popcount64_choose; |
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#else |
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static int pg_popcount32_slow(uint32 word); |
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static int pg_popcount64_slow(uint64 word); |
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int (*pg_popcount32) (uint32 word) = pg_popcount32_slow; |
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int (*pg_popcount64) (uint64 word) = pg_popcount64_slow; |
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#endif /* !HAVE_BUILTIN_POPCOUNT */ |
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/* Array marking the number of 1-bits for each value of 0-255. */ |
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static const uint8 number_of_ones[256] = { |
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0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, |
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1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, |
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1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, |
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, |
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1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, |
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, |
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, |
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3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, |
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1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, |
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, |
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, |
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3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, |
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2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, |
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3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, |
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3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, |
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4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8 |
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}; |
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/*
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* Return true iff we have CPUID support and it indicates that the POPCNT |
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* instruction is available. |
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*/ |
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static bool |
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pg_popcount_available(void) |
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{ |
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#if defined(HAVE__GET_CPUID) || defined(HAVE__CPUID) |
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unsigned int exx[4] = {0, 0, 0, 0}; |
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#if defined(HAVE__GET_CPUID) |
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__get_cpuid(1, &exx[0], &exx[1], &exx[2], &exx[3]); |
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#elif defined(HAVE__CPUID) |
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__cpuid(exx, 1); |
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#endif |
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return (exx[2] & (1 << 23)) != 0; /* POPCNT */ |
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#else /* HAVE__GET_CPUID || HAVE__CPUID */ |
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return false; |
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#endif |
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} |
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#ifdef HAVE__BUILTIN_POPCOUNT |
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/*
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* This gets called on the first call to pg_popcount32. It replaces the |
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* function pointer so that subsequent calls are routed directly to the chosen |
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* implementation. |
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*/ |
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static int |
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pg_popcount32_choose(uint32 word) |
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{ |
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if (pg_popcount_available()) |
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pg_popcount32 = pg_popcount32_hw; |
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else |
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pg_popcount32 = pg_popcount32_builtin; |
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return pg_popcount32(word); |
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} |
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static int |
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pg_popcount32_builtin(uint32 word) |
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{ |
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return __builtin_popcount(word); |
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} |
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#else /* HAVE__BUILTIN_POPCOUNT */ |
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/*
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* pg_popcount32_slow |
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* Return the number of 1 bits set in word |
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*/ |
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static int |
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pg_popcount32_slow(uint32 word) |
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{ |
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int result = 0; |
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while (word != 0) |
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{ |
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result += number_of_ones[word & 255]; |
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word >>= 8; |
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} |
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return result; |
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} |
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#endif |
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/*
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* pg_popcount |
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* Returns the number of 1-bits in buf |
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*/ |
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uint64 |
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pg_popcount(const char *buf, int bytes) |
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{ |
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uint64 popcnt = 0; |
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#if SIZEOF_VOID_P >= 8 |
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/* Process in 64-bit chunks if the buffer is aligned. */ |
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if (buf == (char *) TYPEALIGN(8, buf)) |
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{ |
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uint64 *words = (uint64 *) buf; |
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while (bytes >= 8) |
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{ |
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popcnt += pg_popcount64(*words++); |
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bytes -= 8; |
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} |
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buf = (char *) words; |
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} |
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#else |
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/* Process in 32-bit chunks if the buffer is aligned. */ |
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if (buf == (char *) TYPEALIGN(4, buf)) |
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{ |
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uint32 *words = (uint32 *) buf; |
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while (bytes >= 4) |
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{ |
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popcnt += pg_popcount32(*words++); |
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bytes -= 4; |
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} |
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buf = (char *) words; |
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} |
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#endif |
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/* Process any remaining bytes */ |
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while (bytes--) |
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popcnt += number_of_ones[(unsigned char) *buf++]; |
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return popcnt; |
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} |
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#ifdef HAVE__BUILTIN_POPCOUNT |
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/*
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* This gets called on the first call to pg_popcount64. It replaces the |
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* function pointer so that subsequent calls are routed directly to the chosen |
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* implementation. |
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*/ |
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static int |
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pg_popcount64_choose(uint64 word) |
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{ |
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if (pg_popcount_available()) |
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pg_popcount64 = pg_popcount64_hw; |
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else |
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pg_popcount64 = pg_popcount64_builtin; |
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return pg_popcount64(word); |
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} |
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static int |
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pg_popcount64_builtin(uint64 word) |
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{ |
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#if defined(HAVE_LONG_INT_64) |
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return __builtin_popcountl(word); |
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#elif defined(HAVE_LONG_LONG_INT_64) |
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return __builtin_popcountll(word); |
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#else |
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#error must have a working 64-bit integer datatype |
|
||||||
#endif |
|
||||||
} |
|
||||||
|
|
||||||
#else /* HAVE__BUILTIN_POPCOUNT */ |
|
||||||
/*
|
|
||||||
* pg_popcount64_slow |
|
||||||
* Return the number of 1 bits set in word |
|
||||||
*/ |
|
||||||
static int |
|
||||||
pg_popcount64_slow(uint64 word) |
|
||||||
{ |
|
||||||
int result = 0; |
|
||||||
|
|
||||||
while (word != 0) |
|
||||||
{ |
|
||||||
result += number_of_ones[word & 255]; |
|
||||||
word >>= 8; |
|
||||||
} |
|
||||||
|
|
||||||
return result; |
|
||||||
} |
|
||||||
#endif |
|
||||||
@ -1,36 +0,0 @@ |
|||||||
/*-------------------------------------------------------------------------
|
|
||||||
* |
|
||||||
* pg_bitutils_hwpopcnt.c |
|
||||||
* CPU-optimized implementation of pg_popcount variants |
|
||||||
* |
|
||||||
* This file must be compiled with a compiler-specific flag to enable the |
|
||||||
* POPCNT instruction. |
|
||||||
* |
|
||||||
* Portions Copyright (c) 2019, PostgreSQL Global Development Group |
|
||||||
* |
|
||||||
* IDENTIFICATION |
|
||||||
* src/port/pg_bitutils_hwpopcnt.c |
|
||||||
* |
|
||||||
*------------------------------------------------------------------------- |
|
||||||
*/ |
|
||||||
#include "postgres.h" |
|
||||||
|
|
||||||
#include "port/pg_bitutils.h" |
|
||||||
|
|
||||||
int |
|
||||||
pg_popcount32_hw(uint32 word) |
|
||||||
{ |
|
||||||
return __builtin_popcount(word); |
|
||||||
} |
|
||||||
|
|
||||||
int |
|
||||||
pg_popcount64_hw(uint64 word) |
|
||||||
{ |
|
||||||
#if defined(HAVE_LONG_INT_64) |
|
||||||
return __builtin_popcountl(word); |
|
||||||
#elif defined(HAVE_LONG_LONG_INT_64) |
|
||||||
return __builtin_popcountll(word); |
|
||||||
#else |
|
||||||
#error must have a working 64-bit integer datatype |
|
||||||
#endif |
|
||||||
} |
|
||||||
Loading…
Reference in new issue