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author | maxim-yurchuk <maxim-yurchuk@yandex-team.com> | 2024-10-09 12:29:46 +0300 |
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committer | maxim-yurchuk <maxim-yurchuk@yandex-team.com> | 2024-10-09 13:14:22 +0300 |
commit | 9731d8a4bb7ee2cc8554eaf133bb85498a4c7d80 (patch) | |
tree | a8fb3181d5947c0d78cf402aa56e686130179049 /contrib/libs/cxxsupp/builtins/popcountti2.c | |
parent | a44b779cd359f06c3ebbef4ec98c6b38609d9d85 (diff) | |
download | ydb-9731d8a4bb7ee2cc8554eaf133bb85498a4c7d80.tar.gz |
publishFullContrib: true for ydb
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commit_hash:c82a80ac4594723cebf2c7387dec9c60217f603e
Diffstat (limited to 'contrib/libs/cxxsupp/builtins/popcountti2.c')
-rw-r--r-- | contrib/libs/cxxsupp/builtins/popcountti2.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/contrib/libs/cxxsupp/builtins/popcountti2.c b/contrib/libs/cxxsupp/builtins/popcountti2.c new file mode 100644 index 0000000000..7451bbb286 --- /dev/null +++ b/contrib/libs/cxxsupp/builtins/popcountti2.c @@ -0,0 +1,44 @@ +/* ===-- popcountti2.c - Implement __popcountti2 ----------------------------=== + * + * The LLVM Compiler Infrastructure + * + * This file is dual licensed under the MIT and the University of Illinois Open + * Source Licenses. See LICENSE.TXT for details. + * + * ===----------------------------------------------------------------------=== + * + * This file implements __popcountti2 for the compiler_rt library. + * + * ===----------------------------------------------------------------------=== + */ + +#include "int_lib.h" + +#ifdef CRT_HAS_128BIT + +/* Returns: count of 1 bits */ + +COMPILER_RT_ABI si_int +__popcountti2(ti_int a) +{ + tu_int x3 = (tu_int)a; + x3 = x3 - ((x3 >> 1) & (((tu_int)0x5555555555555555uLL << 64) | + 0x5555555555555555uLL)); + /* Every 2 bits holds the sum of every pair of bits (64) */ + x3 = ((x3 >> 2) & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL)) + + (x3 & (((tu_int)0x3333333333333333uLL << 64) | 0x3333333333333333uLL)); + /* Every 4 bits holds the sum of every 4-set of bits (3 significant bits) (32) */ + x3 = (x3 + (x3 >> 4)) + & (((tu_int)0x0F0F0F0F0F0F0F0FuLL << 64) | 0x0F0F0F0F0F0F0F0FuLL); + /* Every 8 bits holds the sum of every 8-set of bits (4 significant bits) (16) */ + du_int x2 = (du_int)(x3 + (x3 >> 64)); + /* Every 8 bits holds the sum of every 8-set of bits (5 significant bits) (8) */ + su_int x = (su_int)(x2 + (x2 >> 32)); + /* Every 8 bits holds the sum of every 8-set of bits (6 significant bits) (4) */ + x = x + (x >> 16); + /* Every 8 bits holds the sum of every 8-set of bits (7 significant bits) (2) */ + /* Upper 16 bits are garbage */ + return (x + (x >> 8)) & 0xFF; /* (8 significant bits) */ +} + +#endif /* CRT_HAS_128BIT */ |