mirror of
https://github.com/simdjson/simdjson
synced 2026-06-08 17:27:07 +00:00
Danila Kutenin
f46a0f64f2
* Initial PPC64 support * Add travis CI * Fix outdated cmake version for travis * Fix indendtation * Try another workaround for outdated cmake in travis * Try beta cmake * Add dash before beta * Use builtin snaps * Use cmake as rocksdb * Test cmake on bionic * Remove unnecessary things from travis * Remove unnecessary things from travis * Another try of compiler install * Add all major compilers * Add all major compilers * Add all major compilers * Tweak travis a bit * Typo * More robust travis * Typos typos typos * Add fewer compilers, add non specific build for clang and gcc, should be the final config * CMAKE_FLAGS is in incorrect place * Remove default implementation * Limit build thread number * Fall back prefix_xor to a usual implementation, no performance boost is noticed * Test for power9 as it is the main architecture for OpenPOWER right now * Add to documentation to build with power9 as the implementation is compatible but compiler optimizations is not * Replace ARM with PPC in the comment
43 lines
1.4 KiB
C++
43 lines
1.4 KiB
C++
#ifndef SIMDJSON_PPC64_BITMASK_H
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#define SIMDJSON_PPC64_BITMASK_H
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namespace simdjson {
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namespace SIMDJSON_IMPLEMENTATION {
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namespace {
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//
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// Perform a "cumulative bitwise xor," flipping bits each time a 1 is
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// encountered.
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//
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// For example, prefix_xor(00100100) == 00011100
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//
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simdjson_really_inline uint64_t prefix_xor(uint64_t bitmask) {
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// You can use the version below, however gcc sometimes miscompiles
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// vec_pmsum_be, it happens somewhere around between 8 and 9th version.
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// The performance boost was not noticeable, falling back to a usual
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// implementation.
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// __vector unsigned long long all_ones = {~0ull, ~0ull};
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// __vector unsigned long long mask = {bitmask, 0};
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// // Clang and GCC return different values for pmsum for ull so cast it to one.
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// // Generally it is not specified by ALTIVEC ISA what is returned by
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// // vec_pmsum_be.
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// #if defined(__LITTLE_ENDIAN__)
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// return (uint64_t)(((__vector unsigned long long)vec_pmsum_be(all_ones, mask))[0]);
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// #else
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// return (uint64_t)(((__vector unsigned long long)vec_pmsum_be(all_ones, mask))[1]);
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// #endif
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bitmask ^= bitmask << 1;
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bitmask ^= bitmask << 2;
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bitmask ^= bitmask << 4;
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bitmask ^= bitmask << 8;
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bitmask ^= bitmask << 16;
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bitmask ^= bitmask << 32;
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return bitmask;
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}
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} // unnamed namespace
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} // namespace SIMDJSON_IMPLEMENTATION
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} // namespace simdjson
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#endif
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