mirror of
https://github.com/simdjson/simdjson
synced 2026-06-08 17:27:07 +00:00
Olaf Bernstein
40 lines
959 B
C++
40 lines
959 B
C++
#ifndef SIMDJSON_RVV_VLS_BITMASK_H
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#define SIMDJSON_RVV_VLS_BITMASK_H
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#ifndef SIMDJSON_CONDITIONAL_INCLUDE
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#include "simdjson/rvv-vls/base.h"
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#include "simdjson/rvv-vls/intrinsics.h"
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#endif // SIMDJSON_CONDITIONAL_INCLUDE
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namespace simdjson {
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namespace rvv_vls {
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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 encountered.
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//
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// For example, prefix_xor(00100100) == 00011100
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//
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simdjson_inline uint64_t prefix_xor(uint64_t bitmask) {
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#if __riscv_zbc
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return __riscv_clmul_64(bitmask, ~(uint64_t)0);
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#elif __riscv_zvbc
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return __riscv_vmv_x(__riscv_vclmul(__riscv_vmv_s_x_u64m1(bitmask, 1), ~(uint64_t)0, 1));
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#else
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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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#endif
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return bitmask;
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}
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} // unnamed namespace
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} // namespace rvv_vls
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} // namespace simdjson
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#endif // SIMDJSON_RVV_VLS_BITMASK_H
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