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25788431c0
It uses the bitmanip extension to optimize index_fist and index_last with clz/ctz (using generic implementation that routes to compiler builtin) and orc.b to check null bytes. Checked the string test on riscv64 user mode. Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
78 lines
1.9 KiB
C
78 lines
1.9 KiB
C
/* Zero byte detection; indexes. RISCV version.
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Copyright (C) 2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _STRING_RISCV_FZI_H
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#define _STRING_RISCV_FZI_H 1
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#ifdef __riscv_zbb
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# include <sysdeps/generic/string-fzi.h>
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#else
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/* Without bitmap clz/ctz extensions, it is faster to direct test the bits
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instead of calling compiler auxiliary functions. */
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# include <string-optype.h>
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static __always_inline unsigned int
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index_first (find_t c)
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{
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if (c & 0x80U)
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return 0;
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if (c & 0x8000U)
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return 1;
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if (c & 0x800000U)
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return 2;
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if (sizeof (op_t) == 4)
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return 3;
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if (c & 0x80000000U)
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return 3;
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if (c & 0x8000000000UL)
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return 4;
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if (c & 0x800000000000UL)
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return 5;
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if (c & 0x80000000000000UL)
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return 6;
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return 7;
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}
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static __always_inline unsigned int
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index_last (find_t c)
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{
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if (sizeof (op_t) == 8)
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{
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if (c & 0x8000000000000000UL)
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return 7;
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if (c & 0x80000000000000UL)
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return 6;
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if (c & 0x800000000000UL)
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return 5;
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if (c & 0x8000000000UL)
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return 4;
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}
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if (c & 0x80000000U)
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return 3;
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if (c & 0x800000U)
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return 2;
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if (c & 0x8000U)
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return 1;
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return 0;
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}
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#endif
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#endif /* STRING_FZI_H */
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