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c62b1c29c2
Use UXOR,SBZ to test for a zero byte within a word. While we can get semi-decent code out of asm-goto, we would do slightly better with a compiler builtin. For index_zero et al, sequential testing of bytes is less expensive than any tricks that involve a count-leading-zeros insn that we don't have. Checked on hppa-linux-gnu. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
64 lines
1.8 KiB
C
64 lines
1.8 KiB
C
/* string-fzi.h -- zero byte indexes. HPPA 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_FZI_H
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#define _STRING_FZI_H 1
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#include <string-optype.h>
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#include <string-fza.h>
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_Static_assert (sizeof (op_t) == 4, "64-bit not supported");
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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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unsigned int ret;
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/* Since we have no clz insn, direct tests of the bytes is faster
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than loading up the constants to do the masking. */
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asm ("extrw,u,= %1,23,8,%%r0\n\t"
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"ldi 2,%0\n\t"
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"extrw,u,= %1,15,8,%%r0\n\t"
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"ldi 1,%0\n\t"
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"extrw,u,= %1,7,8,%%r0\n\t"
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"ldi 0,%0"
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: "=r"(ret) : "r"(c), "0"(3));
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return ret;
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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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unsigned int ret;
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/* Since we have no ctz insn, direct tests of the bytes is faster
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than loading up the constants to do the masking. */
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asm ("extrw,u,= %1,15,8,%%r0\n\t"
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"ldi 1,%0\n\t"
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"extrw,u,= %1,23,8,%%r0\n\t"
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"ldi 2,%0\n\t"
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"extrw,u,= %1,31,8,%%r0\n\t"
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"ldi 3,%0"
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: "=r"(ret) : "r"(c), "0"(0));
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return ret;
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}
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#endif /* _STRING_FZI_H */
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