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120ad6ed1a
While alpha has the more important string functions in assembly, there are still a few for find the generic routines are used. Use the CMPBGE insn, via the builtin, for testing of zeros. Use a simplified expansion of __builtin_ctz when the insn isn't available. Checked on alpha-linux-gnu. Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
/* Basic zero byte detection. Generic C 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_FZA_H
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#define _STRING_FZA_H 1
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#include <string-misc.h>
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#include <string-optype.h>
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/* The CMPBGE instruction creates a bit mask rather than a byte mask.
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However, if we narrow find_t to either 'int' or 'uint8_t', we get
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unnecessary truncation instructions from the 'unsigned long' type
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returned by __builtin_alpha_cmpbge. */
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typedef op_t find_t;
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static __always_inline find_t
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find_zero_all (op_t x)
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{
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return __builtin_alpha_cmpbge (0, x);
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}
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static __always_inline find_t
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find_eq_all (op_t x1, op_t x2)
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{
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return find_zero_all (x1 ^ x2);
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}
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static __always_inline find_t
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find_zero_eq_all (op_t x1, op_t x2)
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{
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return find_zero_all (x1) | find_zero_all (x1 ^ x2);
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}
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static __always_inline find_t
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find_zero_ne_all (op_t x1, op_t x2)
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{
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return find_zero_all (x1) | (find_zero_all (x1 ^ x2) ^ 0xff);
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}
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/* Define the "inexact" versions in terms of the exact versions. */
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#define find_zero_low find_zero_all
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#define find_eq_low find_eq_all
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#define find_zero_eq_low find_zero_eq_all
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#endif /* _STRING_FZA_H */
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