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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>
53 lines
1.6 KiB
C
53 lines
1.6 KiB
C
/* Zero byte detection; boolean. Alpha 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_FZB_H
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#define _STRING_FZB_H 1
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#include <sys/cdefs.h>
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#include <string-optype.h>
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/* Note that since CMPBGE creates a bit mask rather than a byte mask,
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we cannot simply provide a target-specific string-fza.h. */
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/* Determine if any byte within X is zero. This is a pure boolean test. */
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static __always_inline _Bool
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has_zero (op_t x)
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{
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return __builtin_alpha_cmpbge (0, x) != 0;
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}
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/* Likewise, but for byte equality between X1 and X2. */
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static __always_inline _Bool
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has_eq (op_t x1, op_t x2)
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{
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return has_zero (x1 ^ x2);
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}
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/* Likewise, but for zeros in X1 and equal bytes between X1 and X2. */
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static __always_inline _Bool
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has_zero_eq (op_t x1, op_t x2)
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{
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return has_zero (x1) | has_eq (x1, x2);
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}
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#endif /* _STRING_FZB_H */
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