mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-26 20:51:11 +00:00
00cb84dde7
This patch adds generic string find and detection meant to be used in
generic vectorized string implementation. The idea is to decompose the
basic string operation so each architecture can reimplement if it
provides any specialized hardware instruction.
The 'string-misc.h' provides miscellaneous functions:
- extractbyte: extracts the byte from an specific index.
- repeat_bytes: setup an word by replicate the argument on each byte.
The 'string-fza.h' provides zero byte detection functions:
- find_zero_low, find_zero_all, find_eq_low, find_eq_all,
find_zero_eq_low, find_zero_eq_all, and find_zero_ne_all
The 'string-fzb.h' provides boolean zero byte detection functions:
- has_zero: determine if any byte within a word is zero.
- has_eq: determine byte equality between two words.
- has_zero_eq: determine if any byte within a word is zero along with
byte equality between two words.
The 'string-fzi.h' provides positions for string-fza.h results:
- index_first: return index of first zero byte within a word.
- index_last: return index of first byte different between two words.
The 'string-fzc.h' provides a combined version of fza and fzi:
- index_first_zero_eq: return index of first zero byte within a word or
first byte different between two words.
- index_first_zero_ne: return index of first zero byte within a word or
first byte equal between two words.
- index_last_zero: return index of last zero byte within a word.
- index_last_eq: return index of last byte different between two words.
The 'string-shift.h' provides a way to mask off parts of a work based on
some alignmnet (to handle unaligned arguments):
- shift_find, shift_find_last.
Co-authored-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
50 lines
1.4 KiB
C
50 lines
1.4 KiB
C
/* Zero byte detection, boolean. Generic C version.
|
|
Copyright (C) 2023 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#ifndef _STRING_FZB_H
|
|
#define _STRING_FZB_H 1
|
|
|
|
#include <endian.h>
|
|
#include <string-fza.h>
|
|
|
|
/* Determine if any byte within X is zero. This is a pure boolean test. */
|
|
|
|
static __always_inline _Bool
|
|
has_zero (op_t x)
|
|
{
|
|
return find_zero_low (x) != 0;
|
|
}
|
|
|
|
/* Likewise, but for byte equality between X1 and X2. */
|
|
|
|
static __always_inline _Bool
|
|
has_eq (op_t x1, op_t x2)
|
|
{
|
|
return find_eq_low (x1, x2) != 0;
|
|
}
|
|
|
|
/* Likewise, but for zeros in X1 and equal bytes between X1 and X2. */
|
|
|
|
static __always_inline _Bool
|
|
has_zero_eq (op_t x1, op_t x2)
|
|
{
|
|
return find_zero_eq_low (x1, x2);
|
|
}
|
|
|
|
#endif /* _STRING_FZB_H */
|