mirror of
https://sourceware.org/git/glibc.git
synced 2025-01-07 18:10:07 +00:00
3a4781c16c
The __builtin_arm_uqsub8 is an internal GCC builtin which might change in future release (the correct way is to include "arm_acle.h" and use __uqsub8 ()). Since not all compilers support it, just use the inline assembler instead. Checked on armv7a-linux-gnueabihf. Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
70 lines
2.2 KiB
C
70 lines
2.2 KiB
C
/* Zero byte detection; basics. ARM 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_FZA_H
|
|
#define _STRING_FZA_H 1
|
|
|
|
#include <string-misc.h>
|
|
#include <string-optype.h>
|
|
|
|
/* The functions return a byte mask. */
|
|
typedef op_t find_t;
|
|
|
|
/* This function returns at least one bit set within every byte
|
|
of X that is zero. */
|
|
static __always_inline find_t
|
|
find_zero_all (op_t x)
|
|
{
|
|
/* Use unsigned saturated subtraction from 1 in each byte.
|
|
That leaves 1 for every byte that was zero. */
|
|
op_t ones = repeat_bytes (0x01);
|
|
op_t ret;
|
|
asm ("uqsub8 %0,%1,%2" : "=r"(ret) : "r"(ones), "r"(x));
|
|
return ret;
|
|
}
|
|
|
|
/* Identify bytes that are equal between X1 and X2. */
|
|
static __always_inline find_t
|
|
find_eq_all (op_t x1, op_t x2)
|
|
{
|
|
return find_zero_all (x1 ^ x2);
|
|
}
|
|
|
|
/* Identify zero bytes in X1 or equality between X1 and X2. */
|
|
static __always_inline find_t
|
|
find_zero_eq_all (op_t x1, op_t x2)
|
|
{
|
|
return find_zero_all (x1) | find_zero_all (x1 ^ x2);
|
|
}
|
|
|
|
/* Identify zero bytes in X1 or inequality between X1 and X2. */
|
|
static __always_inline find_t
|
|
find_zero_ne_all (op_t x1, op_t x2)
|
|
{
|
|
/* Make use of the fact that we'll already have ONES in a register. */
|
|
op_t ones = repeat_bytes (0x01);
|
|
return find_zero_all (x1) | (find_zero_all (x1 ^ x2) ^ ones);
|
|
}
|
|
|
|
/* Define the "inexact" versions in terms of the exact versions. */
|
|
#define find_zero_low find_zero_all
|
|
#define find_eq_low find_eq_all
|
|
#define find_zero_eq_low find_zero_eq_all
|
|
|
|
#endif /* _STRING_FZA_H */
|