mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-25 06:20:06 +00:00
63 lines
1.8 KiB
C
63 lines
1.8 KiB
C
/* string-fzi.h -- zero byte detection; indices. Alpha version.
|
|
Copyright (C) 2023-2024 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_FZI_H
|
|
#define _STRING_FZI_H
|
|
|
|
#include <stdint.h>
|
|
#include <string-optype.h>
|
|
#include <string-fza.h>
|
|
|
|
/* Note that since CMPBGE creates a bit mask rather than a byte mask,
|
|
we cannot simply provide a target-specific string-fza.h. */
|
|
|
|
/* A subroutine for the index_zero functions. Given a bitmask C,
|
|
return the index of the first bit set in memory order. */
|
|
static __always_inline unsigned int
|
|
index_first (find_t c)
|
|
{
|
|
#ifdef __alpha_cix__
|
|
return __builtin_ctzl (c);
|
|
#else
|
|
c = c & -c;
|
|
return (c & 0xf0 ? 4 : 0) + (c & 0xcc ? 2 : 0) + (c & 0xaa ? 1 : 0);
|
|
#endif
|
|
}
|
|
|
|
/* Similarly, but return the (memory order) index of the last bit
|
|
that is non-zero. Note that only the least 8 bits may be nonzero. */
|
|
|
|
static __always_inline unsigned int
|
|
index_last (find_t x)
|
|
{
|
|
#ifdef __alpha_cix__
|
|
return __builtin_clzl (x) ^ 63;
|
|
#else
|
|
unsigned r = 0;
|
|
if (x & 0xf0)
|
|
r += 4;
|
|
if (x & (0xc << r))
|
|
r += 2;
|
|
if (x & (0x2 << r))
|
|
r += 1;
|
|
return r;
|
|
#endif
|
|
}
|
|
|
|
#endif /* _STRING_FZI_H */
|