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/* string-fzi.h -- zero byte detection; indices. Alpha 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_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 */
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