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59 lines
2.1 KiB
C
59 lines
2.1 KiB
C
/* Copyright (C) 2011-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
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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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#include <endian.h>
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#include <stdint.h>
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/* Provide a set of macros to help keep endianness #ifdefs out of
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the string functions.
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MASK: Provide a mask based on the pointer alignment that
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sets up non-zero bytes before the beginning of the string.
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The MASK expression works because shift counts are taken mod 64.
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NULMASK: Clear bytes beyond a given point in the string.
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CFZ: Find the first zero bit in the 8 string bytes in a long.
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REVCZ: Find the last zero bit in the 8 string bytes in a long.
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STRSHIFT: Shift N bits towards the start of the string. */
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#if __BYTE_ORDER == __LITTLE_ENDIAN
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#define MASK(x) (__insn_shl(1ULL, (x << 3)) - 1)
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#define NULMASK(x) ((2ULL << x) - 1)
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#define CFZ(x) __insn_ctz(x)
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#define REVCZ(x) __insn_clz(x)
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#define STRSHIFT(x,n) ((x) >> n)
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#else
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#define MASK(x) (__insn_shl(-2LL, ((-x << 3) - 1)))
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#define NULMASK(x) (-2LL << (63 - x))
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#define CFZ(x) __insn_clz(x)
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#define REVCZ(x) __insn_ctz(x)
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#define STRSHIFT(x,n) ((x) << n)
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#endif
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/* Create eight copies of the byte in a uint64_t. Byte Shuffle uses
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the bytes of srcB as the index into the dest vector to select a
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byte. With all indices of zero, the first byte is copied into all
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the other bytes. */
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static inline uint64_t copy_byte(uint8_t byte)
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{
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return __insn_shufflebytes(byte, 0, 0);
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}
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