/* Copyright (C) 2011-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.

   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/>.  */

#include <endian.h>
#include <stdint.h>

/* Provide a set of macros to help keep endianness #ifdefs out of
   the string functions.

   MASK: Provide a mask based on the pointer alignment that
   sets up non-zero bytes before the beginning of the string.
   The MASK expression works because shift counts are taken mod 64.

   NULMASK: Clear bytes beyond a given point in the string.

   CFZ: Find the first zero bit in the 8 string bytes in a long.

   REVCZ: Find the last zero bit in the 8 string bytes in a long.

   STRSHIFT: Shift N bits towards the start of the string.  */

#if __BYTE_ORDER == __LITTLE_ENDIAN
#define MASK(x) (__insn_shl(1ULL, (x << 3)) - 1)
#define NULMASK(x) ((2ULL << x) - 1)
#define CFZ(x) __insn_ctz(x)
#define REVCZ(x) __insn_clz(x)
#define STRSHIFT(x,n) ((x) >> n)
#else
#define MASK(x) (__insn_shl(-2LL, ((-x << 3) - 1)))
#define NULMASK(x) (-2LL << (63 - x))
#define CFZ(x) __insn_clz(x)
#define REVCZ(x) __insn_ctz(x)
#define STRSHIFT(x,n) ((x) << n)
#endif

/* Create eight copies of the byte in a uint64_t.  Byte Shuffle uses
   the bytes of srcB as the index into the dest vector to select a
   byte.  With all indices of zero, the first byte is copied into all
   the other bytes.  */
static inline uint64_t copy_byte(uint8_t byte)
{
  return __insn_shufflebytes(byte, 0, 0);
}