sysdeps/tile/tilegx/string-endian.h

   1 /* Copyright (C) 2011-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library.  If not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <endian.h>
  20 #include <stdint.h>
  21
  22 /* Provide a set of macros to help keep endianness #ifdefs out of
  23    the string functions.
  24
  25    MASK: Provide a mask based on the pointer alignment that
  26    sets up non-zero bytes before the beginning of the string.
  27    The MASK expression works because shift counts are taken mod 64.
  28
  29    NULMASK: Clear bytes beyond a given point in the string.
  30
  31    CFZ: Find the first zero bit in the 8 string bytes in a long.
  32
  33    REVCZ: Find the last zero bit in the 8 string bytes in a long.
  34
  35    STRSHIFT: Shift N bits towards the start of the string.  */
  36
  37 #if __BYTE_ORDER == __LITTLE_ENDIAN
  38 #define MASK(x) (__insn_shl(1ULL, (x << 3)) - 1)
  39 #define NULMASK(x) ((2ULL << x) - 1)
  40 #define CFZ(x) __insn_ctz(x)
  41 #define REVCZ(x) __insn_clz(x)
  42 #define STRSHIFT(x,n) ((x) >> n)
  43 #else
  44 #define MASK(x) (__insn_shl(-2LL, ((-x << 3) - 1)))
  45 #define NULMASK(x) (-2LL << (63 - x))
  46 #define CFZ(x) __insn_clz(x)
  47 #define REVCZ(x) __insn_ctz(x)
  48 #define STRSHIFT(x,n) ((x) << n)
  49 #endif
  50
  51 /* Create eight copies of the byte in a uint64_t.  Byte Shuffle uses
  52    the bytes of srcB as the index into the dest vector to select a
  53    byte.  With all indices of zero, the first byte is copied into all
  54    the other bytes.  */
  55 static inline uint64_t copy_byte(uint8_t byte)
  56 {
  57   return __insn_shufflebytes(byte, 0, 0);
  58 }