arch/tile/lib/string-endian.h

   1 /*
   2  * Copyright 2013 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  *
  14  * Provide a mask based on the pointer alignment that
  15  * sets up non-zero bytes before the beginning of the string.
  16  * The MASK expression works because shift counts are taken mod 64.
  17  * Also, specify how to count "first" and "last" bits
  18  * when the bits have been read as a word.
  19  */
  20
  21 #include <asm/byteorder.h>
  22
  23 #ifdef __LITTLE_ENDIAN
  24 #define MASK(x) (__insn_shl(1ULL, (x << 3)) - 1)
  25 #define NULMASK(x) ((2ULL << x) - 1)
  26 #define CFZ(x) __insn_ctz(x)
  27 #define REVCZ(x) __insn_clz(x)
  28 #else
  29 #define MASK(x) (__insn_shl(-2LL, ((-x << 3) - 1)))
  30 #define NULMASK(x) (-2LL << (63 - x))
  31 #define CFZ(x) __insn_clz(x)
  32 #define REVCZ(x) __insn_ctz(x)
  33 #endif
  34
  35 /*
  36  * Create eight copies of the byte in a uint64_t.  Byte Shuffle uses
  37  * the bytes of srcB as the index into the dest vector to select a
  38  * byte.  With all indices of zero, the first byte is copied into all
  39  * the other bytes.
  40  */
  41 static inline uint64_t copy_byte(uint8_t byte)
  42 {
  43         return __insn_shufflebytes(byte, 0, 0);
  44 }