include/bitop.h

   1 /*
   2   Copyright 2008 Kristian Nielsen
   3
   4   This file is part of BeeDB.
   5
   6   Foobar is free software: you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation, either version 2 of the License, or
   9   (at your option) any later version.
  10
  11   Foobar is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with Foobar.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 /* ToDo: take this from autoconf instead. */
  21 #if defined(__x86_64__)
  22 #define SIZEOF_LONG 8
  23 #define SIZEOF_LONG_LONG 8
  24 #elif defined(__i386__)
  25 #define SIZEOF_LONG 4
  26 #define SIZEOF_LONG_LONG 8
  27 #else
  28 #error Unknown sizeof(long)
  29 #endif
  30
  31 #ifdef __GNUC__
  32
  33 /*
  34   Count leading zero bits, compiler intrinsics to get access to CPU native
  35   instructions, if available.
  36 */
  37 #if SIZEOF_LONG == 8
  38 #define COUNT_LEADING_ZEROS_64(x) __builtin_clzl((x))
  39 #elif SIZEOF_LONG_LONG == 8
  40 #define COUNT_LEADING_ZEROS_64(x) __builtin_clzll((x))
  41 #else
  42 #error No 64-bit integer type available
  43 #endif
  44
  45 #else
  46 #error No COUNT_LEADING_ZEROS_64 defined for compiler
  47 #endif
  48
  49 /*
  50   Non-temporal stores.
  51
  52   These write directly to memory bypassing cache.
  53 */
  54
  55 #ifdef __GNUC__
  56 #define STORE_NON_TEMPORAL_64(p, v) asm("movnti %1, %0" : "=m" (*(p)) : "r" (v))
  57 //  __builtin_ia32_movntq((long long unsigned int*)(p), (long long unsigned)(v))
  58 #else
  59 #define STORE_NON_TEMPORAL_64(p, v) (*(uint64_t *)(p) = (uint64_t)(v))
  60 #endif