libgfortran/intrinsics/bit_intrinsics.c

   1 /* Implementation of the bit intrinsics not implemented as GCC builtins.
   2    Copyright (C) 2009-2015 Free Software Foundation, Inc.
   3
   4 This file is part of the GNU Fortran runtime library (libgfortran).
   5
   6 Libgfortran is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU General Public
   8 License as published by the Free Software Foundation; either
   9 version 3 of the License, or (at your option) any later version.
  10
  11 Libgfortran 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 Under Section 7 of GPL version 3, you are granted additional
  17 permissions described in the GCC Runtime Library Exception, version
  18 3.1, as published by the Free Software Foundation.
  19
  20 You should have received a copy of the GNU General Public License and
  21 a copy of the GCC Runtime Library Exception along with this program;
  22 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 <http://www.gnu.org/licenses/>.  */
  24
  25 #include "libgfortran.h"
  26
  27
  28 #ifdef HAVE_GFC_INTEGER_16
  29 extern int clz128 (GFC_INTEGER_16);
  30 export_proto(clz128);
  31
  32 int
  33 clz128 (GFC_INTEGER_16 x)
  34 {
  35   int res = 127;
  36
  37   // We can't write 0xFFFFFFFFFFFFFFFF0000000000000000, so we work around it
  38   if (x & ((__uint128_t) 0xFFFFFFFFFFFFFFFF << 64))
  39     {
  40       res -= 64;
  41       x >>= 64;
  42     }
  43
  44   if (x & 0xFFFFFFFF00000000)
  45     {
  46       res -= 32;
  47       x >>= 32;
  48     }
  49
  50   if (x & 0xFFFF0000)
  51     {
  52       res -= 16;
  53       x >>= 16;
  54     }
  55
  56   if (x & 0xFF00)
  57     {
  58       res -= 8;
  59       x >>= 8;
  60     }
  61
  62   if (x & 0xF0)
  63     {
  64       res -= 4;
  65       x >>= 4;
  66     }
  67
  68   if (x & 0xC)
  69     {
  70       res -= 2;
  71       x >>= 2;
  72     }
  73
  74   if (x & 0x2)
  75     {
  76       res -= 1;
  77       x >>= 1;
  78     }
  79
  80   return res;
  81 }
  82 #endif
  83
  84
  85 #ifdef HAVE_GFC_INTEGER_16
  86 extern int ctz128 (GFC_INTEGER_16);
  87 export_proto(ctz128);
  88
  89 int
  90 ctz128 (GFC_INTEGER_16 x)
  91 {
  92   int res = 0;
  93
  94   if ((x & 0xFFFFFFFFFFFFFFFF) == 0)
  95     {
  96       res += 64;
  97       x >>= 64;
  98     }
  99
 100   if ((x & 0xFFFFFFFF) == 0)
 101     {
 102       res += 32;
 103       x >>= 32;
 104     }
 105
 106   if ((x & 0xFFFF) == 0)
 107     {
 108       res += 16;
 109       x >>= 16;
 110     }
 111
 112   if ((x & 0xFF) == 0)
 113     {
 114       res += 8;
 115       x >>= 8;
 116     }
 117
 118   if ((x & 0xF) == 0)
 119     {
 120       res += 4;
 121       x >>= 4;
 122     }
 123
 124   if ((x & 0x3) == 0)
 125     {
 126       res += 2;
 127       x >>= 2;
 128     }
 129
 130   if ((x & 0x1) == 0)
 131     {
 132       res += 1;
 133       x >>= 1;
 134     }
 135
 136   return res;
 137 }
 138 #endif