/* Implementation of the bit intrinsics not implemented as GCC builtins.
   Copyright (C) 2009 Free Software Foundation, Inc.

This file is part of the GNU Fortran runtime library (libgfortran).

Libgfortran is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.

Libgfortran 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 General Public License for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#include "libgfortran.h"


#ifdef HAVE_GFC_INTEGER_16
extern int clz128 (GFC_INTEGER_16);
export_proto(clz128);

int
clz128 (GFC_INTEGER_16 x)
{
  int res = 127;

  // We can't write 0xFFFFFFFFFFFFFFFF0000000000000000, so we work around it
  if (x & ((__uint128_t) 0xFFFFFFFFFFFFFFFF << 64))
    {
      res -= 64;
      x >>= 64;
    }

  if (x & 0xFFFFFFFF00000000)
    {
      res -= 32;
      x >>= 32;
    }

  if (x & 0xFFFF0000)
    {
      res -= 16;
      x >>= 16;
    }

  if (x & 0xFF00)
    {
      res -= 8;
      x >>= 8;
    }

  if (x & 0xF0)
    {
      res -= 4;
      x >>= 4;
    }

  if (x & 0xC)
    {
      res -= 2;
      x >>= 2;
    }

  if (x & 0x2)
    {
      res -= 1;
      x >>= 1;
    }

  return res;
}
#endif


#ifdef HAVE_GFC_INTEGER_16
extern int ctz128 (GFC_INTEGER_16);
export_proto(ctz128);

int
ctz128 (GFC_INTEGER_16 x)
{
  int res = 0;

  if ((x & 0xFFFFFFFFFFFFFFFF) == 0)
    {
      res += 64;
      x >>= 64;
    }

  if ((x & 0xFFFFFFFF) == 0)
    {
      res += 32;
      x >>= 32;
    }

  if ((x & 0xFFFF) == 0)
    {
      res += 16;
      x >>= 16;
    }

  if ((x & 0xFF) == 0)
    {
      res += 8;
      x >>= 8;
    }

  if ((x & 0xF) == 0)
    {
      res += 4;
      x >>= 4;
    }

  if ((x & 0x3) == 0)
    {
      res += 2;
      x >>= 2;
    }

  if ((x & 0x1) == 0)
    {
      res += 1;
      x >>= 1;
    }

  return res;
}
#endif
