/* Test whether long double value is canonical.  ldbl-128ibm version.

   Copyright (C) 2016-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <math.h>

#include <math_private.h>

#include <stdint.h>

int

__iscanonicall (long double x)

{

  double xhi, xlo;

  uint64_t hx, lx;

  ldbl_unpack (x, &xhi, &xlo;;

  EXTRACT_WORDS64 (hx, xhi);

  EXTRACT_WORDS64 (lx, xlo);

  int64_t ix = hx & 0x7fffffffffffffffULL;

  int64_t iy = lx & 0x7fffffffffffffffULL;

  int hexp = (ix & 0x7ff0000000000000LL) >> 52;

  int lexp = (iy & 0x7ff0000000000000LL) >> 52;

  if (iy == 0)

    /* Low part 0 is always OK.  */

    return 1;

  if (hexp == 0x7ff)

    /* If a NaN, the low part does not matter.  If an infinity, the

       low part must be 0, in which case we have already returned.  */

    return ix != 0x7ff0000000000000LL;

  /* The high part is finite and the low part is nonzero.  There must

     be sufficient difference between the exponents.  */

  bool low_p2;

  if (lexp == 0)

    {

      /* Adjust the exponent for subnormal low part.  */

      lexp = 12 - __builtin_clzll (iy);

      low_p2 = iy == (1LL << (51 + lexp));

    }

  else

    low_p2 = (iy & 0xfffffffffffffLL) == 0;

  int expdiff = hexp - lexp;

  return expdiff > 53 || (expdiff == 53 && low_p2 && (ix & 1) == 0);

}

libm_hidden_def (__iscanonicall)