1  /* Set NaN payload.  ldbl-128 version.
       2     Copyright (C) 2016-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <math.h>
      20  #include <math_private.h>
      21  #include <libm-alias-ldouble.h>
      22  #include <nan-high-order-bit.h>
      23  #include <stdint.h>
      24  
      25  #define SET_HIGH_BIT (HIGH_ORDER_BIT_IS_SET_FOR_SNAN ? SIG : !SIG)
      26  #define BIAS 0x3fff
      27  #define PAYLOAD_DIG 111
      28  #define EXPLICIT_MANT_DIG 112
      29  
      30  int
      31  FUNC (_Float128 *x, _Float128 payload)
      32  {
      33    uint64_t hx, lx;
      34    GET_LDOUBLE_WORDS64 (hx, lx, payload);
      35    int exponent = hx >> (EXPLICIT_MANT_DIG - 64);
      36    /* Test if argument is (a) negative or too large; (b) too small,
      37       except for 0 when allowed; (c) not an integer.  */
      38    if (exponent >= BIAS + PAYLOAD_DIG
      39        || (exponent < BIAS && !(SET_HIGH_BIT && hx == 0 && lx == 0)))
      40      {
      41        SET_LDOUBLE_WORDS64 (*x, 0, 0);
      42        return 1;
      43      }
      44    int shift = BIAS + EXPLICIT_MANT_DIG - exponent;
      45    if (shift < 64
      46        ? (lx & ((1ULL << shift) - 1)) != 0
      47        : (lx != 0 || (hx & ((1ULL << (shift - 64)) - 1)) != 0))
      48      {
      49        SET_LDOUBLE_WORDS64 (*x, 0, 0);
      50        return 1;
      51      }
      52    if (exponent != 0)
      53      {
      54        hx &= (1ULL << (EXPLICIT_MANT_DIG - 64)) - 1;
      55        hx |= 1ULL << (EXPLICIT_MANT_DIG - 64);
      56        if (shift >= 64)
      57  	{
      58  	  lx = hx >> (shift - 64);
      59  	  hx = 0;
      60  	}
      61        else if (shift != 0)
      62  	{
      63  	  lx = (lx >> shift) | (hx << (64 - shift));
      64  	  hx >>= shift;
      65  	}
      66      }
      67    hx |= 0x7fff000000000000ULL | (SET_HIGH_BIT ? 0x800000000000ULL : 0);
      68    SET_LDOUBLE_WORDS64 (*x, hx, lx);
      69    return 0;
      70  }