1  /* Copyright (C) 2003-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library.  If not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <math.h>
      19  
      20  long double
      21  __frexpl (long double value, int *expptr)
      22  {
      23    long double mantissa, exponent;
      24    int iexponent;
      25    unsigned long fpsr;
      26  
      27    __asm ("ftst%.x %1\n"
      28  	 "fmove%.l %/fpsr, %0"
      29  	 : "=dm" (fpsr) : "f" (value));
      30    if (fpsr & (7 << 24))
      31      {
      32        /* Not finite or zero.  */
      33        *expptr = 0;
      34        return value;
      35      }
      36    __asm ("fgetexp%.x %1, %0" : "=f" (exponent) : "f" (value));
      37    iexponent = (int) exponent + 1;
      38    *expptr = iexponent;
      39    /* Unnormalized numbers must be handled specially, otherwise fscale
      40       results in overflow.  */
      41    if (iexponent <= -16384)
      42      {
      43        value *= 0x1p16383L;
      44        iexponent += 16383;
      45      }
      46    else if (iexponent >= 16384)
      47      {
      48        value *= 0x1p-16383L;
      49        iexponent -= 16383;
      50      }
      51  
      52    __asm ("fscale%.l %2, %0"
      53  	 : "=f" (mantissa)
      54  	 : "0" (value), "dmi" (-iexponent));
      55    return mantissa;
      56  }
      57  
      58  weak_alias (__frexpl, frexpl)