1  /* Copyright (C) 1995-2023 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 "gmp.h"
      19  #include "gmp-impl.h"
      20  #include <ieee754.h>
      21  #include <float.h>
      22  
      23  /* Convert a multi-precision integer of the needed number of bits (24 for
      24     float) and an integral power of two to a `float' in IEEE754 single-
      25     precision format.  */
      26  
      27  float
      28  __mpn_construct_float (mp_srcptr frac_ptr, int expt, int sign)
      29  {
      30    union ieee754_float u;
      31  
      32    u.ieee.negative = sign;
      33    u.ieee.exponent = expt + IEEE754_FLOAT_BIAS;
      34  #if BITS_PER_MP_LIMB > FLT_MANT_DIG
      35    u.ieee.mantissa = frac_ptr[0] & (((mp_limb_t) 1 << FLT_MANT_DIG) - 1);
      36  #else
      37    #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
      38  #endif
      39  
      40    return u.f;
      41  }