glibc/sysdeps/ieee754/flt-32/mpn2flt.c

43 lines
1.5 KiB
C

/* Copyright (C) 1995, 1997 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include "gmp.h"
#include "gmp-impl.h"
#include <ieee754.h>
#include <float.h>
/* Convert a multi-precision integer of the needed number of bits (24 for
float) and an integral power of two to a `float' in IEEE754 single-
precision format. */
float
__mpn_construct_float (mp_srcptr frac_ptr, int expt, int sign)
{
union ieee754_float u;
u.ieee.negative = sign;
u.ieee.exponent = expt + IEEE754_FLOAT_BIAS;
#if BITS_PER_MP_LIMB > FLT_MANT_DIG
u.ieee.mantissa = frac_ptr[0] & ((1 << FLT_MANT_DIG) - 1);
#else
#error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
#endif
return u.f;
}