1 /* Copyright (C) 1995,1997,2002,2003 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, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA. */
18
19 #include "gmp.h"
20 #include "gmp-impl.h"
21 #include <ieee754.h>
22 #include <float.h>
23
24 /* Convert a multi-precision integer of the needed number of bits (24 for
25 float) and an integral power of two to a `float' in IEEE754 single-
26 precision format. */
27
28 float
__mpn_construct_float(mp_srcptr frac_ptr,int expt,int sign)29 __mpn_construct_float (mp_srcptr frac_ptr, int expt, int sign)
30 {
31 union ieee754_float u;
32
33 u.ieee.negative = sign;
34 u.ieee.exponent = expt + IEEE754_FLOAT_BIAS;
35 #if BITS_PER_MP_LIMB > FLT_MANT_DIG
36 u.ieee.mantissa = frac_ptr[0] & (((mp_limb_t) 1 << FLT_MANT_DIG) - 1);
37 #else
38 #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
39 #endif
40
41 return u.f;
42 }
43