1 /* Copyright (C) 1995,1996,1997,2002,2003 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
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
24 /* Convert a multi-precision integer of the needed number of bits (53 for
25 double) and an integral power of two to a `double' in IEEE754 double-
29 __mpn_construct_double (mp_srcptr frac_ptr
, int expt
, int negative
)
31 union ieee754_double u
;
33 u
.ieee
.negative
= negative
;
34 u
.ieee
.exponent
= expt
+ IEEE754_DOUBLE_BIAS
;
35 #if BITS_PER_MP_LIMB == 32
36 u
.ieee
.mantissa1
= frac_ptr
[0];
37 u
.ieee
.mantissa0
= frac_ptr
[1] & (((mp_limb_t
) 1
38 << (DBL_MANT_DIG
- 32)) - 1);
39 #elif BITS_PER_MP_LIMB == 64
40 u
.ieee
.mantissa1
= frac_ptr
[0] & (((mp_limb_t
) 1 << 32) - 1);
41 u
.ieee
.mantissa0
= (frac_ptr
[0] >> 32) & (((mp_limb_t
) 1
42 << (DBL_MANT_DIG
- 32)) - 1);
44 #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"