mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-27 13:10:29 +00:00
54 lines
1.9 KiB
C
54 lines
1.9 KiB
C
/* Copyright (C) 1995,1996,1997,1998,1999,2002,2003
|
|
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 Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include "gmp.h"
|
|
#include "gmp-impl.h"
|
|
#include <ieee754.h>
|
|
#include <float.h>
|
|
#include <math.h>
|
|
|
|
/* Convert a multi-precision integer of the needed number of bits (113 for
|
|
long double) and an integral power of two to a `long double' in IEEE854
|
|
quad-precision format. */
|
|
|
|
long double
|
|
__mpn_construct_long_double (mp_srcptr frac_ptr, int expt, int sign)
|
|
{
|
|
union ieee854_long_double u;
|
|
|
|
u.ieee.negative = sign;
|
|
u.ieee.exponent = expt + IEEE854_LONG_DOUBLE_BIAS;
|
|
#if BITS_PER_MP_LIMB == 32
|
|
u.ieee.mantissa3 = frac_ptr[0];
|
|
u.ieee.mantissa2 = frac_ptr[1];
|
|
u.ieee.mantissa1 = frac_ptr[2];
|
|
u.ieee.mantissa0 = frac_ptr[3] & (((mp_limb_t) 1
|
|
<< (LDBL_MANT_DIG - 96)) - 1);
|
|
#elif BITS_PER_MP_LIMB == 64
|
|
u.ieee.mantissa3 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1);
|
|
u.ieee.mantissa2 = frac_ptr[0] >> 32;
|
|
u.ieee.mantissa1 = frac_ptr[1] & (((mp_limb_t) 1 << 32) - 1);
|
|
u.ieee.mantissa0 = (frac_ptr[1] >> 32) & (((mp_limb_t) 1
|
|
<< (LDBL_MANT_DIG - 96)) - 1);
|
|
#else
|
|
#error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
|
|
#endif
|
|
|
|
return u.d;
|
|
}
|