gcc/libquadmath/strtod/mpn2flt128.c

52 lines
1.8 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <config.h>
#include <float.h>
#include <math.h>
#include "../printf/gmp-impl.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. */
__float128
mpn_construct_float128 (mp_srcptr frac_ptr, int expt, int sign)
{
ieee854_float128 u;
u.ieee.negative = sign;
u.ieee.exponent = expt + IEEE854_FLOAT128_BIAS;
#if BITS_PER_MP_LIMB == 32
u.ieee.mant_low = (((uint64_t) frac_ptr[1]) << 32)
| (frac_ptr[0] & 0xffffffff);
u.ieee.mant_high = (((uint64_t) frac_ptr[3]
& (((mp_limb_t) 1 << (FLT128_MANT_DIG - 96)) - 1))
<< 32) | (frac_ptr[2] & 0xffffffff);
#elif BITS_PER_MP_LIMB == 64
u.ieee.mant_low = frac_ptr[0];
u.ieee.mant_high = frac_ptr[1]
& (((mp_limb_t) 1 << (FLT128_MANT_DIG - 64)) - 1);
#else
#error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
#endif
return u.value;
}