File: [local] / OpenXM_contrib / gmp / mpfr / Attic / mul_2si.c (download)
Revision 1.1.1.1 (vendor branch), Mon Aug 25 16:06:07 2003 UTC (21 years, 1 month ago) by ohara
Branch: GMP
CVS Tags: VERSION_4_1_2, RELEASE_1_2_3, RELEASE_1_2_2_KNOPPIX_b, RELEASE_1_2_2_KNOPPIX Changes since 1.1: +0 -0
lines
Import gmp 4.1.2
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/* mpfr_mul_2si -- multiply a floating-point number by a power of two
Copyright 1999, 2001, 2002 Free Software Foundation, Inc.
This file is part of the MPFR Library.
The MPFR 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 MPFR 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 MPFR 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 "mpfr.h"
#include "mpfr-impl.h"
/* In the overflow test "n > emax - emin" ensures "emax-n" doesn't wrap
around if n is big. It used to done with "emax < MPFR_EMIN_MIN + n", but
that provoked a compiler bug on mips gcc 2.95.3 in -O2 -mabi=n32.
Similarly for the underflow test. */
int
mpfr_mul_2si (mpfr_ptr y, mpfr_srcptr x, long int n, mp_rnd_t rnd_mode)
{
int inexact;
inexact = y != x ? mpfr_set (y, x, rnd_mode) : 0;
if (MPFR_IS_FP(y) && MPFR_NOTZERO(y))
{
if (n > 0
&& ((unsigned long) n >
(unsigned long) (mp_exp_unsigned_t) (__mpfr_emax - __mpfr_emin)
|| MPFR_EXP(y) > __mpfr_emax - n))
return mpfr_set_overflow (y, rnd_mode, MPFR_SIGN(y));
if (n < 0
&& ((unsigned long) -n >
(unsigned long) (mp_exp_unsigned_t) (__mpfr_emax - __mpfr_emin)
|| MPFR_EXP(y) < __mpfr_emin - n))
return mpfr_set_underflow (y, rnd_mode, MPFR_SIGN(y));
MPFR_EXP(y) += n;
}
return inexact;
}