efee5258bc
The MPFR library is a C library for multiple-precision floating-point computations with exact rounding (also called correct rounding). It is based on the GMP multiple-precision library and should replace the MPF class in further releases of GMP. GCC >= 4.2 requires MPFR.
82 lines
2.7 KiB
C
82 lines
2.7 KiB
C
/* mpfr_set -- copy of a floating-point number
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Copyright 1999, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
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Contributed by the Arenaire and Cacao projects, INRIA.
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This file is part of the GNU MPFR Library.
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The GNU MPFR Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 3 of the License, or (at your
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option) any later version.
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The GNU MPFR Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
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http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
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#include "mpfr-impl.h"
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/* set a to abs(b) * signb: a=b when signb = SIGN(b), a=abs(b) when signb=1 */
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int
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mpfr_set4 (mpfr_ptr a, mpfr_srcptr b, mpfr_rnd_t rnd_mode, int signb)
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{
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/* Sign is ALWAYS copied */
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MPFR_SET_SIGN (a, signb);
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/* Exponent is also always copied since if the number is singular,
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the exponent field determined the number.
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Can't use MPFR_SET_EXP since the exponent may be singular */
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MPFR_EXP (a) = MPFR_EXP (b);
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if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (b)))
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{
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/* MPFR_SET_NAN, MPFR_SET_ZERO and MPFR_SET_INF are useless
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since MPFR_EXP (a) = MPFR_EXP (b) does the job */
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if (MPFR_IS_NAN (b))
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MPFR_RET_NAN;
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else
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MPFR_RET (0);
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}
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else if (MPFR_LIKELY (MPFR_PREC (b) == MPFR_PREC (a)))
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{
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/* Same precision and b is not singular:
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* just copy the mantissa, and set the exponent and the sign
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* The result is exact. */
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MPN_COPY (MPFR_MANT (a), MPFR_MANT (b),
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(MPFR_PREC (b) + GMP_NUMB_BITS-1)/GMP_NUMB_BITS);
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MPFR_RET (0);
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}
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else
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{
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int inex;
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/* Else Round B inside a */
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MPFR_RNDRAW (inex, a, MPFR_MANT (b), MPFR_PREC (b), rnd_mode, signb,
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if (MPFR_UNLIKELY ( ++MPFR_EXP (a) > __gmpfr_emax))
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return mpfr_overflow (a, rnd_mode, signb) );
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MPFR_RET (inex);
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}
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}
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/* Set a to b */
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#undef mpfr_set
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int
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mpfr_set (mpfr_ptr a, mpfr_srcptr b, mpfr_rnd_t rnd_mode)
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{
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return mpfr_set4 (a, b, rnd_mode, MPFR_SIGN (b));
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}
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/* Set a to |b| */
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#undef mpfr_abs
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int
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mpfr_abs (mpfr_ptr a, mpfr_srcptr b, mpfr_rnd_t rnd_mode)
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{
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return mpfr_set4 (a, b, rnd_mode, MPFR_SIGN_POS);
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}
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