1 /* mpfr_set -- copy of a floating-point number 2 3 Copyright 1999, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. 4 Contributed by the Arenaire and Caramel projects, INRIA. 5 6 This file is part of the GNU MPFR Library. 7 8 The GNU MPFR Library is free software; you can redistribute it and/or modify 9 it under the terms of the GNU Lesser General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or (at your 11 option) any later version. 12 13 The GNU MPFR Library is distributed in the hope that it will be useful, but 14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 16 License for more details. 17 18 You should have received a copy of the GNU Lesser General Public License 19 along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see 20 http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc., 21 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */ 22 23 #include "mpfr-impl.h" 24 25 /* set a to abs(b) * signb: a=b when signb = SIGN(b), a=abs(b) when signb=1 */ 26 int 27 mpfr_set4 (mpfr_ptr a, mpfr_srcptr b, mpfr_rnd_t rnd_mode, int signb) 28 { 29 /* Sign is ALWAYS copied */ 30 MPFR_SET_SIGN (a, signb); 31 32 /* Exponent is also always copied since if the number is singular, 33 the exponent field determined the number. 34 Can't use MPFR_SET_EXP since the exponent may be singular */ 35 MPFR_EXP (a) = MPFR_EXP (b); 36 37 if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (b))) 38 { 39 /* MPFR_SET_NAN, MPFR_SET_ZERO and MPFR_SET_INF are useless 40 since MPFR_EXP (a) = MPFR_EXP (b) does the job */ 41 if (MPFR_IS_NAN (b)) 42 MPFR_RET_NAN; 43 else 44 MPFR_RET (0); 45 } 46 else if (MPFR_LIKELY (MPFR_PREC (b) == MPFR_PREC (a))) 47 { 48 /* Same precision and b is not singular: 49 * just copy the mantissa, and set the exponent and the sign 50 * The result is exact. */ 51 MPN_COPY (MPFR_MANT (a), MPFR_MANT (b), 52 (MPFR_PREC (b) + GMP_NUMB_BITS-1)/GMP_NUMB_BITS); 53 MPFR_RET (0); 54 } 55 else 56 { 57 int inex; 58 59 /* Else Round B inside a */ 60 MPFR_RNDRAW (inex, a, MPFR_MANT (b), MPFR_PREC (b), rnd_mode, signb, 61 if (MPFR_UNLIKELY ( ++MPFR_EXP (a) > __gmpfr_emax)) 62 return mpfr_overflow (a, rnd_mode, signb) ); 63 MPFR_RET (inex); 64 } 65 } 66 67 /* Set a to b */ 68 #undef mpfr_set 69 int 70 mpfr_set (mpfr_ptr a, mpfr_srcptr b, mpfr_rnd_t rnd_mode) 71 { 72 return mpfr_set4 (a, b, rnd_mode, MPFR_SIGN (b)); 73 } 74 75 /* Set a to |b| */ 76 #undef mpfr_abs 77 int 78 mpfr_abs (mpfr_ptr a, mpfr_srcptr b, mpfr_rnd_t rnd_mode) 79 { 80 return mpfr_set4 (a, b, rnd_mode, MPFR_SIGN_POS); 81 } 82