14a238c70SJohn Marino /* mpfr_add -- add two floating-point numbers
24a238c70SJohn Marino
3*ab6d115fSJohn Marino Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
4*ab6d115fSJohn Marino Contributed by the AriC and Caramel projects, INRIA.
54a238c70SJohn Marino
64a238c70SJohn Marino This file is part of the GNU MPFR Library.
74a238c70SJohn Marino
84a238c70SJohn Marino The GNU MPFR Library is free software; you can redistribute it and/or modify
94a238c70SJohn Marino it under the terms of the GNU Lesser General Public License as published by
104a238c70SJohn Marino the Free Software Foundation; either version 3 of the License, or (at your
114a238c70SJohn Marino option) any later version.
124a238c70SJohn Marino
134a238c70SJohn Marino The GNU MPFR Library is distributed in the hope that it will be useful, but
144a238c70SJohn Marino WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
154a238c70SJohn Marino or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
164a238c70SJohn Marino License for more details.
174a238c70SJohn Marino
184a238c70SJohn Marino You should have received a copy of the GNU Lesser General Public License
194a238c70SJohn Marino along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
204a238c70SJohn Marino http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
214a238c70SJohn Marino 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
224a238c70SJohn Marino
234a238c70SJohn Marino #include "mpfr-impl.h"
244a238c70SJohn Marino
254a238c70SJohn Marino int
mpfr_add(mpfr_ptr a,mpfr_srcptr b,mpfr_srcptr c,mpfr_rnd_t rnd_mode)264a238c70SJohn Marino mpfr_add (mpfr_ptr a, mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t rnd_mode)
274a238c70SJohn Marino {
284a238c70SJohn Marino MPFR_LOG_FUNC
294a238c70SJohn Marino (("b[%Pu]=%.*Rg c[%Pu]=%.*Rg rnd=%d",
304a238c70SJohn Marino mpfr_get_prec (b), mpfr_log_prec, b,
314a238c70SJohn Marino mpfr_get_prec (c), mpfr_log_prec, c, rnd_mode),
324a238c70SJohn Marino ("a[%Pu]=%.*Rg", mpfr_get_prec (a), mpfr_log_prec, a));
334a238c70SJohn Marino
344a238c70SJohn Marino if (MPFR_ARE_SINGULAR(b,c))
354a238c70SJohn Marino {
364a238c70SJohn Marino if (MPFR_IS_NAN(b) || MPFR_IS_NAN(c))
374a238c70SJohn Marino {
384a238c70SJohn Marino MPFR_SET_NAN(a);
394a238c70SJohn Marino MPFR_RET_NAN;
404a238c70SJohn Marino }
414a238c70SJohn Marino /* neither b nor c is NaN here */
424a238c70SJohn Marino else if (MPFR_IS_INF(b))
434a238c70SJohn Marino {
444a238c70SJohn Marino if (!MPFR_IS_INF(c) || MPFR_SIGN(b) == MPFR_SIGN(c))
454a238c70SJohn Marino {
464a238c70SJohn Marino MPFR_SET_INF(a);
474a238c70SJohn Marino MPFR_SET_SAME_SIGN(a, b);
484a238c70SJohn Marino MPFR_RET(0); /* exact */
494a238c70SJohn Marino }
504a238c70SJohn Marino else
514a238c70SJohn Marino {
524a238c70SJohn Marino MPFR_SET_NAN(a);
534a238c70SJohn Marino MPFR_RET_NAN;
544a238c70SJohn Marino }
554a238c70SJohn Marino }
564a238c70SJohn Marino else if (MPFR_IS_INF(c))
574a238c70SJohn Marino {
584a238c70SJohn Marino MPFR_SET_INF(a);
594a238c70SJohn Marino MPFR_SET_SAME_SIGN(a, c);
604a238c70SJohn Marino MPFR_RET(0); /* exact */
614a238c70SJohn Marino }
624a238c70SJohn Marino /* now either b or c is zero */
634a238c70SJohn Marino else if (MPFR_IS_ZERO(b))
644a238c70SJohn Marino {
654a238c70SJohn Marino if (MPFR_IS_ZERO(c))
664a238c70SJohn Marino {
674a238c70SJohn Marino /* for round away, we take the same convention for 0 + 0
684a238c70SJohn Marino as for round to zero or to nearest: it always gives +0,
694a238c70SJohn Marino except (-0) + (-0) = -0. */
704a238c70SJohn Marino MPFR_SET_SIGN(a,
714a238c70SJohn Marino (rnd_mode != MPFR_RNDD ?
724a238c70SJohn Marino ((MPFR_IS_NEG(b) && MPFR_IS_NEG(c)) ? -1 : 1) :
734a238c70SJohn Marino ((MPFR_IS_POS(b) && MPFR_IS_POS(c)) ? 1 : -1)));
744a238c70SJohn Marino MPFR_SET_ZERO(a);
754a238c70SJohn Marino MPFR_RET(0); /* 0 + 0 is exact */
764a238c70SJohn Marino }
774a238c70SJohn Marino return mpfr_set (a, c, rnd_mode);
784a238c70SJohn Marino }
794a238c70SJohn Marino else
804a238c70SJohn Marino {
814a238c70SJohn Marino MPFR_ASSERTD(MPFR_IS_ZERO(c));
824a238c70SJohn Marino return mpfr_set (a, b, rnd_mode);
834a238c70SJohn Marino }
844a238c70SJohn Marino }
854a238c70SJohn Marino
864a238c70SJohn Marino MPFR_ASSERTD (MPFR_IS_PURE_FP (b));
874a238c70SJohn Marino MPFR_ASSERTD (MPFR_IS_PURE_FP (c));
884a238c70SJohn Marino
894a238c70SJohn Marino if (MPFR_UNLIKELY(MPFR_SIGN(b) != MPFR_SIGN(c)))
904a238c70SJohn Marino { /* signs differ, it is a subtraction */
914a238c70SJohn Marino if (MPFR_LIKELY(MPFR_PREC(a) == MPFR_PREC(b)
924a238c70SJohn Marino && MPFR_PREC(b) == MPFR_PREC(c)))
934a238c70SJohn Marino return mpfr_sub1sp(a, b, c, rnd_mode);
944a238c70SJohn Marino else
954a238c70SJohn Marino return mpfr_sub1(a, b, c, rnd_mode);
964a238c70SJohn Marino }
974a238c70SJohn Marino else
984a238c70SJohn Marino { /* signs are equal, it's an addition */
994a238c70SJohn Marino if (MPFR_LIKELY(MPFR_PREC(a) == MPFR_PREC(b)
1004a238c70SJohn Marino && MPFR_PREC(b) == MPFR_PREC(c)))
1014a238c70SJohn Marino if (MPFR_GET_EXP(b) < MPFR_GET_EXP(c))
1024a238c70SJohn Marino return mpfr_add1sp(a, c, b, rnd_mode);
1034a238c70SJohn Marino else
1044a238c70SJohn Marino return mpfr_add1sp(a, b, c, rnd_mode);
1054a238c70SJohn Marino else
1064a238c70SJohn Marino if (MPFR_GET_EXP(b) < MPFR_GET_EXP(c))
1074a238c70SJohn Marino return mpfr_add1(a, c, b, rnd_mode);
1084a238c70SJohn Marino else
1094a238c70SJohn Marino return mpfr_add1(a, b, c, rnd_mode);
1104a238c70SJohn Marino }
1114a238c70SJohn Marino }
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