1 /* mpf_add -- Add two floats.
3 Copyright 1993, 1994, 1996, 2000, 2001, 2005 Free Software Foundation, Inc.
5 This file is part of the GNU MP Library.
7 The GNU MP Library is free software; you can redistribute it and/or modify
8 it under the terms of the GNU Lesser General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or (at your
10 option) any later version.
12 The GNU MP Library is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
15 License for more details.
17 You should have received a copy of the GNU Lesser General Public License
18 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
24 mpf_add (mpf_ptr r, mpf_srcptr u, mpf_srcptr v)
28 mp_size_t usize, vsize, rsize;
39 /* Handle special cases that don't work in generic code below. */
53 /* If signs of U and V are different, perform subtraction. */
54 if ((usize ^ vsize) < 0)
56 __mpf_struct v_negated;
57 v_negated._mp_size = -vsize;
58 v_negated._mp_exp = v->_mp_exp;
59 v_negated._mp_d = v->_mp_d;
60 mpf_sub (r, u, &v_negated);
66 /* Signs are now known to be the same. */
69 /* Make U be the operand with the largest exponent. */
70 if (u->_mp_exp < v->_mp_exp)
85 ediff = u->_mp_exp - v->_mp_exp;
87 /* If U extends beyond PREC, ignore the part that does. */
94 /* If V extends beyond PREC, ignore the part that does.
95 Note that this may make vsize negative. */
96 if (vsize + ediff > prec)
98 vp += vsize + ediff - prec;
103 /* Locate the least significant non-zero limb in (the needed parts
104 of) U and V, to simplify the code below. */
111 /* Allocate temp space for the result. Allocate
112 just vsize + ediff later??? */
113 tp = TMP_ALLOC_LIMBS (prec);
117 /* V completely cancelled. */
119 MPN_COPY_INCR (rp, up, usize);
124 /* uuuu | uuuu | uuuu | uuuu | uuuu */
125 /* vvvvvvv | vv | vvvvv | v | vv */
129 /* U and V partially overlaps. */
130 if (vsize + ediff <= usize)
135 size = usize - ediff - vsize;
136 MPN_COPY (tp, up, size);
137 cy = mpn_add (tp + size, up + size, usize - size, vp, vsize);
145 size = vsize + ediff - usize;
146 MPN_COPY (tp, vp, size);
147 cy = mpn_add (tp + size, up, usize, vp + size, usize - ediff);
148 rsize = vsize + ediff;
156 size = vsize + ediff - usize;
157 MPN_COPY (tp, vp, vsize);
158 MPN_ZERO (tp + vsize, ediff - usize);
159 MPN_COPY (tp + size, up, usize);
161 rsize = size + usize;
164 MPN_COPY (rp, tp, rsize);
170 r->_mp_size = negate ? -rsize : rsize;