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
;