1 /* mpf_add_ui -- Add a float and an unsigned integer.
2
3 Copyright 1993, 1994, 1996, 2000, 2001 Free Software Foundation, Inc.
4
5 This file is part of the GNU MP Library.
6
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 2.1 of the License, or (at your
10 option) any later version.
11
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.
16
17 You should have received a copy of the GNU Lesser General Public License
18 along with the GNU MP Library; see the file COPYING.LIB. If not, write to
19 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
20 MA 02110-1301, USA. */
21
22 #include "mpir.h"
23 #include "gmp-impl.h"
24
25 void
mpf_add_ui(mpf_ptr sum,mpf_srcptr u,mpir_ui v)26 mpf_add_ui (mpf_ptr sum, mpf_srcptr u, mpir_ui v)
27 {
28 mp_srcptr up = u->_mp_d;
29 mp_ptr sump = sum->_mp_d;
30 mp_size_t usize, sumsize;
31 mp_size_t prec = sum->_mp_prec;
32 mp_exp_t uexp = u->_mp_exp;
33
34 usize = u->_mp_size;
35 if (usize <= 0)
36 {
37 if (usize == 0)
38 {
39 mpf_set_ui (sum, v);
40 return;
41 }
42 else
43 {
44 __mpf_struct u_negated;
45 u_negated._mp_size = -usize;
46 u_negated._mp_exp = u->_mp_exp;
47 u_negated._mp_d = u->_mp_d;
48 mpf_sub_ui (sum, &u_negated, v);
49 sum->_mp_size = -(sum->_mp_size);
50 return;
51 }
52 }
53
54 if (v == 0)
55 {
56 sum_is_u:
57 if (u != sum)
58 {
59 sumsize = MIN (usize, prec + 1);
60 MPN_COPY (sum->_mp_d, up + usize - sumsize, sumsize);
61 sum->_mp_size = sumsize;
62 sum->_mp_exp = u->_mp_exp;
63 }
64 return;
65 }
66
67 if (uexp > 0)
68 {
69 /* U >= 1. */
70 if (uexp > prec)
71 {
72 /* U >> V, V is not part of final result. */
73 goto sum_is_u;
74 }
75 else
76 {
77 /* U's "limb point" is somewhere between the first limb
78 and the PREC:th limb.
79 Both U and V are part of the final result. */
80 if (uexp > usize)
81 {
82 /* uuuuuu0000. */
83 /* + v. */
84 /* We begin with moving U to the top of SUM, to handle
85 samevar(U,SUM). */
86 MPN_COPY_DECR (sump + uexp - usize, up, usize);
87 sump[0] = v;
88 MPN_ZERO (sump + 1, uexp - usize - 1);
89 #if 0 /* What is this??? */
90 if (sum == u)
91 MPN_COPY (sum->_mp_d, sump, uexp);
92 #endif
93 sum->_mp_size = uexp;
94 sum->_mp_exp = uexp;
95 }
96 else
97 {
98 /* uuuuuu.uuuu */
99 /* + v. */
100 mp_limb_t cy_limb;
101 if (usize > prec)
102 {
103 /* Ignore excess limbs in U. */
104 up += usize - prec;
105 usize -= usize - prec; /* Eq. usize = prec */
106 }
107 if (sump != up)
108 MPN_COPY_INCR (sump, up, usize - uexp);
109 cy_limb = mpn_add_1 (sump + usize - uexp, up + usize - uexp,
110 uexp, (mp_limb_t) v);
111 sump[usize] = cy_limb;
112 sum->_mp_size = usize + cy_limb;
113 sum->_mp_exp = uexp + cy_limb;
114 }
115 }
116 }
117 else
118 {
119 /* U < 1, so V > U for sure. */
120 /* v. */
121 /* .0000uuuu */
122 if ((-uexp) >= prec)
123 {
124 sump[0] = v;
125 sum->_mp_size = 1;
126 sum->_mp_exp = 1;
127 }
128 else
129 {
130 if (usize + (-uexp) + 1 > prec)
131 {
132 /* Ignore excess limbs in U. */
133 up += usize + (-uexp) + 1 - prec;
134 usize -= usize + (-uexp) + 1 - prec;
135 }
136 if (sump != up)
137 MPN_COPY_INCR (sump, up, usize);
138 MPN_ZERO (sump + usize, -uexp);
139 sump[usize + (-uexp)] = v;
140 sum->_mp_size = usize + (-uexp) + 1;
141 sum->_mp_exp = 1;
142 }
143 }
144 }
145