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 either:
9
10 * the GNU Lesser General Public License as published by the Free
11 Software Foundation; either version 3 of the License, or (at your
12 option) any later version.
13
14 or
15
16 * the GNU General Public License as published by the Free Software
17 Foundation; either version 2 of the License, or (at your option) any
18 later version.
19
20 or both in parallel, as here.
21
22 The GNU MP Library is distributed in the hope that it will be useful, but
23 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
24 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
25 for more details.
26
27 You should have received copies of the GNU General Public License and the
28 GNU Lesser General Public License along with the GNU MP Library. If not,
29 see https://www.gnu.org/licenses/. */
30
31 #include "gmp-impl.h"
32
33 void
34 mpf_add_ui (mpf_ptr sum, mpf_srcptr u, unsigned long int v)
35 {
36 mp_srcptr up = u->_mp_d;
37 mp_ptr sump = sum->_mp_d;
38 mp_size_t usize, sumsize;
39 mp_size_t prec = sum->_mp_prec;
40 mp_exp_t uexp = u->_mp_exp;
41
42 usize = u->_mp_size;
43 if (usize <= 0)
44 {
45 if (usize == 0)
46 {
47 mpf_set_ui (sum, v);
48 return;
49 }
50 else
51 {
52 __mpf_struct u_negated;
53 u_negated._mp_size = -usize;
54 u_negated._mp_exp = u->_mp_exp;
55 u_negated._mp_d = u->_mp_d;
56 mpf_sub_ui (sum, &u_negated, v);
57 sum->_mp_size = -(sum->_mp_size);
58 return;
59 }
60 }
61
62 if (v == 0)
63 {
64 sum_is_u:
65 if (u != sum)
66 {
67 sumsize = MIN (usize, prec + 1);
68 MPN_COPY (sum->_mp_d, up + usize - sumsize, sumsize);
69 sum->_mp_size = sumsize;
70 sum->_mp_exp = u->_mp_exp;
71 }
72 return;
73 }
74
75 if (uexp > 0)
76 {
77 /* U >= 1. */
78 if (uexp > prec)
79 {
80 /* U >> V, V is not part of final result. */
81 goto sum_is_u;
82 }
83 else
84 {
85 /* U's "limb point" is somewhere between the first limb
86 and the PREC:th limb.
87 Both U and V are part of the final result. */
88 if (uexp > usize)
89 {
90 /* uuuuuu0000. */
91 /* + v. */
92 /* We begin with moving U to the top of SUM, to handle
93 samevar(U,SUM). */
94 MPN_COPY_DECR (sump + uexp - usize, up, usize);
95 sump[0] = v;
96 MPN_ZERO (sump + 1, uexp - usize - 1);
97 #if 0 /* What is this??? */
98 if (sum == u)
99 MPN_COPY (sum->_mp_d, sump, uexp);
100 #endif
101 sum->_mp_size = uexp;
102 sum->_mp_exp = uexp;
103 }
104 else
105 {
106 /* uuuuuu.uuuu */
107 /* + v. */
108 mp_limb_t cy_limb;
109 if (usize > prec)
110 {
111 /* Ignore excess limbs in U. */
112 up += usize - prec;
113 usize -= usize - prec; /* Eq. usize = prec */
114 }
115 if (sump != up)
116 MPN_COPY_INCR (sump, up, usize - uexp);
117 cy_limb = mpn_add_1 (sump + usize - uexp, up + usize - uexp,
118 uexp, (mp_limb_t) v);
119 sump[usize] = cy_limb;
120 sum->_mp_size = usize + cy_limb;
121 sum->_mp_exp = uexp + cy_limb;
122 }
123 }
124 }
125 else
126 {
127 /* U < 1, so V > U for sure. */
128 /* v. */
129 /* .0000uuuu */
130 if ((-uexp) >= prec)
131 {
132 sump[0] = v;
133 sum->_mp_size = 1;
134 sum->_mp_exp = 1;
135 }
136 else
137 {
138 if (usize + (-uexp) + 1 > prec)
139 {
140 /* Ignore excess limbs in U. */
141 up += usize + (-uexp) + 1 - prec;
142 usize -= usize + (-uexp) + 1 - prec;
143 }
144 if (sump != up)
145 MPN_COPY_INCR (sump, up, usize);
146 MPN_ZERO (sump + usize, -uexp);
147 sump[usize + (-uexp)] = v;
148 sum->_mp_size = usize + (-uexp) + 1;
149 sum->_mp_exp = 1;
150 }
151 }
152 }