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 3 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. If not, see http://www.gnu.org/licenses/. */
19
20 #include "gmp.h"
21 #include "gmp-impl.h"
22
23 void
mpf_add_ui(mpf_ptr sum,mpf_srcptr u,unsigned long int v)24 mpf_add_ui (mpf_ptr sum, mpf_srcptr u, unsigned long int v)
25 {
26 mp_srcptr up = u->_mp_d;
27 mp_ptr sump = sum->_mp_d;
28 mp_size_t usize, sumsize;
29 mp_size_t prec = sum->_mp_prec;
30 mp_exp_t uexp = u->_mp_exp;
31
32 usize = u->_mp_size;
33 if (usize <= 0)
34 {
35 if (usize == 0)
36 {
37 mpf_set_ui (sum, v);
38 return;
39 }
40 else
41 {
42 __mpf_struct u_negated;
43 u_negated._mp_size = -usize;
44 u_negated._mp_exp = u->_mp_exp;
45 u_negated._mp_d = u->_mp_d;
46 mpf_sub_ui (sum, &u_negated, v);
47 sum->_mp_size = -(sum->_mp_size);
48 return;
49 }
50 }
51
52 if (v == 0)
53 {
54 sum_is_u:
55 if (u != sum)
56 {
57 sumsize = MIN (usize, prec + 1);
58 MPN_COPY (sum->_mp_d, up + usize - sumsize, sumsize);
59 sum->_mp_size = sumsize;
60 sum->_mp_exp = u->_mp_exp;
61 }
62 return;
63 }
64
65 if (uexp > 0)
66 {
67 /* U >= 1. */
68 if (uexp > prec)
69 {
70 /* U >> V, V is not part of final result. */
71 goto sum_is_u;
72 }
73 else
74 {
75 /* U's "limb point" is somewhere between the first limb
76 and the PREC:th limb.
77 Both U and V are part of the final result. */
78 if (uexp > usize)
79 {
80 /* uuuuuu0000. */
81 /* + v. */
82 /* We begin with moving U to the top of SUM, to handle
83 samevar(U,SUM). */
84 MPN_COPY_DECR (sump + uexp - usize, up, usize);
85 sump[0] = v;
86 MPN_ZERO (sump + 1, uexp - usize - 1);
87 #if 0 /* What is this??? */
88 if (sum == u)
89 MPN_COPY (sum->_mp_d, sump, uexp);
90 #endif
91 sum->_mp_size = uexp;
92 sum->_mp_exp = uexp;
93 }
94 else
95 {
96 /* uuuuuu.uuuu */
97 /* + v. */
98 mp_limb_t cy_limb;
99 if (usize > prec)
100 {
101 /* Ignore excess limbs in U. */
102 up += usize - prec;
103 usize -= usize - prec; /* Eq. usize = prec */
104 }
105 if (sump != up)
106 MPN_COPY_INCR (sump, up, usize - uexp);
107 cy_limb = mpn_add_1 (sump + usize - uexp, up + usize - uexp,
108 uexp, (mp_limb_t) v);
109 sump[usize] = cy_limb;
110 sum->_mp_size = usize + cy_limb;
111 sum->_mp_exp = uexp + cy_limb;
112 }
113 }
114 }
115 else
116 {
117 /* U < 1, so V > U for sure. */
118 /* v. */
119 /* .0000uuuu */
120 if ((-uexp) >= prec)
121 {
122 sump[0] = v;
123 sum->_mp_size = 1;
124 sum->_mp_exp = 1;
125 }
126 else
127 {
128 if (usize + (-uexp) + 1 > prec)
129 {
130 /* Ignore excess limbs in U. */
131 up += usize + (-uexp) + 1 - prec;
132 usize -= usize + (-uexp) + 1 - prec;
133 }
134 if (sump != up)
135 MPN_COPY_INCR (sump, up, usize);
136 MPN_ZERO (sump + usize, -uexp);
137 sump[usize + (-uexp)] = v;
138 sum->_mp_size = usize + (-uexp) + 1;
139 sum->_mp_exp = 1;
140 }
141 }
142 }
143