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1.1 maekawa 1: /* mpf_add_ui -- Add a float and an unsigned integer.
2:
3: Copyright (C) 1993, 1994, 1996 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 Library General Public License as published by
9: the Free Software Foundation; either version 2 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 Library General Public
15: License for more details.
16:
17: You should have received a copy of the GNU Library 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., 59 Temple Place - Suite 330, Boston,
20: MA 02111-1307, USA. */
21:
22: #include "gmp.h"
23: #include "gmp-impl.h"
24:
25: void
26: #if __STDC__
27: mpf_add_ui (mpf_ptr sum, mpf_srcptr u, unsigned long int v)
28: #else
29: mpf_add_ui (sum, u, v)
30: mpf_ptr sum;
31: mpf_srcptr u;
32: unsigned long int v;
33: #endif
34: {
35: mp_srcptr up = u->_mp_d;
36: mp_ptr sump = sum->_mp_d;
37: mp_size_t usize, sumsize;
38: mp_size_t prec = sum->_mp_prec;
39: mp_exp_t uexp = u->_mp_exp;
40:
41: usize = u->_mp_size;
42: if (usize <= 0)
43: {
44: if (usize == 0)
45: {
46: mpf_set_ui (sum, v);
47: return;
48: }
49: else
50: {
51: __mpf_struct u_negated;
52: u_negated._mp_size = -usize;
53: u_negated._mp_exp = u->_mp_exp;
54: u_negated._mp_d = u->_mp_d;
55: mpf_sub_ui (sum, &u_negated, v);
56: sum->_mp_size = -(sum->_mp_size);
57: return;
58: }
59: }
60:
61: if (v == 0)
62: {
63: sum_is_u:
64: if (u != sum)
65: {
66: sumsize = MIN (usize, prec + 1);
67: MPN_COPY (sum->_mp_d, up + usize - sumsize, sumsize);
68: sum->_mp_size = sumsize;
69: sum->_mp_exp = u->_mp_exp;
70: }
71: return;
72: }
73:
74: if (uexp > 0)
75: {
76: /* U >= 1. */
77: if (uexp > prec)
78: {
79: /* U >> V, V is not part of final result. */
80: goto sum_is_u;
81: }
82: else
83: {
84: /* U's "limb point" is somewhere between the first limb
85: and the PREC:th limb.
86: Both U and V are part of the final result. */
87: if (uexp > usize)
88: {
89: /* uuuuuu0000. */
90: /* + v. */
91: /* We begin with moving U to the top of SUM, to handle
92: samevar(U,SUM). */
93: MPN_COPY_DECR (sump + uexp - usize, up, usize);
94: sump[0] = v;
95: MPN_ZERO (sump + 1, uexp - usize - 1);
96: #if 0 /* What is this??? */
97: if (sum == u)
98: MPN_COPY (sum->_mp_d, sump, uexp);
99: #endif
100: sum->_mp_size = uexp;
101: sum->_mp_exp = uexp;
102: }
103: else
104: {
105: /* uuuuuu.uuuu */
106: /* + v. */
107: mp_limb_t cy_limb;
108: if (usize > prec)
109: {
110: /* Ignore excess limbs in U. */
111: up += usize - prec;
112: usize -= usize - prec; /* Eq. usize = prec */
113: }
114: if (sump != up)
115: MPN_COPY (sump, up, usize - uexp);
116: cy_limb = mpn_add_1 (sump + usize - uexp, up + usize - uexp,
117: uexp, (mp_limb_t) v);
118: sump[usize] = cy_limb;
119: sum->_mp_size = usize + cy_limb;
120: sum->_mp_exp = uexp + cy_limb;
121: }
122: }
123: }
124: else
125: {
126: /* U < 1, so V > U for sure. */
127: /* v. */
128: /* .0000uuuu */
129: if ((-uexp) >= prec)
130: {
131: sump[0] = v;
132: sum->_mp_size = 1;
133: sum->_mp_exp = 1;
134: }
135: else
136: {
137: if (usize + (-uexp) + 1 > prec)
138: {
139: /* Ignore excess limbs in U. */
140: up += usize + (-uexp) + 1 - prec;
141: usize -= usize + (-uexp) + 1 - prec;
142: }
143: if (sump != up)
144: MPN_COPY (sump, up, usize);
145: MPN_ZERO (sump + usize, -uexp);
146: sump[usize + (-uexp)] = v;
147: sum->_mp_size = usize + (-uexp) + 1;
148: sum->_mp_exp = 1;
149: }
150: }
151: }