1 | /* mpz_xor -- Logical xor. |
---|
2 | |
---|
3 | Copyright 1991, 1993, 1994, 1996, 1997, 2000, 2001 Free Software Foundation, |
---|
4 | Inc. |
---|
5 | |
---|
6 | This file is part of the GNU MP Library. |
---|
7 | |
---|
8 | The GNU MP Library is free software; you can redistribute it and/or modify |
---|
9 | it under the terms of the GNU Lesser General Public License as published by |
---|
10 | the Free Software Foundation; either version 2.1 of the License, or (at your |
---|
11 | option) any later version. |
---|
12 | |
---|
13 | The GNU MP Library is distributed in the hope that it will be useful, but |
---|
14 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
---|
15 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
---|
16 | License for more details. |
---|
17 | |
---|
18 | You should have received a copy of the GNU Lesser General Public License |
---|
19 | along with the GNU MP Library; see the file COPYING.LIB. If not, write to |
---|
20 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
---|
21 | MA 02111-1307, USA. */ |
---|
22 | |
---|
23 | #include "gmp.h" |
---|
24 | #include "gmp-impl.h" |
---|
25 | |
---|
26 | void |
---|
27 | mpz_xor (mpz_ptr res, mpz_srcptr op1, mpz_srcptr op2) |
---|
28 | { |
---|
29 | mp_srcptr op1_ptr, op2_ptr; |
---|
30 | mp_size_t op1_size, op2_size; |
---|
31 | mp_ptr res_ptr; |
---|
32 | mp_size_t res_size, res_alloc; |
---|
33 | mp_size_t i; |
---|
34 | TMP_DECL (marker); |
---|
35 | |
---|
36 | TMP_MARK (marker); |
---|
37 | op1_size = op1->_mp_size; |
---|
38 | op2_size = op2->_mp_size; |
---|
39 | |
---|
40 | op1_ptr = op1->_mp_d; |
---|
41 | op2_ptr = op2->_mp_d; |
---|
42 | res_ptr = res->_mp_d; |
---|
43 | |
---|
44 | if (op1_size >= 0) |
---|
45 | { |
---|
46 | if (op2_size >= 0) |
---|
47 | { |
---|
48 | if (op1_size >= op2_size) |
---|
49 | { |
---|
50 | if (res->_mp_alloc < op1_size) |
---|
51 | { |
---|
52 | _mpz_realloc (res, op1_size); |
---|
53 | op1_ptr = op1->_mp_d; |
---|
54 | op2_ptr = op2->_mp_d; |
---|
55 | res_ptr = res->_mp_d; |
---|
56 | } |
---|
57 | |
---|
58 | if (res_ptr != op1_ptr) |
---|
59 | MPN_COPY (res_ptr + op2_size, op1_ptr + op2_size, |
---|
60 | op1_size - op2_size); |
---|
61 | for (i = op2_size - 1; i >= 0; i--) |
---|
62 | res_ptr[i] = op1_ptr[i] ^ op2_ptr[i]; |
---|
63 | res_size = op1_size; |
---|
64 | } |
---|
65 | else |
---|
66 | { |
---|
67 | if (res->_mp_alloc < op2_size) |
---|
68 | { |
---|
69 | _mpz_realloc (res, op2_size); |
---|
70 | op1_ptr = op1->_mp_d; |
---|
71 | op2_ptr = op2->_mp_d; |
---|
72 | res_ptr = res->_mp_d; |
---|
73 | } |
---|
74 | |
---|
75 | if (res_ptr != op2_ptr) |
---|
76 | MPN_COPY (res_ptr + op1_size, op2_ptr + op1_size, |
---|
77 | op2_size - op1_size); |
---|
78 | for (i = op1_size - 1; i >= 0; i--) |
---|
79 | res_ptr[i] = op1_ptr[i] ^ op2_ptr[i]; |
---|
80 | res_size = op2_size; |
---|
81 | } |
---|
82 | |
---|
83 | MPN_NORMALIZE (res_ptr, res_size); |
---|
84 | res->_mp_size = res_size; |
---|
85 | return; |
---|
86 | } |
---|
87 | else /* op2_size < 0 */ |
---|
88 | { |
---|
89 | /* Fall through to the code at the end of the function. */ |
---|
90 | } |
---|
91 | } |
---|
92 | else |
---|
93 | { |
---|
94 | if (op2_size < 0) |
---|
95 | { |
---|
96 | mp_ptr opx; |
---|
97 | |
---|
98 | /* Both operands are negative, the result will be positive. |
---|
99 | (-OP1) ^ (-OP2) = |
---|
100 | = ~(OP1 - 1) ^ ~(OP2 - 1) = |
---|
101 | = (OP1 - 1) ^ (OP2 - 1) */ |
---|
102 | |
---|
103 | op1_size = -op1_size; |
---|
104 | op2_size = -op2_size; |
---|
105 | |
---|
106 | /* Possible optimization: Decrease mpn_sub precision, |
---|
107 | as we won't use the entire res of both. */ |
---|
108 | opx = (mp_ptr) TMP_ALLOC (op1_size * BYTES_PER_MP_LIMB); |
---|
109 | mpn_sub_1 (opx, op1_ptr, op1_size, (mp_limb_t) 1); |
---|
110 | op1_ptr = opx; |
---|
111 | |
---|
112 | opx = (mp_ptr) TMP_ALLOC (op2_size * BYTES_PER_MP_LIMB); |
---|
113 | mpn_sub_1 (opx, op2_ptr, op2_size, (mp_limb_t) 1); |
---|
114 | op2_ptr = opx; |
---|
115 | |
---|
116 | res_alloc = MAX (op1_size, op2_size); |
---|
117 | if (res->_mp_alloc < res_alloc) |
---|
118 | { |
---|
119 | _mpz_realloc (res, res_alloc); |
---|
120 | res_ptr = res->_mp_d; |
---|
121 | /* Don't re-read OP1_PTR and OP2_PTR. They point to |
---|
122 | temporary space--never to the space RES->_mp_d used |
---|
123 | to point to before reallocation. */ |
---|
124 | } |
---|
125 | |
---|
126 | if (op1_size > op2_size) |
---|
127 | { |
---|
128 | MPN_COPY (res_ptr + op2_size, op1_ptr + op2_size, |
---|
129 | op1_size - op2_size); |
---|
130 | for (i = op2_size - 1; i >= 0; i--) |
---|
131 | res_ptr[i] = op1_ptr[i] ^ op2_ptr[i]; |
---|
132 | res_size = op1_size; |
---|
133 | } |
---|
134 | else |
---|
135 | { |
---|
136 | MPN_COPY (res_ptr + op1_size, op2_ptr + op1_size, |
---|
137 | op2_size - op1_size); |
---|
138 | for (i = op1_size - 1; i >= 0; i--) |
---|
139 | res_ptr[i] = op1_ptr[i] ^ op2_ptr[i]; |
---|
140 | res_size = op2_size; |
---|
141 | } |
---|
142 | |
---|
143 | MPN_NORMALIZE (res_ptr, res_size); |
---|
144 | res->_mp_size = res_size; |
---|
145 | TMP_FREE (marker); |
---|
146 | return; |
---|
147 | } |
---|
148 | else |
---|
149 | { |
---|
150 | /* We should compute -OP1 ^ OP2. Swap OP1 and OP2 and fall |
---|
151 | through to the code that handles OP1 ^ -OP2. */ |
---|
152 | MPZ_SRCPTR_SWAP (op1, op2); |
---|
153 | MPN_SRCPTR_SWAP (op1_ptr,op1_size, op2_ptr,op2_size); |
---|
154 | } |
---|
155 | } |
---|
156 | |
---|
157 | { |
---|
158 | mp_ptr opx; |
---|
159 | mp_limb_t cy; |
---|
160 | |
---|
161 | /* Operand 2 negative, so will be the result. |
---|
162 | -(OP1 ^ (-OP2)) = -(OP1 ^ ~(OP2 - 1)) = |
---|
163 | = ~(OP1 ^ ~(OP2 - 1)) + 1 = |
---|
164 | = (OP1 ^ (OP2 - 1)) + 1 */ |
---|
165 | |
---|
166 | op2_size = -op2_size; |
---|
167 | |
---|
168 | opx = (mp_ptr) TMP_ALLOC (op2_size * BYTES_PER_MP_LIMB); |
---|
169 | mpn_sub_1 (opx, op2_ptr, op2_size, (mp_limb_t) 1); |
---|
170 | op2_ptr = opx; |
---|
171 | |
---|
172 | res_alloc = MAX (op1_size, op2_size) + 1; |
---|
173 | if (res->_mp_alloc < res_alloc) |
---|
174 | { |
---|
175 | _mpz_realloc (res, res_alloc); |
---|
176 | op1_ptr = op1->_mp_d; |
---|
177 | res_ptr = res->_mp_d; |
---|
178 | /* Don't re-read OP2_PTR. It points to temporary space--never |
---|
179 | to the space RES->_mp_d used to point to before reallocation. */ |
---|
180 | } |
---|
181 | |
---|
182 | if (op1_size > op2_size) |
---|
183 | { |
---|
184 | MPN_COPY (res_ptr + op2_size, op1_ptr + op2_size, op1_size - op2_size); |
---|
185 | for (i = op2_size - 1; i >= 0; i--) |
---|
186 | res_ptr[i] = op1_ptr[i] ^ op2_ptr[i]; |
---|
187 | res_size = op1_size; |
---|
188 | } |
---|
189 | else |
---|
190 | { |
---|
191 | MPN_COPY (res_ptr + op1_size, op2_ptr + op1_size, op2_size - op1_size); |
---|
192 | for (i = op1_size - 1; i >= 0; i--) |
---|
193 | res_ptr[i] = op1_ptr[i] ^ op2_ptr[i]; |
---|
194 | res_size = op2_size; |
---|
195 | } |
---|
196 | |
---|
197 | cy = mpn_add_1 (res_ptr, res_ptr, res_size, (mp_limb_t) 1); |
---|
198 | if (cy) |
---|
199 | { |
---|
200 | res_ptr[res_size] = cy; |
---|
201 | res_size++; |
---|
202 | } |
---|
203 | |
---|
204 | MPN_NORMALIZE (res_ptr, res_size); |
---|
205 | res->_mp_size = -res_size; |
---|
206 | TMP_FREE (marker); |
---|
207 | } |
---|
208 | } |
---|