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ae747c9b | 1 | /* -*-c-*- |
2 | * | |
ae747c9b | 3 | * Sqaring binary polynomials |
4 | * | |
5 | * (c) 2000 Straylight/Edgeware | |
6 | */ | |
7 | ||
45c0fd36 | 8 | /*----- Licensing notice --------------------------------------------------* |
ae747c9b | 9 | * |
10 | * This file is part of Catacomb. | |
11 | * | |
12 | * Catacomb is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU Library General Public License as | |
14 | * published by the Free Software Foundation; either version 2 of the | |
15 | * License, or (at your option) any later version. | |
45c0fd36 | 16 | * |
ae747c9b | 17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU Library General Public License for more details. | |
45c0fd36 | 21 | * |
ae747c9b | 22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free | |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
25 | * MA 02111-1307, USA. | |
26 | */ | |
27 | ||
ae747c9b | 28 | /*----- Header files ------------------------------------------------------*/ |
29 | ||
30 | #include "mpx.h" | |
ceb3f0c0 | 31 | #include "gfx.h" |
d9d9e645 | 32 | #include "permute.h" |
ae747c9b | 33 | |
34 | /*----- Main code ---------------------------------------------------------*/ | |
35 | ||
36 | /* --- @gfx_sqr@ --- * | |
37 | * | |
38 | * Arguments: @mpw *dv, *dvl@ = destination vector base and limit | |
39 | * @const mpw *av, *avl@ = argument vector base and limit | |
40 | * | |
41 | * Returns: --- | |
42 | * | |
43 | * Use: Performs squaring of binary polynomials. | |
44 | */ | |
45 | ||
46 | void gfx_sqr(mpw *dv, mpw *dvl, const mpw *av, const mpw *avl) | |
47 | { | |
d9d9e645 MW |
48 | #if MPW_BITS <= 16 |
49 | # define REGWD 16 | |
50 | #elif MPW_BITS <= 32 | |
51 | # define REGWD 32 | |
52 | #elif MPW_BITS <= 64 | |
53 | # define REGWD 64 | |
54 | #elif MPW_BITS <= 128 | |
55 | # define REGWD 128 | |
56 | #else | |
57 | # error "unsupported limb width: extend `gfx-sqr.c'" | |
58 | #endif | |
59 | ||
60 | #if MPW_BITS == REGWD | |
61 | typedef mpw regty; | |
62 | #else | |
63 | typedef mpd regty; | |
64 | #endif | |
65 | ||
66 | regty a, t; | |
ae747c9b | 67 | |
68 | /* --- Simple stuff --- */ | |
69 | ||
70 | if (dv >= dvl) | |
71 | return; | |
72 | MPX_SHRINK(av, avl); | |
73 | ||
74 | /* --- The main algorithm --- * | |
75 | * | |
76 | * Our method depends on the fact that, in a field of characteristic 2, we | |
77 | * have that %$(a + b)^2 = a^2 + b^2$%. Thus, to square a polynomial, it's | |
78 | * sufficient just to put a zero bit between each of the bits of the | |
d9d9e645 | 79 | * original argument. |
ae747c9b | 80 | */ |
81 | ||
d9d9e645 MW |
82 | while (av < avl) { |
83 | a = *av++; | |
84 | /* ..., 7, 6, 5, 4, 3, 2, 1, 0 */ | |
85 | SWIZZLE_EXCH(a, 0, 1); /* ..., 7, 6, 5, 4, 3, 2, 0, 1 */ | |
86 | SWIZZLE_EXCH(a, 0, 2); /* ..., 7, 6, 5, 4, 3, 1, 0, 2 */ | |
87 | SWIZZLE_EXCH(a, 0, 3); /* ..., 7, 6, 5, 4, 2, 1, 0, 3 */ | |
88 | #if MPW_BITS > 16 | |
89 | SWIZZLE_EXCH(a, 0, 4); /* ..., 7, 6, 5, 3, 2, 1, 0, 4 */ | |
90 | #endif | |
91 | #if MPW_BITS > 32 | |
92 | SWIZZLE_EXCH(a, 0, 5); /* ..., 7, 6, 4, 3, 2, 1, 0, 5 */ | |
93 | #endif | |
94 | #if MPW_BITS > 64 | |
95 | SWIZZLE_EXCH(a, 0, 6); /* ..., 7, 5, 4, 3, 2, 1, 0, 6 */ | |
96 | #endif | |
97 | #if MPW_BITS > 128 | |
98 | # error "unsupported limb width: extend `gfx-sqr.c'" | |
99 | #endif | |
100 | ||
101 | /* Write out the low half, which consists of the low-order bits in | |
102 | * even-numbered positions. | |
103 | */ | |
104 | *dv++ = MPW(a&IXMASK(0)); if (dv >= dvl) break; | |
105 | ||
106 | /* Write the high half. This is trickier, since, in general, the bits | |
107 | * are split across even-numbered bits in the high part of the wider | |
108 | * register and odd-numbered bits in the low part. Alas, we can't | |
109 | * resolve this mess without special cases because shifts are broken in | |
110 | * C. | |
111 | */ | |
112 | t = ((a >> 1)&IXMASK(0)) << (REGWD - MPW_BITS); | |
113 | #if MPW_BITS < REGWD | |
114 | t |= (a&IXMASK(0)) >> MPW_BITS; | |
115 | #endif | |
116 | *dv++ = MPW(t); if (dv >= dvl) break; | |
ae747c9b | 117 | } |
118 | ||
119 | /* --- Zero the rest of everything --- */ | |
120 | ||
121 | MPX_ZERO(dv, dvl); | |
d9d9e645 MW |
122 | |
123 | #undef REGWD | |
ae747c9b | 124 | } |
125 | ||
126 | /*----- Test rig ----------------------------------------------------------*/ | |
127 | ||
128 | #ifdef TEST_RIG | |
129 | ||
130 | #include <mLib/alloc.h> | |
131 | #include <mLib/dstr.h> | |
132 | #include <mLib/quis.h> | |
133 | #include <mLib/testrig.h> | |
134 | ||
135 | #define ALLOC(v, vl, sz) do { \ | |
136 | size_t _sz = (sz); \ | |
137 | mpw *_vv = xmalloc(MPWS(_sz)); \ | |
138 | mpw *_vvl = _vv + _sz; \ | |
139 | (v) = _vv; \ | |
140 | (vl) = _vvl; \ | |
141 | } while (0) | |
142 | ||
143 | #define LOAD(v, vl, d) do { \ | |
144 | const dstr *_d = (d); \ | |
145 | mpw *_v, *_vl; \ | |
146 | ALLOC(_v, _vl, MPW_RQ(_d->len)); \ | |
147 | mpx_loadb(_v, _vl, _d->buf, _d->len); \ | |
148 | (v) = _v; \ | |
149 | (vl) = _vl; \ | |
150 | } while (0) | |
151 | ||
152 | #define MAX(x, y) ((x) > (y) ? (x) : (y)) | |
45c0fd36 | 153 | |
ae747c9b | 154 | static void dumpmp(const char *msg, const mpw *v, const mpw *vl) |
155 | { | |
156 | fputs(msg, stderr); | |
157 | MPX_SHRINK(v, vl); | |
158 | while (v < vl) | |
159 | fprintf(stderr, " %08lx", (unsigned long)*--vl); | |
160 | fputc('\n', stderr); | |
161 | } | |
162 | ||
163 | static int vsqr(dstr *v) | |
164 | { | |
165 | mpw *a, *al; | |
166 | mpw *b, *bl; | |
167 | mpw *d, *dl; | |
168 | int ok = 1; | |
169 | ||
170 | LOAD(a, al, &v[0]); | |
171 | LOAD(b, bl, &v[1]); | |
172 | ALLOC(d, dl, 2 * (al - a)); | |
173 | ||
174 | gfx_sqr(d, dl, a, al); | |
175 | if (!mpx_ueq(d, dl, b, bl)) { | |
176 | fprintf(stderr, "\n*** vsqr failed\n"); | |
45c0fd36 | 177 | dumpmp(" a", a, al); |
ae747c9b | 178 | dumpmp("expected", b, bl); |
179 | dumpmp(" result", d, dl); | |
180 | ok = 0; | |
181 | } | |
182 | ||
12ed8a1f | 183 | xfree(a); xfree(b); xfree(d); |
ae747c9b | 184 | return (ok); |
185 | } | |
186 | ||
187 | static test_chunk defs[] = { | |
188 | { "sqr", vsqr, { &type_hex, &type_hex, 0 } }, | |
189 | { 0, 0, { 0 } } | |
190 | }; | |
191 | ||
192 | int main(int argc, char *argv[]) | |
193 | { | |
0f00dc4c | 194 | test_run(argc, argv, defs, SRCDIR"/t/gfx"); |
ae747c9b | 195 | return (0); |
196 | } | |
197 | ||
198 | #endif | |
199 | ||
200 | /*----- That's all, folks -------------------------------------------------*/ |