a2a74efe |
1 | /* -*-apcalc-*- |
2 | * |
3 | * $Id: gfx.cal,v 1.1 2000/10/08 16:01:37 mdw Exp $ |
4 | * |
5 | * Testbed for %$\gf{2}$% poltnomial arithmetic |
6 | * |
7 | * (c) 2000 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: gfx.cal,v $ |
33 | * Revision 1.1 2000/10/08 16:01:37 mdw |
34 | * Prototypes of various bits of code. |
35 | * |
36 | */ |
37 | |
38 | /*----- Object types ------------------------------------------------------*/ |
39 | |
40 | obj gf { x }; |
41 | |
42 | /*----- Static variables --------------------------------------------------*/ |
43 | |
44 | static obj gf example_gf_object; |
45 | |
46 | /*----- Main code ---------------------------------------------------------*/ |
47 | |
48 | dummy = config("lib_debug", -1); |
49 | |
50 | define gf(x) |
51 | { |
52 | local obj gf g; |
53 | g.x = x; |
54 | return (g); |
55 | } |
56 | |
57 | define gfint(x) |
58 | { |
59 | if (istype(x, example_gf_object)) |
60 | return (x.x); |
61 | else |
62 | return (x); |
63 | } |
64 | |
65 | define gf_add(x, y) = gf(xor(gfint(x), gfint(y))); |
66 | define gf_sub(x, y) = gf(xor(gfint(x), gfint(y))); |
67 | define gf_neg(x) = x; |
68 | |
69 | define gf_mul(x, y) |
70 | { |
71 | local a = gfint(x), b = gfint(y), z = 0, i, bits = highbit(a); |
72 | for (i = 0; i <= bits; i++) { |
73 | if (bit(a, i)) |
74 | z = xor(z, b << i); |
75 | } |
76 | return gf(z); |
77 | } |
78 | |
79 | define gfx_div(rx, dx) |
80 | { |
81 | local r = gfint(rx), d = gfint(dx), i; |
82 | local q = 0, dbits = highbit(d), rbits = highbit(r); |
83 | for (i = rbits - dbits; i >= 0; i--) { |
84 | if (bit(r, i + dbits)) { |
85 | r = xor(r, d << i); |
86 | q |= (1 << i); |
87 | } |
88 | } |
89 | return list(q, r); |
90 | } |
91 | |
92 | define gf_div(x, y) |
93 | { |
94 | local l = gfx_div(x, y); |
95 | return gf(l[[0]]); |
96 | } |
97 | |
98 | define gf_mod(x, y) |
99 | { |
100 | local l = gfx_div(x, y); |
101 | return gf(l[[1]]); |
102 | } |
103 | |
104 | /*----- That's all, folks -------------------------------------------------*/ |