3 * $Id: gf-arith.c,v 1.2 2004/03/21 22:52:06 mdw Exp $
5 * Basic arithmetic on binary polynomials
7 * (c) 2004 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Catacomb.
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.
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.
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,
30 /*----- Revision history --------------------------------------------------*
32 * $Log: gf-arith.c,v $
33 * Revision 1.2 2004/03/21 22:52:06 mdw
34 * Merge and close elliptic curve branch.
36 * Revision 1.1.2.1 2004/03/21 22:39:46 mdw
37 * Elliptic curves on binary fields work.
41 /*----- Header files ------------------------------------------------------*/
45 /*----- Macros ------------------------------------------------------------*/
47 #define MAX(x, y) ((x) >= (y) ? (x) : (y))
49 /*----- Main code ---------------------------------------------------------*/
53 * Arguments: @mp *d@ = destination
54 * @mp *a, *b@ = sources
56 * Returns: Result, @a@ added to @b@.
59 mp
*gf_add(mp
*d
, mp
*a
, mp
*b
)
61 MP_DEST(d
, MAX(MP_LEN(a
), MP_LEN(b
)), (a
->f
| b
->f
) & MP_BURN
);
62 gfx_add(d
->v
, d
->vl
, a
->v
, a
->vl
, b
->v
, b
->vl
);
63 d
->f
= (a
->f
| b
->f
) & MP_BURN
;
70 * Arguments: @mp *d@ = destination
71 * @mp *a, *b@ = sources
73 * Returns: Result, @a@ multiplied by @b@.
76 mp
*gf_mul(mp
*d
, mp
*a
, mp
*b
)
81 if (MP_LEN(a
) <= MPK_THRESH
|| MP_LEN(b
) <= GFK_THRESH
) {
82 MP_DEST(d
, MP_LEN(a
) + MP_LEN(b
), a
->f
| b
->f
| MP_UNDEF
);
83 gfx_mul(d
->v
, d
->vl
, a
->v
, a
->vl
, b
->v
, b
->vl
);
85 size_t m
= MAX(MP_LEN(a
), MP_LEN(b
));
87 MP_DEST(d
, 2 * m
, a
->f
| b
->f
| MP_UNDEF
);
88 s
= mpalloc(d
->a
, 2 * m
);
89 gfx_kmul(d
->v
, d
->vl
, a
->v
, a
->vl
, b
->v
, b
->vl
, s
, s
+ 2 * m
);
93 d
->f
= (a
->f
| b
->f
) & MP_BURN
;
100 /* --- @gf_sqr@ --- *
102 * Arguments: @mp *d@ = destination
105 * Returns: Result, @a@ squared.
108 mp
*gf_sqr(mp
*d
, mp
*a
)
111 MP_DEST(d
, 2 * MP_LEN(a
), a
->f
& MP_BURN
);
112 gfx_sqr(d
->v
, d
->vl
, a
->v
, a
->vl
);
113 d
->f
= a
->f
& MP_BURN
;
119 /* --- @gf_div@ --- *
121 * Arguments: @mp **qq, **rr@ = destination, quotient and remainder
122 * @mp *a, *b@ = sources
124 * Use: Calculates the quotient and remainder when @a@ is divided by
125 * @b@. The destinations @*qq@ and @*rr@ must be distinct.
126 * Either of @qq@ or @rr@ may be null to indicate that the
127 * result is irrelevant. (Discarding both results is silly.)
128 * There is a performance advantage if @a == *rr@.
131 void gf_div(mp
**qq
, mp
**rr
, mp
*a
, mp
*b
)
133 mp
*r
= rr ?
*rr
: MP_NEW
;
134 mp
*q
= qq ?
*qq
: MP_NEW
;
136 /* --- Set the remainder up right --- */
143 MP_DEST(r
, MP_LEN(b
) + 2, a
->f
| b
->f
);
145 /* --- Fix up the quotient too --- */
148 MP_DEST(q
, MP_LEN(r
), r
->f
| MP_UNDEF
);
151 /* --- Perform the calculation --- */
153 gfx_div(q
->v
, q
->vl
, r
->v
, r
->vl
, b
->v
, b
->vl
);
155 /* --- Sort out the sign of the results --- *
157 * If the signs of the arguments differ, and the remainder is nonzero, I
158 * must add one to the absolute value of the quotient and subtract the
159 * remainder from @b@.
162 q
->f
= (r
->f
| b
->f
) & MP_BURN
;
163 r
->f
= (r
->f
| b
->f
) & MP_BURN
;
165 /* --- Store the return values --- */
184 /*----- Test rig ----------------------------------------------------------*/
188 static int verify(const char *op
, mp
*expect
, mp
*result
, mp
*a
, mp
*b
)
190 if (!MP_EQ(expect
, result
)) {
191 fprintf(stderr
, "\n*** %s failed", op
);
192 fputs("\n*** a = ", stderr
); mp_writefile(a
, stderr
, 16);
193 fputs("\n*** b = ", stderr
); mp_writefile(b
, stderr
, 16);
194 fputs("\n*** result = ", stderr
); mp_writefile(result
, stderr
, 16);
195 fputs("\n*** expect = ", stderr
); mp_writefile(expect
, stderr
, 16);
202 #define RIG(name, op) \
203 static int t##name(dstr *v) \
205 mp *a = *(mp **)v[0].buf; \
206 mp *b = *(mp **)v[1].buf; \
207 mp *r = *(mp **)v[2].buf; \
208 mp *c = op(MP_NEW, a, b); \
209 int ok = verify(#name, r, c, a, b); \
210 mp_drop(a); mp_drop(b); mp_drop(c); mp_drop(r); \
211 assert(mparena_count(MPARENA_GLOBAL) == 0); \
220 static int tsqr(dstr
*v
)
222 mp
*a
= *(mp
**)v
[0].buf
;
223 mp
*r
= *(mp
**)v
[1].buf
;
226 c
= gf_sqr(MP_NEW
, a
);
227 ok
&= verify("sqr", r
, c
, a
, MP_ZERO
);
228 mp_drop(a
); mp_drop(r
); mp_drop(c
);
229 assert(mparena_count(MPARENA_GLOBAL
) == 0);
233 static int tdiv(dstr
*v
)
235 mp
*a
= *(mp
**)v
[0].buf
;
236 mp
*b
= *(mp
**)v
[1].buf
;
237 mp
*q
= *(mp
**)v
[2].buf
;
238 mp
*r
= *(mp
**)v
[3].buf
;
239 mp
*c
= MP_NEW
, *d
= MP_NEW
;
241 gf_div(&c
, &d
, a
, b
);
242 ok
&= verify("div(quotient)", q
, c
, a
, b
);
243 ok
&= verify("div(remainder)", r
, d
, a
, b
);
244 mp_drop(a
); mp_drop(b
); mp_drop(c
); mp_drop(d
); mp_drop(r
); mp_drop(q
);
245 assert(mparena_count(MPARENA_GLOBAL
) == 0);
249 static test_chunk tests
[] = {
250 { "add", tadd
, { &type_mp
, &type_mp
, &type_mp
, 0 } },
251 { "mul", tmul
, { &type_mp
, &type_mp
, &type_mp
, 0 } },
252 { "sqr", tsqr
, { &type_mp
, &type_mp
, 0 } },
253 { "div", tdiv
, { &type_mp
, &type_mp
, &type_mp
, &type_mp
, 0 } },
257 int main(int argc
, char *argv
[])
260 test_run(argc
, argv
, tests
, SRCDIR
"/tests/gf");
266 /*----- That's all, folks -------------------------------------------------*/