Mercurial > hg > Members > anatofuz > MoarVM

annotate 3rdparty/libtommath/bn_s_mp_mul_digs.c @ 0:2cf249471370

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
convert mercurial for git
author Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
date Tue, 08 May 2018 16:09:12 +0900
parents
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
0
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
1 #include <tommath_private.h>
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
2 #ifdef BN_S_MP_MUL_DIGS_C
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
4 *
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
5 * LibTomMath is a library that provides multiple-precision
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
6 * integer arithmetic as well as number theoretic functionality.
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
7 *
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
8 * The library was designed directly after the MPI library by
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
9 * Michael Fromberger but has been written from scratch with
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
10 * additional optimizations in place.
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
11 *
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
12 * The library is free for all purposes without any express
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
13 * guarantee it works.
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
14 *
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
15 * Tom St Denis, tstdenis82@gmail.com, http://libtom.org
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
16 */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
17
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
18 /* multiplies |a| * |b| and only computes upto digs digits of result
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
19 * HAC pp. 595, Algorithm 14.12 Modified so you can control how
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
20 * many digits of output are created.
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
21 */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
22 int s_mp_mul_digs (mp_int * a, mp_int * b, mp_int * c, int digs)
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
23 {
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
24 mp_int t;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
25 int res, pa, pb, ix, iy;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
26 mp_digit u;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
27 mp_word r;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
28 mp_digit tmpx, *tmpt, *tmpy;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
29
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
30 /* can we use the fast multiplier? */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
31 if (((digs) < MP_WARRAY) &&
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
32 (MIN (a->used, b->used) <
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
33 (1 << ((CHAR_BIT * sizeof(mp_word)) - (2 * DIGIT_BIT))))) {
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
34 return fast_s_mp_mul_digs (a, b, c, digs);
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
35 }
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
36
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
37 if ((res = mp_init_size (&t, digs)) != MP_OKAY) {
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
38 return res;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
39 }
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
40 t.used = digs;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
41
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
42 /* compute the digits of the product directly */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
43 pa = a->used;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
44 for (ix = 0; ix < pa; ix++) {
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
45 /* set the carry to zero */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
46 u = 0;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
47
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
48 /* limit ourselves to making digs digits of output */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
49 pb = MIN (b->used, digs - ix);
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
50
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
51 /* setup some aliases */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
52 /* copy of the digit from a used within the nested loop */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
53 tmpx = a->dp[ix];
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
54
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
55 /* an alias for the destination shifted ix places */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
56 tmpt = t.dp + ix;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
57
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
58 /* an alias for the digits of b */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
59 tmpy = b->dp;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
60
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
61 /* compute the columns of the output and propagate the carry */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
62 for (iy = 0; iy < pb; iy++) {
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
63 /* compute the column as a mp_word */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
64 r = (mp_word)*tmpt +
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
65 ((mp_word)tmpx * (mp_word)*tmpy++) +
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
66 (mp_word)u;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
67
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
68 /* the new column is the lower part of the result */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
69 *tmpt++ = (mp_digit) (r & ((mp_word) MP_MASK));
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
70
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
71 /* get the carry word from the result */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
72 u = (mp_digit) (r >> ((mp_word) DIGIT_BIT));
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
73 }
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
74 /* set carry if it is placed below digs */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
75 if ((ix + iy) < digs) {
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
76 *tmpt = u;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
77 }
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
78 }
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
79
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
80 mp_clamp (&t);
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
81 mp_exch (&t, c);
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
82
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
83 mp_clear (&t);
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
84 return MP_OKAY;
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
85 }
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
86 #endif
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
87
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
88 /* $Source$ */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
89 /* $Revision$ */
2cf249471370 convert mercurial for git
Takahiro SHIMIZU <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
diff changeset
90 /* $Date$ */