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comparison tomsfastmath/src/addsub/s_fp_add.c @ 643:a362b62d38b2 dropbear-tfm

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Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a with Makefile.in renamed
author Matt Johnston <matt@ucc.asn.au>
date Wed, 23 Nov 2011 18:10:20 +0700
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642:33fd2f3499d2 643:a362b62d38b2
1 /* TomsFastMath, a fast ISO C bignum library.
2 *
3 * This project is meant to fill in where LibTomMath
4 * falls short. That is speed ;-)
5 *
6 * This project is public domain and free for all purposes.
7 *
8 * Tom St Denis, [email protected]
9 */
10 #include <tfm.h>
11
12 /* unsigned addition */
13 void s_fp_add(fp_int *a, fp_int *b, fp_int *c)
14 {
15 int x, y, oldused;
16 register fp_word t;
17
18 y = MAX(a->used, b->used);
19 oldused = c->used;
20 c->used = y;
21
22 t = 0;
23 for (x = 0; x < y; x++) {
24 t += ((fp_word)a->dp[x]) + ((fp_word)b->dp[x]);
25 c->dp[x] = (fp_digit)t;
26 t >>= DIGIT_BIT;
27 }
28 if (t != 0 && x < FP_SIZE) {
29 c->dp[c->used++] = (fp_digit)t;
30 ++x;
31 }
32
33 c->used = x;
34 for (; x < oldused; x++) {
35 c->dp[x] = 0;
36 }
37 fp_clamp(c);
38 }
39
40 /* $Source$ */
41 /* $Revision$ */
42 /* $Date$ */