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annotate tomsfastmath/src/mul/fp_mul_d.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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a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a
Matt Johnston <matt@ucc.asn.au>
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1 /* TomsFastMath, a fast ISO C bignum library.
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2 *
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3 * This project is meant to fill in where LibTomMath
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4 * falls short. That is speed ;-)
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5 *
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6 * This project is public domain and free for all purposes.
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7 *
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8 * Tom St Denis, [email protected]
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9 */
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10 #include <tfm.h>
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12 /* c = a * b */
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13 void fp_mul_d(fp_int *a, fp_digit b, fp_int *c)
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14 {
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15 fp_word w;
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16 int x, oldused;
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18 oldused = c->used;
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19 c->used = a->used;
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20 c->sign = a->sign;
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21 w = 0;
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22 for (x = 0; x < a->used; x++) {
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23 w = ((fp_word)a->dp[x]) * ((fp_word)b) + w;
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24 c->dp[x] = (fp_digit)w;
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25 w = w >> DIGIT_BIT;
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26 }
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27 if (w != 0 && (a->used != FP_SIZE)) {
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28 c->dp[c->used++] = w;
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29 ++x;
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30 }
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31 for (; x < oldused; x++) {
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32 c->dp[x] = 0;
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33 }
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34 fp_clamp(c);
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35 }
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38 /* $Source$ */
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39 /* $Revision$ */
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40 /* $Date$ */