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annotate tomsfastmath/src/exptmod/fp_2expt.c @ 646:f10335e5e42f dropbear-tfm

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- More asm constraint fixes. Now seems to build OK on 32-bit OS X.
author Matt Johnston <matt@ucc.asn.au>
date Wed, 30 Nov 2011 23:03:47 +0800
parents a362b62d38b2
children
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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 /* computes a = 2**b */
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13 void fp_2expt(fp_int *a, int b)
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14 {
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15 int z;
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17 /* zero a as per default */
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18 fp_zero (a);
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20 if (b < 0) {
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21 return;
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22 }
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24 z = b / DIGIT_BIT;
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25 if (z >= FP_SIZE) {
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26 return;
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27 }
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29 /* set the used count of where the bit will go */
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30 a->used = z + 1;
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32 /* put the single bit in its place */
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33 a->dp[z] = ((fp_digit)1) << (b % DIGIT_BIT);
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34 }
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37 /* $Source$ */
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38 /* $Revision$ */
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39 /* $Date$ */