Mercurial > dropbear
comparison tomsfastmath/src/mul/fp_mul_d.c @ 643:a362b62d38b2 dropbear-tfm
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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| children |
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| 642:33fd2f3499d2 | 643:a362b62d38b2 |
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| 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 /* c = a * b */ | |
| 13 void fp_mul_d(fp_int *a, fp_digit b, fp_int *c) | |
| 14 { | |
| 15 fp_word w; | |
| 16 int x, oldused; | |
| 17 | |
| 18 oldused = c->used; | |
| 19 c->used = a->used; | |
| 20 c->sign = a->sign; | |
| 21 w = 0; | |
| 22 for (x = 0; x < a->used; x++) { | |
| 23 w = ((fp_word)a->dp[x]) * ((fp_word)b) + w; | |
| 24 c->dp[x] = (fp_digit)w; | |
| 25 w = w >> DIGIT_BIT; | |
| 26 } | |
| 27 if (w != 0 && (a->used != FP_SIZE)) { | |
| 28 c->dp[c->used++] = w; | |
| 29 ++x; | |
| 30 } | |
| 31 for (; x < oldused; x++) { | |
| 32 c->dp[x] = 0; | |
| 33 } | |
| 34 fp_clamp(c); | |
| 35 } | |
| 36 | |
| 37 | |
| 38 /* $Source$ */ | |
| 39 /* $Revision$ */ | |
| 40 /* $Date$ */ |