view 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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/* TomsFastMath, a fast ISO C bignum library.
 * 
 * This project is meant to fill in where LibTomMath
 * falls short.  That is speed ;-)
 *
 * This project is public domain and free for all purposes.
 * 
 * Tom St Denis, [email protected]
 */
#include <tfm.h>

/* c = a * b */
void fp_mul_d(fp_int *a, fp_digit b, fp_int *c)
{
   fp_word  w;
   int      x, oldused;

   oldused = c->used;
   c->used = a->used;
   c->sign = a->sign;
   w       = 0;
   for (x = 0; x < a->used; x++) {
       w         = ((fp_word)a->dp[x]) * ((fp_word)b) + w;
       c->dp[x]  = (fp_digit)w;
       w         = w >> DIGIT_BIT;
   }
   if (w != 0 && (a->used != FP_SIZE)) {
      c->dp[c->used++] = w;
      ++x;
   }
   for (; x < oldused; x++) {
      c->dp[x] = 0;
   }
   fp_clamp(c);
}


/* $Source$ */
/* $Revision$ */
/* $Date$ */