view tomsfastmath/src/exptmod/fp_2expt.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>

/* computes a = 2**b */
void fp_2expt(fp_int *a, int b)
{
   int     z;

   /* zero a as per default */
   fp_zero (a);

   if (b < 0) { 
      return;
   }

   z = b / DIGIT_BIT;
   if (z >= FP_SIZE) {
      return; 
   }

  /* set the used count of where the bit will go */
  a->used = z + 1;

  /* put the single bit in its place */
  a->dp[z] = ((fp_digit)1) << (b % DIGIT_BIT);
}


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