denyhosts/clamscan/libclamav/tomsfastmath/exptmod/fp_2expt.c
2022-10-22 18:41:00 +08:00

40 lines
785 B
C

/* 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, tomstdenis@gmail.com
*/
#include "bignum_fast.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: /cvs/libtom/tomsfastmath/src/exptmod/fp_2expt.c,v $ */
/* $Revision: 1.1 $ */
/* $Date: 2006/12/31 21:25:53 $ */