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#include <tommath_private.h>
#ifdef BN_MP_2EXPT_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
* LibTomMath is a library that provides multiple-precision
* integer arithmetic as well as number theoretic functionality.
*
* The library was designed directly after the MPI library by
* Michael Fromberger but has been written from scratch with
* additional optimizations in place.
*
* The library is free for all purposes without any express
* guarantee it works.
*
* Tom St Denis, tstdenis82@gmail.com, http://libtom.org
*/
/* computes a = 2**b
*
* Simple algorithm which zeroes the int, grows it then just sets one bit
* as required.
*/
int
mp_2expt (mp_int * a, int b)
{
int res;
/* zero a as per default */
mp_zero (a);
/* grow a to accomodate the single bit */
if ((res = mp_grow (a, (b / DIGIT_BIT) + 1)) != MP_OKAY) {
return res;
}
/* set the used count of where the bit will go */
a->used = (b / DIGIT_BIT) + 1;
/* put the single bit in its place */
a->dp[b / DIGIT_BIT] = ((mp_digit)1) << (b % DIGIT_BIT);
return MP_OKAY;
}
#endif
/* ref: tag: v1.0.1, master */
/* git commit: 5953f62e42b24af93748b1ee5e1d062e242c2546 */
/* commit time: 2017-08-29 22:27:36 +0200 */
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