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- #include <tommath.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, tomstdenis@gmail.com, http://math.libtomcrypt.com
- */
- /* 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
- /* $Source: /cvs/libtom/libtommath/bn_mp_2expt.c,v $ */
- /* $Revision: 1.3 $ */
- /* $Date: 2006/03/31 14:18:44 $ */
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