Mercurial > dropbear
view libtommath/bn_mp_2expt.c @ 1692:1051e4eea25a
Update LibTomMath to 1.2.0 (#84)
* update C files
* update other files
* update headers
* update makefiles
* remove mp_set/get_double()
* use ltm 1.2.0 API
* update ltm_desc
* use bundled tommath if system-tommath is too old
* XMALLOC etc. were changed to MP_MALLOC etc.
author | Steffen Jaeckel <s@jaeckel.eu> |
---|---|
date | Tue, 26 May 2020 17:36:47 +0200 |
parents | f52919ffd3b1 |
children |
line wrap: on
line source
#include "tommath_private.h" #ifdef BN_MP_2EXPT_C /* LibTomMath, multiple-precision integer library -- Tom St Denis */ /* SPDX-License-Identifier: Unlicense */ /* computes a = 2**b * * Simple algorithm which zeroes the int, grows it then just sets one bit * as required. */ mp_err mp_2expt(mp_int *a, int b) { mp_err err; /* zero a as per default */ mp_zero(a); /* grow a to accomodate the single bit */ if ((err = mp_grow(a, (b / MP_DIGIT_BIT) + 1)) != MP_OKAY) { return err; } /* set the used count of where the bit will go */ a->used = (b / MP_DIGIT_BIT) + 1; /* put the single bit in its place */ a->dp[b / MP_DIGIT_BIT] = (mp_digit)1 << (mp_digit)(b % MP_DIGIT_BIT); return MP_OKAY; } #endif