Mercurial > dropbear
diff 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> |
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date | Wed, 23 Nov 2011 18:10:20 +0700 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/tomsfastmath/src/exptmod/fp_2expt.c Wed Nov 23 18:10:20 2011 +0700 @@ -0,0 +1,39 @@ +/* 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); +} + + +/* $Source$ */ +/* $Revision$ */ +/* $Date$ */