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author | William Joye <wjoye@cfa.harvard.edu> | 2016-12-21 22:46:09 (GMT) |
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committer | William Joye <wjoye@cfa.harvard.edu> | 2016-12-21 22:46:09 (GMT) |
commit | 768f87f613cc9789fcf8073018fa02178c8c91df (patch) | |
tree | ec633f5608ef498bee52a5f42c12c49493ec8bf8 /tcl8.6/libtommath/bn_mp_2expt.c | |
parent | 07e464099b99459d0a37757771791598ef3395d9 (diff) | |
parent | 05fa4c89f20e9769db0e6c0b429cef2590771ace (diff) | |
download | blt-768f87f613cc9789fcf8073018fa02178c8c91df.zip blt-768f87f613cc9789fcf8073018fa02178c8c91df.tar.gz blt-768f87f613cc9789fcf8073018fa02178c8c91df.tar.bz2 |
Merge commit '05fa4c89f20e9769db0e6c0b429cef2590771ace' as 'tcl8.6'
Diffstat (limited to 'tcl8.6/libtommath/bn_mp_2expt.c')
-rw-r--r-- | tcl8.6/libtommath/bn_mp_2expt.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/tcl8.6/libtommath/bn_mp_2expt.c b/tcl8.6/libtommath/bn_mp_2expt.c new file mode 100644 index 0000000..a32572d --- /dev/null +++ b/tcl8.6/libtommath/bn_mp_2expt.c @@ -0,0 +1,44 @@ +#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 |