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author | William Joye <wjoye@cfa.harvard.edu> | 2017-09-22 18:57:19 (GMT) |
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committer | William Joye <wjoye@cfa.harvard.edu> | 2017-09-22 18:57:19 (GMT) |
commit | 2aff4a96fa0286d875bddec0019648e2c6431cbc (patch) | |
tree | f7a9a4800a3f3ad4b77470b8383529176d8b7181 /tcl8.6/libtommath/bn_mp_2expt.c | |
parent | 3fa8e6dc88e8041b6cb88d1b1e9c05676d3346b7 (diff) | |
parent | 29ccecd87709feda60d191f6aaba324ccad91f55 (diff) | |
download | blt-2aff4a96fa0286d875bddec0019648e2c6431cbc.zip blt-2aff4a96fa0286d875bddec0019648e2c6431cbc.tar.gz blt-2aff4a96fa0286d875bddec0019648e2c6431cbc.tar.bz2 |
Merge commit '29ccecd87709feda60d191f6aaba324ccad91f55' 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 |