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author | jan.nijtmans <nijtmans@users.sourceforge.net> | 2016-11-16 13:04:26 (GMT) |
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committer | jan.nijtmans <nijtmans@users.sourceforge.net> | 2016-11-16 13:04:26 (GMT) |
commit | 2adcff3e5ba6e09366ef4208ab81768803ba15bd (patch) | |
tree | 963ed4c25de0f3f0b60d2392c5fd0e7441e548e5 /libtommath/bn_mp_get_long_long.c | |
parent | fac003f85aeba679d1cc6bea4eb8a84fc0ebd9f0 (diff) | |
download | tcl-2adcff3e5ba6e09366ef4208ab81768803ba15bd.zip tcl-2adcff3e5ba6e09366ef4208ab81768803ba15bd.tar.gz tcl-2adcff3e5ba6e09366ef4208ab81768803ba15bd.tar.bz2 |
import libtommath 1.0
Diffstat (limited to 'libtommath/bn_mp_get_long_long.c')
-rw-r--r-- | libtommath/bn_mp_get_long_long.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/libtommath/bn_mp_get_long_long.c b/libtommath/bn_mp_get_long_long.c new file mode 100644 index 0000000..4b959e6 --- /dev/null +++ b/libtommath/bn_mp_get_long_long.c @@ -0,0 +1,41 @@ +#include <tommath_private.h> +#ifdef BN_MP_GET_LONG_LONG_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, tstdenis82@gmail.com, http://libtom.org + */ + +/* get the lower unsigned long long of an mp_int, platform dependent */ +unsigned long long mp_get_long_long (mp_int * a) +{ + int i; + unsigned long long res; + + if (a->used == 0) { + return 0; + } + + /* get number of digits of the lsb we have to read */ + i = MIN(a->used,(int)(((sizeof(unsigned long long) * CHAR_BIT) + DIGIT_BIT - 1) / DIGIT_BIT)) - 1; + + /* get most significant digit of result */ + res = DIGIT(a,i); + +#if DIGIT_BIT < 64 + while (--i >= 0) { + res = (res << DIGIT_BIT) | DIGIT(a,i); + } +#endif + return res; +} +#endif |