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author | Kevin B Kenny <kennykb@acm.org> | 2005-01-19 22:41:26 (GMT) |
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committer | Kevin B Kenny <kennykb@acm.org> | 2005-01-19 22:41:26 (GMT) |
commit | b9cf65a08e6a59e434685e894e3189c201ac6791 (patch) | |
tree | 1f0868ef44c9f17d83d10dc94343df7b8cfe1842 /libtommath/bn_mp_lcm.c | |
parent | c6a259aeeca4814a97cf6694814c63e74e4e18fa (diff) | |
download | tcl-b9cf65a08e6a59e434685e894e3189c201ac6791.zip tcl-b9cf65a08e6a59e434685e894e3189c201ac6791.tar.gz tcl-b9cf65a08e6a59e434685e894e3189c201ac6791.tar.bz2 |
Import of libtommath 0.33
Diffstat (limited to 'libtommath/bn_mp_lcm.c')
-rw-r--r-- | libtommath/bn_mp_lcm.c | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/libtommath/bn_mp_lcm.c b/libtommath/bn_mp_lcm.c new file mode 100644 index 0000000..8e3a759 --- /dev/null +++ b/libtommath/bn_mp_lcm.c @@ -0,0 +1,56 @@ +#include <tommath.h> +#ifdef BN_MP_LCM_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@iahu.ca, http://math.libtomcrypt.org + */ + +/* computes least common multiple as |a*b|/(a, b) */ +int mp_lcm (mp_int * a, mp_int * b, mp_int * c) +{ + int res; + mp_int t1, t2; + + + if ((res = mp_init_multi (&t1, &t2, NULL)) != MP_OKAY) { + return res; + } + + /* t1 = get the GCD of the two inputs */ + if ((res = mp_gcd (a, b, &t1)) != MP_OKAY) { + goto LBL_T; + } + + /* divide the smallest by the GCD */ + if (mp_cmp_mag(a, b) == MP_LT) { + /* store quotient in t2 such that t2 * b is the LCM */ + if ((res = mp_div(a, &t1, &t2, NULL)) != MP_OKAY) { + goto LBL_T; + } + res = mp_mul(b, &t2, c); + } else { + /* store quotient in t2 such that t2 * a is the LCM */ + if ((res = mp_div(b, &t1, &t2, NULL)) != MP_OKAY) { + goto LBL_T; + } + res = mp_mul(a, &t2, c); + } + + /* fix the sign to positive */ + c->sign = MP_ZPOS; + +LBL_T: + mp_clear_multi (&t1, &t2, NULL); + return res; +} +#endif |