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author | William Joye <wjoye@cfa.harvard.edu> | 2016-12-21 22:13:18 (GMT) |
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committer | William Joye <wjoye@cfa.harvard.edu> | 2016-12-21 22:13:18 (GMT) |
commit | 07e464099b99459d0a37757771791598ef3395d9 (patch) | |
tree | 4ba7d8aad13735e52f59bdce7ca5ba3151ebd7e3 /tcl8.6/libtommath/bn_mp_gcd.c | |
parent | deb3650e37f26f651f280e480c4df3d7dde87bae (diff) | |
download | blt-07e464099b99459d0a37757771791598ef3395d9.zip blt-07e464099b99459d0a37757771791598ef3395d9.tar.gz blt-07e464099b99459d0a37757771791598ef3395d9.tar.bz2 |
new subtree for tcl/tk
Diffstat (limited to 'tcl8.6/libtommath/bn_mp_gcd.c')
-rw-r--r-- | tcl8.6/libtommath/bn_mp_gcd.c | 101 |
1 files changed, 0 insertions, 101 deletions
diff --git a/tcl8.6/libtommath/bn_mp_gcd.c b/tcl8.6/libtommath/bn_mp_gcd.c deleted file mode 100644 index 68cfa03..0000000 --- a/tcl8.6/libtommath/bn_mp_gcd.c +++ /dev/null @@ -1,101 +0,0 @@ -#include <tommath.h> -#ifdef BN_MP_GCD_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 - */ - -/* Greatest Common Divisor using the binary method */ -int mp_gcd (mp_int * a, mp_int * b, mp_int * c) -{ - mp_int u, v; - int k, u_lsb, v_lsb, res; - - /* either zero than gcd is the largest */ - if (mp_iszero (a) == MP_YES) { - return mp_abs (b, c); - } - if (mp_iszero (b) == MP_YES) { - return mp_abs (a, c); - } - - /* get copies of a and b we can modify */ - if ((res = mp_init_copy (&u, a)) != MP_OKAY) { - return res; - } - - if ((res = mp_init_copy (&v, b)) != MP_OKAY) { - goto LBL_U; - } - - /* must be positive for the remainder of the algorithm */ - u.sign = v.sign = MP_ZPOS; - - /* B1. Find the common power of two for u and v */ - u_lsb = mp_cnt_lsb(&u); - v_lsb = mp_cnt_lsb(&v); - k = MIN(u_lsb, v_lsb); - - if (k > 0) { - /* divide the power of two out */ - if ((res = mp_div_2d(&u, k, &u, NULL)) != MP_OKAY) { - goto LBL_V; - } - - if ((res = mp_div_2d(&v, k, &v, NULL)) != MP_OKAY) { - goto LBL_V; - } - } - - /* divide any remaining factors of two out */ - if (u_lsb != k) { - if ((res = mp_div_2d(&u, u_lsb - k, &u, NULL)) != MP_OKAY) { - goto LBL_V; - } - } - - if (v_lsb != k) { - if ((res = mp_div_2d(&v, v_lsb - k, &v, NULL)) != MP_OKAY) { - goto LBL_V; - } - } - - while (mp_iszero(&v) == 0) { - /* make sure v is the largest */ - if (mp_cmp_mag(&u, &v) == MP_GT) { - /* swap u and v to make sure v is >= u */ - mp_exch(&u, &v); - } - - /* subtract smallest from largest */ - if ((res = s_mp_sub(&v, &u, &v)) != MP_OKAY) { - goto LBL_V; - } - - /* Divide out all factors of two */ - if ((res = mp_div_2d(&v, mp_cnt_lsb(&v), &v, NULL)) != MP_OKAY) { - goto LBL_V; - } - } - - /* multiply by 2**k which we divided out at the beginning */ - if ((res = mp_mul_2d (&u, k, c)) != MP_OKAY) { - goto LBL_V; - } - c->sign = MP_ZPOS; - res = MP_OKAY; -LBL_V:mp_clear (&u); -LBL_U:mp_clear (&v); - return res; -} -#endif |