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authorWilliam Joye <wjoye@cfa.harvard.edu>2016-12-21 22:13:18 (GMT)
committerWilliam Joye <wjoye@cfa.harvard.edu>2016-12-21 22:13:18 (GMT)
commit07e464099b99459d0a37757771791598ef3395d9 (patch)
tree4ba7d8aad13735e52f59bdce7ca5ba3151ebd7e3 /tcl8.6/libtommath/bn_mp_reduce.c
parentdeb3650e37f26f651f280e480c4df3d7dde87bae (diff)
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new subtree for tcl/tk
Diffstat (limited to 'tcl8.6/libtommath/bn_mp_reduce.c')
-rw-r--r--tcl8.6/libtommath/bn_mp_reduce.c96
1 files changed, 0 insertions, 96 deletions
diff --git a/tcl8.6/libtommath/bn_mp_reduce.c b/tcl8.6/libtommath/bn_mp_reduce.c
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--- a/tcl8.6/libtommath/bn_mp_reduce.c
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@@ -1,96 +0,0 @@
-#include <tommath.h>
-#ifdef BN_MP_REDUCE_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
- */
-
-/* reduces x mod m, assumes 0 < x < m**2, mu is
- * precomputed via mp_reduce_setup.
- * From HAC pp.604 Algorithm 14.42
- */
-int mp_reduce (mp_int * x, mp_int * m, mp_int * mu)
-{
- mp_int q;
- int res, um = m->used;
-
- /* q = x */
- if ((res = mp_init_copy (&q, x)) != MP_OKAY) {
- return res;
- }
-
- /* q1 = x / b**(k-1) */
- mp_rshd (&q, um - 1);
-
- /* according to HAC this optimization is ok */
- if (((unsigned long) um) > (((mp_digit)1) << (DIGIT_BIT - 1))) {
- if ((res = mp_mul (&q, mu, &q)) != MP_OKAY) {
- goto CLEANUP;
- }
- } else {
-#ifdef BN_S_MP_MUL_HIGH_DIGS_C
- if ((res = s_mp_mul_high_digs (&q, mu, &q, um)) != MP_OKAY) {
- goto CLEANUP;
- }
-#elif defined(BN_FAST_S_MP_MUL_HIGH_DIGS_C)
- if ((res = fast_s_mp_mul_high_digs (&q, mu, &q, um)) != MP_OKAY) {
- goto CLEANUP;
- }
-#else
- {
- res = MP_VAL;
- goto CLEANUP;
- }
-#endif
- }
-
- /* q3 = q2 / b**(k+1) */
- mp_rshd (&q, um + 1);
-
- /* x = x mod b**(k+1), quick (no division) */
- if ((res = mp_mod_2d (x, DIGIT_BIT * (um + 1), x)) != MP_OKAY) {
- goto CLEANUP;
- }
-
- /* q = q * m mod b**(k+1), quick (no division) */
- if ((res = s_mp_mul_digs (&q, m, &q, um + 1)) != MP_OKAY) {
- goto CLEANUP;
- }
-
- /* x = x - q */
- if ((res = mp_sub (x, &q, x)) != MP_OKAY) {
- goto CLEANUP;
- }
-
- /* If x < 0, add b**(k+1) to it */
- if (mp_cmp_d (x, 0) == MP_LT) {
- mp_set (&q, 1);
- if ((res = mp_lshd (&q, um + 1)) != MP_OKAY)
- goto CLEANUP;
- if ((res = mp_add (x, &q, x)) != MP_OKAY)
- goto CLEANUP;
- }
-
- /* Back off if it's too big */
- while (mp_cmp (x, m) != MP_LT) {
- if ((res = s_mp_sub (x, m, x)) != MP_OKAY) {
- goto CLEANUP;
- }
- }
-
-CLEANUP:
- mp_clear (&q);
-
- return res;
-}
-#endif