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- #include "tommath_private.h"
- #ifdef BN_MP_LCM_C
- /* LibTomMath, multiple-precision integer library -- Tom St Denis */
- /* SPDX-License-Identifier: Unlicense */
- /* computes least common multiple as |a*b|/(a, b) */
- mp_err mp_lcm(const mp_int *a, const mp_int *b, mp_int *c)
- {
- mp_err err;
- mp_int t1, t2;
- if ((err = mp_init_multi(&t1, &t2, NULL)) != MP_OKAY) {
- return err;
- }
- /* t1 = get the GCD of the two inputs */
- if ((err = 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 ((err = mp_div(a, &t1, &t2, NULL)) != MP_OKAY) {
- goto LBL_T;
- }
- err = mp_mul(b, &t2, c);
- } else {
- /* store quotient in t2 such that t2 * a is the LCM */
- if ((err = mp_div(b, &t1, &t2, NULL)) != MP_OKAY) {
- goto LBL_T;
- }
- err = mp_mul(a, &t2, c);
- }
- /* fix the sign to positive */
- c->sign = MP_ZPOS;
- LBL_T:
- mp_clear_multi(&t1, &t2, NULL);
- return err;
- }
- #endif
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