diff options
Diffstat (limited to 'libtommath/bn_mp_exteuclid.c')
| -rw-r--r-- | libtommath/bn_mp_exteuclid.c | 94 |
1 files changed, 68 insertions, 26 deletions
diff --git a/libtommath/bn_mp_exteuclid.c b/libtommath/bn_mp_exteuclid.c index 3c9612e..98eef76 100644 --- a/libtommath/bn_mp_exteuclid.c +++ b/libtommath/bn_mp_exteuclid.c @@ -20,7 +20,7 @@ */ int mp_exteuclid(mp_int *a, mp_int *b, mp_int *U1, mp_int *U2, mp_int *U3) { - mp_int u1,u2,u3,v1,v2,v3,t1,t2,t3,q,tmp; + mp_int u1, u2, u3, v1, v2, v3, t1, t2, t3, q, tmp; int err; if ((err = mp_init_multi(&u1, &u2, &u3, &v1, &v2, &v3, &t1, &t2, &t3, &q, &tmp, NULL)) != MP_OKAY) { @@ -29,47 +29,89 @@ int mp_exteuclid(mp_int *a, mp_int *b, mp_int *U1, mp_int *U2, mp_int *U3) /* initialize, (u1,u2,u3) = (1,0,a) */ mp_set(&u1, 1); - if ((err = mp_copy(a, &u3)) != MP_OKAY) { goto LBL_ERR; } + if ((err = mp_copy(a, &u3)) != MP_OKAY) { + goto LBL_ERR; + } /* initialize, (v1,v2,v3) = (0,1,b) */ mp_set(&v2, 1); - if ((err = mp_copy(b, &v3)) != MP_OKAY) { goto LBL_ERR; } + if ((err = mp_copy(b, &v3)) != MP_OKAY) { + goto LBL_ERR; + } /* loop while v3 != 0 */ while (mp_iszero(&v3) == MP_NO) { - /* q = u3/v3 */ - if ((err = mp_div(&u3, &v3, &q, NULL)) != MP_OKAY) { goto LBL_ERR; } + /* q = u3/v3 */ + if ((err = mp_div(&u3, &v3, &q, NULL)) != MP_OKAY) { + goto LBL_ERR; + } - /* (t1,t2,t3) = (u1,u2,u3) - (v1,v2,v3)q */ - if ((err = mp_mul(&v1, &q, &tmp)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_sub(&u1, &tmp, &t1)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_mul(&v2, &q, &tmp)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_sub(&u2, &tmp, &t2)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_mul(&v3, &q, &tmp)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_sub(&u3, &tmp, &t3)) != MP_OKAY) { goto LBL_ERR; } + /* (t1,t2,t3) = (u1,u2,u3) - (v1,v2,v3)q */ + if ((err = mp_mul(&v1, &q, &tmp)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_sub(&u1, &tmp, &t1)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_mul(&v2, &q, &tmp)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_sub(&u2, &tmp, &t2)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_mul(&v3, &q, &tmp)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_sub(&u3, &tmp, &t3)) != MP_OKAY) { + goto LBL_ERR; + } - /* (u1,u2,u3) = (v1,v2,v3) */ - if ((err = mp_copy(&v1, &u1)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_copy(&v2, &u2)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_copy(&v3, &u3)) != MP_OKAY) { goto LBL_ERR; } + /* (u1,u2,u3) = (v1,v2,v3) */ + if ((err = mp_copy(&v1, &u1)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_copy(&v2, &u2)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_copy(&v3, &u3)) != MP_OKAY) { + goto LBL_ERR; + } - /* (v1,v2,v3) = (t1,t2,t3) */ - if ((err = mp_copy(&t1, &v1)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_copy(&t2, &v2)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_copy(&t3, &v3)) != MP_OKAY) { goto LBL_ERR; } + /* (v1,v2,v3) = (t1,t2,t3) */ + if ((err = mp_copy(&t1, &v1)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_copy(&t2, &v2)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_copy(&t3, &v3)) != MP_OKAY) { + goto LBL_ERR; + } } /* make sure U3 >= 0 */ if (u3.sign == MP_NEG) { - if ((err = mp_neg(&u1, &u1)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_neg(&u2, &u2)) != MP_OKAY) { goto LBL_ERR; } - if ((err = mp_neg(&u3, &u3)) != MP_OKAY) { goto LBL_ERR; } + if ((err = mp_neg(&u1, &u1)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_neg(&u2, &u2)) != MP_OKAY) { + goto LBL_ERR; + } + if ((err = mp_neg(&u3, &u3)) != MP_OKAY) { + goto LBL_ERR; + } } /* copy result out */ - if (U1 != NULL) { mp_exch(U1, &u1); } - if (U2 != NULL) { mp_exch(U2, &u2); } - if (U3 != NULL) { mp_exch(U3, &u3); } + if (U1 != NULL) { + mp_exch(U1, &u1); + } + if (U2 != NULL) { + mp_exch(U2, &u2); + } + if (U3 != NULL) { + mp_exch(U3, &u3); + } err = MP_OKAY; LBL_ERR: |