diff options
Diffstat (limited to 'libtommath/bn_mp_gcd.c')
-rw-r--r-- | libtommath/bn_mp_gcd.c | 54 |
1 files changed, 21 insertions, 33 deletions
diff --git a/libtommath/bn_mp_gcd.c b/libtommath/bn_mp_gcd.c index 05030c2..53029ba 100644 --- a/libtommath/bn_mp_gcd.c +++ b/libtommath/bn_mp_gcd.c @@ -1,37 +1,29 @@ #include "tommath_private.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. - * - * SPDX-License-Identifier: Unlicense - */ +/* LibTomMath, multiple-precision integer library -- Tom St Denis */ +/* SPDX-License-Identifier: Unlicense */ /* Greatest Common Divisor using the binary method */ -int mp_gcd(const mp_int *a, const mp_int *b, mp_int *c) +mp_err mp_gcd(const mp_int *a, const mp_int *b, mp_int *c) { mp_int u, v; - int k, u_lsb, v_lsb, res; + int k, u_lsb, v_lsb; + mp_err err; /* either zero than gcd is the largest */ - if (mp_iszero(a) == MP_YES) { + if (MP_IS_ZERO(a)) { return mp_abs(b, c); } - if (mp_iszero(b) == MP_YES) { + if (MP_IS_ZERO(b)) { 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 ((err = mp_init_copy(&u, a)) != MP_OKAY) { + return err; } - if ((res = mp_init_copy(&v, b)) != MP_OKAY) { + if ((err = mp_init_copy(&v, b)) != MP_OKAY) { goto LBL_U; } @@ -41,33 +33,33 @@ int mp_gcd(const mp_int *a, const mp_int *b, mp_int *c) /* 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); + k = MP_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) { + if ((err = mp_div_2d(&u, k, &u, NULL)) != MP_OKAY) { goto LBL_V; } - if ((res = mp_div_2d(&v, k, &v, NULL)) != MP_OKAY) { + if ((err = 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) { + if ((err = 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) { + if ((err = mp_div_2d(&v, v_lsb - k, &v, NULL)) != MP_OKAY) { goto LBL_V; } } - while (mp_iszero(&v) == MP_NO) { + while (!MP_IS_ZERO(&v)) { /* make sure v is the largest */ if (mp_cmp_mag(&u, &v) == MP_GT) { /* swap u and v to make sure v is >= u */ @@ -75,30 +67,26 @@ int mp_gcd(const mp_int *a, const mp_int *b, mp_int *c) } /* subtract smallest from largest */ - if ((res = s_mp_sub(&v, &u, &v)) != MP_OKAY) { + if ((err = 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) { + if ((err = 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) { + if ((err = mp_mul_2d(&u, k, c)) != MP_OKAY) { goto LBL_V; } c->sign = MP_ZPOS; - res = MP_OKAY; + err = MP_OKAY; LBL_V: mp_clear(&u); LBL_U: mp_clear(&v); - return res; + return err; } #endif - -/* ref: $Format:%D$ */ -/* git commit: $Format:%H$ */ -/* commit time: $Format:%ai$ */ |