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| author | Brian Smith <brian@briansmith.org> | 2016-03-26 03:29:52 +0300 |
|---|---|---|
| committer | David Benjamin <davidben@google.com> | 2016-04-21 01:58:36 +0300 |
| commit | 3f3358ac150465fafffaf1c51c2928dd2b2018a9 (patch) | |
| tree | 32fcec52ea525503a78ec2d24786908654c23d6e /crypto/ec | |
| parent | a7aa2bb8f86f9891bba9d05544e2b9796b2da864 (diff) | |
Save one call to |ecp_nistz256_from_mont| in |ecp_nistz256_get_affine|.
Change-Id: I38faa5c4e9101c100614ebadf421bde0a05af360
Reviewed-on: https://boringssl-review.googlesource.com/7589
Reviewed-by: David Benjamin <davidben@google.com>
Diffstat (limited to 'crypto/ec')
| -rw-r--r-- | crypto/ec/p256-x86_64.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/crypto/ec/p256-x86_64.c b/crypto/ec/p256-x86_64.c index b11e37fd..e1afec48 100644 --- a/crypto/ec/p256-x86_64.c +++ b/crypto/ec/p256-x86_64.c @@ -519,32 +519,32 @@ static int ecp_nistz256_get_affine(const EC_GROUP *group, const EC_POINT *point, ecp_nistz256_mod_inverse(z_inv3, point_z); ecp_nistz256_sqr_mont(z_inv2, z_inv3); - if (x != NULL) { - BN_ULONG x_aff[P256_LIMBS]; + /* Instead of using |ecp_nistz256_from_mont| to convert the |x| coordinate + * and then calling |ecp_nistz256_from_mont| again to convert the |y| + * coordinate below, convert the common factor |z_inv2| once now, saving one + * reduction. */ + ecp_nistz256_from_mont(z_inv2, z_inv2); - ecp_nistz256_mul_mont(x_aff, z_inv2, point_x); + if (x != NULL) { if (bn_wexpand(x, P256_LIMBS) == NULL) { OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE); return 0; } x->top = P256_LIMBS; x->neg = 0; - ecp_nistz256_from_mont(x->d, x_aff); + ecp_nistz256_mul_mont(x->d, z_inv2, point_x); bn_correct_top(x); } if (y != NULL) { - BN_ULONG y_aff[P256_LIMBS]; - ecp_nistz256_mul_mont(z_inv3, z_inv3, z_inv2); - ecp_nistz256_mul_mont(y_aff, z_inv3, point_y); if (bn_wexpand(y, P256_LIMBS) == NULL) { OPENSSL_PUT_ERROR(EC, ERR_R_MALLOC_FAILURE); return 0; } y->top = P256_LIMBS; y->neg = 0; - ecp_nistz256_from_mont(y->d, y_aff); + ecp_nistz256_mul_mont(y->d, z_inv3, point_y); bn_correct_top(y); } |