27df6aeef
Denys Vlasenko
2021-12-11
Subject
tls: P256: factor out "multiply then reduce" operation
Binary
No binary (build failed)
Architecture & Compiler Flags
—
Build Log
(log yok)
Commit Diff GitHub →
networking/tls_sp_c32.c+13 -7
| @@ -1091,6 +1091,17 @@ static void sp_256_mont_sqr_8(sp_digit* r, const sp_digit* a | |
| sp_256_mont_mul_8(r, a, a /*, m, mp*/); | |
| } | |
| + | static NOINLINE void sp_256_mont_mul_and_reduce_8(sp_digit* r, |
| + | const sp_digit* a, const sp_digit* b |
| + | /*, const sp_digit* m, sp_digit mp*/) |
| + | { |
| + | sp_digit rr[2 * 8]; |
| + | |
| + | sp_256_mont_mul_8(rr, a, b /*, p256_mod, p256_mp_mod*/); |
| + | memset(rr + 8, 0, sizeof(rr) / 2); |
| + | sp_512to256_mont_reduce_8(r, rr /*, p256_mod, p256_mp_mod*/); |
| + | } |
| + | |
| /* Invert the number, in Montgomery form, modulo the modulus (prime) of the | |
| * P256 curve. (r = 1 / a mod m) | |
| * | |
| @@ -1186,7 +1197,6 @@ static void sp_256_map_8(sp_point* r, sp_point* p) | |
| { | |
| sp_digit t1[8]; | |
| sp_digit t2[8]; | |
| - | sp_digit rr[2 * 8]; |
| sp_256_mont_inv_8(t1, p->z); | |
| @@ -1194,18 +1204,14 @@ static void sp_256_map_8(sp_point* r, sp_point* p) | |
| sp_256_mont_mul_8(t1, t2, t1 /*, p256_mod, p256_mp_mod*/); | |
| /* x /= z^2 */ | |
| - | sp_256_mont_mul_8(rr, p->x, t2 /*, p256_mod, p256_mp_mod*/); |
| - | memset(rr + 8, 0, sizeof(rr) / 2); |
| - | sp_512to256_mont_reduce_8(r->x, rr /*, p256_mod, p256_mp_mod*/); |
| + | sp_256_mont_mul_and_reduce_8(r->x, p->x, t2 /*, p256_mod, p256_mp_mod*/); |
| /* Reduce x to less than modulus */ | |
| if (sp_256_cmp_8(r->x, p256_mod) >= 0) | |
| sp_256_sub_8_p256_mod(r->x); | |
| sp_256_norm_8(r->x); | |
| /* y /= z^3 */ | |
| - | sp_256_mont_mul_8(rr, p->y, t1 /*, p256_mod, p256_mp_mod*/); |
| - | memset(rr + 8, 0, sizeof(rr) / 2); |
| - | sp_512to256_mont_reduce_8(r->y, rr /*, p256_mod, p256_mp_mod*/); |
| + | sp_256_mont_mul_and_reduce_8(r->y, p->y, t1 /*, p256_mod, p256_mp_mod*/); |
| /* Reduce y to less than modulus */ | |
| if (sp_256_cmp_8(r->y, p256_mod) >= 0) | |
| sp_256_sub_8_p256_mod(r->y); | |