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tls: simplify sp_256_proj_point_dbl_10

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function                                             old     new   delta
sp_256_proj_point_dbl_10                             490     435     -55

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2021-04-26 15:21:38 +02:00
parent 03ab2a90bb
commit 4d3a5c135c
1 changed files with 22 additions and 36 deletions
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58
networking/tls_sp_c32.c
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@ -626,68 +626,54 @@ static void sp_256_map_10(sp_point* r, sp_point* p, sp_digit* t)
*/
static void sp_256_proj_point_dbl_10(sp_point* r, sp_point* p, sp_digit* t)
{
sp_point *rp[2];
sp_point tp;
sp_digit* t1 = t;
sp_digit* t2 = t + 2*10;
sp_digit* x;
sp_digit* y;
sp_digit* z;
int i;
/* When infinity don't double point passed in - constant time. */
rp[0] = r;
rp[1] = &tp;
x = rp[p->infinity]->x;
y = rp[p->infinity]->y;
z = rp[p->infinity]->z;
/* Put point to double into result - good for infinity. */
if (r != p) {
for (i = 0; i < 10; i++)
r->x[i] = p->x[i];
for (i = 0; i < 10; i++)
r->y[i] = p->y[i];
for (i = 0; i < 10; i++)
r->z[i] = p->z[i];
r->infinity = p->infinity;
/* Put point to double into result */
if (r != p)
*r = *p; /* struct copy */
if (r->infinity) {
/* If infinity, don't double (work on dummy value) */
r = &tp;
}
/* T1 = Z * Z */
sp_256_mont_sqr_10(t1, z, p256_mod, p256_mp_mod);
sp_256_mont_sqr_10(t1, r->z, p256_mod, p256_mp_mod);
/* Z = Y * Z */
sp_256_mont_mul_10(z, y, z, p256_mod, p256_mp_mod);
sp_256_mont_mul_10(r->z, r->y, r->z, p256_mod, p256_mp_mod);
/* Z = 2Z */
sp_256_mont_dbl_10(z, z, p256_mod);
sp_256_mont_dbl_10(r->z, r->z, p256_mod);
/* T2 = X - T1 */
sp_256_mont_sub_10(t2, x, t1, p256_mod);
sp_256_mont_sub_10(t2, r->x, t1, p256_mod);
/* T1 = X + T1 */
sp_256_mont_add_10(t1, x, t1, p256_mod);
sp_256_mont_add_10(t1, r->x, t1, p256_mod);
/* T2 = T1 * T2 */
sp_256_mont_mul_10(t2, t1, t2, p256_mod, p256_mp_mod);
/* T1 = 3T2 */
sp_256_mont_tpl_10(t1, t2, p256_mod);
/* Y = 2Y */
sp_256_mont_dbl_10(y, y, p256_mod);
sp_256_mont_dbl_10(r->y, r->y, p256_mod);
/* Y = Y * Y */
sp_256_mont_sqr_10(y, y, p256_mod, p256_mp_mod);
sp_256_mont_sqr_10(r->y, r->y, p256_mod, p256_mp_mod);
/* T2 = Y * Y */
sp_256_mont_sqr_10(t2, y, p256_mod, p256_mp_mod);
sp_256_mont_sqr_10(t2, r->y, p256_mod, p256_mp_mod);
/* T2 = T2/2 */
sp_256_div2_10(t2, t2, p256_mod);
/* Y = Y * X */
sp_256_mont_mul_10(y, y, x, p256_mod, p256_mp_mod);
sp_256_mont_mul_10(r->y, r->y, r->x, p256_mod, p256_mp_mod);
/* X = T1 * T1 */
sp_256_mont_mul_10(x, t1, t1, p256_mod, p256_mp_mod);
sp_256_mont_mul_10(r->x, t1, t1, p256_mod, p256_mp_mod);
/* X = X - Y */
sp_256_mont_sub_10(x, x, y, p256_mod);
sp_256_mont_sub_10(r->x, r->x, r->y, p256_mod);
/* X = X - Y */
sp_256_mont_sub_10(x, x, y, p256_mod);
sp_256_mont_sub_10(r->x, r->x, r->y, p256_mod);
/* Y = Y - X */
sp_256_mont_sub_10(y, y, x, p256_mod);
sp_256_mont_sub_10(r->y, r->y, r->x, p256_mod);
/* Y = Y * T1 */
sp_256_mont_mul_10(y, y, t1, p256_mod, p256_mp_mod);
sp_256_mont_mul_10(r->y, r->y, t1, p256_mod, p256_mp_mod);
/* Y = Y - T2 */
sp_256_mont_sub_10(y, y, t2, p256_mod);
sp_256_mont_sub_10(r->y, r->y, t2, p256_mod);
}
/* Add two Montgomery form projective points.