1151 /* P = (x1, y1) => 2P, (x2, y2) => P' */
1152 static void xycz_initial_double(u64 *x1, u64 *y1, u64 *x2, u64 *y2,  in xycz_initial_double()  argument
1159 	vli_set(y2, y1, ndigits);  in xycz_initial_double()
1171 	apply_z(x2, y2, z, curve);  in xycz_initial_double()
1174 /* Input P = (x1, y1, Z), Q = (x2, y2, Z)
1178 static void xycz_add(u64 *x1, u64 *y1, u64 *x2, u64 *y2,  in xycz_add()  argument
1181 	/* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */  in xycz_add()
1194 	/* t4 = y2 - y1 */  in xycz_add()
1195 	vli_mod_sub(y2, y2, y1, curve_prime, ndigits);  in xycz_add()
1196 	/* t5 = (y2 - y1)^2 = D */  in xycz_add()
1197 	vli_mod_square_fast(t5, y2, curve);  in xycz_add()
1209 	/* t4 = (y2 - y1)*(B - x3) */  in xycz_add()
1210 	vli_mod_mult_fast(y2, y2, x2, curve);  in xycz_add()
1212 	vli_mod_sub(y2, y2, y1, curve_prime, ndigits);  in xycz_add()
1217 /* Input P = (x1, y1, Z), Q = (x2, y2, Z)
1221 static void xycz_add_c(u64 *x1, u64 *y1, u64 *x2, u64 *y2,  in xycz_add_c()  argument
1224 	/* t1 = X1, t2 = Y1, t3 = X2, t4 = Y2 */  in xycz_add_c()
1239 	/* t4 = y2 + y1 */  in xycz_add_c()
1240 	vli_mod_add(t5, y2, y1, curve_prime, ndigits);  in xycz_add_c()
1241 	/* t4 = y2 - y1 */  in xycz_add_c()
1242 	vli_mod_sub(y2, y2, y1, curve_prime, ndigits);  in xycz_add_c()
1250 	/* t3 = (y2 - y1)^2 */  in xycz_add_c()
1251 	vli_mod_square_fast(x2, y2, curve);  in xycz_add_c()
1257 	/* t4 = (y2 - y1)*(B - x3) */  in xycz_add_c()
1258 	vli_mod_mult_fast(y2, y2, t7, curve);  in xycz_add_c()
1260 	vli_mod_sub(y2, y2, y1, curve_prime, ndigits);  in xycz_add_c()
1262 	/* t7 = (y2 + y1)^2 = F */  in xycz_add_c()
1268 	/* t6 = (y2 + y1)*(x3' - B) */  in xycz_add_c()