static void mrg_orig_step(mrg_state* state) { /* Use original A, not fully optimized yet */
uint_fast32_t new_elt = mod_mac_y(mod_mul_x(state->z1), state->z5);
state->z5 = state->z4;
state->z4 = state->z3;
state->z3 = state->z2;
state->z2 = state->z1;
state->z1 = new_elt;
}
static void mrg_update_cache(mrg_transition_matrix* p) { /* Set a, b, c, and d */
p->a = mod_add(mod_mul_x(p->s), p->t);
p->b = mod_add(mod_mul_x(p->a), p->u);
p->c = mod_add(mod_mul_x(p->b), p->v);
p->d = mod_add(mod_mul_x(p->c), p->w);
}
/* [b v w s*y a*y] */
/* [a u v w s*y] */
/* [s t u v w ] */
/* for some values of s, t, u, v, and w */
/* Note that A^n is determined by its bottom row (and x and y, which are */
/* fixed), and that it has a large part that is a Toeplitz matrix. You */
/* can multiply two A-like matrices by: */
/* (defining a..d1 and a..d2 for the two matrices) */
/* s3 = s1 d2 + t1 c2 + u1 b2 + v1 a2 + w1 s2, */
/* t3 = s1 s2 y + t1 w2 + u1 v2 + v1 u2 + w1 t2, */
/* u3 = s1 a2 y + t1 s2 y + u1 w2 + v1 v2 + w1 u2, */
/* v3 = s1 b2 y + t1 a2 y + u1 s2 y + v1 w2 + w1 v2, */
/* w3 = s1 c2 y + t1 b2 y + u1 a2 y + v1 s2 y + w1 w2 */
static void mrg_update_cache(mrg_transition_matrix* restrict p) { /* Set a, b, c, and d */
p->a = mod_add(mod_mul_x(p->s), p->t);
p->b = mod_add(mod_mul_x(p->a), p->u);
p->c = mod_add(mod_mul_x(p->b), p->v);
p->d = mod_add(mod_mul_x(p->c), p->w);
}
static void mrg_make_identity(mrg_transition_matrix* result) {
result->s = result->t = result->u = result->v = 0;
result->w = 1;
mrg_update_cache(result);
}
static void mrg_make_A(mrg_transition_matrix* result) { /* Initial RNG transition matrix */
result->s = result->t = result->u = result->w = 0;
result->v = 1;
mrg_update_cache(result);
