static void ed_mul_reg_imp(ed_t r, const ed_t p, const bn_t k) {
int l, i, j, n;
int8_t reg[RLC_CEIL(RLC_FP_BITS + 1, ED_WIDTH - 1)], *_k;
ed_t t[1 << (ED_WIDTH - 2)];
TRY {
/* Prepare the precomputation table. */
for (i = 0; i < (1 << (ED_WIDTH - 2)); i++) {
ed_null(t[i]);
ed_new(t[i]);
}
/* Compute the precomputation table. */
ed_tab(t, p, ED_WIDTH);
/* Compute the w-NAF representation of k. */
l = RLC_CEIL(RLC_FP_BITS + 1, ED_WIDTH - 1);
bn_rec_reg(reg, &l, k, RLC_FP_BITS, ED_WIDTH);
_k = reg + l - 1;
ed_set_infty(r);
for (i = l - 1; i >= 0; i--, _k--) {
for (j = 0; j < ED_WIDTH - 1; j++) {
r->norm = 2;
ed_dbl(r, r);
}
n = *_k;
if (n > 0) {
ed_add(r, r, t[n / 2]);
}
if (n < 0) {
ed_sub(r, r, t[-n / 2]);
}
}
/* Convert r to affine coordinates. */
ed_norm(r, r);
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
/* Free the precomputation table. */
for (i = 0; i < (1 << (ED_WIDTH - 2)); i++) {
ed_free(t[i]);
}
}
}
void ed_mul_pre_lwnaf_mixed(ed_t *t, const ed_t p) {
ed_tab(t, p, ED_DEPTH);
}
static void ed_mul_naf_imp(ed_t r, const ed_t p, const bn_t k) {
int l, i, n;
int8_t naf[RLC_FP_BITS + 1];
ed_t t[1 << (ED_WIDTH - 2)];
if (bn_is_zero(k)) {
ed_set_infty(r);
return;
}
TRY {
/* Prepare the precomputation table. */
for (i = 0; i < (1 << (ED_WIDTH - 2)); i++) {
ed_null(t[i]);
ed_new(t[i]);
}
/* Compute the precomputation table. */
ed_tab(t, p, ED_WIDTH);
/* Compute the w-NAF representation of k. */
l = sizeof(naf);
bn_rec_naf(naf, &l, k, EP_WIDTH);
ed_set_infty(r);
for (i = l - 1; i > 0; i--) {
n = naf[i];
if (n == 0) {
/* This point will be doubled in the previous iteration. */
r->norm = 2;
ed_dbl(r, r);
} else {
ed_dbl(r, r);
if (n > 0) {
ed_add(r, r, t[n / 2]);
} else if (n < 0) {
ed_sub(r, r, t[-n / 2]);
}
}
}
/* Last iteration. */
n = naf[0];
ed_dbl(r, r);
if (n > 0) {
ed_add(r, r, t[n / 2]);
} else if (n < 0) {
ed_sub(r, r, t[-n / 2]);
}
/* Convert r to affine coordinates. */
ed_norm(r, r);
if (bn_sign(k) == RLC_NEG) {
ed_neg(r, r);
}
}
CATCH_ANY {
THROW(ERR_CAUGHT);
}
FINALLY {
/* Free the precomputation table. */
for (i = 0; i < (1 << (ED_WIDTH - 2)); i++) {
ed_free(t[i]);
}
}
}
