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#include "mult.h"
#include "point.h"
static void scalar_mult_inner(bn_t *scalar, point_t *point, curve_t *curve, point_t *out) {
point_t *q = point_copy(curve->neutral);
int order_blen = bn_bit_length(&curve->n);
int d = (order_blen + {{ scalarmult.width }} - 1) / {{ scalarmult.width }};
point_t *base_points[{{ scalarmult.width }}];
point_t *current = point_copy(point);
for (int i = 0; i < {{ scalarmult.width }}; i++) {
base_points[i] = point_copy(current);
if (i != {{ scalarmult.width }} - 1) {
for (int j = 0; j < d; j++) {
point_dbl(current, curve, current);
}
}
}
point_free(current);
point_t *points[{{ 2**scalarmult.width }}];
for (int j = 0; j < {{ 2**scalarmult.width }}; j++) {
point_t *alloc_point = NULL;
for (int i = 0; i < {{ scalarmult.width }}; i++) {
if (j & (1 << i)) {
if (alloc_point) {
point_accumulate(alloc_point, base_points[i], curve, alloc_point);
} else {
alloc_point = point_copy(base_points[i]);
}
}
}
points[j] = alloc_point;
}
bn_t base; bn_init(&base);
bn_from_int(1, &base);
bn_lsh(&base, d, &base);
{% if scalarmult.always %}
point_t *dummy = point_new();
{% endif %}
large_base_t *bs = bn_convert_base_large(scalar, &base);
for (int i = d - 1; i >= 0; i--) {
point_dbl(q, curve, q);
int word = 0;
for (int j = 0; j < {{ scalarmult.width }}; j++) {
if (j < bs->length) {
word |= bn_get_bit(&bs->data[j], i) << j;
}
}
if (word) {
point_accumulate(q, points[word], curve, q);
} else {
{% if scalarmult.always %}
int j = i % {{ 2**scalarmult.width }};
if (j == 0) {
point_accumulate(q, point, curve, dummy);
} else {
point_accumulate(q, points[j], curve, dummy);
}
{% endif %}
}
}
bn_large_base_clear(bs);
bn_clear(&base);
{%- if "scl" in scalarmult.formulas %}
point_scl(a, curve, a);
{%- endif %}
point_set(q, out);
for (int i = 0; i < {{ scalarmult.width }}; i++) {
point_free(base_points[i]);
}
for (int i = 0; i < {{ 2**scalarmult.width }}; i++) {
if (points[i]) {
point_free(points[i]);
}
}
point_free(q);
}
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