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#include <stdlib.h>
#include <string.h>
#include "engine/ttable.h"
#include "random.h"
void zobrist_init() {
for (int i = 0; i < PIECE_TYPE_COUNT; i++) {
for (int j = 0; j < 64; j++) {
zobrist_keys.piece[i][j] = random_u64();
}
}
for (int i = 0; i < CASTLE_COUNT; i++) {
zobrist_keys.castle[i] = random_u64();
}
for (int i = 0; i < TURN_COUNT; i++) {
zobrist_keys.turn[i] = random_u64();
}
for (int i = 0; i < 64; i++) {
zobrist_keys.en_passant[i] = random_u64();
}
}
u64 zobrist_hash(position_t position) {
u64 output = 0;
for (int i = 0; i < 64; i++) {
int piece_type = find_piece_on_square(&position, i);
output ^= zobrist_keys.piece[piece_type][i];
}
if (position.castling & WHITE_SHORT_CASTLE) {
output ^= zobrist_keys.castle[0];
}
if (position.castling & WHITE_LONG_CASTLE) {
output ^= zobrist_keys.castle[1];
}
if (position.castling & BLACK_SHORT_CASTLE) {
output ^= zobrist_keys.castle[2];
}
if (position.castling & BLACK_LONG_CASTLE) {
output ^= zobrist_keys.castle[3];
}
output ^= zobrist_keys.turn[position.turn];
output ^= zobrist_keys.en_passant[position.passantable_file];
return output;
}
void ttable_init(ttable_t *table, size_t size_in_binary_log) {
assert(size_in_binary_log < 64);
int size = 1ULL << size_in_binary_log;
table->buckets = calloc(size, sizeof(tbucket_t));
table->mask = size - 1;
}
void ttable_deinit(ttable_t table) {
free(table.buckets);
}
void __ttable_insert(ttable_t table, struct ttable_insert_args args) {
tbucket_t *bucket = table.buckets + (args.key & table.mask);
tentry_t *best = bucket->entries;
int ci = 0;
for (int i = 0; i < TT_BUCKET_SIZE; i++) {
if (atomic_load(&bucket->entries[i].key) == args.key) {
best = bucket->entries + i;
break;
}
if (bucket->entries[i].depth >= best->depth) continue;
best = bucket->entries + i;
}
tentry_t object;
object.best_move = args.move;
object.score = args.score;
object.eval = args.eval;
object.depth = args.depth;
object.flag = args.flag;
object.generation = args.generation;
memcpy(best, &object, sizeof(object));
atomic_store(&best->key, args.key);
}
tentry_t *ttable_find(ttable_t table, u64 key) {
tbucket_t *bucket = table.buckets + (key & table.mask);
for (int i = 0; i < TT_BUCKET_SIZE; i++) {
if (atomic_load(&(bucket->entries + i)->key) != key) continue;
return bucket->entries + i;
}
return NULL;
}
#ifdef TEST_MOD
bool test_ttable_empty() {
ttable_t table;
ttable_init(&table, 4);
if (ttable_find(table, 123456789ULL) != NULL) return false;
ttable_deinit(table);
return true;
}
bool test_ttable_insert_and_find() {
ttable_t table;
ttable_init(&table, 4);
u64 key = 0x123456789ABCDEF0ULL;
ttable_insert(table, .key = key, .depth = 8, .flag = TT_EXACT);
tentry_t *e = ttable_find(table, key);
assert(e != NULL);
assert(e->key == key);
assert(e->depth == 8);
assert(e->flag == TT_EXACT);
ttable_deinit(table);
return true;
}
bool test_ttable_wrong_key() {
ttable_t table;
ttable_init(&table, 4);
u64 key = 0x123456789ABCDEF0ULL;
ttable_insert(table, .key = key, .depth = 8, .flag = TT_EXACT);
assert(ttable_find(table, --key) == NULL);
ttable_deinit(table);
return true;
}
bool test_ttable_update_existing() {
ttable_t table;
ttable_init(&table, 4);
u64 key = 987654321ULL;
ttable_insert(table, .key = key, .depth = 10, .flag = TT_LOWERBOUND);
ttable_insert(table, .key = key, .depth = 11, .flag = TT_EXACT);
tentry_t *e = ttable_find(table, key);
assert(e != NULL);
assert(e->key == key);
assert(e->depth == 11);
assert(e->flag == TT_EXACT);
ttable_deinit(table);
return true;
}
bool test_bucket_collision() {
ttable_t table;
ttable_init(&table, 2);
ttable_insert(table, .key = 1, .depth = 10, .flag = TT_EXACT);
ttable_insert(table, .key = 2, .depth = 20, .flag = TT_EXACT);
ttable_insert(table, .key = 3, .depth = 30, .flag = TT_EXACT);
ttable_insert(table, .key = 4, .depth = 40, .flag = TT_EXACT);
if (ttable_find(table, 1) == NULL) return false;
if (ttable_find(table, 2) == NULL) return false;
if (ttable_find(table, 3) == NULL) return false;
if (ttable_find(table, 4) == NULL) return false;
ttable_deinit(table);
return true;
}
bool test_ttable_replace_shallowest() {
ttable_t table;
ttable_init(&table, 0);
ttable_insert(table, .key = 1, .depth = 10, .flag = TT_EXACT);
ttable_insert(table, .key = 2, .depth = 20, .flag = TT_EXACT);
ttable_insert(table, .key = 3, .depth = 30, .flag = TT_EXACT);
ttable_insert(table, .key = 4, .depth = 40, .flag = TT_EXACT);
// Bucket is full.
ttable_insert(table, .key = 5, .depth = 25, .flag = TT_EXACT);
if (ttable_find(table, 1) != NULL) return false;
if (ttable_find(table, 2) == NULL) return false;
if (ttable_find(table, 3) == NULL) return false;
if (ttable_find(table, 4) == NULL) return false;
if (ttable_find(table, 5) == NULL) return false;
ttable_deinit(table);
return true;
}
bool test_ttable_many_entries() {
ttable_t table;
ttable_init(&table, 16);
for (u64 i = 0; i < 50000; i++) {
ttable_insert(table, .key = i * 7919, .depth = i % 64, .flag = TT_EXACT);
}
for (u64 i = 0; i < 50000; i++) {
tentry_t *e = ttable_find(table, i * 7919);
if (e == NULL) continue;
if (e->key != i * 7919) return false;
}
ttable_deinit(table);
return true;
}
#endif
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