int
tt_get(Transposition_table *table,
enum routine_id routine,
int target1, int target2, int remaining_depth,
Hash_data *extra_hash,
int *value1, int *value2, int *move)
{
Hash_data hashval;
Hashentry *entry;
Hashnode *node;
/* Sanity check. */
if (remaining_depth < 0 || remaining_depth > HN_MAX_REMAINING_DEPTH)
return 0;
/* Get the combined hash value. */
calculate_hashval_for_tt(&hashval, routine, target1, target2, extra_hash);
/* Get the correct entry and node. */
entry = &table->entries[hashdata_remainder(hashval, table->num_entries)];
if (hashdata_is_equal(hashval, entry->deepest.key))
node = &entry->deepest;
else if (hashdata_is_equal(hashval, entry->newest.key))
node = &entry->newest;
else
return 0;
stats.read_result_hits++;
/* Return data. Only set the result if remaining depth in the table
* is big enough to be trusted. The move can always be used for move
* ordering if nothing else.
*/
if (move)
*move = hn_get_move(node->data);
if (remaining_depth <= (int) hn_get_remaining_depth(node->data)) {
if (value1)
*value1 = hn_get_value1(node->data);
if (value2)
*value2 = hn_get_value2(node->data);
stats.trusted_read_result_hits++;
return 2;
}
return 1;
}
/* Find a cache entry matching the data given in the parameters.
* Important: We assume that unused parameters are normalized to NO_MOVE
* when storing or retrieving, so that we can ignore them here.
*/
static struct persistent_cache_entry *
find_persistent_cache_entry(struct persistent_cache *cache,
enum routine_id routine, int apos, int bpos,
int cpos, Hash_data *goal_hash, int node_limit)
{
int k;
for (k = 0; k < cache->current_size; k++) {
struct persistent_cache_entry *entry = cache->table + k;
if (entry->routine == routine
&& entry->apos == apos
&& entry->bpos == bpos
&& entry->cpos == cpos
&& depth - stackp <= entry->remaining_depth
&& (entry->node_limit >= node_limit || entry->result_certain)
&& (goal_hash == NULL
|| hashdata_is_equal(entry->goal_hash, *goal_hash))
&& verify_stored_board(entry->board))
return entry;
}
return NULL;
}
void
tt_update(Transposition_table *table,
enum routine_id routine, int target1, int target2,
int remaining_depth, Hash_data *extra_hash,
int value1, int value2, int move)
{
Hash_data hashval;
Hashentry *entry;
Hashnode *deepest;
Hashnode *newest;
unsigned int data;
/* Get routine costs definitions from liberty.h. */
static const int routine_costs[] = { ROUTINE_COSTS };
gg_assert(routine_costs[NUM_CACHE_ROUTINES] == -1);
/* Sanity check. */
if (remaining_depth < 0 || remaining_depth > HN_MAX_REMAINING_DEPTH)
return;
/* Get the combined hash value. */
calculate_hashval_for_tt(&hashval, routine, target1, target2, extra_hash);
data = hn_create_data(remaining_depth, value1, value2, move,
routine_costs[routine]);
/* Get the entry and nodes. */
entry = &table->entries[hashdata_remainder(hashval, table->num_entries)];
deepest = &entry->deepest;
newest = &entry->newest;
/* See if we found an already existing node. */
if (hashdata_is_equal(hashval, deepest->key)
&& remaining_depth >= (int) hn_get_remaining_depth(deepest->data)) {
/* Found deepest */
deepest->data = data;
}
else if (hashdata_is_equal(hashval, newest->key)
&& remaining_depth >= (int) hn_get_remaining_depth(newest->data)) {
/* Found newest */
newest->data = data;
/* If newest has become deeper than deepest, then switch them. */
if (hn_get_remaining_depth(newest->data)
> hn_get_remaining_depth(deepest->data)) {
Hashnode temp;
temp = *deepest;
*deepest = *newest;
*newest = temp;
}
}
else if (hn_get_total_cost(data) > hn_get_total_cost(deepest->data)) {
if (hn_get_total_cost(newest->data) < hn_get_total_cost(deepest->data))
*newest = *deepest;
deepest->key = hashval;
deepest->data = data;
}
else {
/* Replace newest. */
newest->key = hashval;
newest->data = data;
}
stats.read_result_entered++;
table->is_clean = 0;
}