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Use calloc() in TranspositionTable::set_size()
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Function calloc() already initializes memory to
zero, so avoid calling clear() afterwards.

Also some renaming while there (inspired by DiscoCheck).

No functional change.
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@mcostalba
mcostalba committed Jun 29, 2013
1 parent 17d41b3 commit 203fdc9
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Showing 3 changed files with 42 additions and 44 deletions.
22 changes: 11 additions & 11 deletions src/search.cpp
View file
Expand Up @@ -570,9 +570,9 @@ namespace {
&& tte
&& tte->depth() >= depth
&& ttValue != VALUE_NONE // Only in case of TT access race
&& ( PvNode ? tte->type() == BOUND_EXACT
: ttValue >= beta ? (tte->type() & BOUND_LOWER)
: (tte->type() & BOUND_UPPER)))
&& ( PvNode ? tte->bound() == BOUND_EXACT
: ttValue >= beta ? (tte->bound() & BOUND_LOWER)
: (tte->bound() & BOUND_UPPER)))
{
TT.refresh(tte);
ss->currentMove = ttMove; // Can be MOVE_NONE
Expand Down Expand Up @@ -601,8 +601,8 @@ namespace {

// Can ttValue be used as a better position evaluation?
if (ttValue != VALUE_NONE)
if ( ((tte->type() & BOUND_LOWER) && ttValue > eval)
|| ((tte->type() & BOUND_UPPER) && ttValue < eval))
if ( ((tte->bound() & BOUND_LOWER) && ttValue > eval)
|| ((tte->bound() & BOUND_UPPER) && ttValue < eval))
eval = ttValue;
}
else
Expand Down Expand Up @@ -775,7 +775,7 @@ namespace {
&& depth >= (PvNode ? 6 * ONE_PLY : 8 * ONE_PLY)
&& ttMove != MOVE_NONE
&& !excludedMove // Recursive singular search is not allowed
&& (tte->type() & BOUND_LOWER)
&& (tte->bound() & BOUND_LOWER)
&& tte->depth() >= depth - 3 * ONE_PLY;

// Step 11. Loop through moves
Expand Down Expand Up @@ -1172,9 +1172,9 @@ namespace {
if ( tte
&& tte->depth() >= ttDepth
&& ttValue != VALUE_NONE // Only in case of TT access race
&& ( PvNode ? tte->type() == BOUND_EXACT
: ttValue >= beta ? (tte->type() & BOUND_LOWER)
: (tte->type() & BOUND_UPPER)))
&& ( PvNode ? tte->bound() == BOUND_EXACT
: ttValue >= beta ? (tte->bound() & BOUND_LOWER)
: (tte->bound() & BOUND_UPPER)))
{
ss->currentMove = ttMove; // Can be MOVE_NONE
return ttValue;
Expand Down Expand Up @@ -1584,7 +1584,7 @@ namespace {
void RootMove::extract_pv_from_tt(Position& pos) {

StateInfo state[MAX_PLY_PLUS_2], *st = state;
TTEntry* tte;
const TTEntry* tte;
int ply = 0;
Move m = pv[0];

Expand Down Expand Up @@ -1617,7 +1617,7 @@ void RootMove::extract_pv_from_tt(Position& pos) {
void RootMove::insert_pv_in_tt(Position& pos) {

StateInfo state[MAX_PLY_PLUS_2], *st = state;
TTEntry* tte;
const TTEntry* tte;
int ply = 0;

do {
Expand Down
49 changes: 24 additions & 25 deletions src/tt.cpp
View file
Expand Up @@ -41,7 +41,7 @@ void TranspositionTable::set_size(size_t mbSize) {

hashMask = size - ClusterSize;
free(mem);
mem = malloc(size * sizeof(TTEntry) + CACHE_LINE_SIZE - 1);
mem = calloc(size * sizeof(TTEntry) + CACHE_LINE_SIZE - 1, 1);

if (!mem)
{
Expand All @@ -51,7 +51,6 @@ void TranspositionTable::set_size(size_t mbSize) {
}

table = (TTEntry*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
clear(); // Operator new is not guaranteed to initialize memory to zero
}


Expand All @@ -65,6 +64,23 @@ void TranspositionTable::clear() {
}


/// TranspositionTable::probe() looks up the current position in the
/// transposition table. Returns a pointer to the TTEntry or NULL if
/// position is not found.

const TTEntry* TranspositionTable::probe(const Key key) const {

const TTEntry* tte = first_entry(key);
uint32_t key32 = key >> 32;

for (unsigned i = 0; i < ClusterSize; i++, tte++)
if (tte->key() == key32)
return tte;

return NULL;
}


/// TranspositionTable::store() writes a new entry containing position key and
/// valuable information of current position. The lowest order bits of position
/// key are used to decide on which cluster the position will be placed.
Expand All @@ -85,38 +101,21 @@ void TranspositionTable::store(const Key key, Value v, Bound t, Depth d, Move m,
{
if (!tte->key() || tte->key() == key32) // Empty or overwrite old
{
// Preserve any existing ttMove
if (m == MOVE_NONE)
m = tte->move();
if (!m)
m = tte->move(); // Preserve any existing ttMove

tte->save(key32, v, t, d, m, generation, statV, kingD);
return;
replace = tte;
break;
}

// Implement replace strategy
c1 = (replace->generation() == generation ? 2 : 0);
c2 = (tte->generation() == generation || tte->type() == BOUND_EXACT ? -2 : 0);
c2 = (tte->generation() == generation || tte->bound() == BOUND_EXACT ? -2 : 0);
c3 = (tte->depth() < replace->depth() ? 1 : 0);

if (c1 + c2 + c3 > 0)
replace = tte;
}
replace->save(key32, v, t, d, m, generation, statV, kingD);
}


/// TranspositionTable::probe() looks up the current position in the
/// transposition table. Returns a pointer to the TTEntry or NULL if
/// position is not found.

TTEntry* TranspositionTable::probe(const Key key) const {

TTEntry* tte = first_entry(key);
uint32_t key32 = key >> 32;

for (unsigned i = 0; i < ClusterSize; i++, tte++)
if (tte->key() == key32)
return tte;

return NULL;
replace->save(key32, v, t, d, m, generation, statV, kingD);
}
15 changes: 7 additions & 8 deletions src/tt.h
View file
Expand Up @@ -34,35 +34,34 @@
/// static value: 16 bit
/// static margin: 16 bit

class TTEntry {
struct TTEntry {

public:
void save(uint32_t k, Value v, Bound b, Depth d, Move m, int g, Value ev, Value em) {

key32 = (uint32_t)k;
move16 = (uint16_t)m;
bound = (uint8_t)b;
bound8 = (uint8_t)b;
generation8 = (uint8_t)g;
value16 = (int16_t)v;
depth16 = (int16_t)d;
evalValue = (int16_t)ev;
evalMargin = (int16_t)em;
}
void set_generation(int g) { generation8 = (uint8_t)g; }
void set_generation(uint8_t g) { generation8 = g; }

uint32_t key() const { return key32; }
Depth depth() const { return (Depth)depth16; }
Move move() const { return (Move)move16; }
Value value() const { return (Value)value16; }
Bound type() const { return (Bound)bound; }
Bound bound() const { return (Bound)bound8; }
int generation() const { return (int)generation8; }
Value eval_value() const { return (Value)evalValue; }
Value eval_margin() const { return (Value)evalMargin; }

private:
uint32_t key32;
uint16_t move16;
uint8_t bound, generation8;
uint8_t bound8, generation8;
int16_t value16, depth16, evalValue, evalMargin;
};

Expand All @@ -81,7 +80,7 @@ class TranspositionTable {
~TranspositionTable() { free(mem); }
void new_search() { generation++; }

TTEntry* probe(const Key key) const;
const TTEntry* probe(const Key key) const;
TTEntry* first_entry(const Key key) const;
void refresh(const TTEntry* tte) const;
void set_size(size_t mbSize);
Expand All @@ -92,7 +91,7 @@ class TranspositionTable {
uint32_t hashMask;
TTEntry* table;
void* mem;
uint8_t generation; // Size must be not bigger then TTEntry::generation8
uint8_t generation; // Size must be not bigger than TTEntry::generation8
};

extern TranspositionTable TT;
Expand Down

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