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Fix an off-by-one bug in extract_pv()

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In case we reach ply == PLY_MAX we exit the function
writing

pv[PLY_MAX] = MOVE_NONE;

And because SearchStack is defined as:

struct SearchStack {
  Move pv[PLY_MAX];
  Move currentMove;
  .....

We end up with the unwanted assignment

SearchStack.currentMove = MOVE_NONE;

Fortunatly this is harmless because currentMove is not used where
extarct_pv() is called. But neverthless this is a bug that
needs to be fixed.

Thanks to Uri Blass for spotting out this.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2009-10-09 10:04:55 +01:00
parent d892063cd3
commit 06a5b602dc
3 changed files with 4 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
src/search.h
View File

@@ -48,7 +48,7 @@ const int KILLER_MAX = 2;
/// current ply. /// current ply.
struct SearchStack { struct SearchStack {
Move pv[PLY_MAX]; Move pv[PLY_MAX_PLUS_2];
Move currentMove; Move currentMove;
Move mateKiller; Move mateKiller;
Move threatMove; Move threatMove;

4
src/tt.cpp
View File

@@ -220,7 +220,7 @@ void TranspositionTable::insert_pv(const Position& pos, Move pv[]) {
/// will often get single-move PVs when the search stops while failing high, /// will often get single-move PVs when the search stops while failing high,
/// and a single-move PV means that we don't have a ponder move. /// and a single-move PV means that we don't have a ponder move.
void TranspositionTable::extract_pv(const Position& pos, Move pv[], int pvSize) { void TranspositionTable::extract_pv(const Position& pos, Move pv[], const int PLY_MAX) {
const TTEntry* tte; const TTEntry* tte;
StateInfo st; StateInfo st;
@@ -236,7 +236,7 @@ void TranspositionTable::extract_pv(const Position& pos, Move pv[], int pvSize)
&& tte->move() != MOVE_NONE && tte->move() != MOVE_NONE
&& move_is_legal(p, tte->move()) && move_is_legal(p, tte->move())
&& (!p.is_draw() || ply < 2) && (!p.is_draw() || ply < 2)
&& ply < pvSize) && ply < PLY_MAX)
{ {
pv[ply] = tte->move(); pv[ply] = tte->move();
p.do_move(pv[ply++], st); p.do_move(pv[ply++], st);

2
src/tt.h
View File

@@ -102,7 +102,7 @@ public:
void prefetch(const Key posKey) const; void prefetch(const Key posKey) const;
void new_search(); void new_search();
void insert_pv(const Position& pos, Move pv[]); void insert_pv(const Position& pos, Move pv[]);
void extract_pv(const Position& pos, Move pv[], int pvSize); void extract_pv(const Position& pos, Move pv[], const int PLY_MAX);
int full() const; int full() const;
private: private: