-/// A TTEntry needs 128 bits to be stored
-///
-/// bit 0-31: key
-/// bit 32-63: data
-/// bit 64-79: value
-/// bit 80-95: depth
-/// bit 96-111: static value
-/// bit 112-127: margin of static value
-///
-/// the 32 bits of the data field are so defined
-///
-/// bit 0-15: move
-/// bit 16-20: not used
-/// bit 21-22: value type
-/// bit 23-31: generation
-
-class TTEntry {
-
-public:
- void save(uint32_t k, Value v, Bound b, Depth d, Move m, int g) {
-
- key32 = (uint32_t)k;
- move16 = (uint16_t)m;
- bound = (uint8_t)b;
- generation8 = (uint8_t)g;
- valueUpper = (int16_t)(b & BOUND_UPPER ? v : VALUE_NONE);
- depthUpper = (int16_t)(b & BOUND_UPPER ? d : DEPTH_NONE);
- valueLower = (int16_t)(b & BOUND_LOWER ? v : VALUE_NONE);
- depthLower = (int16_t)(b & BOUND_LOWER ? d : DEPTH_NONE);
- }
-
- void update(Value v, Bound b, Depth d, Move m, int g) {
-
- move16 = (uint16_t)m;
- generation8 = (uint8_t)g;
-
- if (bound == BOUND_EXACT)
- bound = BOUND_UPPER | BOUND_LOWER; // Drop 'EXACT' flag
-
- if (b & BOUND_UPPER)
- {
- valueUpper = (int16_t)v;
- depthUpper = (int16_t)d;
-
- if ((bound & BOUND_LOWER) && v < valueLower)
- {
- bound ^= BOUND_LOWER;
- valueLower = VALUE_NONE;
- depthLower = DEPTH_NONE;
- }
- }
-
- if (b & BOUND_LOWER)
+/// key 16 bit
+/// move 16 bit
+/// value 16 bit
+/// eval value 16 bit
+/// generation 6 bit
+/// bound type 2 bit
+/// depth 8 bit
+
+struct TTEntry {
+
+ Move move() const { return (Move )move16; }
+ Value value() const { return (Value)value16; }
+ Value eval() const { return (Value)eval16; }
+ Depth depth() const { return (Depth)(depth8 * int(ONE_PLY)); }
+ Bound bound() const { return (Bound)(genBound8 & 0x3); }
+
+ void save(Key k, Value v, Bound b, Depth d, Move m, Value ev, uint8_t g) {
+
+ assert(d / ONE_PLY * ONE_PLY == d);
+
+ // Preserve any existing move for the same position
+ if (m || (k >> 48) != key16)
+ move16 = (uint16_t)m;
+
+ // Don't overwrite more valuable entries
+ if ( (k >> 48) != key16
+ || d / ONE_PLY > depth8 - 4
+ /* || g != (genBound8 & 0xFC) // Matching non-zero keys are already refreshed by probe() */
+ || b == BOUND_EXACT)