TTEntry Struct Reference

16-byte Transposition Table entry for search results. More...

#include <TT.h>

Public Member Functions
bool	probe (uint64_t key, uint64_t &out_data) const
	Probes the entry to safely retrieve data if the key matches.
void	save (uint64_t key, int16_t score, int16_t sEval, uint8_t depth, Bound bound, uint16_t move, uint8_t age)
	Atomically stores search data into the entry.

Static Public Member Functions
static uint16_t	getMove (uint64_t d)
static int16_t	getScore (uint64_t d)
static int16_t	getStaticEval (uint64_t d)
static uint8_t	getDepth (uint64_t d)
static Bound	getBound (uint64_t d)
static uint8_t	getAge (uint64_t d)

Public Attributes
uint64_t	data
	Packed search data.
uint64_t	signature
	Checksum signature (Key ^ Data).

Detailed Description

16-byte Transposition Table entry for search results.

Uses a lockless XOR signature approach to detect data tearing during concurrent reads and writes. Layout: [Move:16][Score:16][StaticEval:16][Depth:8][Bound:3][Age:5] = 64 bits.

Member Function Documentation

getAge()

uint8_t TTEntry::getAge ( uint64_t d )

inlinestatic

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getBound()

Bound TTEntry::getBound ( uint64_t d )

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getDepth()

uint8_t TTEntry::getDepth ( uint64_t d )

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getMove()

uint16_t TTEntry::getMove ( uint64_t d )

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getScore()

int16_t TTEntry::getScore ( uint64_t d )

inlinestatic

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getStaticEval()

int16_t TTEntry::getStaticEval ( uint64_t d )

inlinestatic

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probe()

bool TTEntry::probe ( uint64_t key, uint64_t & out_data ) const

inline

Probes the entry to safely retrieve data if the key matches.

Parameters

key	The 64-bit Zobrist key of the position.
out_data	Output parameter for the packed data if successful.

Returns

True if the entry belongs to the key and is not torn.

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save()

void TTEntry::save ( uint64_t key, int16_t score, int16_t sEval, uint8_t depth, Bound bound, uint16_t move, uint8_t age )

inline

Atomically stores search data into the entry.

Parameters

key	64-bit Zobrist key.
score	Minimax score.
sEval	Static evaluation score.
depth	Remaining search depth.
bound	Score bound type.
move	Best move found.
age	Search generation age.

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Member Data Documentation

data

uint64_t TTEntry::data

Packed search data.

signature

uint64_t TTEntry::signature

Checksum signature (Key ^ Data).

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The documentation for this struct was generated from the following file:

• engine/src/search/TT.h