From a0970bddbd9f6b97b6a12ba7f73fd1810a2e1e1b Mon Sep 17 00:00:00 2001
From: Aargh Rai <aargh.rai+git@gmail.com>
Date: Sun, 19 Jul 2026 17:52:26 +0530
Subject: ttable lookup & probe

---
 include/engine/transposition_table.h | 16 --------------
 include/engine/ttable.h              | 43 ++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 16 deletions(-)
 delete mode 100644 include/engine/transposition_table.h
 create mode 100644 include/engine/ttable.h

(limited to 'include/engine')

diff --git a/include/engine/transposition_table.h b/include/engine/transposition_table.h
deleted file mode 100644
index f06ddbe..0000000
--- a/include/engine/transposition_table.h
+++ /dev/null
@@ -1,16 +0,0 @@
-#ifndef TRANSPOSITION_TABLE_H
-#define TRANSPOSITION_TABLE_H
-
-#include "bitboard.h"
-
-static struct zobrist_keys {
-  u64 piece[PIECE_TYPE_COUNT][64];
-  u64 castle[CASTLE_COUNT];
-  u64 turn[TURN_COUNT];
-  u64 en_passant[64];
-} zobrist_keys;
-
-void transposition_table_init();
-u64 zobrist_hash(position_t position);
-
-#endif // TRANSPOSITION_TABLE_H
diff --git a/include/engine/ttable.h b/include/engine/ttable.h
new file mode 100644
index 0000000..2ee1a5c
--- /dev/null
+++ b/include/engine/ttable.h
@@ -0,0 +1,43 @@
+#ifndef TTABLE_H
+#define TTABLE_H
+
+#include "bitboard.h"
+
+#define TABLE_BITS 24
+#define TABLE_SIZE (1ULL << TABLE_BITS)
+#define MASK (TABLE_SIZE - 1)
+#define TT_BUCKET_SIZE 4
+
+static struct zobrist_keys {
+  u64 piece[PIECE_TYPE_COUNT][64];
+  u64 castle[CASTLE_COUNT];
+  u64 turn[TURN_COUNT];
+  u64 en_passant[64];
+} zobrist_keys;
+
+enum { TT_EXACT, TT_LOWERBOUND, TT_UPPERBOUND };
+typedef struct {
+  atomic_uint_fast64_t key;
+  move_t best_move;
+  i16 score; // depth analysed
+  i16 eval; // non-depth analysed
+  u16 depth;
+  u16 generation;
+  u8 flag;
+} tentry_t;
+
+typedef struct {
+  tentry_t entries[TT_BUCKET_SIZE];
+} tbucket_t;
+
+typedef tbucket_t* ttable_t;
+
+void ttable_init();
+u64 zobrist_hash(position_t position);
+void ttable_store(
+  ttable_t *ttable, u64 key, move_t move, i16 score,
+  i16 eval, u16 depth, u16 generation, u8 flag
+);
+tentry_t *ttable_probe(ttable_t *table, u64 key);
+
+#endif // TTABLE_H
-- 
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