1 files changed, 16 insertions, 6 deletions
diff --git a/include/tt.c b/include/tt.c
index b1f583e..8ad6c56 100644
--- a/include/tt.c
+++ b/include/tt.c
@@ -43,18 +43,28 @@ tt_entry_t *tt_seek(const uint64_t key) {
   return NULL;
 }
 
-int tt_insert(const uint64_t key, const enum TT_FLAG flag,
-              const uint8_t depth, const float value,
-              const action_t action) {
+tt_entry_t *tt_store(const uint64_t key, const enum TT_FLAG flag,
+                     const uint8_t depth, const float value,
+                     const action_t action) {
   tt_entry_t *e = &table[key & TT_SIZE];
-  // Replacement scheme: keep a stale-but-deeper entry over a shallower new one.
+  if (e->gen == tt_gen && e->key == key) {
+    // The slot holds this very position: update it (gen and key are already
+    // correct).
+    e->flag = flag;
+    e->value = value;
+    e->depth = depth;
+    e->action = action;
+    return e;
+  }
+  // Empty slot, stale generation, or a different position: keep a deeper search
+  // of a foreign position over this shallower one.
   if (e->gen == tt_gen && e->depth > depth)
-    return EXIT_SUCCESS;
+    return NULL;
   e->key = key;
   e->value = value;
   e->action = action;
   e->gen = tt_gen;
   e->flag = flag;
   e->depth = depth;
-  return EXIT_SUCCESS;
+  return e;
 }