Optimised square mirroring and reverted move ordering behaviour

konsolas · konsolas · commit 38ec0b343fe7 · 2021-08-15T11:27:03.000+01:00
diff --git a/board.cpp b/board.cpp
@@ -562,7 +562,7 @@ void board_t::mirror() {
     // Mirror en-passant
     if (record.back().ep_square != 0) {
         record.back().hash ^= zobrist::ep[record.back().ep_square];
-        record.back().ep_square = MIRROR_TABLE[record.back().ep_square];
+        record.back().ep_square = rel_sq(BLACK, record.back().ep_square);
         record.back().hash ^= zobrist::ep[record.back().ep_square];
     }
 
@@ -585,7 +585,7 @@ void board_t::mirror() {
         if(old_data[sq].occupied()) switch_piece<true>(old_data[sq].team(), old_data[sq].piece(), sq);
     }
     for (uint8_t sq = 0; sq < 64; sq++) {
-        if(old_data[sq].occupied()) switch_piece<true>(Team(!old_data[sq].team()), old_data[sq].piece(), MIRROR_TABLE[sq]);
+        if(old_data[sq].occupied()) switch_piece<true>(Team(!old_data[sq].team()), old_data[sq].piece(), rel_sq(BLACK, sq));
     }
 }
 
diff --git a/eval.cpp b/eval.cpp
@@ -81,7 +81,7 @@ processed_params_t::processed_params_t(const eval_params_t &params)
     // Mirror PST for black
     for (int piece = 0; piece < 6; piece++) {
         for (int square = 0; square < 64; square++) {
-            pst[BLACK][piece][MIRROR_TABLE[square]] = pst[WHITE][piece][square];
+            pst[BLACK][piece][rel_sq(BLACK, square)] = pst[WHITE][piece][square];
         }
     }
 
diff --git a/movesort.cpp b/movesort.cpp
@@ -10,6 +10,18 @@ movesort_t::movesort_t(GenMode mode,  const heuristic_set_t &heuristics, const b
     killer_1 = heur.killers.primary(ply);
     killer_2 = heur.killers.secondary(ply);
     killer_3 = ply > 2 ? heur.killers.primary(ply - 2) : EMPTY_MOVE;
+
+    if(killer_1 == hash_move) {
+        killer_1 = EMPTY_MOVE;
+    }
+
+    if(killer_2 == killer_1 || killer_2 == hash_move) {
+        killer_2 = EMPTY_MOVE;
+    }
+
+    if(killer_3 == killer_2 || killer_3 == killer_1 || killer_3 == hash_move) {
+        killer_3 = EMPTY_MOVE;
+    }
 }
 
 // Pray that the compiler optimises tail recursion here - this is a very hot method
@@ -61,9 +73,7 @@ move_t movesort_t::next(GenStage &stage, int &score, bool skip_quiets) {
 
                 // Score quiets
                 for (int i = 0; i < main_buf_size; i++) {
-                    if (main_buf[i] == hash_move) {
-                        main_scores[i] = -1000000000;
-                    } else if (main_buf[i] == killer_1) {
+                    if (main_buf[i] == killer_1) {
                         main_scores[i] = 1000000003;
                     } else if (main_buf[i] == killer_2) {
                         main_scores[i] = 1000000002;
diff --git a/types.h b/types.h
@@ -63,17 +63,6 @@ enum Square {
     A8, B8, C8, D8, E8, F8, G8, H8,
 };
 
-constexpr uint8_t MIRROR_TABLE[64] = {
-        56, 57, 58, 59, 60, 61, 62, 63,
-        48, 49, 50, 51, 52, 53, 54, 55,
-        40, 41, 42, 43, 44, 45, 46, 47,
-        32, 33, 34, 35, 36, 37, 38, 39,
-        24, 25, 26, 27, 28, 29, 30, 31,
-        16, 17, 18, 19, 20, 21, 22, 23,
-        8, 9, 10, 11, 12, 13, 14, 15,
-        0, 1, 2, 3, 4, 5, 6, 7
-};
-
 enum Direction {
     D_SW = -9, D_S = -8, D_SE = -7, D_W = -1, D_X = 0, D_E = 1, D_NW = 7, D_N = 8, D_NE = 9
 };
@@ -83,7 +72,7 @@ constexpr Direction rel_offset(Team side, Direction dir) {
 }
 
 constexpr uint8_t rel_sq(Team side, uint8_t square) {
-    return side ? MIRROR_TABLE[square] : square;
+    return side ? square ^ 56 : square;
 }
 
 constexpr uint8_t rel_rank(Team side, uint8_t rank) {

Original file line number	Diff line number	Diff line change
`@@ -562,7 +562,7 @@ void board_t::mirror() {`
`562`	`562`	`// Mirror en-passant`
`563`	`563`	`if (record.back().ep_square != 0) {`
`564`	`564`	`record.back().hash ^= zobrist::ep[record.back().ep_square];`
`565`		`- record.back().ep_square = MIRROR_TABLE[record.back().ep_square];`
	`565`	`+ record.back().ep_square = rel_sq(BLACK, record.back().ep_square);`
`566`	`566`	`record.back().hash ^= zobrist::ep[record.back().ep_square];`
`567`	`567`	`}`
`568`	`568`
`@@ -585,7 +585,7 @@ void board_t::mirror() {`
`585`	`585`	`if(old_data[sq].occupied()) switch_piece<true>(old_data[sq].team(), old_data[sq].piece(), sq);`
`586`	`586`	`}`
`587`	`587`	`for (uint8_t sq = 0; sq < 64; sq++) {`
`588`		`- if(old_data[sq].occupied()) switch_piece<true>(Team(!old_data[sq].team()), old_data[sq].piece(), MIRROR_TABLE[sq]);`
	`588`	`+ if(old_data[sq].occupied()) switch_piece<true>(Team(!old_data[sq].team()), old_data[sq].piece(), rel_sq(BLACK, sq));`
`589`	`589`	`}`
`590`	`590`	`}`
`591`	`591`
Original file line number	Diff line number	Diff line change
`@@ -81,7 +81,7 @@ processed_params_t::processed_params_t(const eval_params_t &params)`
`81`	`81`	`// Mirror PST for black`
`82`	`82`	`for (int piece = 0; piece < 6; piece++) {`
`83`	`83`	`for (int square = 0; square < 64; square++) {`
`84`		`- pst[BLACK][piece][MIRROR_TABLE[square]] = pst[WHITE][piece][square];`
	`84`	`+ pst[BLACK][piece][rel_sq(BLACK, square)] = pst[WHITE][piece][square];`
`85`	`85`	`}`
`86`	`86`	`}`
`87`	`87`