-16 bytes (#241)

kz04px · Oct 29, 2023 · 48d76f2 · 48d76f2
1 parent 7909bac
commit 48d76f2
Show file tree

Hide file tree

Showing 2 changed files with 31 additions and 21 deletions.
diff --git a/README.md b/README.md
@@ -28,7 +28,7 @@ bash build-mini.sh
 
 ## 4ku-mini Size
 ```
-3,946 bytes
+3,930 bytes
 ```
 
 ---

diff --git a/src/main.cpp b/src/main.cpp
@@ -356,25 +356,35 @@ void generate_piece_moves(Move *const movelist,
 const i32 phases[] = {0, 1, 1, 2, 4, 0};
 const i32 max_material[] = {139, 449, 452, 841, 1674, 0, 0};
 const i32 material[] = {S(100, 139), S(329, 449), S(341, 452), S(455, 841), S(825, 1674), 0};
-const i32 pst_rank[][8] = {
-    {0, S(-2, 0), S(-3, -1), S(-1, -1), S(1, 0), S(5, 2), 0, 0},
-    {S(-4, -5), S(-2, -3), S(-1, -1), S(1, 3), S(3, 4), S(7, 1), S(5, 0), S(-11, 1)},
-    {S(-2, -2), S(1, -2), S(1, 0), S(1, 0), S(2, 1), S(4, 0), S(1, 0), S(-8, 2)},
-    {S(-2, -4), S(-2, -4), S(-3, -2), S(-4, 1), S(-1, 2), S(3, 2), S(3, 3), S(6, 1)},
-    {S(1, -13), S(1, -10), S(0, -5), S(-1, 1), S(-1, 6), S(1, 5), S(-2, 9), S(1, 7)},
-    {S(0, -6), S(0, -2), S(-2, 0), S(-4, 3), S(-1, 4), S(5, 4), S(3, 3), S(4, -4)},
+const i32 pst_rank[] = {
+    0,         S(-2, 0),  S(-3, -1), S(-1, -1), S(1, 0),  S(5, 2), 0,        0,          // Pawn
+    S(-4, -5), S(-2, -3), S(-1, -1), S(1, 3),   S(3, 4),  S(7, 1), S(5, 0),  S(-11, 1),  // Knight
+    S(-2, -2), S(1, -2),  S(1, 0),   S(1, 0),   S(2, 1),  S(4, 0), S(1, 0),  S(-8, 2),   // Bishop
+    S(-2, -4), S(-2, -4), S(-3, -2), S(-4, 1),  S(-1, 2), S(3, 2), S(3, 3),  S(6, 1),    // Rook
+    S(1, -13), S(1, -10), S(0, -5),  S(-1, 1),  S(-1, 6), S(1, 5), S(-2, 9), S(1, 7),    // Queen
+    S(0, -6),  S(0, -2),  S(-2, 0),  S(-4, 3),  S(-1, 4), S(5, 4), S(3, 3),  S(4, -4)    // King
 };
-const i32 pst_file[][8] = {
-    {S(-2, 1), S(-1, 1), S(-1, 0), S(0, -1), S(1, 0), S(2, 0), S(2, 0), S(-1, -1)},
-    {S(-4, -3), S(-2, -1), S(0, 1), S(2, 3), S(2, 2), S(2, 0), S(1, -1), S(-1, -3)},
-    {S(-2, 0), 0, S(1, 0), S(0, 1), S(0, 1), S(-1, 1), S(2, -1), S(0, -1)},
-    {S(-2, 0), S(-2, 1), S(-1, 1), S(1, 0), S(1, -1), S(1, 0), S(2, 0), S(-1, -1)},
-    {S(-3, -4), S(-2, -2), S(-1, 0), S(0, 1), S(0, 2), S(1, 3), S(2, 1), S(3, -1)},
-    {S(-2, -5), S(2, -1), S(-2, 1), S(-3, 2), S(-4, 2), S(-1, 1), S(2, -1), S(0, -5)},
+const i32 pst_file[] = {
+    S(-2, 1),  S(-1, 1),  S(-1, 0), S(0, -1), S(1, 0),  S(2, 0),  S(2, 0),  S(-1, -1),  // Pawn
+    S(-4, -3), S(-2, -1), S(0, 1),  S(2, 3),  S(2, 2),  S(2, 0),  S(1, -1), S(-1, -3),  // Knight
+    S(-2, 0),  0,         S(1, 0),  S(0, 1),  S(0, 1),  S(-1, 1), S(2, -1), S(0, -1),   // Bishop
+    S(-2, 0),  S(-2, 1),  S(-1, 1), S(1, 0),  S(1, -1), S(1, 0),  S(2, 0),  S(-1, -1),  // Rook
+    S(-3, -4), S(-2, -2), S(-1, 0), S(0, 1),  S(0, 2),  S(1, 3),  S(2, 1),  S(3, -1),   // Queen
+    S(-2, -5), S(2, -1),  S(-2, 1), S(-3, 2), S(-4, 2), S(-1, 1), S(2, -1), S(0, -5)    // King
 };
-const i32 open_files[][5] = {
-    {S(3, 4), S(-4, 20), S(20, 16), S(3, 19), S(-23, 10)},
-    {S(-3, -12), S(-11, 0), S(47, 0), S(-13, 35), S(-63, 1)},
+const i32 open_files[] = {
+    // Semi open files
+    S(3, 4),
+    S(-4, 20),
+    S(20, 16),
+    S(3, 19),
+    S(-23, 10),
+    // Open files
+    S(-3, -12),
+    S(-11, 0),
+    S(47, 0),
+    S(-13, 35),
+    S(-63, 1),
 };
 const i32 mobilities[] = {S(9, 5), S(8, 7), S(4, 4), S(4, 3), S(-5, -1)};
 const i32 pawn_protection[] = {S(24, 14), S(2, 16), S(8, 17), S(9, 8), S(-5, 23), S(-34, 26)};
@@ -425,8 +435,8 @@ const i32 pawn_attacked_penalty[] = {S(64, 14), S(155, 142)};
                 const i32 file = sq % 8;
 
                 // Split quantized PSTs
-                score += pst_rank[p][rank] * 8;
-                score += pst_file[p][file] * 8;
+                score += pst_rank[p * 8 + rank] * 8;
+                score += pst_file[p * 8 + file] * 8;
 
                 // Pawn protection
                 const u64 piece_bb = 1ULL << sq;
@@ -480,7 +490,7 @@ const i32 pawn_attacked_penalty[] = {S(64, 14), S(155, 142)};
                     // Open or semi-open files
                     const u64 file_bb = 0x101010101010101ULL << file;
                     if (!(file_bb & pawns[0]))
-                        score += open_files[!(file_bb & pawns[1])][p - 1];
+                        score += open_files[!(file_bb & pawns[1]) * 5 + p - 1];
 
                     if (p == King && piece_bb & 0xC3D7) {
                         // C3D7 = Reasonable king squares