Fix UB (#155)

Passes Nonregr
```
Elo   | 0.02 +- 1.23 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=32MB
LLR   | 2.95 (-2.94, 2.94) [-3.00, 1.00]
Games | N: 85856 W: 19311 L: 19306 D: 47239
Penta | [471, 10150, 21668, 10181, 458]
```
https://furybench.com/test/1180/

bench: 8916225

Author: Vast342

src/eval.h

@@ -61,17 +61,22 @@ constexpr std::array<int, 64> inputBuckets = []{
 }();
 
 // organizing this somewhat similarly to code I've seen, mostly from clarity_sp_nnue, made by Ciekce.
-
-struct Network {
-    alignas(64) std::array<std::int16_t, inputSize * inputBucketCount * layer1Size> featureWeights;
-    alignas(64) std::array<std::int16_t, layer1Size> featureBiases;
-    alignas(64) std::array<std::int16_t, layer1Size * 2 * outputBucketCount> outputWeights;
-    alignas(64) std::array<std::int16_t, outputBucketCount> outputBiases;
+#if defined(__AVX512F__) && defined(__AVX512BW__)
+constexpr int alignmentAmount = 64;
+#else 
+constexpr int alignmentAmount = 32;
+#endif
+
+struct alignas(alignmentAmount) Network {
+    std::array<std::int16_t, inputSize * inputBucketCount * layer1Size> featureWeights;
+    std::array<std::int16_t, layer1Size> featureBiases;
+    std::array<std::int16_t, layer1Size * 2 * outputBucketCount> outputWeights;
+    std::array<std::int16_t, outputBucketCount> outputBiases;
 };
 
 struct Accumulator {
-    alignas(64) std::array<std::int16_t, layer1Size> black;
-    alignas(64) std::array<std::int16_t, layer1Size> white;
+    alignas(alignmentAmount) std::array<std::int16_t, layer1Size> black;
+    alignas(alignmentAmount) std::array<std::int16_t, layer1Size> white;
     void initialize(std::span<const std::int16_t, layer1Size> bias);
     void initHalf(std::span<const std::int16_t, layer1Size> bias, int color);
 };
@@ -132,4 +137,4 @@ constexpr bool refreshRequired(int color, int oldKingSquare, int newKingSquare)
     }
 
     return inputBuckets[oldKingSquare] != inputBuckets[newKingSquare];
-}
+}

src/globals.cpp

@@ -77,7 +77,11 @@ std::array<std::array<uint8_t, 218>, 150> reductions;
 void calculateReductions() {
     for(int depth = 0; depth < 150; depth++) {
         for(int move = 0; move < 218; move++) {
-            reductions[depth][move] = uint8_t(std::clamp(lmrBase.value + log(depth) * log(move) * lmrMultiplier.value, -32678.0, 32678.0));
+            if (depth == 0 || move == 0) {
+                reductions[depth][move] = 0;
+                continue;
+            }
+            reductions[depth][move] = uint8_t(lmrBase.value + log(depth) * log(move) * lmrMultiplier.value);
         }
     }
 }
@@ -144,14 +148,3 @@ void sortMoves(std::array<int, 256> &values, std::array<Move, 256> &moves, int n
 int flipIndex(int index) {
     return index ^ 56;
 }
-
-// thanks z5
-// also I completely misunderstood how this was supposed to work, this isn't it lol
-void incrementalSort(std::array<int, 256> &values, std::array<Move, 256> &moves, int numMoves, int i) {
-    for(int j = i + 1; j < numMoves; j++) {
-        if(values[j] > values[i]) {
-            std::swap(values[j], values[i]);
-            std::swap(moves[j], moves[i]);
-        }
-    }
-}

src/movegen.cpp

@@ -37,9 +37,9 @@ uint64_t getBishopAttacksOld(int square, uint64_t occupiedBitboard) {
 	for(int direction = 4; direction < 8; direction++) {
 		uint64_t currentAttack = slideyPieceRays[direction][square];
 		if((direction & 1) == 0) {
-			currentAttack ^= slideyPieceRays[direction][std::countr_zero(currentAttack & occupiedBitboard)];
+			currentAttack ^= slideyPieceRays[direction][std::clamp(std::countr_zero(currentAttack & occupiedBitboard), 0, 63)];
 		} else {
-			currentAttack ^= slideyPieceRays[direction][63 - std::countl_zero(currentAttack & occupiedBitboard)];
+			currentAttack ^= slideyPieceRays[direction][std::clamp(63 - std::countl_zero(currentAttack & occupiedBitboard), 0, 63)];
 		}
 		attacks |= currentAttack;
     }

src/search.cpp

@@ -494,7 +494,7 @@ int16_t Engine::negamax(Board &board, int depth, int alpha, int beta, int16_t pl
         improving = true;
     }
     bool opponent_worsening = false;
-    if(!inCheck) {
+    if(!inCheck && ply > 0) {
         opponent_worsening = stack[ply].staticEval + stack[ply - 1].staticEval > 1;
     }
 
@@ -515,7 +515,7 @@ int16_t Engine::negamax(Board &board, int depth, int alpha, int beta, int16_t pl
         }
     }
 
-    if(!isPV && !inCheck && stack[ply - 1].reduction >= 3 && !opponent_worsening) {
+    if(!isPV && !inCheck && ply > 0 && stack[ply - 1].reduction >= 3 && !opponent_worsening) {
         ++depth;
     }
 

src/uci.cpp

@@ -23,6 +23,7 @@
 #include "external/fathom/tbprobe.h"
 #include "uci.h"
 #include "tunables.h"
+#include "eval.h"
 
 bool useSyzygy = false;