MmioPatterns optimisation

arithmetization/src/main/java/net/consensys/linea/zktracer/module/mmio/MmioPatterns.java

@@ -182,17 +182,6 @@ public static Bytes16 excision(
 
   public static void updateTemporaryTargetRam(
       MmuData mmuData, final long targetLimbOffsetToUpdate, final Bytes16 newLimb) {
-    final Bytes bytesPreLimb =
-        Bytes.repeat(
-            (byte) 0,
-            (int)
-                (LLARGE
-                    * targetLimbOffsetToUpdate)); // We won't access the preLimb again, so we don't
-    // care
-    // of its value
-    final Bytes bytesPostLimb =
-        mmuData.targetRamBytes().slice((int) ((targetLimbOffsetToUpdate + 1) * LLARGE));
-
-    mmuData.targetRamBytes(Bytes.concatenate(bytesPreLimb, newLimb, bytesPostLimb));
+    mmuData.targetRamBytes().set((int) targetLimbOffsetToUpdate, newLimb);
   }
 }

arithmetization/src/main/java/net/consensys/linea/zktracer/module/mmu/MmuData.java

@@ -37,6 +37,7 @@
 import net.consensys.linea.zktracer.module.mmu.values.MmuToMmioInstruction;
 import net.consensys.linea.zktracer.module.mmu.values.MmuWcpCallRecord;
 import org.apache.tuweni.bytes.Bytes;
+import org.apache.tuweni.bytes.MutableBytes;
 
 @AllArgsConstructor
 @Getter
@@ -56,7 +57,7 @@ public class MmuData {
   private boolean mmuInstAnyToRamWithPaddingIsPurePadding;
   private Bytes exoBytes;
   private Bytes sourceRamBytes;
-  private Bytes targetRamBytes;
+  private MutableBytes targetRamBytes;
   private final boolean exoLimbIsSource;
   private final boolean exoLimbIsTarget;
   private static final List<Integer> MMU_INST_EXO_IS_SOURCE =
@@ -83,7 +84,7 @@ public MmuData(final MmuCall mmuCall) {
         false,
         Bytes.EMPTY,
         Bytes.EMPTY,
-        Bytes.EMPTY,
+        MutableBytes.EMPTY,
         MMU_INST_EXO_IS_SOURCE.contains(mmuCall.instruction()),
         MMU_INST_EXO_IS_TARGET.contains(mmuCall.instruction()));
 
@@ -112,7 +113,7 @@ public void setSourceRamBytes() {
 
   public void setTargetRamBytes() {
     if (mmuCall.targetRamBytes().isPresent()) {
-      targetRamBytes(mmuCall.targetRamBytes().get());
+      targetRamBytes(mmuCall.targetRamBytes().get().mutableCopy());
     }
   }
 

arithmetization/src/main/java/net/consensys/linea/zktracer/module/mmu/instructions/ExoToRamTransplants.java

@@ -32,6 +32,7 @@
 import net.consensys.linea.zktracer.module.mmu.values.MmuToMmioInstruction;
 import net.consensys.linea.zktracer.module.mmu.values.MmuWcpCallRecord;
 import org.apache.tuweni.bytes.Bytes;
+import org.apache.tuweni.bytes.MutableBytes;
 
 public class ExoToRamTransplants implements MmuInstruction {
   private final Euc euc;
@@ -89,7 +90,7 @@ public MmuData setMicroInstructions(MmuData mmuData) {
     // Setting the target ram bytes
     // The target CN is ALWAYS a new, virgin, fictitious context, where is either write the call
     // data, or the result of a precompile
-    mmuData.targetRamBytes(Bytes.EMPTY);
+    mmuData.targetRamBytes(MutableBytes.EMPTY);
 
     // setting the MMIO instructions
     for (int i = 0; i < mmuData.totalNonTrivialInitials(); i++) {