Implementation of PUSH0 (#4660)

Initial implementation of  PUSH0

Signed-off-by: lukelee-sl <luke.lee@swirldslabs.com>
Signed-off-by: Danno Ferrin <danno.ferrin@swirldslabs.com>

ethereum/core/src/test/java/org/hyperledger/besu/ethereum/vm/operations/Push0OperationTest.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright contributors to Hyperledger Besu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package org.hyperledger.besu.ethereum.vm.operations;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.hyperledger.besu.evm.Code.EMPTY_CODE;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import org.hyperledger.besu.datatypes.Wei;
+import org.hyperledger.besu.ethereum.core.BlockHeader;
+import org.hyperledger.besu.evm.frame.MessageFrame;
+import org.hyperledger.besu.evm.gascalculator.BerlinGasCalculator;
+import org.hyperledger.besu.evm.gascalculator.GasCalculator;
+import org.hyperledger.besu.evm.operation.Operation;
+import org.hyperledger.besu.evm.operation.Operation.OperationResult;
+import org.hyperledger.besu.evm.operation.Push0Operation;
+
+import java.util.Optional;
+
+import org.apache.tuweni.bytes.Bytes;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+public class Push0OperationTest {
+
+  private final GasCalculator gasCalculator = new BerlinGasCalculator();
+
+  @Test
+  public void shouldPush0OntoStack() {
+    final MessageFrame frame = createMessageFrame(100, Optional.of(Wei.of(5L)));
+    final Operation operation = new Push0Operation(gasCalculator);
+    final OperationResult result = operation.execute(frame, null);
+    Mockito.verify(frame).pushStackItem(Bytes.EMPTY);
+    assertThat(result.getGasCost()).isEqualTo(gasCalculator.getBaseTierGasCost());
+    assertSuccessResult(result);
+  }
+
+  private void assertSuccessResult(final OperationResult result) {
+    assertThat(result).isNotNull();
+    assertThat(result.getHaltReason()).isNull();
+  }
+
+  private MessageFrame createMessageFrame(final long initialGas, final Optional<Wei> baseFee) {
+    final MessageFrame frame = mock(MessageFrame.class);
+    when(frame.getRemainingGas()).thenReturn(initialGas);
+    final BlockHeader blockHeader = mock(BlockHeader.class);
+    when(blockHeader.getBaseFee()).thenReturn(baseFee);
+    when(frame.getBlockValues()).thenReturn(blockHeader);
+    when(frame.getCode()).thenReturn(EMPTY_CODE);
+    return frame;
+  }
+}

evm/src/main/java/org/hyperledger/besu/evm/MainnetEVMs.java

@@ -82,6 +82,7 @@ import org.hyperledger.besu.evm.operation.OriginOperation;
 import org.hyperledger.besu.evm.operation.PCOperation;
 import org.hyperledger.besu.evm.operation.PopOperation;
 import org.hyperledger.besu.evm.operation.PrevRanDaoOperation;
+import org.hyperledger.besu.evm.operation.Push0Operation;
 import org.hyperledger.besu.evm.operation.PushOperation;
 import org.hyperledger.besu.evm.operation.ReturnDataCopyOperation;
 import org.hyperledger.besu.evm.operation.ReturnDataSizeOperation;
@@ -425,6 +426,7 @@ public class MainnetEVMs {
       final GasCalculator gasCalculator,
       final BigInteger chainID) {
     registerParisOperations(registry, gasCalculator, chainID);
-    // PUSH0
+    // Register the PUSH0 operation.
+    registry.put(new Push0Operation(gasCalculator));
   }
 }

evm/src/main/java/org/hyperledger/besu/evm/operation/Push0Operation.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright contributors to Hyperledger Besu
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package org.hyperledger.besu.evm.operation;
+
+import org.hyperledger.besu.evm.EVM;
+import org.hyperledger.besu.evm.frame.MessageFrame;
+import org.hyperledger.besu.evm.gascalculator.GasCalculator;
+
+import org.apache.tuweni.bytes.Bytes;
+
+public class Push0Operation extends AbstractFixedCostOperation {
+
+  public static final int PUSH_BASE = 0x5F;
+  static final OperationResult push0Success = new OperationResult(2, null);
+
+  public Push0Operation(final GasCalculator gasCalculator) {
+    super(PUSH_BASE, "PUSH0", 0, 1, 1, gasCalculator, gasCalculator.getBaseTierGasCost());
+  }
+
+  @Override
+  public OperationResult executeFixedCostOperation(final MessageFrame frame, final EVM evm) {
+    return staticOperation(frame, frame.getPC());
+  }
+
+  public static OperationResult staticOperation(final MessageFrame frame, final int pc) {
+    frame.pushStackItem(Bytes.EMPTY);
+    frame.setPC(pc + 1);
+    return push0Success;
+  }
+}