[feature] basic interpreting

Author: lvntky

src/execute_engine/cvm_execute.cpp

@@ -38,6 +38,10 @@ void CVM::execute(const Classfile& cf, const std::string& methodName) {
 
   const uint8_t* bytecode = getByteCode(cf, methodInfo);
   validateByteCode(bytecode);
+
+  spdlog::info("Size of bytecode: {}", sizeof(bytecode));
+
+  interprete(bytecode, cf);
 }
 
 std::string CVM::getUtf8FromConstantPool(const Classfile& cf, uint16_t index) {
@@ -71,3 +75,18 @@ const uint8_t* CVM::getByteCode(const Classfile& cf,
   }
   return nullptr;
 }
+
+void CVM::interprete(const uint8_t* byteCode, const Classfile& cf) {
+  size_t pc = 0;
+  std::stack<int> operandStack;
+  size_t codeLength = sizeof(byteCode);
+
+  while (pc < 100) {
+    uint8_t opcode = byteCode[pc++];
+    switch (opcode) {
+      default:
+        spdlog::error("Unknown Opcode: {:#04x} at PC: {}", opcode, pc);
+        break;
+    }
+  }
+}