The Idea

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The Idea#

Working with C++ can sometimes be challenging, so the implementation presented here will be kept simple. The core concept is to create a Fetch-Decode-Execute loop that delegates opcode execution to a switch statement, which handles all the defined opcodes. Here’s a pseudocode example of how this might look:

Pseudo code of a possible implementation#
void interpret(VM &vm) {
  // we assume the bytecode is already loaded and pc is set
  while (!vm.should_stop()) {
    // fetch & decode in one statement
    uint16_t opcode = vm.current_opcode();
    // execute instruction
    if (ops::interpret_op(vm, opcode) < 0) {
      break;
    }
  }
}

The next step is to base opcode interpretation on the instructions and the instruction formats we’ve previously defined:

int ops::interpret_op(VM &vm, const uint16_t opcode) {
  int result_code;
  switch(opcode) {
    /* opcode handlers */
    default:
      result_code = -1;
      break;
  };
  return result_code;
}

What’s next?#

TODO

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