#include "VM.hpp"

namespace roza
{
  /*explicit*/ VM::VM(StatusLog& log)
    : m_log { log }
  {
  }

  /*virtual*/ VM::~VM()
  {
  }

  void VM::exec(std::shared_ptr<Program> program)
  {
    while (m_pc < program->size())
      {
        switch (program->opcode(m_pc))
          {
          case OP_PUSH_CONST: {
            param_t param = *program->param(m_pc);
            push(param);
            m_pc++;
          } break;

          case OP_POP: {
            pop();
            m_pc++;
          } break;

          default:
            m_log.fatal(SrcLoc {},
                        std::string()
                        + "cannot execute opcode '"
                        + OpcodeStr[program->opcode(m_pc)]
                        + "'"); break;
          }
      }
  }

  void VM::push(param_t param)
  {
    m_stack.push_back(param);
  }

  param_t VM::pop()
  {
    assert(m_stack.size() > 0);

    param_t res = m_stack.back();
    m_stack.pop_back();
    return res;
  }
}