SecurityEmulator/src/ExecutorCases.cpp

#include "ExecutorCases.h"

#include "DataTransfer.h"
#include "ControlFlow.h"
#include "Arithmetic.h"
#include "Misc.h"

#include "Instruction.h"
#include "Bus.h"

#include <bitset>
#include <iostream>

CPUContext::CPUContext(Instruction& i, uint32_t& ip, uint32_t& flags, uint32_t* reg, std::shared_ptr<Bus>& bus, bool& isHalted) : m_Instruction(i), m_InstructionPointer(ip), m_Flags(flags), m_Registers(reg), m_Bus(bus), m_IsHalted(isHalted) { }

CPUContext::~CPUContext() = default;

constexpr std::array<ExecutorCase, 255> GenerateExecutorTable(){
  std::array<ExecutorCase, 255> table{};
  table[Opcode::NOP] = executor_cases::Nop;
  table[Opcode::HLT] = executor_cases::Hlt;
  table[Opcode::MOV_R32_IMM32] = executor_cases::Mov_r32_imm32;
  table[Opcode::MOV_RM32_R32] = executor_cases::Mov_rm32_r32;
  table[Opcode::ADD_RM32_R32] = executor_cases::Add_rm32_r32;
  return table;
}

static constexpr std::array<ExecutorCase, 255> s_ExecutorTable = GenerateExecutorTable();

const std::array<ExecutorCase, 255>& GetExecutorTable() {
  return s_ExecutorTable;
}

namespace executor_cases::helpers {
  
  uint32_t ResolveModRMAddress(CPUContext& cc) {
    x86::ModRM modrm = cc.m_Instruction.optional.m_ModRM;
    uint32_t value = 0;
    
    switch(modrm.m_State) {
    case x86::ModRMState::LR_DISP32:
    case x86::ModRMState::LR_DISP8:
      value = cc.m_Registers[modrm.m_Rm] + cc.m_Instruction.m_Operand1;
      break;
    case x86::ModRMState::DISP32:
      value = cc.m_Instruction.m_Operand1;
      break;
    case x86::ModRMState::LR:
      value = cc.m_Registers[modrm.m_Rm];
      break;
    case x86::ModRMState::R:
      std::cout << "x86::ModRM reached x86::ModRMState::R during ResolveModRMAddress()" << std::endl;
      std::cout << "This behavior is unexpected." << std::endl;
      break;
    default:
      throw std::runtime_error("Undefined MODRM state encountered!");
    }
  
    return value;
  }
  
}