risc-v-tlm/src/CPU.cpp

#include "CPU.h"

SC_HAS_PROCESS(CPU);
CPU::CPU(sc_module_name name, uint32_t PC): sc_module(name)
, instr_bus("instr_bus")
{
   register_bank = new Registers();
   exec = new Execute("Execute", register_bank);
   perf = Performance::getInstance();
   log = Log::getInstance();

   register_bank->setPC(PC);
   SC_THREAD(CPU_thread);
}

CPU::~CPU() {
  cout << "*********************************************" << endl;
  register_bank->dump();
  cout << "end time: " << sc_time_stamp() << endl;
  perf->dump();
  cout << "*********************************************" << endl;
}

bool CPU::cpu_process_IRQ() {
  uint32_t csr_temp;
  uint32_t new_pc, old_pc;
  bool ret_value = false;

  if (interrupt == true){
    csr_temp = register_bank->getCSR(CSR_MIP);

    if ( (csr_temp & (1 << 11) ) == 0 )  {
      csr_temp |= (1 << 11);  // MEIP bit in MIP register (11th bit)
      register_bank->setCSR(CSR_MIP, csr_temp);
      // cout << "time: " << sc_time_stamp() << ". CPU: interrupt" << endl;
      log->SC_log(Log::INFO) << "Interrupt!" << endl;

      /* updated MEPC register */
      old_pc = register_bank->getPC();
      register_bank->setCSR(CSR_MEPC, old_pc);
      // log->SC_log(Log::INFO) << "Old PC Value 0x" << hex << old_pc << endl;

      /* update MCAUSE register */
      register_bank->setCSR(CSR_MCAUSE, 0x8000000);

      /* set new PC address */
      new_pc = register_bank->getCSR(CSR_MTVEC);
      new_pc = new_pc & 0xFFFFFFFC; // last two bits always to 0
      // log->SC_log(Log::DEBUG) << "NEW PC Value 0x" << hex << new_pc << endl;
      register_bank->setPC(new_pc);

      ret_value = true;
    }
  } else  {
    csr_temp = register_bank->getCSR(CSR_MIP);
    csr_temp &= ~(1 << 11);
    register_bank->setCSR(CSR_MIP, csr_temp);
  }

  return ret_value;
}

bool CPU::process_c_instruction(Instruction &inst) {
  bool PC_not_affected = true;

  C_Instruction c_inst(inst.getInstr());

  switch(c_inst.decode()) {
    case OP_C_ADDI4SPN:
      PC_not_affected = exec->C_ADDI4SPN(inst);
      break;
    case OP_C_LW:
      exec->LW(inst, true);
      break;
    case OP_C_SW:
      exec->SW(inst, true);
      break;
    case OP_C_ADDI:
      exec->ADDI(inst, true);
      break;
    case OP_C_JAL:
      exec->JAL(inst, true, 1);
      PC_not_affected = false;
      break;
    case OP_C_J:
      exec->JAL(inst, true, 0);
      PC_not_affected = false;
      break;
    case OP_C_LI:
      exec->C_LI(inst);
      break;
    case OP_C_SLLI:
      exec->C_SLLI(inst);
      break;
    case OP_C_LWSP:
      exec->C_LWSP(inst);
      break;
    case OP_C_JR:
      exec->C_JR(inst);
      PC_not_affected = false;
      break;
    case OP_C_MV:
      exec->C_MV(inst);
      break;
    case OP_C_JALR:
      exec->JALR(inst, true);
      PC_not_affected = false;
      break;
    case OP_C_ADD:
      exec->C_ADD(inst);
      break;
    case OP_C_SWSP:
      exec->C_SWSP(inst);
      break;
    case OP_C_ADDI16SP:
      exec->C_ADDI16SP(inst);
      break;
    case OP_C_BEQZ:
      exec->C_BEQZ(inst);
      PC_not_affected = false;
      break;
    case OP_C_BNEZ:
      exec->C_BNEZ(inst);
      PC_not_affected = false;
      break;
    case OP_C_SRLI:
      exec->C_SRLI(inst);
      break;
    case OP_C_SRAI:
      exec->C_SRAI(inst);
      break;
    case OP_C_ANDI:
      exec->C_ANDI(inst);
      break;
    case OP_C_SUB:
      exec->C_SUB(inst);
      break;
    case OP_C_XOR:
      exec->C_XOR(inst);
      break;
    case OP_C_OR:
      exec->C_OR(inst);
      break;
    case OP_C_AND:
      exec->C_AND(inst);
      break;
    default:
      std::cout << "C instruction not implemented yet" << endl;
      inst.dump();
      exec->NOP(inst);
      //sc_stop();
      break;

  }

  return PC_not_affected;
}

bool CPU::process_m_instruction(Instruction &inst) {
  bool PC_not_affected = true;

  M_Instruction m_inst(inst.getInstr());

  switch(m_inst.decode()) {
    case OP_M_MUL:
      exec->M_MUL(inst);
      break;
    case OP_M_MULH:
      exec->M_MULH(inst);
      break;
    case OP_M_MULHSU:
      exec->M_MULHSU(inst);
      break;
    case OP_M_MULHU:
      exec->M_MULHU(inst);
      break;
    case OP_M_DIV:
      exec->M_DIV(inst);
      break;
    case OP_M_DIVU:
      exec->M_DIVU(inst);
      break;
    case OP_M_REM:
      exec->M_REM(inst);
      break;
    case OP_M_REMU:
      exec->M_REMU(inst);
      break;
    default:
      std::cout << "M instruction not implemented yet" << endl;
      inst.dump();
      exec->NOP(inst);
      break;
  }

  return PC_not_affected;
}


bool CPU::process_a_instruction(Instruction inst) {
  bool PC_not_affected = true;

  A_Instruction a_inst(inst.getInstr());

  switch(a_inst.decode()) {
    case OP_A_LR:
      exec->A_LR(inst);
      break;
    case OP_A_SC:
      exec->A_SC(inst);
      break;
    case OP_A_AMOSWAP:
      exec->A_AMOSWAP(inst);
      break;
    case OP_A_AMOADD:
      exec->A_AMOADD(inst);
      break;
    case OP_A_AMOXOR:
      exec->A_AMOXOR(inst);
      break;
    case OP_A_AMOAND:
      exec->A_AMOAND(inst);
      break;
    case OP_A_AMOOR:
      exec->A_AMOOR(inst);
      break;
    case OP_A_AMOMIN:
      exec->A_AMOMIN(inst);
      break;
    case OP_A_AMOMAX:
      exec->A_AMOMAX(inst);
      break;
    case OP_A_AMOMINU:
      exec->A_AMOMINU(inst);
      break;
    case OP_A_AMOMAXU:
      exec->A_AMOMAXU(inst);
      break;
    default:
      std::cout << "A instruction not implemented yet" << endl;
      inst.dump();
      exec->NOP(inst);
      break;
  }

  return PC_not_affected;
}

bool CPU::process_base_instruction(Instruction &inst) {
  bool PC_not_affected = true;

  switch(inst.decode()) {
    case OP_LUI:
      exec->LUI(inst);
      break;
    case OP_AUIPC:
      exec->AUIPC(inst);
      break;
    case OP_JAL:
      exec->JAL(inst);
      PC_not_affected = false;
      break;
    case OP_JALR:
      exec->JALR(inst);
      PC_not_affected = false;
      break;
    case OP_BEQ:
      exec->BEQ(inst);
      PC_not_affected = false;
      break;
    case OP_BNE:
      exec->BNE(inst);
      PC_not_affected = false;
      break;
    case OP_BLT:
      exec->BLT(inst);
      PC_not_affected = false;
      break;
    case OP_BGE:
      exec->BGE(inst);
      PC_not_affected = false;
      break;
    case OP_BLTU:
      exec->BLTU(inst);
      PC_not_affected = false;
      break;
    case OP_BGEU:
      exec->BGEU(inst);
      PC_not_affected = false;
      break;
    case OP_LB:
      exec->LB(inst);
      break;
    case OP_LH:
      exec->LH(inst);
      break;
    case OP_LW:
      exec->LW(inst);
      break;
    case OP_LBU:
      exec->LBU(inst);
      break;
    case OP_LHU:
      exec->LHU(inst);
      break;
    case OP_SB:
      exec->SB(inst);
      break;
    case OP_SH:
      exec->SH(inst);
      break;
    case OP_SW:
      exec->SW(inst);
      break;
    case OP_ADDI:
      exec->ADDI(inst);
      break;
    case OP_SLTI:
      exec->SLTI(inst);
      break;
    case OP_SLTIU:
      exec->SLTIU(inst);
      break;
    case OP_XORI:
      exec->XORI(inst);
      break;
    case OP_ORI:
      exec->ORI(inst);
      break;
    case OP_ANDI:
      exec->ANDI(inst);
      break;
    case OP_SLLI:
      PC_not_affected = exec->SLLI(inst);
      break;
    case OP_SRLI:
      exec->SRLI(inst);
      break;
    case OP_SRAI:
      exec->SRAI(inst);
      break;
    case OP_ADD:
      exec->ADD(inst);
      break;
    case OP_SUB:
      exec->SUB(inst);
      break;
    case OP_SLL:
      exec->SLL(inst);
      break;
    case OP_SLT:
      exec->SLT(inst);
      break;
    case OP_SLTU:
      exec->SLTU(inst);
      break;
    case OP_XOR:
      exec->XOR(inst);
      break;
    case OP_SRL:
      exec->SRL(inst);
      break;
    case OP_SRA:
      exec->SRA(inst);
      break;
    case OP_OR:
      exec->OR(inst);
      break;
    case OP_AND:
      exec->AND(inst);
      break;
    case OP_FENCE:
      exec->FENCE(inst);
      break;
    case OP_ECALL:
      exec->ECALL(inst);
      break;
    case OP_EBREAK:
      exec->EBREAK(inst);
      break;
    case OP_CSRRW:
      exec->CSRRW(inst);
      break;
    case OP_CSRRS:
      exec->CSRRS(inst);
      break;
    case OP_CSRRC:
      exec->CSRRC(inst);
      break;
    case OP_CSRRWI:
      exec->CSRRWI(inst);
      break;
    case OP_CSRRSI:
      exec->CSRRSI(inst);
      break;
    case OP_CSRRCI:
      exec->CSRRCI(inst);
      break;

    case OP_MRET:
      exec->MRET(inst);
      PC_not_affected = false;
      break;
    case OP_SRET:
      exec->SRET(inst);
      PC_not_affected = false;
      break;
    case OP_WFI:
      exec->WFI(inst);
      break;
    case OP_SFENCE:
      exec->SFENCE(inst);
      break;
    default:
      std::cout << "Wrong instruction" << endl;
      inst.dump();
      exec->NOP(inst);
      //sc_stop();
      break;
  }

  return PC_not_affected;
}

/**
 * main thread for CPU simulation
 * @brief CPU mai thread
 */
void CPU::CPU_thread(void) {

  tlm::tlm_generic_payload* trans = new tlm::tlm_generic_payload;
  uint32_t INSTR;
  sc_time delay = SC_ZERO_TIME;
  bool PC_not_affected = false;
  bool incPCby2 = false;

  trans->set_command( tlm::TLM_READ_COMMAND );
  trans->set_data_ptr( reinterpret_cast<unsigned char*>(&INSTR) );
  trans->set_data_length( 4 );
  trans->set_streaming_width( 4 ); // = data_length to indicate no streaming
  trans->set_byte_enable_ptr( 0 ); // 0 indicates unused
  trans->set_dmi_allowed( false ); // Mandatory initial value
  trans->set_response_status( tlm::TLM_INCOMPLETE_RESPONSE );

  //register_bank->dump();

  while(1) {
      /* Get new PC value */
      //cout << "CPU: PC 0x" << hex << (uint32_t) register_bank->getPC() << endl;
      trans->set_address( register_bank->getPC() );
      instr_bus->b_transport( *trans, delay);

      perf->codeMemoryRead();

      if ( trans->is_response_error() ) {
        SC_REPORT_ERROR("CPU base", "Read memory");
      } else {
        log->SC_log(Log::INFO) << "PC: 0x" << hex
              << register_bank->getPC() << ". ";

        Instruction inst(INSTR);

        /* check what type of instruction is and execute it */
        switch(inst.check_extension()) {
          case BASE_EXTENSION:
            PC_not_affected = process_base_instruction(inst);
            incPCby2 = false;
            break;
          case C_EXTENSION:
            PC_not_affected = process_c_instruction(inst);
            incPCby2 = true;
            break;
          case M_EXTENSION:
            PC_not_affected = process_m_instruction(inst);
            incPCby2 = false;
            break;
          case A_EXTENSION:
            PC_not_affected = process_a_instruction(inst);
            incPCby2 = false;
            break;
          default:
            std::cout << "Extension not implemented yet" << std::endl;
            inst.dump();
            exec->NOP(inst);
          } // switch (inst.check_extension())
        }

        perf->instructionsInc();

        if (PC_not_affected == true) {
          register_bank->incPC(incPCby2);
        }

        /* Process IRQ (if any) */
        cpu_process_IRQ();

        /* Fixed instruction time to 10 ns (i.e. 100 MHz)*/
        sc_core::wait(10, SC_NS);


  } // while(1)
} // CPU_thread