Files
matar/include/cpu/cpu.hh
2024-06-16 07:45:54 +05:30

115 lines
3.1 KiB
C++

#pragma once
#include "arm/instruction.hh"
#include "bus.hh"
#include "cpu/psr.hh"
#include "thumb/instruction.hh"
#include <cstdint>
#include <memory>
#ifdef GDB_DEBUG
#include <unordered_set>
#endif
namespace matar {
#ifdef GDB_DEBUG
class GdbRsp;
#endif
class Cpu {
public:
Cpu(std::shared_ptr<Bus>) noexcept;
void step();
void chg_mode(const Mode to);
inline bool is_halted() { return halted; }
inline void resume() { halted = false; }
private:
bool halted = false;
friend void arm::Instruction::exec(Cpu& cpu);
friend void thumb::Instruction::exec(Cpu& cpu);
static constexpr uint8_t GPR_COUNT = 16;
static constexpr uint8_t GPR_FIQ_FIRST = 8;
static constexpr uint8_t GPR_SVC_FIRST = 13;
static constexpr uint8_t GPR_ABT_FIRST = 13;
static constexpr uint8_t GPR_IRQ_FIRST = 13;
static constexpr uint8_t GPR_UND_FIRST = 13;
static constexpr uint8_t GPR_OLD_FIRST = 8;
std::shared_ptr<Bus> bus;
std::array<uint32_t, GPR_COUNT> gpr = {}; // general purpose registers
Psr cpsr = {}; // current program status register
Psr spsr = {}; // status program status register
static constexpr uint8_t SP_INDEX = 13;
static_assert(SP_INDEX < GPR_COUNT);
uint32_t& sp = gpr[SP_INDEX];
static constexpr uint8_t LR_INDEX = 14;
static_assert(LR_INDEX < GPR_COUNT);
uint32_t& lr = gpr[LR_INDEX];
static constexpr uint8_t PC_INDEX = 15;
static_assert(PC_INDEX < GPR_COUNT);
uint32_t& pc = gpr[PC_INDEX];
struct {
std::array<uint32_t, GPR_COUNT - GPR_FIQ_FIRST - 1> fiq;
std::array<uint32_t, GPR_COUNT - GPR_SVC_FIRST - 1> svc;
std::array<uint32_t, GPR_COUNT - GPR_ABT_FIRST - 1> abt;
std::array<uint32_t, GPR_COUNT - GPR_IRQ_FIRST - 1> irq;
std::array<uint32_t, GPR_COUNT - GPR_UND_FIRST - 1> und;
// visible registers before the mode switch
std::array<uint32_t, GPR_COUNT - GPR_OLD_FIRST - 1> old;
} gpr_banked = {}; // banked general purpose registers
struct {
Psr fiq;
Psr svc;
Psr abt;
Psr irq;
Psr und;
} spsr_banked = {}; // banked saved program status registers
inline void internal_cycle() { bus->internal_cycle(); }
// whether read is going to be sequential or not
bool sequential = true;
// raw instructions in the pipeline
std::array<uint32_t, 2> opcodes = {};
inline void advance_pc_arm() { pc += arm::INSTRUCTION_SIZE; };
inline void advance_pc_thumb() { pc += thumb::INSTRUCTION_SIZE; }
bool is_flushed = false;
inline void flush_pipeline() {
if (cpsr.state() == State::Arm) {
opcodes[0] = bus->read_word(pc, false);
advance_pc_arm();
opcodes[1] = bus->read_word(pc);
advance_pc_arm();
} else {
opcodes[0] = bus->read_halfword(pc, false);
advance_pc_thumb();
opcodes[1] = bus->read_halfword(pc);
advance_pc_thumb();
}
sequential = true;
};
#ifdef GDB_DEBUG
friend class GdbRsp;
std::unordered_set<uint32_t> breakpoints = {};
#endif
};
}