EightBit/inc/Processor.h

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C
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#pragma once
#include <cstdint>
#include "Chip.h"
#include "Bus.h"
#include "Register.h"
#include "Signal.h"
#include "EightBitCompilerDefinitions.h"
namespace EightBit {
class Processor : public Chip {
public:
// b: number of bits representing the number in x
// x: sign extend this b-bit number to r
[[nodiscard]] static int8_t signExtend(int b, uint8_t x);
~Processor() {};
Signal<EventArgs> Ticked;
[[nodiscard]] auto& PC() noexcept { return m_pc; }
[[nodiscard]] auto& RESET() noexcept { return m_resetLine; }
[[nodiscard]] auto& HALT() noexcept { return m_haltLine; }
[[nodiscard]] auto& INT() noexcept { return m_intLine; }
[[nodiscard]] auto& IRQ() noexcept { return INT(); } // Synonym
void powerOn() override;
void reset() noexcept { lower(RESET()); }
int run(int limit);
virtual int step() = 0;
virtual int execute() = 0;
int execute(uint8_t value);
[[nodiscard]] auto cycles() const noexcept { return m_cycles; }
[[nodiscard]] virtual register16_t peekWord(register16_t address) = 0;
virtual void pokeWord(register16_t address, register16_t value) = 0;
protected:
Processor(Bus& memory);
[[nodiscard]] auto& opcode() noexcept { return m_opcode; }
[[nodiscard]] auto& BUS() noexcept { return m_bus; }
[[nodiscard]] auto halted() noexcept { return lowered(HALT()); }
void halt() noexcept { --PC(); lower(HALT()); }
void proceed() noexcept { ++PC(); raise(HALT()); }
virtual void handleRESET();
virtual void handleINT();
virtual void handleIRQ();
void busWrite(register16_t address, uint8_t data);
void busWrite(uint8_t data);
virtual void busWrite();
uint8_t busRead(register16_t address);
virtual uint8_t busRead();
auto getBytePaged(const uint8_t page, const uint8_t offset) {
return busRead(register16_t(offset, page));
}
void setBytePaged(const uint8_t page, const uint8_t offset, const uint8_t value) {
busWrite(register16_t(offset, page), value);
}
auto fetchByte() {
return busRead(PC()++);
}
[[nodiscard]] virtual register16_t getWord() = 0;
virtual void setWord(register16_t value) = 0;
[[nodiscard]] virtual register16_t getWordPaged(uint8_t page, uint8_t offset) = 0;
virtual void setWordPaged(uint8_t page, uint8_t offset, register16_t value) = 0;
[[nodiscard]] virtual register16_t fetchWord() = 0;
virtual void push(uint8_t value) = 0;
[[nodiscard]] virtual uint8_t pop() = 0;
virtual void pushWord(register16_t value) = 0;
[[nodiscard]] virtual register16_t popWord() = 0;
[[nodiscard]] auto getWord(const register16_t address) {
BUS().ADDRESS() = address;
return getWord();
}
void setWord(const register16_t address, const register16_t value) {
BUS().ADDRESS() = address;
return setWord(value);
}
void jump(const register16_t destination) noexcept {
PC() = destination;
}
void call(const register16_t destination) {
pushWord(PC());
jump(destination);
}
virtual void ret();
void resetCycles() noexcept { m_cycles = 0; }
void tick(const int extra) { for (int i = 0; i < extra; ++i) tick(); }
void tick() { ++m_cycles; Ticked.fire(EventArgs::empty()); }
private:
Bus& m_bus;
uint8_t m_opcode = Mask8;
int m_cycles = 0;
register16_t m_pc;
PinLevel m_intLine = PinLevel::Low;
PinLevel m_haltLine = PinLevel::Low;
PinLevel m_resetLine = PinLevel::Low;
};
}