EightBit/inc/Processor.h

114 lines
2.6 KiB
C
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#pragma once
#include <cstdint>
#include "Chip.h"
#include "Bus.h"
#include "Register.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
static int8_t signExtend(int b, uint8_t x);
auto& PC() { return m_pc; }
auto& RESET() { return m_resetLine; }
auto& HALT() { return m_haltLine; }
auto& INT() { return m_intLine; }
auto& IRQ() { return INT(); } // Synonym
virtual void powerOn();
void reset() { lower(RESET()); }
int run(int limit);
virtual int step() = 0;
virtual int execute(uint8_t opcode) = 0;
auto cycles() const { return m_cycles; }
virtual register16_t peekWord(register16_t address) = 0;
virtual void pokeWord(register16_t address, register16_t value) = 0;
protected:
Processor(Bus& memory);
virtual ~Processor() = default;
auto& BUS() { return m_bus; }
auto halted() { return lowered(HALT()); }
auto halt() { --PC(); lower(HALT()); }
auto proceed() { ++PC(); raise(HALT()); }
virtual void handleRESET();
virtual void handleINT();
virtual void handleIRQ();
auto getBytePaged(const uint8_t page, const uint8_t offset) {
return BUS().read(register16_t(offset, page));
}
void setBytePaged(const uint8_t page, const uint8_t offset, const uint8_t value) {
BUS().write(register16_t(offset, page), value);
}
auto fetchByte() {
return BUS().read(PC()++);
}
virtual register16_t getWord() = 0;
virtual void setWord(register16_t value) = 0;
virtual register16_t getWordPaged(uint8_t page, uint8_t offset) = 0;
virtual void setWordPaged(uint8_t page, uint8_t offset, register16_t value) = 0;
virtual register16_t fetchWord() = 0;
virtual void push(uint8_t value) = 0;
virtual uint8_t pop() = 0;
virtual void pushWord(const register16_t value) = 0;
virtual register16_t popWord() = 0;
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) {
PC() = destination;
}
void call(const register16_t destination) {
pushWord(PC());
jump(destination);
}
virtual void ret() {
jump(popWord());
}
void resetCycles() { m_cycles = 0; }
void addCycles(const int extra) { m_cycles += extra; }
void addCycle() { ++m_cycles; }
private:
Bus& m_bus;
int m_cycles = 0;
register16_t m_pc;
PinLevel m_intLine = Low;
PinLevel m_haltLine = Low;
PinLevel m_resetLine = Low;
};
}