EightBit/inc/Processor.h

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#pragma once
#include <cstdint>
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#include "ClockedChip.h"
#include "Bus.h"
#include "Register.h"
#include "EightBitCompilerDefinitions.h"
namespace EightBit {
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class Processor : public ClockedChip {
public:
// http://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend
// b: number of bits representing the number in x
// x: sign extend this b-bit number to r
[[nodiscard]] static constexpr int8_t signExtend(int b, uint8_t x) noexcept {
const uint8_t m = bit(b - 1); // mask can be pre-computed if b is fixed
x = x & (bit(b) - 1); // (Skip this if bits in x above position b are already zero.)
const auto result = (x ^ m) - m;
return result;
}
Processor(const Processor& rhs);
bool operator==(const Processor& rhs) const;
[[nodiscard]] constexpr auto& PC() noexcept { return m_pc; }
[[nodiscard]] constexpr const auto& PC() const noexcept { return m_pc; }
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int run(int limit) noexcept;
virtual int step() noexcept = 0;
virtual int execute() noexcept = 0;
int execute(uint8_t value) noexcept;
[[nodiscard]] virtual register16_t peekWord(register16_t address) noexcept = 0;
virtual void pokeWord(register16_t address, register16_t value) noexcept = 0;
DECLARE_PIN_INPUT(RESET)
DECLARE_PIN_INPUT(INT)
protected:
Processor(Bus& memory) noexcept;
[[nodiscard]] constexpr auto& opcode() noexcept { return m_opcode; }
[[nodiscard]] constexpr auto& BUS() noexcept { return m_bus; }
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virtual void handleRESET() noexcept;
virtual void handleINT() noexcept;
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void memoryWrite(register16_t address, uint8_t data) noexcept;
void memoryWrite(register16_t address) noexcept;
void memoryWrite(uint8_t data) noexcept;
virtual void memoryWrite() noexcept;
virtual void busWrite() noexcept;
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uint8_t memoryRead(register16_t address) noexcept;
virtual uint8_t memoryRead() noexcept;
virtual uint8_t busRead() noexcept;
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uint8_t getBytePaged(uint8_t page, uint8_t offset) noexcept;
void setBytePaged(uint8_t page, uint8_t offset, uint8_t value) noexcept;
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uint8_t fetchByte() noexcept;
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[[nodiscard]] virtual register16_t getWord() noexcept = 0;
virtual void setWord(register16_t value) noexcept = 0;
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[[nodiscard]] virtual register16_t getWordPaged(uint8_t page, uint8_t offset) noexcept = 0;
virtual void setWordPaged(uint8_t page, uint8_t offset, register16_t value) noexcept = 0;
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[[nodiscard]] virtual register16_t fetchWord() noexcept = 0;
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virtual void push(uint8_t value) noexcept = 0;
[[nodiscard]] virtual uint8_t pop() noexcept = 0;
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virtual void pushWord(register16_t value) noexcept = 0;
[[nodiscard]] virtual register16_t popWord() noexcept = 0;
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[[nodiscard]] register16_t getWord(register16_t address) noexcept;
void setWord(register16_t address, register16_t value) noexcept;
void jump(const register16_t destination) noexcept;
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virtual void call(register16_t destination) noexcept;
virtual void ret() noexcept;
private:
Bus& m_bus;
uint8_t m_opcode = Mask8;
register16_t m_pc;
};
}