EightBit/inc/IntelProcessor.h
Adrian Conlon 6bf28f1480 Correct some virtual and constexpr expressions.
Signed-off-by: Adrian Conlon <adrian.conlon@gmail.com>
2021-08-23 09:44:48 +01:00

153 lines
4.9 KiB
C++

#pragma once
#include <cstdint>
#include <array>
#include "LittleEndianProcessor.h"
#include "Register.h"
#include "EventArgs.h"
#include "Signal.h"
#include "EightBitCompilerDefinitions.h"
namespace EightBit {
class Bus;
class IntelProcessor : public LittleEndianProcessor {
public:
struct opcode_decoded_t {
int x = 0;
int y = 0;
int z = 0;
int p = 0;
int q = 0;
constexpr opcode_decoded_t() noexcept {}
constexpr opcode_decoded_t(const uint8_t opcode) noexcept {
x = (opcode & 0b11000000) >> 6; // 0 - 3
y = (opcode & 0b00111000) >> 3; // 0 - 7
z = (opcode & 0b00000111); // 0 - 7
p = (y & 0b110) >> 1; // 0 - 3
q = (y & 1); // 0 - 1
}
};
virtual ~IntelProcessor() {};
[[nodiscard]] constexpr const auto& getDecodedOpcode(const size_t i) const noexcept {
return m_decodedOpcodes[i];
}
[[nodiscard]] constexpr auto& MEMPTR() noexcept { return m_memptr; }
[[nodiscard]] constexpr auto& SP() noexcept { return m_sp; }
[[nodiscard]] virtual register16_t& AF() noexcept = 0;
[[nodiscard]] auto& A() noexcept { return AF().high; }
[[nodiscard]] auto& F() noexcept { return AF().low; }
[[nodiscard]] virtual register16_t& BC() noexcept = 0;
[[nodiscard]] auto& B() noexcept { return BC().high; }
[[nodiscard]] auto& C() noexcept { return BC().low; }
[[nodiscard]] virtual register16_t& DE() noexcept = 0;
[[nodiscard]] auto& D() noexcept { return DE().high; }
[[nodiscard]] auto& E() noexcept { return DE().low; }
[[nodiscard]] virtual register16_t& HL() noexcept = 0;
[[nodiscard]] auto& H() noexcept { return HL().high; }
[[nodiscard]] auto& L() noexcept { return HL().low; }
DECLARE_PIN_OUTPUT(HALT)
protected:
IntelProcessor(Bus& bus);
template<class T> [[nodiscard]] static constexpr uint8_t adjustSign(uint8_t f, const uint8_t value) noexcept {
return setBit(f, T::SF, value & T::SF);
}
template<class T> [[nodiscard]] static constexpr uint8_t adjustZero(uint8_t f, const uint8_t value) noexcept {
return clearBit(f, T::ZF, value);
}
template<class T> [[nodiscard]] static constexpr uint8_t adjustParity(uint8_t f, const uint8_t value) noexcept {
return clearBit(f, T::PF, PARITY(value));
}
template<class T> [[nodiscard]] static constexpr uint8_t adjustSZ(uint8_t f, const uint8_t value) noexcept {
const auto intermediate = adjustSign<T>(f, value);
return adjustZero<T>(intermediate, value);
}
template<class T> [[nodiscard]] static constexpr uint8_t adjustSZP(uint8_t f, const uint8_t value) noexcept {
const auto intermediate = adjustSZ<T>(f, value);
return adjustParity<T>(intermediate, value);
}
template<class T> [[nodiscard]] static constexpr uint8_t adjustXY(uint8_t f, const uint8_t value) noexcept {
const auto intermediate = setBit(f, T::XF, value & T::XF);
return setBit(intermediate, T::YF, value & T::YF);
}
template<class T> [[nodiscard]] static constexpr uint8_t adjustSZPXY(uint8_t f, const uint8_t value) noexcept {
const auto intermediate = adjustSZP<T>(f, value);
return adjustXY<T>(intermediate, value);
}
template<class T> [[nodiscard]] static constexpr uint8_t adjustSZXY(uint8_t f, const uint8_t value) noexcept {
const auto intermediate = adjustSZ<T>(f, value);
return adjustXY<T>(intermediate, value);
}
//
[[nodiscard]] static constexpr auto buildHalfCarryIndex(const uint8_t before, const uint8_t value, const int calculation) noexcept {
return ((before & 0x88) >> 1) | ((value & 0x88) >> 2) | ((calculation & 0x88) >> 3);
}
[[nodiscard]] static constexpr auto calculateHalfCarry(const std::array<int, 8>& table, const uint8_t before, const uint8_t value, const int calculation) noexcept {
const auto index = buildHalfCarryIndex(before, value, calculation);
return table[index & Mask3];
}
[[nodiscard]] static constexpr auto calculateHalfCarryAdd(const uint8_t before, const uint8_t value, const int calculation) noexcept {
return calculateHalfCarry(m_halfCarryTableAdd, before, value, calculation);
}
[[nodiscard]] static constexpr auto calculateHalfCarrySub(const uint8_t before, const uint8_t value, const int calculation) noexcept {
return calculateHalfCarry(m_halfCarryTableSub, before, value, calculation);
}
void handleRESET() override;
void push(uint8_t value) final;
[[nodiscard]] uint8_t pop() final;
//
[[nodiscard]] register16_t getWord() final;
void setWord(register16_t value) final;
//
virtual void restart(uint8_t address);
virtual int callConditional(int condition);
virtual int jumpConditional(int condition);
virtual int returnConditional(int condition);
virtual void jr(int8_t offset);
virtual int jrConditional(int condition);
void ret() override;
private:
static std::array<int, 8> m_halfCarryTableAdd;
static std::array<int, 8> m_halfCarryTableSub;
std::array<opcode_decoded_t, 0x100> m_decodedOpcodes;
register16_t m_sp = Mask16;
register16_t m_memptr;
};
}