mirror of
https://github.com/MoleskiCoder/EightBit.git
synced 2024-09-01 00:28:55 +00:00
178 lines
4.9 KiB
C++
178 lines
4.9 KiB
C++
#pragma once
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#include <cstdint>
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#include <array>
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#include "Bus.h"
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#include "LittleEndianProcessor.h"
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#include "Register.h"
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#include "EventArgs.h"
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#include "Signal.h"
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#include "EightBitCompilerDefinitions.h"
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namespace EightBit {
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class IntelProcessor : public LittleEndianProcessor {
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public:
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struct opcode_decoded_t {
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int x = 0;
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int y = 0;
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int z = 0;
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int p = 0;
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int q = 0;
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opcode_decoded_t() noexcept {}
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opcode_decoded_t(const uint8_t opcode) noexcept {
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x = (opcode & 0b11000000) >> 6; // 0 - 3
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y = (opcode & 0b00111000) >> 3; // 0 - 7
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z = (opcode & 0b00000111); // 0 - 7
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p = (y & 0b110) >> 1; // 0 - 3
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q = (y & 1); // 0 - 1
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}
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};
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~IntelProcessor() = default;
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[[nodiscard]] const auto& getDecodedOpcode(const size_t i) const noexcept {
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return m_decodedOpcodes.at(i);
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}
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[[nodiscard]] auto& MEMPTR() noexcept { return m_memptr; }
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[[nodiscard]] auto& SP() noexcept { return m_sp; }
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[[nodiscard]] virtual register16_t& AF() = 0;
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[[nodiscard]] auto& A() { return AF().high; }
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[[nodiscard]] auto& F() { return AF().low; }
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[[nodiscard]] virtual register16_t& BC() = 0;
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[[nodiscard]] auto& B() { return BC().high; }
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[[nodiscard]] auto& C() { return BC().low; }
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[[nodiscard]] virtual register16_t& DE() = 0;
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[[nodiscard]] auto& D() { return DE().high; }
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[[nodiscard]] auto& E() { return DE().low; }
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[[nodiscard]] virtual register16_t& HL() = 0;
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[[nodiscard]] auto& H() { return HL().high; }
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[[nodiscard]] auto& L() { return HL().low; }
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DECLARE_PIN_OUTPUT(HALT)
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protected:
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IntelProcessor(Bus& bus);
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template<class T> [[nodiscard]] static uint8_t adjustSign(uint8_t f, const uint8_t value) {
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return setBit(f, T::SF, value & T::SF);
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}
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template<class T> [[nodiscard]] static uint8_t adjustZero(uint8_t f, const uint8_t value) {
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return clearBit(f, T::ZF, value);
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}
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template<class T> [[nodiscard]] static uint8_t adjustParity(uint8_t f, const uint8_t value) {
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return clearBit(f, T::PF, PARITY(value));
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}
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template<class T> [[nodiscard]] static uint8_t adjustSZ(uint8_t f, const uint8_t value) {
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const auto intermediate = adjustSign<T>(f, value);
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return adjustZero<T>(intermediate, value);
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}
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template<class T> [[nodiscard]] static uint8_t adjustSZP(uint8_t f, const uint8_t value) {
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const auto intermediate = adjustSZ<T>(f, value);
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return adjustParity<T>(intermediate, value);
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}
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template<class T> [[nodiscard]] static uint8_t adjustXY(uint8_t f, const uint8_t value) {
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const auto intermediate = setBit(f, T::XF, value & T::XF);
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return setBit(intermediate, T::YF, value & T::YF);
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}
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template<class T> [[nodiscard]] static uint8_t adjustSZPXY(uint8_t f, const uint8_t value) {
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const auto intermediate = adjustSZP<T>(f, value);
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return adjustXY<T>(intermediate, value);
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}
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template<class T> [[nodiscard]] static uint8_t adjustSZXY(uint8_t f, const uint8_t value) {
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const auto intermediate = adjustSZ<T>(f, value);
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return adjustXY<T>(intermediate, value);
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}
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//
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[[nodiscard]] static constexpr auto buildHalfCarryIndex(const uint8_t before, const uint8_t value, const int calculation) {
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return ((before & 0x88) >> 1) | ((value & 0x88) >> 2) | ((calculation & 0x88) >> 3);
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}
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[[nodiscard]] static auto calculateHalfCarryAdd(const uint8_t before, const uint8_t value, const int calculation) noexcept {
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static std::array<int, 8> halfCarryTableAdd = { { 0, 0, 1, 0, 1, 0, 1, 1} };
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const auto index = buildHalfCarryIndex(before, value, calculation);
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return halfCarryTableAdd.at(index & Mask3);
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}
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[[nodiscard]] static auto calculateHalfCarrySub(const uint8_t before, const uint8_t value, const int calculation) noexcept {
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std::array<int, 8> halfCarryTableSub = { { 0, 1, 1, 1, 0, 0, 0, 1 } };
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const auto index = buildHalfCarryIndex(before, value, calculation);
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return halfCarryTableSub.at(index & Mask3);
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}
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void handleRESET() override;
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void push(uint8_t value) final;
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[[nodiscard]] uint8_t pop() final;
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//
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[[nodiscard]] register16_t getWord() final;
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void setWord(register16_t value) final;
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//
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void restart(const uint8_t address) {
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call(MEMPTR() = { address, 0 });
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}
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auto callConditional(const int condition) {
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MEMPTR() = fetchWord();
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if (condition)
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call(MEMPTR());
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return !!condition;
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}
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auto jumpConditional(const int condition) {
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MEMPTR() = fetchWord();
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if (condition)
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jump(MEMPTR());
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return !!condition;
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}
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auto returnConditional(const int condition) {
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if (condition)
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ret();
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return !!condition;
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}
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void jr(const int8_t offset) noexcept {
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jump(MEMPTR() = PC() + offset);
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}
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auto jrConditional(const int condition) {
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const auto offsetAddress = PC()++;
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if (condition) {
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const auto offset = busRead(offsetAddress);
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jr(offset);
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}
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return !!condition;
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}
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void ret() final;
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private:
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std::array<opcode_decoded_t, 0x100> m_decodedOpcodes;
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register16_t m_sp = Mask16;
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register16_t m_memptr;
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};
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}
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