EightBit/inc/IntelProcessor.h
Adrian Conlon 934a1f7025 Use the virtual methods, busRead and busWrite for all processor bus actions.
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
2019-03-02 21:58:34 +00:00

182 lines
4.6 KiB
C++

#pragma once
#include <cstdint>
#include <array>
#include "Bus.h"
#include "LittleEndianProcessor.h"
#include "Register.h"
#include "EventArgs.h"
#include "Signal.h"
#include "EightBitCompilerDefinitions.h"
namespace EightBit {
class IntelProcessor : public LittleEndianProcessor {
public:
struct opcode_decoded_t {
int x = 0;
int y = 0;
int z = 0;
int p = 0;
int q = 0;
opcode_decoded_t() {}
opcode_decoded_t(const uint8_t opcode) {
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
}
};
~IntelProcessor() = default;
[[nodiscard]] const auto& getDecodedOpcode(const size_t i) const noexcept {
return m_decodedOpcodes[i];
}
[[nodiscard]] auto& MEMPTR() noexcept { return m_memptr; }
[[nodiscard]] auto& SP() noexcept { return m_sp; }
[[nodiscard]] virtual register16_t& AF() = 0;
[[nodiscard]] auto& A() { return AF().high; }
[[nodiscard]] auto& F() { return AF().low; }
[[nodiscard]] virtual register16_t& BC() = 0;
[[nodiscard]] auto& B() { return BC().high; }
[[nodiscard]] auto& C() { return BC().low; }
[[nodiscard]] virtual register16_t& DE() = 0;
[[nodiscard]] auto& D() { return DE().high; }
[[nodiscard]] auto& E() { return DE().low; }
[[nodiscard]] virtual register16_t& HL() = 0;
[[nodiscard]] auto& H() { return HL().high; }
[[nodiscard]] auto& L() { return HL().low; }
void raisePOWER() override;
DECLARE_PIN_INPUT(HALT)
protected:
IntelProcessor(Bus& bus);
template<class T> static void adjustSign(uint8_t& f, const uint8_t value) {
setFlag(f, T::SF, value & T::SF);
}
template<class T> static void adjustZero(uint8_t& f, const uint8_t value) {
clearFlag(f, T::ZF, value);
}
template<class T> static void adjustParity(uint8_t& f, const uint8_t value) {
clearFlag(f, T::PF, PARITY(value));
}
template<class T> static void adjustSZ(uint8_t& f, const uint8_t value) {
adjustSign<T>(f, value);
adjustZero<T>(f, value);
}
template<class T> static void adjustSZP(uint8_t& f, const uint8_t value) {
adjustSZ<T>(f, value);
adjustParity<T>(f, value);
}
template<class T> static void adjustXY(uint8_t& f, const uint8_t value) {
setFlag(f, T::XF, value & T::XF);
setFlag(f, T::YF, value & T::YF);
}
template<class T> static void adjustSZPXY(uint8_t& f, const uint8_t value) {
adjustSZP<T>(f, value);
adjustXY<T>(f, value);
}
template<class T> static void adjustSZXY(uint8_t& f, const uint8_t value) {
adjustSZ<T>(f, value);
adjustXY<T>(f, value);
}
//
static constexpr auto buildHalfCarryIndex(const uint8_t before, const uint8_t value, const int calculation) {
return ((before & 0x88) >> 1) | ((value & 0x88) >> 2) | ((calculation & 0x88) >> 3);
}
[[nodiscard]] static auto calculateHalfCarryAdd(const uint8_t before, const uint8_t value, const int calculation) noexcept {
static std::array<int, 8> halfCarryTableAdd = { { 0, 0, 1, 0, 1, 0, 1, 1} };
const auto index = buildHalfCarryIndex(before, value, calculation);
return halfCarryTableAdd[index & Mask3];
}
[[nodiscard]] static auto calculateHalfCarrySub(const uint8_t before, const uint8_t value, const int calculation) noexcept {
std::array<int, 8> halfCarryTableSub = { { 0, 1, 1, 1, 0, 0, 0, 1 } };
const auto index = buildHalfCarryIndex(before, value, calculation);
return halfCarryTableSub[index & Mask3];
}
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;
//
void restart(const uint8_t address) {
call(MEMPTR() = { address, 0 });
}
auto callConditional(const int condition) {
MEMPTR() = fetchWord();
if (condition)
call(MEMPTR());
return !!condition;
}
auto jumpConditional(const int condition) {
MEMPTR() = fetchWord();
if (condition)
jump(MEMPTR());
return !!condition;
}
auto returnConditional(const int condition) {
if (condition)
ret();
return !!condition;
}
void jr(const int8_t offset) {
jump(MEMPTR() = PC() + offset);
}
auto jrConditional(const int condition) {
const int8_t offset = fetchByte();
if (condition)
jr(offset);
return !!condition;
}
void ret() final;
[[nodiscard]] auto halted() noexcept { return lowered(HALT()); }
void halt() noexcept { --PC(); lowerHALT(); }
void proceed() noexcept { ++PC(); raiseHALT(); }
private:
std::array<opcode_decoded_t, 0x100> m_decodedOpcodes;
register16_t m_sp = Mask16;
register16_t m_memptr;
};
}