EightBit/inc/IntelProcessor.h
Adrian.Conlon c803387023 A few modifications:
1) Simplify REFRESH register handling via bit fields.
2) Use static methods in the Z80 emulator, if at all possible
3) Use a decoded opcode lookup, rather than decoding per instruction

Signed-off-by: Adrian.Conlon <adrian.conlon@gmail.com>
2017-06-26 23:22:32 +01:00

206 lines
5.1 KiB
C++

#pragma once
#include <cstdint>
#include <array>
#include "Processor.h"
namespace EightBit {
class IntelProcessor : public Processor
{
public:
register16_t& MEMPTR() { return m_memptr; }
virtual void initialise();
virtual register16_t& AF() = 0;
uint8_t& A() { return AF().high; }
uint8_t& F() { return AF().low; }
virtual register16_t& BC() = 0;
uint8_t& B() { return BC().high; }
uint8_t& C() { return BC().low; }
virtual register16_t& DE() = 0;
uint8_t& D() { return DE().high; }
uint8_t& E() { return DE().low; }
virtual register16_t& HL() = 0;
uint8_t& H() { return HL().high; }
uint8_t& L() { return HL().low; }
protected:
IntelProcessor(Memory& memory);
static void clearFlag(uint8_t& f, int flag) { f &= ~flag; }
static void setFlag(uint8_t& f, int flag) { f |= flag; }
static void setFlag(uint8_t& f, int flag, int condition) { setFlag(f, flag, condition != 0); }
static void setFlag(uint8_t& f, int flag, uint32_t condition) { setFlag(f, flag, condition != 0); }
static void setFlag(uint8_t& f, int flag, bool condition) { condition ? setFlag(f, flag) : clearFlag(f, flag); }
static void clearFlag(uint8_t& f, int flag, int condition) { clearFlag(f, flag, condition != 0); }
static void clearFlag(uint8_t& f, int flag, uint32_t condition) { clearFlag(f, flag, condition != 0); }
static void clearFlag(uint8_t& f, int flag, bool condition) { condition ? clearFlag(f, flag) : setFlag(f, flag); }
//
template<class T> static void adjustSign(uint8_t& f, uint8_t value) {
setFlag(f, T::SF, value & T::SF);
}
template<class T> static void adjustZero(uint8_t& f, uint8_t value) {
clearFlag(f, T::ZF, value);
}
template<class T> static void adjustParity(uint8_t& f, uint8_t value) {
static const uint8_t lookup[0x10] = { 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4 };
auto set = lookup[highNibble(value)] + lookup[lowNibble(value)];
clearFlag(f, T::PF, set % 2);
}
template<class T> static void adjustSZ(uint8_t& f, uint8_t value) {
adjustSign<T>(f, value);
adjustZero<T>(f, value);
}
template<class T> static void adjustSZP(uint8_t& f, uint8_t value) {
adjustSZ<T>(f, value);
adjustParity<T>(f, value);
}
template<class T> static void adjustXY(uint8_t& f, 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, uint8_t value) {
adjustSZP<T>(f, value);
adjustXY<T>(f, value);
}
template<class T> static void adjustSZXY(uint8_t& f, uint8_t value) {
adjustSZ<T>(f, value);
adjustXY<T>(f, value);
}
//
static int buildHalfCarryIndex(uint8_t before, uint8_t value, int calculation) {
return ((before & 0x88) >> 1) | ((value & 0x88) >> 2) | ((calculation & 0x88) >> 3);
}
static bool calculateHalfCarryAdd(uint8_t before, uint8_t value, int calculation) {
static std::array<bool, 8> m_halfCarryTableAdd = { { false, false, true, false, true, false, true, true } };
auto index = buildHalfCarryIndex(before, value, calculation);
return m_halfCarryTableAdd[index & Mask3];
}
static bool calculateHalfCarrySub(uint8_t before, uint8_t value, int calculation) {
std::array<bool, 8> m_halfCarryTableSub = { { false, true, true, true, false, false, false, true } };
auto index = buildHalfCarryIndex(before, value, calculation);
return m_halfCarryTableSub[index & Mask3];
}
void push(uint8_t value) {
m_memory.ADDRESS().word = --SP().word;
m_memory.reference() = value;
}
void pushWord(const register16_t& value) {
push(value.high);
push(value.low);
}
uint8_t pop() {
m_memory.ADDRESS().word = SP().word++;
return m_memory.reference();
}
void popWord(register16_t& output) {
output.low = pop();
output.high = pop();
}
void fetchWord() {
Processor::fetchWord(MEMPTR());
}
//
uint8_t& memptrReference() {
m_memory.ADDRESS() = MEMPTR();
MEMPTR().word++;
return m_memory.reference();
}
void getWordViaMemptr(register16_t& value) {
value.low = memptrReference();
m_memory.ADDRESS().word++;
value.high = m_memory.reference();
}
void setWordViaMemptr(register16_t value) {
memptrReference() = value.low;
m_memory.ADDRESS().word++;
m_memory.reference() = value.high;
}
//
void jump() {
PC() = MEMPTR();
}
void call() {
pushWord(PC());
jump();
}
void restart(uint8_t address) {
MEMPTR().low = address;
MEMPTR().high = 0;
call();
}
bool callConditional(int condition) {
fetchWord();
if (condition)
call();
return condition != 0;
}
bool jumpConditional(int conditional) {
fetchWord();
if (conditional)
jump();
return conditional != 0;
}
void ret() {
popWord(MEMPTR());
jump();
}
bool returnConditional(int condition) {
if (condition)
ret();
return condition != 0;
}
void jr(int8_t offset) {
MEMPTR().word = PC().word + offset;
jump();
}
bool jrConditional(int conditional) {
auto offset = fetchByte();
if (conditional)
jr(offset);
return conditional != 0;
}
private:
register16_t m_memptr;
};
}