Fixed CPU page crossing cycles
This commit is contained in:
Souryo
parent
5574f1c4bf
commit
16b6ebeb84
2 changed files with 61 additions and 53 deletions
63
Core/CPU.cpp
63
Core/CPU.cpp
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@ -27,27 +27,47 @@ CPU::CPU(MemoryManager *memoryManager) : _memoryManager(memoryManager)
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&CPU::BEQ, &CPU::SBC_IndY, nullptr, nullptr, nullptr, &CPU::SBC_ZeroX, &CPU::INC_ZeroX, nullptr, &CPU::SED, &CPU::SBC_AbsY, nullptr, nullptr, nullptr, &CPU::SBC_AbsX, &CPU::INC_AbsX, nullptr //F
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};
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uint8_t cycles[] = {
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7,6,2,8,3,3,5,5,3,2,2,2,4,4,6,6,
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2,5,2,8,4,4,6,6,2,4,2,7,5,5,7,7,
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6,6,2,8,3,3,5,5,4,2,2,2,4,4,6,6,
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2,5,2,8,4,4,6,6,2,4,2,7,5,5,7,7,
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6,6,2,8,3,3,5,5,3,2,2,2,3,4,6,6,
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2,5,2,8,4,4,6,6,2,4,2,7,5,5,7,7,
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6,6,2,8,3,3,5,5,4,2,2,2,5,4,6,6,
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2,5,2,8,4,4,6,6,2,4,2,7,5,5,7,7,
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2,6,2,6,3,3,3,3,2,2,2,2,4,4,4,4,
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2,6,2,6,4,4,4,4,2,5,2,5,5,5,5,5,
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2,6,2,6,3,3,3,3,2,2,2,2,4,4,4,4,
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2,5,2,5,4,4,4,4,2,4,2,5,4,4,4,4,
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2,6,2,8,3,3,5,5,2,2,2,2,4,4,6,6,
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2,5,2,8,4,4,6,6,2,4,2,7,5,5,7,7,
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2,6,2,8,3,3,5,5,2,2,2,2,4,4,6,6,
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2,5,2,8,4,4,6,6,2,4,2,7,5,5,7,7
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uint8_t cycles[] {
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7, 6, 2, 8, 3, 3, 5, 5, 3, 2, 2, 2, 4, 4, 6, 6,
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2, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,
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6, 6, 2, 8, 3, 3, 5, 5, 4, 2, 2, 2, 4, 4, 6, 6,
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2, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,
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6, 6, 2, 8, 3, 3, 5, 5, 3, 2, 2, 2, 3, 4, 6, 6,
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2, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,
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6, 6, 2, 8, 3, 3, 5, 5, 4, 2, 2, 2, 5, 4, 6, 6,
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2, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,
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2, 6, 2, 6, 3, 3, 3, 3, 2, 2, 2, 2, 4, 4, 4, 4,
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2, 6, 2, 6, 4, 4, 4, 4, 2, 5, 2, 5, 5, 5, 5, 5,
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2, 6, 2, 6, 3, 3, 3, 3, 2, 2, 2, 2, 4, 4, 4, 4,
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2, 5, 2, 5, 4, 4, 4, 4, 2, 4, 2, 4, 4, 4, 4, 4,
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2, 6, 2, 8, 3, 3, 5, 5, 2, 2, 2, 2, 4, 4, 6, 6,
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2, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,
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2, 6, 3, 8, 3, 3, 5, 5, 2, 2, 2, 2, 4, 4, 6, 6,
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2, 5, 2, 8, 4, 4, 6, 6, 2, 4, 2, 7, 4, 4, 7, 7,
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};
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uint8_t cyclesPageCrossed[] {
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7, 6, 2, 8, 3, 3, 5, 5, 3, 2, 2, 2, 4, 4, 6, 6,
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2, 6, 2, 8, 4, 4, 6, 6, 2, 5, 2, 7, 5, 5, 7, 7,
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6, 6, 2, 8, 3, 3, 5, 5, 4, 2, 2, 2, 4, 4, 6, 6,
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2, 6, 2, 8, 4, 4, 6, 6, 2, 5, 2, 7, 5, 5, 7, 7,
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6, 6, 2, 8, 3, 3, 5, 5, 3, 2, 2, 2, 3, 4, 6, 6,
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2, 6, 2, 8, 4, 4, 6, 6, 2, 5, 2, 7, 5, 5, 7, 7,
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6, 6, 2, 8, 3, 3, 5, 5, 4, 2, 2, 2, 5, 4, 6, 6,
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2, 6, 2, 8, 4, 4, 6, 6, 2, 5, 2, 7, 5, 5, 7, 7,
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2, 6, 2, 6, 3, 3, 3, 3, 2, 2, 2, 2, 4, 4, 4, 4,
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2, 6, 2, 6, 4, 4, 4, 4, 2, 5, 2, 5, 5, 5, 5, 5,
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2, 6, 2, 6, 3, 3, 3, 3, 2, 2, 2, 2, 4, 4, 4, 4,
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2, 6, 2, 5, 4, 4, 4, 4, 2, 5, 2, 5, 5, 5, 5, 5,
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2, 6, 2, 8, 3, 3, 5, 5, 2, 2, 2, 2, 4, 4, 6, 6,
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2, 6, 2, 8, 4, 4, 6, 6, 2, 5, 2, 7, 5, 5, 7, 7,
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2, 6, 3, 8, 3, 3, 5, 5, 2, 2, 2, 2, 4, 4, 6, 6,
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2, 6, 2, 8, 4, 4, 6, 6, 2, 5, 2, 7, 5, 5, 7, 7,
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};
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memcpy(_opTable, opTable, sizeof(Func) * 256);
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memcpy(_cycles, cycles, sizeof(uint8_t) * 256);
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memcpy(_cyclesPageCrossed, cyclesPageCrossed, sizeof(uint8_t) * 256);
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}
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void CPU::Reset()
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@ -63,11 +83,15 @@ void CPU::Reset()
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void CPU::Exec()
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{
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if(!CPU::NMIFlag) {
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if(!_runNMI) {
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if(CPU::NMIFlag) {
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_runNMI = true;
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}
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uint8_t opCode = ReadByte();
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if(_opTable[opCode] != nullptr) {
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(this->*_opTable[opCode])();
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CPU::CycleCount += this->_cycles[opCode];
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CPU::CycleCount += GetPageCrossed() ? this->_cyclesPageCrossed[opCode] : this->_cycles[opCode];
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} else {
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//std::cout << "Invalid opcode: " << std::hex << (short)opCode;
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//throw exception("Invalid opcode");
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@ -75,6 +99,7 @@ void CPU::Exec()
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} else {
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NMI();
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CPU::CycleCount += 7;
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_runNMI = false;
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CPU::NMIFlag = false;
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}
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}
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51
Core/CPU.h
51
Core/CPU.h
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@ -35,6 +35,7 @@ private:
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Func _opTable[256];
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uint8_t _cycles[256];
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uint8_t _cyclesPageCrossed[256];
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State _state;
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@ -42,9 +43,10 @@ private:
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static uint64_t CycleCount;
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static bool NMIFlag;
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bool _runNMI = false;
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uint16_t _currentPC = 0;
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uint8_t _cyclePenalty = 0;
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bool _pageCrossed = false;
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uint8_t ReadByte()
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{
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@ -82,21 +84,14 @@ private:
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}
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}
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bool IsPageCrossed(uint16_t valA, uint8_t valB)
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bool IsPageCrossed(uint16_t valA, int8_t valB)
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{
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return (uint8_t)valA + valB >= 0x100;
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return ((valA + valB) & 0xFF00) != (valA & 0xFF00);
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}
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void MemoryWrite(uint16_t addr, uint8_t value)
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{
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_memoryManager->Write(addr, value);
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/*if(addr == 0x200) {
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std::cout << "------------------" << std::endl;
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std::cout << "(0x" << std::hex << (short)_currentPC << ") TEST NUMBER: " << std::dec << (int)value << std::endl;
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std::cout << "------------------" << std::endl;
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} else {
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//std::cout << "(0x" << std::hex << (short)_currentPC << ") W: 0x" << std::hex << (short)addr << " = 0x" << std::hex << (short)value << std::endl;
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}*/
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}
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uint8_t MemoryRead(uint16_t addr) {
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@ -165,7 +160,7 @@ private:
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uint16_t GetAbsXAddr() {
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uint16_t baseAddr = ReadWord();
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if(IsPageCrossed(baseAddr, X())) {
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SetCyclePenalty(1);
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SetPageCrossed();
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}
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return baseAddr + X();
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}
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@ -174,7 +169,7 @@ private:
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uint16_t GetAbsYAddr() {
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uint16_t baseAddr = ReadWord();
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if(IsPageCrossed(baseAddr, Y())) {
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SetCyclePenalty(1);
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SetPageCrossed();
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}
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return baseAddr + Y();
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@ -213,7 +208,7 @@ private:
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addr = MemoryReadWord(zero);
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}
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if(IsPageCrossed(addr, Y())) {
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SetCyclePenalty(1);
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SetPageCrossed();
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}
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return addr + Y();
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}
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@ -341,7 +336,6 @@ private:
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}
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void JMP(uint16_t addr) {
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//std::cout << "JMP from 0x" << std::hex << _currentPC << " to " << addr << std::endl;
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SetPC(addr);
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}
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@ -349,20 +343,11 @@ private:
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int8_t offset = GetImmediate();
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if(branch) {
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if(IsPageCrossed(PC(), offset)) {
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SetCyclePenalty(2);
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} else {
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SetCyclePenalty(1);
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SetPageCrossed();
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}
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SetPC(PC() + offset);
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CPU::CycleCount++;
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if(_currentPC == PC()) {
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if(_currentPC != 0x33a7) {
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std::cout << "Infinite loop at: 0x" << std::hex << (short)_currentPC;
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std::cout << std::endl;
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} else {
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Reset();
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}
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}
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SetPC(PC() + offset);
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}
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}
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@ -379,14 +364,14 @@ private:
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}
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}
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void SetCyclePenalty(uint8_t penalty) {
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_cyclePenalty = penalty;
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void SetPageCrossed() {
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_pageCrossed = true;
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}
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uint8_t GetCyclePenalty() {
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uint8_t penalty = _cyclePenalty;
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_cyclePenalty = 0;
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return penalty;
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bool GetPageCrossed() {
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bool pageCrossed = _pageCrossed;
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_pageCrossed = false;
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return pageCrossed;
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}
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#pragma region OP Codes
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@ -555,13 +540,11 @@ private:
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void JMP_Ind() { JMP(GetInd()); }
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void JSR() {
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uint16_t addr = GetAbsAddr();
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//std::cout << "JSR from 0x" << std::hex << _currentPC << " to " << addr;
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Push((uint16_t)(PC() - 1));
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JMP(addr);
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}
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void RTS() {
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uint16_t addr = PopWord();
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//std::cout << "RTS from 0x" << std::hex << _currentPC << " to " << addr;
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SetPC(addr + 1);
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}
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