mirror of
https://github.com/MoleskiCoder/EightBit.git
synced 2024-12-29 07:30:14 +00:00
MC6809: Add a cycle eater routine.
Signed-off-by: Adrian Conlon <adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon
parent
c81204512c
commit
ff02159886
@ -123,6 +123,11 @@ namespace EightBit {
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const uint8_t SWI3vector = 0xf2; // SWI3 vector
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const uint8_t RESERVEDvector = 0xf0; // RESERVED vector
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void eat(int cycles = 1) {
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for (int cycle = 0; cycle < cycles; ++cycle)
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memoryRead(0xffff);
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}
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// Stack manipulation
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void push(register16_t& stack, uint8_t value);
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@ -305,7 +310,7 @@ namespace EightBit {
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void branchLong(const int condition) {
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if (branch(Address_relative_word(), condition))
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memoryRead(0xffff);
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eat();
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}
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// Miscellaneous
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@ -10,7 +10,7 @@
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const auto data = ACCESSOR(); \
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const auto address = BUS().ADDRESS(); \
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const auto result = OPERATION(data); \
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memoryRead(0xffff); \
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eat(); \
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memoryWrite(address, result); \
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}
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@ -72,7 +72,7 @@ void EightBit::mc6809::handleRESET() {
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memoryRead(0xfffe);
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memoryRead(0xfffe);
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jump(getWordPaged(0xff, RESETvector));
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memoryRead(0xffff);
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eat();
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}
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void EightBit::mc6809::handleNMI() {
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@ -81,13 +81,13 @@ void EightBit::mc6809::handleNMI() {
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raiseBS();
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memoryRead();
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memoryRead();
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memoryRead(0xffff);
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eat();
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saveEntireRegisterState();
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memoryRead(0xffff);
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eat();
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CC() = setBit(CC(), IF); // Disable IRQ
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CC() = setBit(CC(), FF); // Disable FIRQ
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jump(getWordPaged(0xff, NMIvector));
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memoryRead(0xffff);
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eat();
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}
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void EightBit::mc6809::handleINT() {
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@ -96,12 +96,12 @@ void EightBit::mc6809::handleINT() {
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raiseBS();
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memoryRead();
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memoryRead();
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memoryRead(0xffff);
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eat();
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saveEntireRegisterState();
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memoryRead(0xffff);
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eat();
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CC() = setBit(CC(), IF); // Disable IRQ
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jump(getWordPaged(0xff, IRQvector));
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memoryRead(0xffff);
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eat();
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}
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void EightBit::mc6809::handleFIRQ() {
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@ -110,13 +110,13 @@ void EightBit::mc6809::handleFIRQ() {
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raiseBS();
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memoryRead();
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memoryRead();
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memoryRead(0xffff);
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eat();
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savePartialRegisterState();
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memoryRead(0xffff);
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eat();
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CC() = setBit(CC(), IF); // Disable IRQ
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CC() = setBit(CC(), FF); // Disable FIRQ
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jump(getWordPaged(0xff, FIRQvector));
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memoryRead(0xffff);
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eat();
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}
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//
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@ -137,7 +137,7 @@ uint8_t EightBit::mc6809::busRead() {
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void EightBit::mc6809::call(register16_t destination) {
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memoryRead(destination);
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memoryRead(0xffff);
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eat();
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BigEndianProcessor::pushWord(PC());
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jump(destination);
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}
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@ -172,7 +172,7 @@ void EightBit::mc6809::executeUnprefixed() {
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case 0x11: m_prefix11 = true; Processor::execute(fetchByte()); break;
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// ABX
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case 0x3a: memoryRead(); X() += B(); memoryRead(0xffff); break; // ABX (inherent)
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case 0x3a: memoryRead(); X() += B(); eat(); break; // ABX (inherent)
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// ADC
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case 0x89: A() = adc(A(), AM_immediate_byte()); break; // ADC (ADCA immediate)
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@ -212,7 +212,7 @@ void EightBit::mc6809::executeUnprefixed() {
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case 0xe4: B() = andr(B(), AM_indexed_byte()); break; // AND (ANDB indexed)
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case 0xf4: B() = andr(B(), AM_extended_byte()); break; // AND (ANDB extended)
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case 0x1c: CC() &= AM_immediate_byte(); memoryRead(0xffff); break; // AND (ANDCC immediate)
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case 0x1c: CC() &= AM_immediate_byte(); eat(); break; // AND (ANDCC immediate)
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// ASL/LSL
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case 0x08: RMW(AM_direct_byte, asl); break; // ASL (direct)
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@ -393,7 +393,7 @@ void EightBit::mc6809::executeUnprefixed() {
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case 0xfa: B() = orr(B(), AM_extended_byte()); break; // OR (ORB extended)
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// ORCC
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case 0x1a: CC() |= AM_immediate_byte(); memoryRead(0xffff); break; // OR (ORCC immediate)
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case 0x1a: CC() |= AM_immediate_byte(); eat(); break; // OR (ORCC immediate)
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// PSH
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case 0x34: psh(S(), AM_immediate_byte()); break; // PSH (PSHS immediate)
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@ -670,7 +670,7 @@ EightBit::register16_t& EightBit::mc6809::RR(const int which) {
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EightBit::register16_t EightBit::mc6809::Address_relative_byte() {
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const auto address = PC() + (int8_t)fetchByte();
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memoryRead(0xffff);
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eat();
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return address;
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}
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@ -680,7 +680,7 @@ EightBit::register16_t EightBit::mc6809::Address_relative_word() {
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EightBit::register16_t EightBit::mc6809::Address_direct() {
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const auto offset = fetchByte();
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memoryRead(0xffff);
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eat();
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return register16_t(offset, DP());
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}
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@ -696,31 +696,25 @@ EightBit::register16_t EightBit::mc6809::Address_indexed() {
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ASSUME(!indirect);
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address = r++;
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memoryRead(PC());
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(2);
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break;
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case 0b0001: // ,R++
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address = r;
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r += 2;
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memoryRead(PC());
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(3);
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break;
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case 0b0010: // ,-R
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ASSUME(!indirect);
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address = --r;
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memoryRead(PC());
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(2);
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break;
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case 0b0011: // ,--R
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r -= 2;
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address = r;
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memoryRead(PC());
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(3);
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break;
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case 0b0100: // ,R
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address = r;
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@ -729,30 +723,28 @@ EightBit::register16_t EightBit::mc6809::Address_indexed() {
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case 0b0101: // B,R
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address = r + (int8_t)B();
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memoryRead(PC());
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memoryRead(0xffff);
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eat();
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break;
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case 0b0110: // A,R
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address = r + (int8_t)A();
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memoryRead(PC());
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memoryRead(0xffff);
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eat();
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break;
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case 0b1000: // n,R (eight-bit)
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address = r + (int8_t)fetchByte();
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memoryRead(0xffff);
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eat();
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break;
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case 0b1001: // n,R (sixteen-bit)
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address = r + (int16_t)fetchWord().word;
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memoryRead(PC());
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(2);
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break;
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case 0b1011: // D,R
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address = r + D();
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memoryRead(PC());
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memoryRead(PC() + 1);
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memoryRead(PC() + 2);
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(2);
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break;
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case 0b1100: // n,PCR (eight-bit)
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address = Address_relative_byte();
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@ -760,9 +752,7 @@ EightBit::register16_t EightBit::mc6809::Address_indexed() {
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case 0b1101: // n,PCR (sixteen-bit)
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address = Address_relative_word();
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memoryRead(PC());
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(3);
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break;
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case 0b1111: // [n]
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assert(indirect);
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@ -774,19 +764,20 @@ EightBit::register16_t EightBit::mc6809::Address_indexed() {
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}
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if (indirect) {
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address = Processor::getWord(address);
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memoryRead(0xffff);
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eat();
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}
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} else {
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// EA = ,R + 5-bit offset
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address = r + signExtend(5, type & Mask5);
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memoryRead(0xffff);
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memoryRead(PC());
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eat();
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}
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return address;
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}
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EightBit::register16_t EightBit::mc6809::Address_extended() {
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const auto ea = fetchWord();
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memoryRead(0xffff);
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eat();
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return ea;
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}
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@ -861,7 +852,7 @@ uint8_t EightBit::mc6809::add(const uint8_t operand, const uint8_t data, const u
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EightBit::register16_t EightBit::mc6809::add(const register16_t operand, const register16_t data) {
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const uint32_t addition = operand.word + data.word;
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adjustAddition(operand, data, addition);
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memoryRead(0xffff);
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eat();
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return addition & Mask16;
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}
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@ -909,7 +900,7 @@ uint8_t EightBit::mc6809::com(const uint8_t operand) {
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void EightBit::mc6809::cwai(const uint8_t data) {
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CC() &= data;
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memoryRead(PC());
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memoryRead(0xffff);
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eat();
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saveEntireRegisterState();
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halt();
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}
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@ -988,12 +979,7 @@ void EightBit::mc6809::exg(const uint8_t data) {
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else
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std::swap(referenceTransfer16(reg1), referenceTransfer16(reg2));
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(6);
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}
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uint8_t EightBit::mc6809::inc(uint8_t operand) {
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@ -1019,15 +1005,7 @@ EightBit::register16_t EightBit::mc6809::mul(const uint8_t first, const uint8_t
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const register16_t result = first * second;
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adjustZero(result);
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CC() = setBit(CC(), CF, result.low & Bit7);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(9);
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return result;
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}
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@ -1045,8 +1023,7 @@ uint8_t EightBit::mc6809::orr(const uint8_t operand, const uint8_t data) {
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}
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void EightBit::mc6809::psh(register16_t& stack, const uint8_t data) {
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(2);
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memoryRead(stack);
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if (data & Bit7)
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pushWord(stack, PC());
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@ -1068,8 +1045,7 @@ void EightBit::mc6809::psh(register16_t& stack, const uint8_t data) {
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}
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void EightBit::mc6809::pul(register16_t& stack, const uint8_t data) {
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(2);
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if (data & Bit0)
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CC() = pop(stack);
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if (data & Bit1)
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@ -1109,35 +1085,35 @@ uint8_t EightBit::mc6809::ror(const uint8_t operand) {
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void EightBit::mc6809::rti() {
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restoreRegisterState();
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memoryRead(0xffff);
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eat();
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}
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void EightBit::mc6809::rts() {
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ret();
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memoryRead(0xffff);
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eat();
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}
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void EightBit::mc6809::swi() {
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memoryRead(0xffff);
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eat();
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saveEntireRegisterState();
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CC() = setBit(CC(), IF); // Disable IRQ
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CC() = setBit(CC(), FF); // Disable FIRQ
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jump(getWordPaged(0xff, SWIvector));
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memoryRead(0xffff);
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eat();
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}
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void EightBit::mc6809::swi2() {
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memoryRead(0xffff);
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eat();
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saveEntireRegisterState();
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jump(getWordPaged(0xff, SWI2vector));
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memoryRead(0xffff);
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eat();
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}
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void EightBit::mc6809::swi3() {
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memoryRead(0xffff);
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eat();
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saveEntireRegisterState();
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jump(getWordPaged(0xff, SWI3vector));
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memoryRead(0xffff);
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eat();
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}
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uint8_t EightBit::mc6809::sex(const uint8_t from) {
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@ -1158,10 +1134,7 @@ void EightBit::mc6809::tfr(const uint8_t data) {
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else
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referenceTransfer16(reg2) = referenceTransfer16(reg1);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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memoryRead(0xffff);
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eat(4);
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}
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uint8_t EightBit::mc6809::sbc(const uint8_t operand, const uint8_t data) {
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@ -1177,7 +1150,7 @@ uint8_t EightBit::mc6809::sub(const uint8_t operand, const uint8_t data, const u
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EightBit::register16_t EightBit::mc6809::sub(const register16_t operand, const register16_t data) {
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const uint32_t subtraction = operand.word - data.word;
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adjustSubtraction(operand, data, subtraction);
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memoryRead(0xffff);
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eat();
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return subtraction & Mask16;
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}
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