mirror of
https://github.com/MoleskiCoder/EightBit.git
synced 2026-04-20 10:16:48 +00:00
Implement enough changes to build LR35902
This commit is contained in:
Adrian.Conlon
+41
-41
@@ -12,7 +12,7 @@ LR35902::LR35902(Bus& memory)
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void LR35902::reset() {
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Processor::reset();
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setStackPointer(0xfffe);
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sp.word = 0xfffe;
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di();
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}
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@@ -60,13 +60,13 @@ void LR35902::postDecrement(uint8_t value) {
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void LR35902::restart(uint8_t address) {
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pushWord(pc);
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pc = address;
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pc.word = address;
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}
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void LR35902::jrConditional(int conditional) {
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auto offset = (int8_t)fetchByte();
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if (conditional) {
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pc += offset;
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pc.word += offset;
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cycles++;
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}
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}
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@@ -121,22 +121,25 @@ void LR35902::jumpConditionalFlag(int flag) {
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cycles--; // Giving 8 cycles
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break;
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case 5: // GB: LD (nn),A
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m_memory.set(fetchWord(), A());
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m_memory.ADDRESS() = fetchWord();
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m_memory.reference() = A();
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cycles++; // Giving 16 cycles
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break;
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case 6: // GB: LD A,(FF00 + C)
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A() = m_memory.get(0xff00 + C());
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m_memory.ADDRESS().word = 0xff00 + C();
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A() = m_memory.reference();
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cycles--; // 8 cycles
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break;
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case 7: // GB: LD A,(nn)
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A() = m_memory.get(fetchWord());
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m_memory.ADDRESS() = fetchWord();
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A() = m_memory.reference();
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cycles++; // Giving 16 cycles
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break;
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}
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}
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void LR35902::ret() {
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pc = popWord();
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popWord(pc);
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}
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void LR35902::reti() {
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@@ -172,10 +175,10 @@ void LR35902::returnConditionalFlag(int flag) {
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case 5: { // GB: ADD SP,dd
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auto before = sp;
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auto value = fetchByte();
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sp += (int8_t)value;
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sp.word += (int8_t)value;
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clearFlag(ZF | NF);
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setFlag(CF, sp & Bit16);
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adjustHalfCarryAdd(Memory::highByte(before), value, Memory::highByte(sp));
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setFlag(CF, sp.word & Bit16);
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adjustHalfCarryAdd(before.high, value, sp.high);
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}
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cycles += 2; // 16 cycles
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break;
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@@ -186,11 +189,10 @@ void LR35902::returnConditionalFlag(int flag) {
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case 7: { // GB: LD HL,SP + dd
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auto before = sp;
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auto value = fetchByte();
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uint16_t result = before + (int8_t)value;
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HL().word = result;
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HL().word = before.word + (int8_t)value;
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clearFlag(ZF | NF);
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setFlag(CF, result & Bit16);
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adjustHalfCarryAdd(Memory::highByte(before), value, Memory::highByte(result));
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setFlag(CF, HL().word & Bit16);
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adjustHalfCarryAdd(before.high, value, HL().high);
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}
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cycles++; // 12 cycles
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break;
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@@ -198,16 +200,14 @@ void LR35902::returnConditionalFlag(int flag) {
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}
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void LR35902::call(uint16_t address) {
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pushWord(pc + 2);
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pc = address;
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pushWord(pc);
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pc.word = address;
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}
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void LR35902::callConditional(uint16_t address, int condition) {
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if (condition) {
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call(address);
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cycles += 3;
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} else {
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pc += 2;
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}
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}
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@@ -238,14 +238,14 @@ uint16_t LR35902::sbc(uint16_t value) {
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auto hl = RP(HL_IDX);
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auto high = Memory::highByte(hl);
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auto highValue = Memory::highByte(value);
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auto high = hl.high;
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auto highValue = EightBit::Memory::highByte(value);
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auto applyCarry = F() & CF;
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uint32_t result = (int)hl - (int)value;
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uint32_t result = (int)hl.word - (int)value;
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if (applyCarry)
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--result;
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auto highResult = Memory::highByte(result);
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auto highResult = EightBit::Memory::highByte(result);
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adjustZero(result);
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adjustHalfCarrySub(high, highValue, highResult);
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@@ -260,14 +260,14 @@ uint16_t LR35902::adc(uint16_t value) {
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auto hl = RP(HL_IDX);
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auto high = Memory::highByte(hl);
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auto highValue = Memory::highByte(value);
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auto high = hl.high;
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auto highValue = EightBit::Memory::highByte(value);
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auto applyCarry = F() & CF;
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uint32_t result = (int)hl + (int)value;
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uint32_t result = (int)hl.word + (int)value;
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if (applyCarry)
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++result;
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auto highResult = Memory::highByte(result);
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auto highResult = EightBit::Memory::highByte(result);
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adjustZero(result);
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adjustHalfCarryAdd(high, highValue, highResult);
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@@ -282,12 +282,12 @@ uint16_t LR35902::add(uint16_t value) {
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auto hl = RP(HL_IDX);
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auto high = Memory::highByte(hl);
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auto highValue = Memory::highByte(value);
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auto high = hl.high;
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auto highValue = EightBit::Memory::highByte(value);
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uint32_t result = (int)hl + (int)value;
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uint32_t result = (int)hl.word + (int)value;
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auto highResult = Memory::highByte(result);
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auto highResult = EightBit::Memory::highByte(result);
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clearFlag(NF);
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setFlag(CF, result & Bit16);
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@@ -304,7 +304,7 @@ void LR35902::sub(uint8_t& operand, uint8_t value, bool carry) {
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if (carry && (F() & CF))
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--result;
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operand = Memory::lowByte(result);
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operand = EightBit::Memory::lowByte(result);
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adjustZero(operand);
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adjustHalfCarrySub(before, value, result);
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@@ -328,7 +328,7 @@ void LR35902::add(uint8_t& operand, uint8_t value, bool carry) {
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if (carry && (F() & CF))
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++result;
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operand = Memory::lowByte(result);
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operand = EightBit::Memory::lowByte(result);
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adjustZero(operand);
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adjustHalfCarryAdd(before, value, result);
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@@ -625,7 +625,7 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
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cycles++;
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break;
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case 1: // GB: LD (nn),SP
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m_memory.setWord(fetchWord(), sp);
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m_memory.setWord(fetchWord().word, sp);
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cycles += 5;
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break;
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case 2: // GB: STOP
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@@ -649,7 +649,7 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
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cycles += 3;
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break;
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case 1: // ADD HL,rp
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RP(HL_IDX) = add(RP(p));
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RP(HL_IDX).word = add(RP(p).word);
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cycles += 2;
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break;
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}
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@@ -701,10 +701,10 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
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case 3: // 16-bit INC/DEC
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switch (q) {
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case 0: // INC rp
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++RP(p);
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++RP(p).word;
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break;
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case 1: // DEC rp
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--RP(p);
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--RP(p).word;
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break;
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}
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cycles += 2;
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@@ -806,7 +806,7 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
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case 1: // POP & various ops
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switch (q) {
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case 0: // POP rp2[p]
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RP2(p) = popWord();
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popWord(RP2(p));
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cycles += 3;
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break;
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case 1:
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@@ -820,11 +820,11 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
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cycles += 4;
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break;
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case 2: // JP HL
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pc = HL().word;
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pc = HL();
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cycles += 1;
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break;
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case 3: // LD SP,HL
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sp = HL().word;
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sp = HL();
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cycles += 2;
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break;
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}
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@@ -855,7 +855,7 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
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}
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break;
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case 4: // Conditional call: CALL cc[y], nn
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callConditionalFlag(getWord(pc), y);
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callConditionalFlag(fetchWord().word, y);
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cycles += 3;
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break;
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case 5: // PUSH & various ops
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@@ -867,7 +867,7 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
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case 1:
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switch (p) {
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case 0: // CALL nn
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callConditional(getWord(pc), true);
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callConditional(fetchWord().word, true);
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cycles += 3;
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break;
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}
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