6502/EightBit
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More cycle accuracy changes, concentrating on stack operations.

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Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2019-01-05 23:21:43 +00:00
parent f5125b2a35
commit 3337f57747
2 changed files with 15 additions and 11 deletions
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2
M6502/inc/mos6502.h
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@ -147,7 +147,7 @@ namespace EightBit {
uint8_t dec(uint8_t value); uint8_t dec(uint8_t value);
uint8_t eorr(uint8_t operand, uint8_t data); uint8_t eorr(uint8_t operand, uint8_t data);
uint8_t inc(uint8_t value); uint8_t inc(uint8_t value);
void jsr(register16_t destination); void jsr();
uint8_t lsr(uint8_t value); uint8_t lsr(uint8_t value);
uint8_t orr(uint8_t operand, uint8_t data); uint8_t orr(uint8_t operand, uint8_t data);
void php(); void php();

24
M6502/src/mos6502.cpp
View File

@ -104,7 +104,7 @@ int EightBit::MOS6502::execute() {
case 0x05: A() = orr(A(), AM_ZeroPage()); break; // ORA (zero page) case 0x05: A() = orr(A(), AM_ZeroPage()); break; // ORA (zero page)
case 0x06: busReadModifyWrite(asl(AM_ZeroPage())); break; // ASL (zero page) case 0x06: busReadModifyWrite(asl(AM_ZeroPage())); break; // ASL (zero page)
case 0x07: slo(AM_ZeroPage()); break; // *SLO (zero page) case 0x07: slo(AM_ZeroPage()); break; // *SLO (zero page)
case 0x08: addCycle(); php(); break; // PHP (implied) case 0x08: busRead(); php(); break; // PHP (implied)
case 0x09: A() = orr(A(), AM_Immediate()); break; // ORA (immediate) case 0x09: A() = orr(A(), AM_Immediate()); break; // ORA (immediate)
case 0x0a: busRead(); A() = asl(A()); break; // ASL A (implied) case 0x0a: busRead(); A() = asl(A()); break; // ASL A (implied)
case 0x0b: addCycle(); anc(AM_Immediate()); break; // *ANC (immediate) case 0x0b: addCycle(); anc(AM_Immediate()); break; // *ANC (immediate)
@ -130,7 +130,7 @@ int EightBit::MOS6502::execute() {
case 0x1e: addCycle(); busReadModifyWrite(asl(AM_AbsoluteX())); break; // ASL (absolute, X) case 0x1e: addCycle(); busReadModifyWrite(asl(AM_AbsoluteX())); break; // ASL (absolute, X)
case 0x1f: slo(AM_AbsoluteX()); break; // *SLO (absolute, X) case 0x1f: slo(AM_AbsoluteX()); break; // *SLO (absolute, X)
case 0x20: addCycle(); jsr(Address_Absolute()); break; // JSR (absolute) case 0x20: jsr(); break; // JSR (absolute)
case 0x21: A() = andr(A(), AM_IndexedIndirectX()); break; // AND (indexed indirect X) case 0x21: A() = andr(A(), AM_IndexedIndirectX()); break; // AND (indexed indirect X)
case 0x22: break; case 0x22: break;
case 0x23: rla(AM_IndexedIndirectX()); break; // *RLA (indexed indirect X) case 0x23: rla(AM_IndexedIndirectX()); break; // *RLA (indexed indirect X)
@ -138,7 +138,7 @@ int EightBit::MOS6502::execute() {
case 0x25: A() = andr(A(), AM_ZeroPage()); break; // AND (zero page) case 0x25: A() = andr(A(), AM_ZeroPage()); break; // AND (zero page)
case 0x26: busReadModifyWrite(rol(AM_ZeroPage())); break; // ROL (zero page) case 0x26: busReadModifyWrite(rol(AM_ZeroPage())); break; // ROL (zero page)
case 0x27: rla(AM_ZeroPage()); break; // *RLA (zero page) case 0x27: rla(AM_ZeroPage()); break; // *RLA (zero page)
case 0x28: addCycles(2); plp(); break; // PLP (implied) case 0x28: busRead(); getBytePaged(1, S()); plp(); break; // PLP (implied)
case 0x29: A() = andr(A(), AM_Immediate()); break; // AND (immediate) case 0x29: A() = andr(A(), AM_Immediate()); break; // AND (immediate)
case 0x2a: busRead(); A() = rol(A()); break; // ROL A (implied) case 0x2a: busRead(); A() = rol(A()); break; // ROL A (implied)
case 0x2b: addCycle(); anc(AM_Immediate()); break; // *ANC (immediate) case 0x2b: addCycle(); anc(AM_Immediate()); break; // *ANC (immediate)
@ -172,7 +172,7 @@ int EightBit::MOS6502::execute() {
case 0x45: A() = eorr(A(), AM_ZeroPage()); break; // EOR (zero page) case 0x45: A() = eorr(A(), AM_ZeroPage()); break; // EOR (zero page)
case 0x46: busReadModifyWrite(lsr(AM_ZeroPage())); break; // LSR (zero page) case 0x46: busReadModifyWrite(lsr(AM_ZeroPage())); break; // LSR (zero page)
case 0x47: sre(AM_ZeroPage()); break; // *SRE (zero page) case 0x47: sre(AM_ZeroPage()); break; // *SRE (zero page)
case 0x48: addCycle(); push(A()); break; // PHA (implied) case 0x48: busRead(); push(A()); break; // PHA (implied)
case 0x49: A() = eorr(A(), AM_Immediate()); break; // EOR (immediate) case 0x49: A() = eorr(A(), AM_Immediate()); break; // EOR (immediate)
case 0x4a: busRead(); A() = lsr(A()); break; // LSR A (implied) case 0x4a: busRead(); A() = lsr(A()); break; // LSR A (implied)
case 0x4b: asr(AM_Immediate()); break; // *ASR (immediate) case 0x4b: asr(AM_Immediate()); break; // *ASR (immediate)
@ -198,7 +198,7 @@ int EightBit::MOS6502::execute() {
case 0x5e: addCycle(); busReadModifyWrite(lsr(AM_AbsoluteX())); break; // LSR (absolute, X) case 0x5e: addCycle(); busReadModifyWrite(lsr(AM_AbsoluteX())); break; // LSR (absolute, X)
case 0x5f: sre(AM_AbsoluteX()); break; // *SRE (absolute, X) case 0x5f: sre(AM_AbsoluteX()); break; // *SRE (absolute, X)
case 0x60: addCycles(3); rts(); break; // RTS (implied) case 0x60: busRead(); rts(); break; // RTS (implied)
case 0x61: A() = adc(A(), AM_IndexedIndirectX()); break; // ADC (indexed indirect X) case 0x61: A() = adc(A(), AM_IndexedIndirectX()); break; // ADC (indexed indirect X)
case 0x62: break; case 0x62: break;
case 0x63: rra(AM_IndexedIndirectX()); break; // *RRA (indexed indirect X) case 0x63: rra(AM_IndexedIndirectX()); break; // *RRA (indexed indirect X)
@ -206,7 +206,7 @@ int EightBit::MOS6502::execute() {
case 0x65: A() = adc(A(), AM_ZeroPage()); break; // ADC (zero page) case 0x65: A() = adc(A(), AM_ZeroPage()); break; // ADC (zero page)
case 0x66: busReadModifyWrite(ror(AM_ZeroPage())); break; // ROR (zero page) case 0x66: busReadModifyWrite(ror(AM_ZeroPage())); break; // ROR (zero page)
case 0x67: rra(AM_ZeroPage()); break; // *RRA (zero page) case 0x67: rra(AM_ZeroPage()); break; // *RRA (zero page)
case 0x68: addCycles(2); A() = through(pop()); break; // PLA (implied) case 0x68: busRead(); getBytePaged(1, S()); A() = through(pop()); break; // PLA (implied)
case 0x69: A() = adc(A(), AM_Immediate()); break; // ADC (immediate) case 0x69: A() = adc(A(), AM_Immediate()); break; // ADC (immediate)
case 0x6a: busRead(); A() = ror(A()); break; // ROR A (implied) case 0x6a: busRead(); A() = ror(A()); break; // ROR A (implied)
case 0x6b: addCycle(); arr(AM_Immediate()); break; // *ARR (immediate) case 0x6b: addCycle(); arr(AM_Immediate()); break; // *ARR (immediate)
@ -618,9 +618,12 @@ uint8_t EightBit::MOS6502::inc(const uint8_t value) {
return through(value + 1); return through(value + 1);
} }
void EightBit::MOS6502::jsr(const register16_t destination) { void EightBit::MOS6502::jsr() {
--PC(); const auto low = fetchByte();
call(destination); getBytePaged(1, S()); // dummy read
pushWord(PC());
PC().high = fetchByte();
PC().low = low;
} }
uint8_t EightBit::MOS6502::lsr(const uint8_t value) { uint8_t EightBit::MOS6502::lsr(const uint8_t value) {
@ -660,8 +663,9 @@ void EightBit::MOS6502::rti() {
} }
void EightBit::MOS6502::rts() { void EightBit::MOS6502::rts() {
getBytePaged(1, S()); // dummy read
ret(); ret();
++PC(); fetchByte();
} }
// Undocumented compound instructions // Undocumented compound instructions