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Add a bunch of undocumented 6502 instructions. Abandoned ATX implementation. Too poorly documented.

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Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
This commit is contained in:
Adrian Conlon 2018-12-30 12:01:23 +00:00
parent 815c99710a
commit 5ade05a689
2 changed files with 37 additions and 11 deletions
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4
M6502/inc/mos6502.h
View File

@ -168,6 +168,10 @@ namespace EightBit {
// Undocumented compound instructions
void anc(uint8_t value);
void arr(uint8_t value);
void asr(uint8_t value);
void axs(uint8_t value);
void dcp(uint8_t value);
void isb(uint8_t value);
void rla(uint8_t value);

44
M6502/src/mos6502.cpp
View File

@ -107,7 +107,7 @@ int EightBit::MOS6502::execute() {
case 0x08: addCycle(); php(); break; // PHP
case 0x09: A() = orr(A(), AM_Immediate()); break; // ORA (immediate)
case 0x0a: addCycle(); A() = asl(A()); break; // ASL A
case 0x0b: break;
case 0x0b: addCycle(); anc(AM_Immediate()); break; // *ANC (immediate)
case 0x0c: AM_Absolute(); break; // *NOP (absolute)
case 0x0d: A() = orr(A(), AM_Absolute()); break; // ORA (absolute)
case 0x0e: addCycle(); Processor::busWrite(asl(AM_Absolute())); break; // ASL (absolute)
@ -141,7 +141,7 @@ int EightBit::MOS6502::execute() {
case 0x28: addCycles(2); plp(); break; // PLP
case 0x29: A() = andr(A(), AM_Immediate()); break; // AND (immediate)
case 0x2a: addCycle(); A() = rol(A()); break; // ROL A
case 0x2b: break;
case 0x2b: addCycle(); anc(AM_Immediate()); break; // *ANC (immediate)
case 0x2c: bit(A(), AM_Absolute()); break; // BIT (absolute)
case 0x2d: A() = andr(A(), AM_Absolute()); break; // AND (absolute)
case 0x2e: addCycle(); Processor::busWrite(rol(AM_Absolute())); break; // ROL (absolute)
@ -175,7 +175,7 @@ int EightBit::MOS6502::execute() {
case 0x48: addCycle(); push(A()); break; // PHA
case 0x49: A() = eorr(A(), AM_Immediate()); break; // EOR (immediate)
case 0x4a: addCycle(); A() = lsr(A()); break; // LSR A
case 0x4b: break;
case 0x4b: asr(AM_Immediate()); break; // *ASR (immediate)
case 0x4c: jump(Address_Absolute()); break; // JMP (absolute)
case 0x4d: A() = eorr(A(), AM_Absolute()); break; // EOR (absolute)
case 0x4e: addCycle(); Processor::busWrite(lsr(AM_Absolute())); break; // LSR (absolute)
@ -209,7 +209,7 @@ int EightBit::MOS6502::execute() {
case 0x68: addCycles(2); A() = through(pop()); break; // PLA
case 0x69: A() = adc(A(), AM_Immediate()); break; // ADC (immediate)
case 0x6a: addCycle(); A() = ror(A()); break; // ROR A
case 0x6b: break;
case 0x6b: addCycle(); arr(AM_Immediate()); break; // *ARR (immediate)
case 0x6c: jump(Address_Indirect()); break; // JMP (indirect)
case 0x6d: A() = adc(A(), AM_Absolute()); break; // ADC (absolute)
case 0x6e: addCycle(); Processor::busWrite(ror(AM_Absolute())); break; // ROR (absolute)
@ -234,14 +234,14 @@ int EightBit::MOS6502::execute() {
case 0x80: AM_Immediate(); break; // *NOP (immediate)
case 0x81: addCycle(); Processor::busWrite(Address_IndexedIndirectX(), A()); break; // STA (indexed indirect X)
case 0x82: break;
case 0x82: AM_Immediate(); break; // *NOP (immediate)
case 0x83: addCycle(); Processor::busWrite(Address_IndexedIndirectX(), A() & X()); break; // *SAX (indexed indirect X)
case 0x84: Processor::busWrite(Address_ZeroPage(), Y()); break; // STY (zero page)
case 0x85: Processor::busWrite(Address_ZeroPage(), A()); break; // STA (zero page)
case 0x86: Processor::busWrite(Address_ZeroPage(), X()); break; // STX (zero page)
case 0x87: Processor::busWrite(Address_ZeroPage(), A() & X()); break; // *SAX (zero page)
case 0x88: addCycle(); Y() = dec(Y()); break; // DEY
case 0x89: break;
case 0x89: AM_Immediate(); break; // *NOP (immediate)
case 0x8a: addCycle(); A() = through(X()); break; // TXA
case 0x8b: break;
case 0x8c: Processor::busWrite(Address_Absolute(), Y()); break; // STY (absolute)
@ -277,7 +277,7 @@ int EightBit::MOS6502::execute() {
case 0xa8: addCycle(); Y() = through(A()); break; // TAY
case 0xa9: A() = through(AM_Immediate()); break; // LDA (immediate)
case 0xaa: addCycle(); X() = through(A()); break; // TAX
case 0xab: break;
case 0xab: break; // *ATX (immediate)
case 0xac: Y() = through(AM_Absolute()); break; // LDY (absolute)
case 0xad: A() = through(AM_Absolute()); break; // LDA (absolute)
case 0xae: X() = through(AM_Absolute()); break; // LDX (absolute)
@ -302,7 +302,7 @@ int EightBit::MOS6502::execute() {
case 0xc0: cmp(Y(), AM_Immediate()); break; // CPY (immediate)
case 0xc1: addCycle(); cmp(A(), AM_IndexedIndirectX()); break; // CMP (indexed indirect X)
case 0xc2: break;
case 0xc2: AM_Immediate(); break; // *NOP (immediate)
case 0xc3: addCycles(2); dcp(AM_IndexedIndirectX()); break; // *DCP (indexed indirect X)
case 0xc4: cmp(Y(), AM_ZeroPage()); break; // CPY (zero page)
case 0xc5: cmp(A(), AM_ZeroPage()); break; // CMP (zero page)
@ -311,7 +311,7 @@ int EightBit::MOS6502::execute() {
case 0xc8: addCycle(); Y() = inc(Y()); break; // INY
case 0xc9: cmp(A(), AM_Immediate()); break; // CMP (immediate)
case 0xca: addCycle(); X() = dec(X()); break; // DEX
case 0xcb: break;
case 0xcb: axs(AM_Immediate()); break; // *AXS (immediate)
case 0xcc: cmp(Y(), AM_Absolute()); break; // CPY (absolute)
case 0xcd: cmp(A(), AM_Absolute()); break; // CMP (absolute)
case 0xce: addCycle(); Processor::busWrite(dec(AM_Absolute())); break; // DEC (absolute)
@ -336,7 +336,7 @@ int EightBit::MOS6502::execute() {
case 0xe0: cmp(X(), AM_Immediate()); break; // CPX (immediate)
case 0xe1: addCycle(); A() = sbc(A(), AM_IndexedIndirectX()); break; // SBC (indexed indirect X)
case 0xe2: break;
case 0xe2: AM_Immediate(); break; // *NOP (immediate)
case 0xe3: addCycles(2); isb(AM_IndexedIndirectX()); break; // *ISB (indexed indirect X)
case 0xe4: cmp(X(), AM_ZeroPage()); break; // CPX (zero page)
case 0xe5: A() = sbc(A(), AM_ZeroPage()); break; // SBC (zero page)
@ -568,7 +568,7 @@ uint8_t EightBit::MOS6502::andr(const uint8_t operand, const uint8_t data) {
}
uint8_t EightBit::MOS6502::asl(const uint8_t value) {
setFlag(P(), CF, (value & Bit7) >> 7);
setFlag(P(), CF, value & Bit7);
return through(value << 1);
}
@ -651,6 +651,28 @@ void EightBit::MOS6502::rts() {
// Undocumented compound instructions
void EightBit::MOS6502::anc(const uint8_t value) {
A() = andr(A(), value);
setFlag(P(), CF, A() & Bit7);
}
void EightBit::MOS6502::arr(const uint8_t value) {
A() = andr(A(), value);
A() = ror(A());
setFlag(P(), CF, A() & Bit6);
setFlag(P(), VF, ((A() & Bit6) >> 6) ^((A() & Bit5) >> 5));
}
void EightBit::MOS6502::asr(const uint8_t value) {
A() = andr(A(), value);
A() = lsr(A());
}
void EightBit::MOS6502::axs(const uint8_t value) {
X() = through(sub(A() & X(), value));
clearFlag(P(), CF, m_intermediate.high);
}
void EightBit::MOS6502::dcp(const uint8_t value) {
Processor::busWrite(dec(value));
cmp(A(), BUS().DATA());