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Implement Exclusive OR Instructions

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Palindromic Bread Loaf
2025-07-23 20:23:33 -04:00
parent 2037e3f076
commit 1f9051a60d
2 changed files with 338 additions and 1 deletions
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323
src/cpu.cpp
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@@ -142,7 +142,7 @@ uint16_t CPU::PopWord() {
return (high << 8) | low;
}
void CPU::DoADC(uint16_t value) {
void CPU::DoADC(const uint16_t value) {
uint32_t result;
if (P & FLAG_M) {
@@ -389,6 +389,23 @@ void CPU::ExecuteInstruction() {
case 0xC6: DEC_DirectPage(); break; // DEC $nn
case 0xD6: DEC_DirectPageX(); break; // DEC $nn,X
// EOR - Exclusive OR
case 0x49: EOR_Immediate(); break; // EOR #$nn or #$nnnn
case 0x4D: EOR_Absolute(); break; // EOR $nnnn
case 0x5D: EOR_AbsoluteX(); break; // EOR $nnnn,X
case 0x59: EOR_AbsoluteY(); break; // EOR $nnnn,Y
case 0x45: EOR_DirectPage(); break; // EOR $nn
case 0x55: EOR_DirectPageX(); break; // EOR $nn,X
case 0x52: EOR_IndirectDirectPage(); break; // EOR ($nn)
case 0x47: EOR_IndirectDirectPageLong(); break; // EOR [$nn]
case 0x41: EOR_IndexedIndirectDirectPageX(); break; // EOR ($nn,X)
case 0x51: EOR_IndirectDirectPageY(); break; // EOR ($nn),Y
case 0x57: EOR_IndirectDirectPageLongY(); break; // EOR [$nn],Y
case 0x4F: EOR_AbsoluteLong(); break; // EOR $nnnnnn
case 0x5F: EOR_AbsoluteLongX(); break; // EOR $nnnnnn,X
case 0x43: EOR_StackRelative(); break; // EOR $nn,S
case 0x53: EOR_StackRelativeIndirectY(); break; // EOR ($nn,S),Y
// JMP - Jump to an Address
case 0x4C: JMP_Absolute(); break; // JMP $nnnn
case 0x6C: JMP_AbsoluteIndirect(); break; // JMP ($nnnn)
@@ -2903,3 +2920,307 @@ void CPU::CMP_IndirectDirectPageLongY() {
if (D & 0xFF) cycles++;
}
}
void CPU::EOR_Immediate() {
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(PC++);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 2;
} else { // 16-bit mode
const uint16_t operand = ReadWord(PC);
PC += 2;
A ^= operand;
UpdateNZ16(A);
cycles += 3;
}
}
void CPU::EOR_Absolute() {
const uint16_t address = ReadWord(PC);
PC += 2;
const uint32_t full_address = (DB << 16) | address;
if (P & FLAG_M) { // 8-bit mode
uint8_t operand = ReadByte(full_address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 4;
} else { // 16-bit mode
uint16_t operand = ReadWord(full_address);
A ^= operand;
UpdateNZ16(A);
cycles += 5;
}
}
void CPU::EOR_AbsoluteX() {
const uint16_t base_address = ReadWord(PC);
PC += 2;
const uint32_t full_address = (DB << 16) | (base_address + X);
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(full_address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 4;
if ((base_address & 0xFF00) != ((base_address + X) & 0xFF00)) {
cycles++;
}
} else { // 16-bit mode
const uint16_t operand = ReadWord(full_address);
A ^= operand;
UpdateNZ16(A);
cycles += 5;
if ((base_address & 0xFF00) != ((base_address + X) & 0xFF00)) {
cycles++;
}
}
}
void CPU::EOR_AbsoluteY() {
const uint16_t base_address = ReadWord(PC);
PC += 2;
const uint32_t full_address = (DB << 16) | (base_address + Y);
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(full_address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 4;
if ((base_address & 0xFF00) != ((base_address + Y) & 0xFF00)) {
cycles++;
}
} else { // 16-bit mode
const uint16_t operand = ReadWord(full_address);
A ^= operand;
UpdateNZ16(A);
cycles += 5;
if ((base_address & 0xFF00) != ((base_address + Y) & 0xFF00)) {
cycles++;
}
}
}
void CPU::EOR_DirectPage() {
const uint8_t offset = ReadByte(PC++);
const uint32_t address = D + offset;
if (P & FLAG_M) { // 8-bit mode
uint8_t operand = ReadByte(address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 3;
if (D & 0xFF) cycles++;
} else { // 16-bit mode
const uint16_t operand = ReadWord(address);
A ^= operand;
UpdateNZ16(A);
cycles += 4;
if (D & 0xFF) cycles++;
}
}
void CPU::EOR_DirectPageX() {
const uint8_t offset = ReadByte(PC++);
const uint32_t address = D + offset + X;
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 4;
if (D & 0xFF) cycles++;
} else { // 16-bit mode
const uint16_t operand = ReadWord(address);
A ^= operand;
UpdateNZ16(A);
cycles += 5;
if (D & 0xFF) cycles++;
}
}
void CPU::EOR_IndirectDirectPage() {
const uint8_t offset = ReadByte(PC++);
const uint32_t pointer_address = D + offset;
const uint16_t indirect_address = ReadWord(pointer_address);
const uint32_t full_address = (DB << 16) | indirect_address;
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(full_address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 5;
if (D & 0xFF) cycles++;
} else { // 16-bit mode
const uint16_t operand = ReadWord(full_address);
A ^= operand;
UpdateNZ16(A);
cycles += 6;
if (D & 0xFF) cycles++;
}
}
void CPU::EOR_IndirectDirectPageLong() {
const uint8_t offset = ReadByte(PC++);
const uint32_t pointer_address = D + offset;
const uint32_t full_address = ReadByte(pointer_address) |
(ReadByte(pointer_address + 1) << 8) |
(ReadByte(pointer_address + 2) << 16);
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(full_address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 6;
if (D & 0xFF) cycles++;
} else { // 16-bit mode
const uint16_t operand = ReadWord(full_address);
A ^= operand;
UpdateNZ16(A);
cycles += 7;
if (D & 0xFF) cycles++;
}
}
void CPU::EOR_IndexedIndirectDirectPageX() {
const uint8_t offset = ReadByte(PC++);
const uint32_t pointer_address = D + offset + X;
const uint16_t indirect_address = ReadWord(pointer_address);
const uint32_t full_address = (DB << 16) | indirect_address;
if (P & FLAG_M) { // 8-bit mode
uint8_t operand = ReadByte(full_address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 6;
if (D & 0xFF) cycles++;
} else { // 16-bit mode
const uint16_t operand = ReadWord(full_address);
A ^= operand;
UpdateNZ16(A);
cycles += 7;
if (D & 0xFF) cycles++;
}
}
void CPU::EOR_IndirectDirectPageY() {
const uint8_t offset = ReadByte(PC++);
const uint32_t pointer_address = D + offset;
const uint16_t base_address = ReadWord(pointer_address);
const uint32_t full_address = (DB << 16) | (base_address + Y);
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(full_address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 5;
if (D & 0xFF) cycles++;
if ((base_address & 0xFF00) != ((base_address + Y) & 0xFF00)) {
cycles++;
}
} else { // 16-bit mode
const uint16_t operand = ReadWord(full_address);
A ^= operand;
UpdateNZ16(A);
cycles += 6;
if (D & 0xFF) cycles++;
if ((base_address & 0xFF00) != ((base_address + Y) & 0xFF00)) {
cycles++;
}
}
}
void CPU::EOR_IndirectDirectPageLongY() {
const uint8_t offset = ReadByte(PC++);
const uint32_t pointer_address = D + offset;
const uint32_t base_address = ReadByte(pointer_address) |
(ReadByte(pointer_address + 1) << 8) |
(ReadByte(pointer_address + 2) << 16);
const uint32_t full_address = base_address + Y;
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(full_address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 6;
if (D & 0xFF) cycles++;
} else { // 16-bit mode
const uint16_t operand = ReadWord(full_address);
A ^= operand;
UpdateNZ16(A);
cycles += 7;
if (D & 0xFF) cycles++;
}
}
void CPU::EOR_AbsoluteLong() {
const uint32_t address = ReadByte(PC) | (ReadByte(PC + 1) << 8) | (ReadByte(PC + 2) << 16);
PC += 3;
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 5;
} else { // 16-bit mode
const uint16_t operand = ReadWord(address);
A ^= operand;
UpdateNZ16(A);
cycles += 6;
}
}
void CPU::EOR_AbsoluteLongX() {
const uint32_t base_address = ReadByte(PC) | (ReadByte(PC + 1) << 8) | (ReadByte(PC + 2) << 16);
PC += 3;
const uint32_t full_address = base_address + X;
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(full_address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 5;
} else { // 16-bit mode
const uint16_t operand = ReadWord(full_address);
A ^= operand;
UpdateNZ16(A);
cycles += 6;
}
}
void CPU::EOR_StackRelative() {
const uint8_t offset = ReadByte(PC++);
const uint32_t address = SP + offset;
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 4;
} else { // 16-bit mode
const uint16_t operand = ReadWord(address);
A ^= operand;
UpdateNZ16(A);
cycles += 5;
}
}
void CPU::EOR_StackRelativeIndirectY() {
const uint8_t offset = ReadByte(PC++);
const uint32_t pointer_address = SP + offset;
const uint16_t base_address = ReadWord(pointer_address);
const uint32_t full_address = (DB << 16) | (base_address + Y);
if (P & FLAG_M) { // 8-bit mode
const uint8_t operand = ReadByte(full_address);
A = (A & 0xFF00) | ((A & 0xFF) ^ operand);
UpdateNZ8(A & 0xFF);
cycles += 7;
} else { // 16-bit mode
const uint16_t operand = ReadWord(full_address);
A ^= operand;
UpdateNZ16(A);
cycles += 8;
}
}

16
src/cpu.h
View File

@@ -260,6 +260,22 @@ public:
void CMP_IndirectDirectPageLong();
void CMP_StackRelativeIndirectY();
void CMP_IndirectDirectPageLongY();
void EOR_Immediate();
void EOR_Absolute();
void EOR_AbsoluteX();
void EOR_AbsoluteY();
void EOR_DirectPage();
void EOR_DirectPageX();
void EOR_IndirectDirectPage();
void EOR_IndirectDirectPageLong();
void EOR_IndexedIndirectDirectPageX();
void EOR_IndirectDirectPageY();
void EOR_IndirectDirectPageLongY();
void EOR_AbsoluteLong();
void EOR_AbsoluteLongX();
void EOR_StackRelative();
void EOR_StackRelativeIndirectY();
};
#endif //CPU_H