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Implement AND Instructions

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Palindromic Bread Loaf
2025-07-23 09:44:52 -04:00
parent 748cb6e43d
commit 574d3e1312
2 changed files with 337 additions and 0 deletions
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321
src/cpu.cpp
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@@ -205,6 +205,23 @@ uint16_t CPU::AdjustDecimal(const uint16_t binary_result, const bool is_16bit) {
void CPU::ExecuteInstruction() {
// TODO: Actual Opcode decoding
switch (const uint8_t opcode = bus->Read(PC++)) {
// Bitwise AND Instructions
case 0x29: AND_Immediate(); break; // AND #$nn or #$nnnn
case 0x2D: AND_Absolute(); break; // AND $nnnn
case 0x3D: AND_AbsoluteX(); break; // AND $nnnn,X
case 0x39: AND_AbsoluteY(); break; // AND $nnnn,Y
case 0x25: AND_DirectPage(); break; // AND $nn
case 0x35: AND_DirectPageX(); break; // AND $nn,X
case 0x32: AND_IndirectDirectPage(); break; // AND ($nn)
case 0x27: AND_IndirectDirectPageLong(); break; // AND [$nn]
case 0x21: AND_IndexedIndirectDirectPageX(); break; // AND ($nn,X)
case 0x31: AND_IndirectDirectPageY(); break; // AND ($nn),Y
case 0x37: AND_IndirectDirectPageLongY(); break; // AND [$nn],Y
case 0x2F: AND_AbsoluteLong(); break; // AND $nnnnnn
case 0x3F: AND_AbsoluteLongX(); break; // AND $nnnnnn,X
case 0x23: AND_StackRelative(); break; // AND $nn,S
case 0x33: AND_StackRelativeIndirectY(); break; // AND ($nn,S),Y
// ADC - Add with Carry
case 0x69: ADC_Immediate(); break; // ADC #$nn/#$nnnn
case 0x6D: ADC_Absolute(); break; // ADC $nnnn
@@ -2126,4 +2143,308 @@ void CPU::ADC_StackRelativeIndirectY() {
DoADC(value);
cycles += 8;
}
}
void CPU::AND_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::AND_Absolute() {
const uint16_t address = ReadWord(PC);
PC += 2;
const uint32_t full_address = (DB << 16) | 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 += 4;
} else { // 16-bit mode
const uint16_t operand = ReadWord(full_address);
A &= operand;
UpdateNZ16(A);
cycles += 5;
}
}
void CPU::AND_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::AND_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::AND_DirectPage() {
const uint8_t offset = ReadByte(PC++);
const uint32_t address = D + offset;
if (P & FLAG_M) { // 8-bit mode
const 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::AND_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::AND_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::AND_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::AND_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
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::AND_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::AND_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
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
uint16_t operand = ReadWord(full_address);
A &= operand;
UpdateNZ16(A);
cycles += 7;
if (D & 0xFF) cycles++;
}
}
void CPU::AND_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::AND_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::AND_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::AND_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;
}
}