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More refactoring of functions

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This commit is contained in:
Palindromic Bread Loaf
2025-07-29 10:16:18 -04:00
parent d40414efd8
commit 45f688e8c9
2 changed files with 40 additions and 166 deletions
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203
src/cpu.cpp
View File

@@ -201,6 +201,22 @@ uint16_t CPU::AdjustDecimal(const uint16_t binary_result, const bool is_16bit) {
return result;
}
void CPU::LDA_Mem(const uint32_t address, const int base_cycles, const bool addDPExtraCycle = false, const bool addPageCrossCycle = false, const uint16_t base = 0, const uint16_t offset = 0) {
if (P & FLAG_M) {
const uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += base_cycles;
} else {
A = ReadWord(address);
UpdateNZ16(A);
cycles += base_cycles + 1;
}
if (addDPExtraCycle && (D & 0xFF)) cycles++;
if (addPageCrossCycle && ((base & 0xFF00) != ((base + offset) & 0xFF00))) cycles++;
}
void CPU::UpdateASLFlags8(const uint8_t original_value, const uint8_t result) {
if (original_value & 0x80) {
P |= FLAG_C;
@@ -922,215 +938,70 @@ void CPU::LDA_Absolute() {
const uint16_t address = ReadWord(PC);
PC += 2;
if (P & FLAG_M) {
// 8-bit mode
const uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += 4;
} else {
// 16-bit mode
A = ReadWord(address);
UpdateNZ16(A);
cycles += 5;
}
LDA_Mem(address, 4);
}
void CPU::LDA_AbsoluteX() {
const uint16_t base_address = ReadWord(PC);
const uint16_t base = ReadWord(PC);
PC += 2;
const uint32_t address = base_address + X;
// Page boundary crossing adds a cycle in some cases
if ((base_address & 0xFF00) != (address & 0xFF00)) {
cycles++;
}
if (P & FLAG_M) {
// 8-bit mode
const uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += 4;
} else {
// 16-bit mode
A = ReadWord(address);
UpdateNZ16(A);
cycles += 5;
}
LDA_Mem(base + X, 4, false, true, base, X);
}
void CPU::LDA_AbsoluteY() {
uint16_t base_address = ReadWord(PC);
const uint16_t base = ReadWord(PC);
PC += 2;
uint32_t address = base_address + Y;
// Page boundary crossing adds a cycle
if ((base_address & 0xFF00) != (address & 0xFF00)) {
cycles++;
}
if (P & FLAG_M) {
// 8-bit mode
uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += 4;
} else {
// 16-bit mode
A = ReadWord(address);
UpdateNZ16(A);
cycles += 5;
}
LDA_Mem(base + Y, 4, false, true, base, Y);
}
void CPU::LDA_DirectPage() {
const uint8_t offset = ReadByte(PC++);
const uint32_t address = D + offset;
if (P & FLAG_M) {
// 8-bit mode
uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += 3;
} else {
// 16-bit mode
A = ReadWord(address);
UpdateNZ16(A);
cycles += 4;
}
// Extra cycle if D register is not page-aligned
if (D & 0xFF) cycles++;
LDA_Mem(D + offset, 3, true);
}
void CPU::LDA_DirectPageX() {
const uint8_t offset = ReadByte(PC++);
const uint32_t address = D + offset + (P & FLAG_X ? (X & 0xFF) : X);
const uint16_t x_offset = (P & FLAG_X) ? (X & 0xFF) : X;
if (P & FLAG_M) {
// 8-bit mode
const uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += 4;
} else {
// 16-bit mode
A = ReadWord(address);
UpdateNZ16(A);
cycles += 5;
}
// Extra cycle if D register is not page-aligned
if (D & 0xFF) cycles++;
LDA_Mem(D + offset + x_offset, 4, true);
}
void CPU::LDA_IndirectDirectPage() {
const uint8_t offset = ReadByte(PC++);
const uint32_t pointer_address = D + offset;
const uint16_t address = ReadWord(pointer_address);
const uint32_t ptr = D + offset;
const uint16_t address = ReadWord(ptr);
if (P & FLAG_M) {
// 8-bit mode
const uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += 5;
} else {
// 16-bit mode
A = ReadWord(address);
UpdateNZ16(A);
cycles += 6;
}
// Extra cycle if D register is not page-aligned
if (D & 0xFF) cycles++;
LDA_Mem(address, 5, true);
}
void CPU::LDA_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 address = base_address + Y;
const uint32_t ptr = D + offset;
const uint16_t base = ReadWord(ptr);
// Page boundary crossing adds a cycle
if ((base_address & 0xFF00) != (address & 0xFF00)) {
cycles++;
}
if (P & FLAG_M) {
// 8-bit mode
const uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += 5;
} else {
// 16-bit mode
A = ReadWord(address);
UpdateNZ16(A);
cycles += 6;
}
// Extra cycle if D register is not page-aligned
if (D & 0xFF) cycles++;
LDA_Mem(base + Y, 5, true, true, base, Y);
}
void CPU::LDA_DirectPageIndirectX() {
const uint8_t offset = ReadByte(PC++);
const uint32_t pointer_address = D + offset + (P & FLAG_X ? (X & 0xFF) : X);
const uint16_t address = ReadWord(pointer_address);
const uint16_t x_offset = (P & FLAG_X) ? (X & 0xFF) : X;
const uint32_t ptr = D + offset + x_offset;
const uint16_t address = ReadWord(ptr);
if (P & FLAG_M) {
// 8-bit mode
uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += 6;
} else {
// 16-bit mode
A = ReadWord(address);
UpdateNZ16(A);
cycles += 7;
}
// Extra cycle if D register is not page-aligned
if (D & 0xFF) cycles++;
LDA_Mem(address, 6, true);
}
void CPU::LDA_Long() {
const uint32_t address = ReadByte(PC++) | (ReadByte(PC++) << 8) | (ReadByte(PC++) << 16);
if (P & FLAG_M) {
// 8-bit mode
const uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += 5;
} else {
// 16-bit mode
A = ReadWord(address);
UpdateNZ16(A);
cycles += 6;
}
LDA_Mem(address, 5);
}
void CPU::LDA_LongX() {
const uint32_t base_address = ReadByte(PC++) | (ReadByte(PC++) << 8) | (ReadByte(PC++) << 16);
const uint32_t address = base_address + X;
const uint32_t base = ReadByte(PC++) | (ReadByte(PC++) << 8) | (ReadByte(PC++) << 16);
if (P & FLAG_M) {
// 8-bit mode
const uint8_t value = ReadByte(address);
A = (A & 0xFF00) | value;
UpdateNZ8(value);
cycles += 5;
} else {
// 16-bit mode
A = ReadWord(address);
UpdateNZ16(A);
cycles += 6;
}
LDA_Mem(base + X, 5);
}
// Load X Register Instructions

3
src/cpu.h
View File

@@ -67,6 +67,9 @@ class CPU {
// Helper method to check for decimal mode adjustment
static uint16_t AdjustDecimal(uint16_t binary_result, bool is_16bit);
void LDA_Mem(uint32_t address, int base_cycles, bool addDPExtraCycle, bool addPageCrossCycle, uint16_t base,
uint16_t offset);
// General ORA Logic
void ORA_Mem(uint32_t address, int base_cycles, bool addDPExtraCycle, bool addPageCrossCycle, uint16_t base_address,
uint16_t offset);