breadloaf/BreadedSNES
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Cleanup ROL instructions

Browse Source
This commit is contained in:
Palindromic Bread Loaf
2025-07-28 12:40:13 -04:00
parent 9ba05a45ef
commit 265cd69937
2 changed files with 22 additions and 57 deletions
Download Patch File Download Diff File Expand all files Collapse all files

77
src/cpu.cpp
View File

@@ -335,6 +335,20 @@ uint16_t CPU::ROL16(uint16_t value) {
return value;
}
void CPU::ROL_AtAddress(const uint32_t address, const int base_cycles_8bit, const int base_cycles_16bit) {
if (P & FLAG_M) {
uint8_t value = ReadByte(address);
value = ROL8(value);
WriteByte(address, value);
cycles += base_cycles_8bit;
} else {
uint16_t value = ReadWord(address);
value = ROL16(value);
WriteWord(address, value);
cycles += base_cycles_16bit;
}
}
uint8_t CPU::ROR8(uint8_t value) {
const bool old_carry = (P & FLAG_C) != 0;
const bool new_carry = (value & 0x01) != 0;
@@ -4190,8 +4204,8 @@ void CPU::MVN() {
}
void CPU::MVP() {
uint8_t dest_bank = ReadByte(PC++);
uint8_t src_bank = ReadByte(PC++);
const uint8_t dest_bank = ReadByte(PC++);
const uint8_t src_bank = ReadByte(PC++);
const uint32_t src_address = (src_bank << 16) | X;
const uint32_t dest_address = (dest_bank << 16) | Y;
@@ -4232,19 +4246,7 @@ void CPU::ROL_Absolute() {
const uint16_t address = ReadWord(PC);
PC += 2;
if (P & FLAG_M) {
// 8-bit mode
uint8_t value = ReadByte((DB << 16) | address);
value = ROL8(value);
WriteByte((DB << 16) | address, value);
cycles += 6;
} else {
// 16-bit mode
uint16_t value = ReadWord((DB << 16) | address);
value = ROL16(value);
WriteWord((DB << 16) | address, value);
cycles += 7;
}
ROL_AtAddress((DB << 16) | address, 6, 7);
}
void CPU::ROL_AbsoluteX() {
@@ -4252,40 +4254,14 @@ void CPU::ROL_AbsoluteX() {
PC += 2;
const uint32_t address = (DB << 16) | (base_address + X);
if (P & FLAG_M) {
// 8-bit mode
uint8_t value = ReadByte(address);
value = ROL8(value);
WriteByte(address, value);
cycles += 7;
} else {
// 16-bit mode
uint16_t value = ReadWord(address);
value = ROL16(value);
WriteWord(address, value);
cycles += 8;
}
ROL_AtAddress(address, 7, 8);
}
void CPU::ROL_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);
value = ROL8(value);
WriteByte(address, value);
cycles += 5;
} else {
// 16-bit mode
uint16_t value = ReadWord(address);
value = ROL16(value);
WriteWord(address, value);
cycles += 6;
}
// Add extra cycle if D register low byte is non-zero
ROL_AtAddress(address, 5, 6);
if (D & 0xFF) cycles++;
}
@@ -4293,20 +4269,7 @@ void CPU::ROL_DirectPageX() {
const uint8_t offset = ReadByte(PC++);
const uint32_t address = D + offset + (P & FLAG_X ? (X & 0xFF) : X);
if (P & FLAG_M) {
// 8-bit mode
uint8_t value = ReadByte(address);
value = ROL8(value);
WriteByte(address, value);
cycles += 6;
} else {
// 16-bit mode
uint16_t value = ReadWord(address);
value = ROL16(value);
WriteWord(address, value);
cycles += 7;
}
ROL_AtAddress(address, 6, 7);
if (D & 0xFF) cycles++;
}