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Refactor register bit length detection

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This commit is contained in:
Franco Colmenarez 2021-10-15 09:49:35 -05:00
parent dbe95bedf2
commit c55256a5b7
1 changed files with 30 additions and 8 deletions
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38
src/cpu.rs
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@ -28,6 +28,21 @@ pub enum Register {
PC, // Program counter
}
type Rg = Register;
impl Register {
pub fn is_8bit(&self) -> bool {
match self {
Rg::A | Rg::F | Rg::B | Rg::C | Rg::D | Rg::E | Rg::H | Rg::L => true,
Rg::AF | Rg::BC | Rg::DE | Rg::HL | Rg::SP | Rg::PC => false,
}
}
pub fn is_16bit(&self) -> bool {
!self.is_8bit()
}
}
#[derive(Debug, Copy, Clone)]
pub enum FlagRegister {
Zero, // Set when the result of a math operation is zero or if two values matches using the CP instruction
@ -275,14 +290,11 @@ impl CPU {
self.registers.increment(Register::PC, 3);
},
OpcodeParameter::U16_Register(address, register) => {
type Rg = Register;
let value = self.registers.get(register);
let bytes = value.to_be_bytes();
match register {
Rg::A | Rg::F | Rg::B | Rg::C | Rg::D | Rg::E | Rg::H | Rg::L => {
bus.write(address, bytes[1]);
},
Rg::AF | Rg::BC | Rg::DE | Rg::HL | Rg::SP | Rg::PC => {
match register.is_8bit() {
true => bus.write(address, bytes[1]),
false => {
bus.write(address, bytes[1]);
bus.write(address + 1, bytes[0]);
}
@ -297,7 +309,12 @@ impl CPU {
self.registers.increment(register, 1);
if affect_flags {
self.registers.set_flag(FlagRegister::Substract, false);
if add_half_carry(prev_value.to_be_bytes()[1], 1) {
let mut byte_compare = 0;
match register.is_8bit() {
true => byte_compare = prev_value.to_be_bytes()[1],
false => byte_compare = prev_value.to_be_bytes()[0],
}
if add_half_carry(byte_compare, 1) {
self.registers.set_flag(FlagRegister::HalfCarry, true);
}
let result = self.registers.get(register);
@ -313,7 +330,12 @@ impl CPU {
self.registers.decrement(register, 1);
if affect_flags {
self.registers.set_flag(FlagRegister::Substract, true);
if sub_half_carry(prev_value.to_be_bytes()[1], 1) {
let mut byte_compare = 0;
match register.is_8bit() {
true => byte_compare = prev_value.to_be_bytes()[1],
false => byte_compare = prev_value.to_be_bytes()[0],
}
if sub_half_carry(byte_compare, 1) {
self.registers.set_flag(FlagRegister::HalfCarry, true);
}
let result = self.registers.get(register);