mirror of https://github.com/mre/mos6502.git
Fix addition and subtraction (#72)
* extract decimal logic into separate function * squash me * I think we should be doing unsigned arithmetic here * squash me * remove unused function * update the sign checks * cargo fmt * get tests to compile again * get tests passing again * squash me * remove pointless conversion from u8 to u8 * cargo fmt * accumulator is now u8 * add adc test from solid65 * pass the new test --------- Co-authored-by: Sam M W <you@example.com>
This commit is contained in:
omarandlorraine
GitHub
parent
65817524a2
commit
aa1a47a76f
221
src/cpu.rs
221
src/cpu.rs
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@ -185,27 +185,27 @@ impl<M: Bus> CPU<M> {
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match decoded_instr {
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(Instruction::ADC, OpInput::UseImmediate(val)) => {
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debug!("add with carry immediate: {}", val);
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self.add_with_carry(val as i8);
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self.add_with_carry(val);
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}
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(Instruction::ADC, OpInput::UseAddress(addr)) => {
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let val = self.memory.get_byte(addr) as i8;
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let val = self.memory.get_byte(addr);
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debug!("add with carry. address: {:?}. value: {}", addr, val);
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self.add_with_carry(val);
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}
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(Instruction::AND, OpInput::UseImmediate(val)) => {
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self.and(val as i8);
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self.and(val);
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}
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(Instruction::AND, OpInput::UseAddress(addr)) => {
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let val = self.memory.get_byte(addr) as i8;
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let val = self.memory.get_byte(addr);
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self.and(val);
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}
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(Instruction::ASL, OpInput::UseImplied) => {
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// Accumulator mode
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let mut val = self.registers.accumulator as u8;
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let mut val = self.registers.accumulator;
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CPU::<M>::shift_left_with_flags(&mut val, &mut self.registers.status);
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self.registers.accumulator = val as i8;
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self.registers.accumulator = val;
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}
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(Instruction::ASL, OpInput::UseAddress(addr)) => {
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let mut operand: u8 = self.memory.get_byte(addr);
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@ -234,7 +234,7 @@ impl<M: Bus> CPU<M> {
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}
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(Instruction::BIT, OpInput::UseAddress(addr)) => {
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let a: u8 = self.registers.accumulator as u8;
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let a: u8 = self.registers.accumulator;
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let m: u8 = self.memory.get_byte(addr);
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let res = a & m;
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@ -372,12 +372,12 @@ impl<M: Bus> CPU<M> {
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(Instruction::LDA, OpInput::UseImmediate(val)) => {
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debug!("load A immediate: {}", val);
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self.load_accumulator(val as i8);
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self.load_accumulator(val);
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}
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(Instruction::LDA, OpInput::UseAddress(addr)) => {
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let val = self.memory.get_byte(addr);
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debug!("load A. address: {:?}. value: {}", addr, val);
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self.load_accumulator(val as i8);
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self.load_accumulator(val);
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}
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(Instruction::LDX, OpInput::UseImmediate(val)) => {
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@ -402,9 +402,9 @@ impl<M: Bus> CPU<M> {
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(Instruction::LSR, OpInput::UseImplied) => {
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// Accumulator mode
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let mut val = self.registers.accumulator as u8;
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let mut val = self.registers.accumulator;
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CPU::<M>::shift_right_with_flags(&mut val, &mut self.registers.status);
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self.registers.accumulator = val as i8;
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self.registers.accumulator = val;
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}
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(Instruction::LSR, OpInput::UseAddress(addr)) => {
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let mut operand: u8 = self.memory.get_byte(addr);
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@ -422,7 +422,7 @@ impl<M: Bus> CPU<M> {
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(Instruction::PHA, OpInput::UseImplied) => {
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// Push accumulator
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let val = self.registers.accumulator as u8;
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let val = self.registers.accumulator;
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self.push_on_stack(val);
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}
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(Instruction::PHP, OpInput::UseImplied) => {
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@ -434,12 +434,12 @@ impl<M: Bus> CPU<M> {
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// Pull accumulator
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self.pull_from_stack();
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let val: u8 = self.fetch_from_stack();
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self.registers.accumulator = val as i8;
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self.registers.accumulator = val;
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self.registers.status.set_with_mask(
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Status::PS_ZERO | Status::PS_NEGATIVE,
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Status::new(StatusArgs {
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zero: val == 0,
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negative: self.registers.accumulator < 0,
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negative: self.registers.accumulator > 127,
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..StatusArgs::none()
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}),
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);
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@ -456,9 +456,9 @@ impl<M: Bus> CPU<M> {
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(Instruction::ROL, OpInput::UseImplied) => {
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// Accumulator mode
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let mut val = self.registers.accumulator as u8;
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let mut val = self.registers.accumulator;
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CPU::<M>::rotate_left_with_flags(&mut val, &mut self.registers.status);
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self.registers.accumulator = val as i8;
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self.registers.accumulator = val;
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}
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(Instruction::ROL, OpInput::UseAddress(addr)) => {
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let mut operand: u8 = self.memory.get_byte(addr);
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@ -467,9 +467,9 @@ impl<M: Bus> CPU<M> {
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}
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(Instruction::ROR, OpInput::UseImplied) => {
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// Accumulator mode
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let mut val = self.registers.accumulator as u8;
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let mut val = self.registers.accumulator;
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CPU::<M>::rotate_right_with_flags(&mut val, &mut self.registers.status);
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self.registers.accumulator = val as i8;
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self.registers.accumulator = val;
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}
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(Instruction::ROR, OpInput::UseAddress(addr)) => {
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let mut operand: u8 = self.memory.get_byte(addr);
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@ -497,10 +497,10 @@ impl<M: Bus> CPU<M> {
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(Instruction::SBC, OpInput::UseImmediate(val)) => {
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debug!("subtract with carry immediate: {}", val);
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self.subtract_with_carry(val as i8);
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self.subtract_with_carry(val);
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}
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(Instruction::SBC, OpInput::UseAddress(addr)) => {
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let val = self.memory.get_byte(addr) as i8;
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let val = self.memory.get_byte(addr);
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debug!("subtract with carry. address: {:?}. value: {}", addr, val);
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self.subtract_with_carry(val);
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}
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@ -516,7 +516,7 @@ impl<M: Bus> CPU<M> {
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}
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(Instruction::STA, OpInput::UseAddress(addr)) => {
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self.memory.set_byte(addr, self.registers.accumulator as u8);
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self.memory.set_byte(addr, self.registers.accumulator);
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}
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(Instruction::STX, OpInput::UseAddress(addr)) => {
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self.memory.set_byte(addr, self.registers.index_x);
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@ -527,11 +527,11 @@ impl<M: Bus> CPU<M> {
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(Instruction::TAX, OpInput::UseImplied) => {
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let val = self.registers.accumulator;
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self.load_x_register(val as u8);
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self.load_x_register(val);
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}
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(Instruction::TAY, OpInput::UseImplied) => {
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let val = self.registers.accumulator;
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self.load_y_register(val as u8);
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self.load_y_register(val);
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}
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(Instruction::TSX, OpInput::UseImplied) => {
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let StackPointer(val) = self.registers.stack_pointer;
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@ -539,7 +539,7 @@ impl<M: Bus> CPU<M> {
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}
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(Instruction::TXA, OpInput::UseImplied) => {
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let val = self.registers.index_x;
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self.load_accumulator(val as i8);
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self.load_accumulator(val);
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}
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(Instruction::TXS, OpInput::UseImplied) => {
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// Note that this is the only 'transfer' instruction that does
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@ -550,7 +550,7 @@ impl<M: Bus> CPU<M> {
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}
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(Instruction::TYA, OpInput::UseImplied) => {
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let val = self.registers.index_y;
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self.load_accumulator(val as i8);
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self.load_accumulator(val);
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}
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(Instruction::NOP, OpInput::UseImplied) => {
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@ -671,11 +671,6 @@ impl<M: Bus> CPU<M> {
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CPU::<M>::set_flags_from_u8(status, value);
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}
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fn set_i8_with_flags(mem: &mut i8, status: &mut Status, value: i8) {
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*mem = value;
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CPU::<M>::set_flags_from_i8(status, value);
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}
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fn load_x_register(&mut self, value: u8) {
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CPU::<M>::set_u8_with_flags(
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&mut self.registers.index_x,
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@ -692,50 +687,50 @@ impl<M: Bus> CPU<M> {
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);
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}
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fn load_accumulator(&mut self, value: i8) {
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CPU::<M>::set_i8_with_flags(
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fn load_accumulator(&mut self, value: u8) {
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CPU::<M>::set_u8_with_flags(
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&mut self.registers.accumulator,
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&mut self.registers.status,
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value,
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);
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}
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fn add_with_carry(&mut self, value: i8) {
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let a_before: i8 = self.registers.accumulator;
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let c_before: i8 = i8::from(self.registers.status.contains(Status::PS_CARRY));
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let a_after: i8 = a_before.wrapping_add(c_before).wrapping_add(value);
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fn add_with_carry(&mut self, value: u8) {
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#[cfg(feature = "decimal_mode")]
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fn decimal_adjust(result: u8) -> u8 {
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let bcd1: u8 = if (result & 0x0f) > 0x09 { 0x06 } else { 0x00 };
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debug_assert_eq!(
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a_after as u8,
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a_before.wrapping_add(c_before).wrapping_add(value) as u8
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);
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let bcd2: u8 = if (result.wrapping_add(bcd1) & 0xf0) > 0x90 {
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0x60
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} else {
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0x00
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};
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let bcd1: i8 = if (a_after & 0x0f) as u8 > 0x09 {
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0x06
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} else {
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0x00
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};
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result.wrapping_add(bcd1).wrapping_add(bcd2)
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}
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let bcd2: i8 = if (a_after.wrapping_add(bcd1) as u8 & 0xf0) > 0x90 {
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0x60
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} else {
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0x00
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};
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let a_before: u8 = self.registers.accumulator;
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let c_before: u8 = u8::from(self.registers.status.contains(Status::PS_CARRY));
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let a_after: u8 = a_before.wrapping_add(c_before).wrapping_add(value);
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debug_assert_eq!(a_after, a_before.wrapping_add(c_before).wrapping_add(value));
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#[cfg(feature = "decimal_mode")]
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let result: i8 = if self.registers.status.contains(Status::PS_DECIMAL_MODE) {
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a_after.wrapping_add(bcd1).wrapping_add(bcd2)
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let result: u8 = if self.registers.status.contains(Status::PS_DECIMAL_MODE) {
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decimal_adjust(a_after)
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} else {
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a_after
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};
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#[cfg(not(feature = "decimal_mode"))]
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let result: i8 = a_after;
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let result: u8 = a_after;
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let did_carry = (result as u8) < (a_before as u8) || (c_before == 1 && value == -1);
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let did_carry = (result) < (a_before)
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|| (a_after == 0 && c_before == 0x01)
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|| (value == 0xff && c_before == 0x01);
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let did_overflow = (a_before < 0 && value < 0 && a_after >= 0)
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|| (a_before > 0 && value > 0 && a_after <= 0);
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let did_overflow = (a_before > 127 && value > 127 && a_after < 128)
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|| (a_before < 128 && value < 128 && a_after > 127);
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let mask = Status::PS_CARRY | Status::PS_OVERFLOW;
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@ -753,22 +748,22 @@ impl<M: Bus> CPU<M> {
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debug!("accumulator: {}", self.registers.accumulator);
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}
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fn and(&mut self, value: i8) {
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fn and(&mut self, value: u8) {
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let a_after = self.registers.accumulator & value;
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self.load_accumulator(a_after);
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}
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fn subtract_with_carry(&mut self, value: i8) {
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fn subtract_with_carry(&mut self, value: u8) {
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// A - M - (1 - C)
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// nc -- 'not carry'
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let nc: i8 = if self.registers.status.contains(Status::PS_CARRY) {
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let nc: u8 = if self.registers.status.contains(Status::PS_CARRY) {
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0
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} else {
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1
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};
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let a_before: i8 = self.registers.accumulator;
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let a_before = self.registers.accumulator;
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let a_after = a_before.wrapping_sub(value).wrapping_sub(nc);
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@ -778,40 +773,39 @@ impl<M: Bus> CPU<M> {
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// range of - M - (1 - C) is -128 to 128
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// -(127 + 1) to -(-128 + 0)
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//
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let over =
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((nc == 0 && value < 0) || (nc == 1 && value < -1)) && a_before >= 0 && a_after < 0;
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let over = (nc == 0 && value > 127) && a_before < 128 && a_after > 127;
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let under =
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(a_before < 0) && (0i8.wrapping_sub(value).wrapping_sub(nc) < 0) && a_after >= 0;
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(a_before > 127) && (0u8.wrapping_sub(value).wrapping_sub(nc) > 127) && a_after < 128;
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let did_overflow = over || under;
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let mask = Status::PS_CARRY | Status::PS_OVERFLOW;
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let bcd1: i8 = if (a_before & 0x0f).wrapping_sub(nc) < (value & 0x0f) {
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let bcd1: u8 = if (a_before & 0x0f).wrapping_sub(nc) < (value & 0x0f) {
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0x06
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} else {
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0x00
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};
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let bcd2: i8 = if (a_after.wrapping_sub(bcd1) as u8 & 0xf0) > 0x90 {
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let bcd2: u8 = if (a_after.wrapping_sub(bcd1) & 0xf0) > 0x90 {
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0x60
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} else {
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0x00
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};
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#[cfg(feature = "decimal_mode")]
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let result: i8 = if self.registers.status.contains(Status::PS_DECIMAL_MODE) {
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let result: u8 = if self.registers.status.contains(Status::PS_DECIMAL_MODE) {
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a_after.wrapping_sub(bcd1).wrapping_sub(bcd2)
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} else {
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a_after
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};
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#[cfg(not(feature = "decimal_mode"))]
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let result: i8 = a_after;
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let result = a_after;
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// The carry flag is set on unsigned overflow.
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let did_carry = (result as u8) > (a_before as u8);
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let did_carry = (result) > (a_before);
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self.registers.status.set_with_mask(
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mask,
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@ -918,20 +912,20 @@ impl<M: Bus> CPU<M> {
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// If the C flag is 1, then A (unsigned) >= NUM (unsigned) and BCS will branch
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// ...
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// The N flag contains most significant bit of the subtraction result.
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fn compare(&mut self, r: i8, val: u8) {
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if r as u8 >= val {
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fn compare(&mut self, r: u8, val: u8) {
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if r >= val {
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self.registers.status.insert(Status::PS_CARRY);
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} else {
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self.registers.status.remove(Status::PS_CARRY);
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}
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if r == val as i8 {
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if r == val {
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self.registers.status.insert(Status::PS_ZERO);
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} else {
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self.registers.status.remove(Status::PS_ZERO);
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}
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let diff: i8 = r.wrapping_sub(val as i8);
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let diff: i8 = (r as i8).wrapping_sub(val as i8);
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if diff < 0 {
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self.registers.status.insert(Status::PS_NEGATIVE);
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} else {
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@ -948,21 +942,21 @@ impl<M: Bus> CPU<M> {
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debug!("compare_with_x_register");
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let x = self.registers.index_x;
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self.compare(x as i8, val);
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self.compare(x, val);
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}
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fn compare_with_y_register(&mut self, val: u8) {
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let y = self.registers.index_y;
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self.compare(y as i8, val);
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self.compare(y, val);
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}
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fn exclusive_or(&mut self, val: u8) {
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let a_after = self.registers.accumulator ^ (val as i8);
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let a_after = self.registers.accumulator ^ val;
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self.load_accumulator(a_after);
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}
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fn inclusive_or(&mut self, val: u8) {
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let a_after = self.registers.accumulator | (val as i8);
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let a_after = self.registers.accumulator | val;
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self.load_accumulator(a_after);
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}
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@ -1006,14 +1000,14 @@ mod tests {
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#[test]
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fn dont_panic_for_overflow() {
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let mut cpu = CPU::new(Ram::new());
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cpu.add_with_carry(-128);
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assert_eq!(cpu.registers.accumulator, -128);
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cpu.add_with_carry(-128);
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cpu.add_with_carry(0x80);
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assert_eq!(cpu.registers.accumulator, 0x80);
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||||
cpu.add_with_carry(0x80);
|
||||
assert_eq!(cpu.registers.accumulator, 0);
|
||||
|
||||
cpu.subtract_with_carry(-128);
|
||||
assert_eq!(cpu.registers.accumulator, -128);
|
||||
cpu.subtract_with_carry(-128);
|
||||
cpu.subtract_with_carry(0x80);
|
||||
assert_eq!(cpu.registers.accumulator, 0x80);
|
||||
cpu.subtract_with_carry(0x80);
|
||||
assert_eq!(cpu.registers.accumulator, 0);
|
||||
}
|
||||
|
||||
|
|
@ -1053,7 +1047,7 @@ mod tests {
|
|||
cpu.registers.accumulator = 0;
|
||||
|
||||
cpu.subtract_with_carry(0x48);
|
||||
assert_eq!(cpu.registers.accumulator as u8, 0x52);
|
||||
assert_eq!(cpu.registers.accumulator, 0x52);
|
||||
assert!(cpu.registers.status.contains(Status::PS_CARRY));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
|
|
@ -1077,7 +1071,7 @@ mod tests {
|
|||
assert!(!cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_OVERFLOW));
|
||||
|
||||
cpu.add_with_carry(-1);
|
||||
cpu.add_with_carry(0xff);
|
||||
assert_eq!(cpu.registers.accumulator, 0);
|
||||
assert!(cpu.registers.status.contains(Status::PS_CARRY));
|
||||
assert!(cpu.registers.status.contains(Status::PS_ZERO));
|
||||
|
|
@ -1093,6 +1087,7 @@ mod tests {
|
|||
|
||||
let mut cpu = CPU::new(Ram::new());
|
||||
|
||||
assert_eq!(cpu.registers.accumulator, 0);
|
||||
cpu.add_with_carry(127);
|
||||
assert_eq!(cpu.registers.accumulator, 127);
|
||||
assert!(!cpu.registers.status.contains(Status::PS_CARRY));
|
||||
|
|
@ -1100,7 +1095,7 @@ mod tests {
|
|||
assert!(!cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_OVERFLOW));
|
||||
|
||||
cpu.add_with_carry(-127);
|
||||
cpu.add_with_carry(-127i8 as u8);
|
||||
assert_eq!(cpu.registers.accumulator, 0);
|
||||
assert!(cpu.registers.status.contains(Status::PS_CARRY));
|
||||
assert!(cpu.registers.status.contains(Status::PS_ZERO));
|
||||
|
|
@ -1108,15 +1103,15 @@ mod tests {
|
|||
assert!(!cpu.registers.status.contains(Status::PS_OVERFLOW));
|
||||
|
||||
cpu.registers.status.remove(Status::PS_CARRY);
|
||||
cpu.add_with_carry(-128);
|
||||
assert_eq!(cpu.registers.accumulator, -128);
|
||||
cpu.add_with_carry(0x80);
|
||||
assert_eq!(cpu.registers.accumulator, 0x80);
|
||||
assert!(!cpu.registers.status.contains(Status::PS_CARRY));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_OVERFLOW));
|
||||
|
||||
cpu.add_with_carry(127);
|
||||
assert_eq!(cpu.registers.accumulator, -1);
|
||||
assert_eq!(cpu.registers.accumulator, 0xff);
|
||||
assert!(!cpu.registers.status.contains(Status::PS_CARRY));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
|
|
@ -1132,7 +1127,7 @@ mod tests {
|
|||
assert!(!cpu.registers.status.contains(Status::PS_OVERFLOW));
|
||||
|
||||
cpu.add_with_carry(1);
|
||||
assert_eq!(cpu.registers.accumulator, -128);
|
||||
assert_eq!(cpu.registers.accumulator, 0x80);
|
||||
assert!(!cpu.registers.status.contains(Status::PS_CARRY));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
|
|
@ -1140,36 +1135,50 @@ mod tests {
|
|||
|
||||
let mut cpu = CPU::new(Ram::new());
|
||||
cpu.registers.status.or(Status::PS_CARRY);
|
||||
cpu.add_with_carry(-1);
|
||||
cpu.add_with_carry(0xff);
|
||||
assert_eq!(cpu.registers.accumulator, 0);
|
||||
assert!(cpu.registers.status.contains(Status::PS_CARRY));
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn solid65_adc_immediate() {
|
||||
let mut cpu = CPU::new(Ram::new());
|
||||
|
||||
// Adding $FF plus carry should be the same as adding $00 and no carry, so these three
|
||||
// instructions should leave the carry flags unaffected, i.e. set.
|
||||
cpu.execute_instruction((Instruction::LDA, OpInput::UseImmediate(0x9c)));
|
||||
cpu.execute_instruction((Instruction::SEC, OpInput::UseImplied));
|
||||
cpu.execute_instruction((Instruction::ADC, OpInput::UseImmediate(0xff)));
|
||||
|
||||
assert_eq!(cpu.registers.accumulator, 0x9c);
|
||||
assert!(cpu.registers.status.contains(Status::PS_CARRY));
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn and_test() {
|
||||
let mut cpu = CPU::new(Ram::new());
|
||||
|
||||
cpu.registers.accumulator = 0;
|
||||
cpu.and(-1);
|
||||
cpu.and(0xff);
|
||||
assert_eq!(cpu.registers.accumulator, 0);
|
||||
assert!(cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
|
||||
cpu.registers.accumulator = -1;
|
||||
cpu.registers.accumulator = 0xff;
|
||||
cpu.and(0);
|
||||
assert_eq!(cpu.registers.accumulator, 0);
|
||||
assert!(cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
|
||||
cpu.registers.accumulator = -1;
|
||||
cpu.registers.accumulator = 0xff;
|
||||
cpu.and(0x0f);
|
||||
assert_eq!(cpu.registers.accumulator, 0x0f);
|
||||
assert!(!cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
|
||||
cpu.registers.accumulator = -1;
|
||||
cpu.and(-128);
|
||||
assert_eq!(cpu.registers.accumulator, -128);
|
||||
cpu.registers.accumulator = 0xff;
|
||||
cpu.and(0x80);
|
||||
assert_eq!(cpu.registers.accumulator, 0x80);
|
||||
assert!(!cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
}
|
||||
|
|
@ -1182,14 +1191,14 @@ mod tests {
|
|||
cpu.registers.accumulator = 0;
|
||||
|
||||
cpu.subtract_with_carry(1);
|
||||
assert_eq!(cpu.registers.accumulator, -1);
|
||||
assert_eq!(cpu.registers.accumulator, 0xff);
|
||||
assert!(cpu.registers.status.contains(Status::PS_CARRY));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_OVERFLOW));
|
||||
|
||||
cpu.execute_instruction((Instruction::SEC, OpInput::UseImplied));
|
||||
cpu.registers.accumulator = -128;
|
||||
cpu.registers.accumulator = 0x80;
|
||||
cpu.subtract_with_carry(1);
|
||||
assert_eq!(cpu.registers.accumulator, 127);
|
||||
assert!(!cpu.registers.status.contains(Status::PS_CARRY));
|
||||
|
|
@ -1199,15 +1208,15 @@ mod tests {
|
|||
|
||||
cpu.execute_instruction((Instruction::SEC, OpInput::UseImplied));
|
||||
cpu.registers.accumulator = 127;
|
||||
cpu.subtract_with_carry(-1);
|
||||
assert_eq!(cpu.registers.accumulator, -128);
|
||||
cpu.subtract_with_carry(0xff);
|
||||
assert_eq!(cpu.registers.accumulator, 0x80);
|
||||
assert!(cpu.registers.status.contains(Status::PS_CARRY));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
assert!(cpu.registers.status.contains(Status::PS_OVERFLOW));
|
||||
|
||||
cpu.execute_instruction((Instruction::CLC, OpInput::UseImplied));
|
||||
cpu.registers.accumulator = -64;
|
||||
cpu.registers.accumulator = -64i8 as u8;
|
||||
cpu.subtract_with_carry(64);
|
||||
assert_eq!(cpu.registers.accumulator, 127);
|
||||
assert!(!cpu.registers.status.contains(Status::PS_CARRY));
|
||||
|
|
@ -1217,8 +1226,8 @@ mod tests {
|
|||
|
||||
cpu.execute_instruction((Instruction::SEC, OpInput::UseImplied));
|
||||
cpu.registers.accumulator = 0;
|
||||
cpu.subtract_with_carry(-128);
|
||||
assert_eq!(cpu.registers.accumulator, -128);
|
||||
cpu.subtract_with_carry(0x80);
|
||||
assert_eq!(cpu.registers.accumulator, 0x80);
|
||||
assert!(cpu.registers.status.contains(Status::PS_CARRY));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
|
|
@ -1227,7 +1236,7 @@ mod tests {
|
|||
cpu.execute_instruction((Instruction::CLC, OpInput::UseImplied));
|
||||
cpu.registers.accumulator = 0;
|
||||
cpu.subtract_with_carry(127);
|
||||
assert_eq!(cpu.registers.accumulator, -128);
|
||||
assert_eq!(cpu.registers.accumulator, 0x80);
|
||||
assert!(cpu.registers.status.contains(Status::PS_CARRY));
|
||||
assert!(!cpu.registers.status.contains(Status::PS_ZERO));
|
||||
assert!(cpu.registers.status.contains(Status::PS_NEGATIVE));
|
||||
|
|
@ -1583,7 +1592,7 @@ mod tests {
|
|||
cpu.exclusive_or(val);
|
||||
|
||||
let a_after = a_before ^ val;
|
||||
assert_eq!(cpu.registers.accumulator, a_after as i8);
|
||||
assert_eq!(cpu.registers.accumulator, a_after);
|
||||
|
||||
if a_after == 0 {
|
||||
assert!(cpu.registers.status.contains(Status::PS_ZERO));
|
||||
|
|
@ -1611,7 +1620,7 @@ mod tests {
|
|||
cpu.inclusive_or(val);
|
||||
|
||||
let a_after = a_before | val;
|
||||
assert_eq!(cpu.registers.accumulator, a_after as i8);
|
||||
assert_eq!(cpu.registers.accumulator, a_after);
|
||||
|
||||
if a_after == 0 {
|
||||
assert!(cpu.registers.status.contains(Status::PS_ZERO));
|
||||
|
|
|
|||
|
|
@ -162,7 +162,7 @@ impl StackPointer {
|
|||
|
||||
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
|
||||
pub struct Registers {
|
||||
pub accumulator: i8,
|
||||
pub accumulator: u8,
|
||||
pub index_x: u8,
|
||||
pub index_y: u8,
|
||||
pub stack_pointer: StackPointer,
|
||||
|
|
|
|||
Loading…
Reference in New Issue