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Merge pull request #25 from amw-zero/ark-bcs

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Implement BCS instruction
This commit is contained in:
Andrew Keeton 2014-11-06 19:42:42 -05:00
commit d42922a788
1 changed files with 24 additions and 0 deletions
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24
src/machine.rs
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@ -116,6 +116,11 @@ impl Machine {
self.branch_if_carry_clear(addr);
}
(instruction::BCS, instruction::UseRelative(rel)) => {
let addr = self.registers.program_counter
+ AddressDiff(rel as i32);
self.branch_if_carry_set(addr);
}
(instruction::BIT, instruction::UseAddress(addr)) => {
let a: u8 = self.registers.accumulator as u8;
@ -554,6 +559,12 @@ impl Machine {
}
}
fn branch_if_carry_set(&mut self, addr: Address) {
if self.registers.status.contains(PS_CARRY) {
self.registers.program_counter = addr;
}
}
fn branch_if_minus(&mut self, addr: Address) {
if self.registers.status.contains(PS_NEGATIVE) {
self.registers.program_counter = addr;
@ -886,6 +897,19 @@ fn branch_if_carry_clear_test() {
assert_eq!(machine.registers.program_counter, Address(0xABCD));
}
#[test]
fn branch_if_carry_set_test() {
let mut machine = Machine::new();
machine.execute_instruction((instruction::CLC, instruction::UseImplied));
machine.branch_if_carry_set(Address(0xABCD));
assert_eq!(machine.registers.program_counter, Address(0));
machine.execute_instruction((instruction::SEC, instruction::UseImplied));
machine.branch_if_carry_set(Address(0xABCD));
assert_eq!(machine.registers.program_counter, Address(0xABCD));
}
#[test]
fn branch_if_minus_test() {
{