65 lines
1 KiB
Rust
65 lines
1 KiB
Rust
use crate::cpu::CPU;
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#[allow(dead_code)]
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enum Bit
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{
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Negative = 7,
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Overflow = 6,
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Decimal = 3,
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Interrupt = 2,
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Zero = 1,
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Carry = 0,
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}
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macro_rules! set_flag
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{
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($target: expr, $flag: expr) =>
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{
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$target |= (1u8 << ($flag as u8))
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}
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}
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macro_rules! clear_flag
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{
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($target: expr, $flag: expr) =>
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{
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$target &= !(1u8 << ($flag as u8))
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}
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}
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macro_rules! set_flag_to
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{
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($target: expr, $flag: expr, $value: expr) =>
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{
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$target = ($target & !(1u8 << ($flag as u8))) | (($value as u8) << ($flag as u8));
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}
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}
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impl CPU
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{
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fn fetch(&mut self) -> u8
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{
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let bus = self.bus.upgrade().unwrap();
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return bus.borrow().read_cpu(self.absolute_addr);
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}
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pub fn jmp(&mut self)
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{
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self.pc = self.absolute_addr;
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}
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pub fn ldx(&mut self)
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{
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self.x = self.fetch();
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set_flag_to!(self.p, Bit::Negative, (self.x & (1u8 << 7)) > 0);
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set_flag_to!(self.p, Bit::Zero, self.x == 0);
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}
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pub fn stx(&mut self)
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{
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let bus = self.bus.upgrade().unwrap();
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bus.borrow_mut().write_cpu(self.absolute_addr, self.x);
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}
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} |