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221 lines
7.8 KiB
221 lines
7.8 KiB
use crate::run_thread::{ThreadToken, RunThread};
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use asm::instr::{Op, Cond};
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use crate::fault::Fault;
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use crate::frame::StackFrame;
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use asm::data::literal::{Value, is_positive, is_negative, Addr};
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pub type CyclesSpent = usize;
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pub struct EvalRes {
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pub cycles: u8,
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pub advance: i64,
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}
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impl RunThread {
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pub fn eval_op(&mut self) -> Result<EvalRes, Fault> {
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let mut cycles = 1;
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let mut advance = 1;
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let mut frame = &mut self.frame;
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let op = self.program.read(frame.pc);
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debug!("{} | {:?}", frame.pc, op);
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/* Operations can be given different execution times when run in slow mode. */
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/* Presently, all that do anything use 1 cycle. */
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match op {
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Op::Nop => {}
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Op::FarLabel(_) | Op::Routine(_) => {
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/* this is nop, but without any cost - just markers */
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cycles = 0;
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}
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Op::Barrier(msg) => {
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return Err(Fault::Barrier {
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msg: msg.clone().unwrap_or_else(|| "No msg".into())
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})
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}
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Op::Fault(msg) => {
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return Err(Fault::FaultInstr {
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msg: msg.clone().unwrap_or_else(|| "No msg".into())
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})
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}
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Op::FarJump(name) => {
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debug!("Far jump to {}", name);
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match self.program.find_far_label(name) {
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Ok(pos) => {
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debug!("label is at {}", pos);
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self.frame.pc = pos;
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}
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Err(e) => {
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return Err(e);
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}
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}
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},
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Op::Call(name, args) => {
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debug!("Call routine {}", name);
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match self.program.find_routine(name) {
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Ok(pos) => {
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debug!("routine is at {}", pos);
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let mut values = Vec::with_capacity(args.len());
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for arg in args {
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values.push(self.frame.read(*arg)?);
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}
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let mut frame2 = StackFrame::new(pos, &values);
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std::mem::swap(&mut self.frame, &mut frame2);
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self.call_stack.push(frame2);
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advance = 0;
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}
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Err(e) => {
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return Err(e);
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}
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}
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},
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Op::Ret(retvals) => {
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match self.call_stack.pop() {
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Some(previous) => {
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let mut values = Vec::with_capacity(retvals.len());
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for arg in retvals {
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values.push(frame.read(*arg)?);
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}
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*frame = previous;
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frame.set_retvals(&values);
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advance = 1; // advance past the call
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}
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None => {
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return Err(Fault::CallStackUnderflow);
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}
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}
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},
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Op::Skip(val) => {
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let steps = frame.read(*val)?;
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advance = i64::from_ne_bytes(steps.to_ne_bytes());
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self.program.validate_jump(frame.pc, Addr((frame.pc.0 as i64 + advance) as u64))?;
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}
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Op::SkipIf(cond, val) => {
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if frame.status.test(*cond) {
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let steps = frame.read(*val)?;
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advance = i64::from_ne_bytes(steps.to_ne_bytes());
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self.program.validate_jump(frame.pc, Addr((frame.pc.0 as i64 + advance) as u64))?;
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}
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}
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Op::Mov(dst, src) => {
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frame.status.clear();
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let val = frame.read(*src)?;
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frame.status.zero = (val == 0);
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frame.status.positive = is_positive(val);
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frame.status.negative = is_negative(val);
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frame.write(*dst, val)?;
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}
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Op::Cmp(a, b) => {
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frame.status.clear();
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let a = frame.read(*a)?;
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let b = frame.read(*b)?;
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frame.status.equal = a == b;
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frame.status.zero = a == 0 && b == 0;
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frame.status.lower = a < b;
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frame.status.greater = a > b;
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frame.status.positive = is_positive(a) && is_positive(b);
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frame.status.negative = is_negative(a) && is_negative(b);
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}
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Op::Inc(reg) => {
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frame.status.clear();
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let mut val = frame.read(reg.as_rd())?;
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val = val.wrapping_add(1);
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frame.status.overflow = (val == 0);
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frame.status.zero = (val == 0);
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frame.status.positive = is_positive(val);
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frame.status.negative = is_negative(val);
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frame.write(*reg, val)?;
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}
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Op::Dec(reg) => {
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frame.status.clear();
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let mut val = frame.read(reg.as_rd())?;
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frame.status.overflow = (val == 0); // will overflow
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val = val.wrapping_sub(1);
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frame.status.zero = (val == 0);
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frame.status.positive = is_positive(val);
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frame.status.negative = is_negative(val);
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frame.write(*reg, val)?;
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}
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Op::Add(dst, src) => {
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frame.status.clear();
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let mut a = frame.read(dst.as_rd())?;
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let mut b = frame.read(*src)?;
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let val = a.wrapping_add(b);
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frame.status.zero = (val == 0);
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frame.status.positive = is_positive(val);
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frame.status.negative = is_negative(val);
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frame.status.overflow = b > Value::MAX - a; // TODO check
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// TODO carry?
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frame.write(*dst, val)?;
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}
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Op::Sub(dst, src) => {
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frame.status.clear();
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let mut a = frame.read(dst.as_rd())?;
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let mut b = frame.read(*src)?;
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let val = a.wrapping_sub(b);
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frame.status.zero = (val == 0);
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frame.status.positive = is_positive(val);
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frame.status.negative = is_negative(val);
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frame.status.overflow = b > a;
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// TODO carry?
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frame.write(*dst, val)?;
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}
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Op::Mul(dst, src) => {
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frame.status.clear();
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let mut a = frame.read(dst.as_rd())?;
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let mut b = frame.read(*src)?;
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let val = a.wrapping_mul(b);
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frame.status.zero = (val == 0);
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frame.status.positive = is_positive(val);
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frame.status.negative = is_negative(val);
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//frame.status.overflow = b > a; // TODO detect overflow
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frame.write(*dst, val)?;
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}
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Op::Div(_, _) => {
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unimplemented!()
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}
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Op::Mod(_, _, _) => {
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unimplemented!()
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}
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Op::And(_, _) => {
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unimplemented!()
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}
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Op::Or(_, _) => {
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unimplemented!()
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}
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Op::Xor(_, _) => {
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unimplemented!()
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}
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Op::Cpl(_) => {
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unimplemented!()
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}
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Op::Rol(_, _) => {
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unimplemented!()
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}
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Op::Ror(_, _) => {
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unimplemented!()
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}
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Op::Lsl(_, _) => {
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unimplemented!()
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}
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Op::Lsr(_, _) => {
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unimplemented!()
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}
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Op::Asr(_, _) => {
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unimplemented!()
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}
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}
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Ok(EvalRes {
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cycles,
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advance,
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})
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}
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}
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