stak_native/
arithmetic.rs

1use stak_vm::{Error, Heap, Memory, PrimitiveSet};
2use winter_maybe_async::maybe_async;
3
4/// An arithmetic primitive.
5pub enum ArithmeticPrimitive {
6    /// A `quotient` procedure.
7    Quotient,
8}
9
10impl ArithmeticPrimitive {
11    const QUOTIENT: usize = Self::Quotient as _;
12}
13
14/// An arithmetic primitive set.
15#[derive(Debug, Default)]
16pub struct ArithmeticPrimitiveSet {}
17
18impl ArithmeticPrimitiveSet {
19    /// Creates a primitive set.
20    pub fn new() -> Self {
21        Self::default()
22    }
23}
24
25impl<H: Heap> PrimitiveSet<H> for ArithmeticPrimitiveSet {
26    type Error = Error;
27
28    #[maybe_async]
29    fn operate(&mut self, memory: &mut Memory<H>, primitive: usize) -> Result<(), Self::Error> {
30        match primitive {
31            ArithmeticPrimitive::QUOTIENT => {
32                let [x, y] = memory.pop_many()?;
33                let x = x.assume_number();
34                let y = y.assume_number();
35
36                memory.push((x - x.remainder(y)?).divide(y)?.into())?;
37            }
38            _ => return Err(Error::IllegalPrimitive),
39        }
40
41        Ok(())
42    }
43}
44
45#[cfg(test)]
46mod tests {
47    use super::*;
48    use stak_util::block_on;
49    use stak_vm::{Number, Value};
50
51    const HEAP_SIZE: usize = 1 << 8;
52
53    fn quotient(x: i64, y: i64) -> Result<i64, Error> {
54        let mut memory = Memory::new([Value::default(); HEAP_SIZE]).unwrap();
55        memory.set_stack(memory.null().unwrap());
56        memory.push(Number::from_i64(x).into()).unwrap();
57        memory.push(Number::from_i64(y).into()).unwrap();
58
59        let mut set = ArithmeticPrimitiveSet::new();
60        block_on!(set.operate(&mut memory, ArithmeticPrimitive::QUOTIENT))?;
61
62        Ok(memory.pop().unwrap().assume_number().to_i64())
63    }
64
65    #[test]
66    fn calculate_quotient() {
67        assert_eq!(quotient(7, 2), Ok(3));
68        assert_eq!(quotient(6, 3), Ok(2));
69        assert_eq!(quotient(-7, 2), Ok(-3));
70    }
71
72    #[test]
73    fn calculate_quotient_by_zero() {
74        assert!(matches!(quotient(1, 0), Ok(_) | Err(Error::DivisionByZero)));
75    }
76}
stak_native/arithmetic.rs

stak_native/
arithmetic.rs
