meap/meap-code/ch5/ch5-fixed-width.rs


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use num::{Float};

/// Q1_7 - single byte representation of a fixed point number with range [-1, 1]. 
/// The name refers to the Texas Instrument representation
/// 
/// References:
///  - English Wikipedia: "Q (number format)" https://en.wikipedia.org/wiki/Q_(number_format)
struct Q1_7(i8); // tuple struct holding a i8 value

impl From<T: Float> for Q1_7 {
    fn from (n:T) -> Self {
        let val = if n > 1.0 { // out of bounds numbers are coerced to the maximum of the range
            1
        } else if n < -1.0 {
            -1
        } else {
            n * (2**7)
        }

        Q1_7(val as i8)
    }
}

impl From for U: Float {
    fn from(q: Q1_7) -> U {
        q.0 * (2 ** -7)
    }
}

mod tests {
    use super::*;

    test
}