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use std::ops::*;

pub trait MachineInteger
: Sized +
  Copy +
  Clone +
  PartialEq +
  Eq +
  Shr<u32,Output=Self> + // MI >> u32
  Shl<u32,Output=Self> + // MI << u32
  BitAnd<Output=Self> +  // MI & MI
  BitOr<Output=Self> +   // MI | MI
  From<i32>
{
    const XLEN : u32;
    fn bit_slice(&self, i:usize, j:usize) -> Self;

    fn slice_mask(a:usize, b:usize) -> Self {
        let all_ones = Self::all_set();
        all_ones.bit_slice(a, b) << (b as u32)
    }

    fn all_set() -> Self;
    fn zero() -> Self { Self::from(0) }
}

impl MachineInteger for i32 {
    const XLEN : u32 = 32;
    fn bit_slice(&self, i:usize, j:usize) -> i32 {
        (self >> j) & ((1 << (i-j)) - 1)
    }

    fn all_set() -> Self { -1 }
}

impl MachineInteger for i64 {
    const XLEN : u32 = 64;
    fn bit_slice(&self, i:usize, j:usize) -> i64 {
        (self >> j) & ((1 << (i-j)) - 1)
    }

    fn all_set() -> Self { -1 }
}
impl MachineInteger for i128 {
    const XLEN : u32 = 128;
    fn bit_slice(&self, i:usize, j:usize) -> i128 {
        (self >> j) & ((1 << (i-j)) - 1)
    }

    fn all_set() -> Self { -1 }
}