addWrap

    pub fn addWrap(r: *Mutable, a: Const, b: Const, signedness: Signedness, bit_count: usize) bool {
        const req_limbs = calcTwosCompLimbCount(bit_count);

        // Slice of the upper bits if they exist, these will be ignored and allows us to use addCarry to determine
        // if an overflow occurred.
        const x: Const = .{
            .positive = a.positive,
            .limbs = a.limbs[0..@min(req_limbs, a.limbs.len)],
        };

        const y: Const = .{
            .positive = b.positive,
            .limbs = b.limbs[0..@min(req_limbs, b.limbs.len)],
        };

        var carry_truncated = false;
        if (r.addCarry(x, y)) {
            // There are two possibilities here:
            // - We overflowed req_limbs. In this case, the carry is ignored, as it would be removed by
            //   truncate anyway.
            // - a and b had less elements than req_limbs, and those were overflowed. This case needs to be handled.
            //   Note: after this we still might need to wrap.
            const msl = @max(a.limbs.len, b.limbs.len);
            if (msl < req_limbs) {
                r.len = msl + 1;
                r.limbs[msl] = 1;
            } else {
                carry_truncated = true;
            }
        }

        if (!r.toConst().fitsInTwosComp(signedness, bit_count)) {
            r.truncate(r.toConst(), signedness, bit_count);
            return true;
        }

        return carry_truncated;
    }