fn swap_l(cpu: &mut Cpu) {
        let l = cpu.l();

        let r = swap(cpu, l);

        cpu.set_l(r);
    }
/// Swap low and high nibbles of `L`
Swap low and high nibbles of `L`
Swap low and high nibbles of ` L `
fn swap_l(cpu: &mut Cpu) {
        let l = cpu.l();
        let r = swap(cpu, l);
        cpu.set_l(r);
    }
fn swap_l ( cpu : & mut Cpu ) { let l = cpu . l ( ) ; let r = swap ( cpu , l ) ; cpu . set_l ( r ) ; }
Swap low and high nibbles of `L`
Swap low and high nibbles of ` L `
cpu
&mut Cpu
cpu
&mut Cpu