Method init

os/src/mm/frame_allocator.rs:48–52

(&mut self, l: PhysPageNum, r: PhysPageNum)

impl StackFrameAllocator {
    pub fn init(&mut self, l: PhysPageNum, r: PhysPageNum) {
        self.current = l.0;
        self.end = r.0;
        // println!("last {} Physical Frames.", self.end - self.current);
    }
}
impl FrameAllocator for StackFrameAllocator {
    fn new() -> Self {