You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: old.rs
    path of file: ./repos/c2rust/c2rust-refactor/tests/ownership_upgrade_ptrs
    
    the code of the file until where you have to start completion: #![feature(
    rustc_private,
    c_variadic,
    extern_types,
    register_tool,
    register_attr,
)]
#![register_tool(c2rust)]
#![register_attr(slice, nonnull, ownership_constraints)]

extern "C" {
    fn malloc(_: libc::c_ulong) -> *mut libc::c_void;
    #[ownership_constraints(le(WRITE, _0), le(_0, WRITE))]
    
pub unsafe extern "C" fn eshdn1(#[slice] mut x: *mut libc::c_ushort) {
    let mut bits: libc::c_ushort = 0; /* point to significand area */
    let mut i: libc::c_int = 0;
    x = x.offset(2);
    bits = 0i32 as libc::c_ushort;
    i = 2i32;
    while i < 10i32 + 3i32 {
        if *x as libc::c_int & 1i32 != 0 {
            bits = (bits as libc::c_int | 1i32) as libc::c_ushort
        }
        *x = (*x as libc::c_int >> 1i32) as libc::c_ushort;
        if bits as libc::c_int & 2i32 != 0 {
            *x = (*x as libc::c_int | 0x8000i32) as libc::c_ushort
        }
        bits = ((bits as libc::c_int) << 1i32) as libc::c_ushort;
        x = x.offset(1);
        i += 1
    };
}