X86_64 load from variable address

3

I can do this:

#[test]
fn test_00() {
    let mut ops = dynasmrt::x64::Assembler::new().unwrap();

    let instrs = ops.offset();

    let mut x: i64 = 23;

    dynasm!(ops
        ; .arch x64
        ; mov rax, QWORD (&mut x as *mut i64 as u64 as i64)
        ; mov rax, [rax]
        ; ret
    );

    x = 24;
    let buf = ops.finalize().unwrap();

    let hello_fn: extern "sysv64" fn() -> u64 = unsafe { mem::transmute(buf.ptr(instrs)) };

    assert_eq!(hello_fn(), 24);}

but I am having problem trying to convert it to a single instruction. In particular, the inside of '[x] seems to want a i32 instead of an i64.