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: compare.rs
    path of file: ./repos/rosenpass/constant-time/src
    
    the code of the file until where you have to start completion: use core::ptr;

/// Little endian memcmp version of quinier/memsec
/// http
    
pub unsafe fn memcmp_le(b1: *const u8, b2: *const u8, len: usize) -> i32 {
    let mut res = 0;
    for i in 0..len {
        let diff =
            i32::from(ptr::read_volatile(b1.add(i))) - i32::from(ptr::read_volatile(b2.add(i)));
        res = (res & (((diff - 1) & !diff) >> 8)) | diff;
    }
    ((res - 1) >> 8) + (res >> 8) + 1
}