Function nonzero_bit_index

kernel/src/memory/frame_allocator.rs:21–30

Return the index of a non-zero bit Uses the BSF instruction: Assumes that at least one bit is not zero

(bitmap: u32)

///
/// Assumes that at least one bit is not zero
fn nonzero_bit_index(bitmap: u32) -> u32 {
    let index: u32;
    unsafe {
        asm!("bsf eax, ecx",
             in("ecx") bitmap,
             lateout("eax") index,
             options(pure, nomem, nostack));
    }
    index
}

#[test_case]
fn test_nonzero_bit_index() {