Re: [Qemu-devel] [RFC] find_next_bit optimizations

[Peter Maydell]

On 11 March 2013 13:44, Peter Lieven <address@hidden> wrote:

> @@ -24,12 +24,13 @@ unsigned long find_next_bit(const unsigned long *addr,
> unsigned long size,
>      const unsigned long *p = addr + BITOP_WORD(offset);
>      unsigned long result = offset & ~(BITS_PER_LONG-1);
>      unsigned long tmp;
> +    unsigned long d0,d1,d2,d3;
>
>      if (offset >= size) {
>          return size;
>      }
>      size -= result;
> -    offset %= BITS_PER_LONG;
> +    offset &= (BITS_PER_LONG-1);

This change at least is unnecessary -- I just checked, and gcc
is already smart enough to turn the % operation into a logical
and. The generated object files are identical.

-- PMM