On 03/22/2013 06:46 AM, Peter Lieven wrote: > this adds buffer_find_nonzero_offset() which is a SSE2/Altivec > optimized function that searches for non-zero content in a > buffer. > > due to the optimizations used in the function there are restrictions > on buffer address and search length. the function > can_use_buffer_find_nonzero_content() can be used to check if > the function can be used safely. > > Signed-off-by: Peter Lieven <p...@kamp.de> > --- > include/qemu-common.h | 13 +++++++++++++ > util/cutils.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 58 insertions(+)
> +#define BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR 8
> +static inline bool
> +can_use_buffer_find_nonzero_offset(const void *buf, size_t len)
> +{
> + if (len % (BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR
> + * sizeof(VECTYPE)) == 0
> + && ((uintptr_t) buf) % sizeof(VECTYPE) == 0) {
I know that emacs tends to indent the second line to the column after
the ( that it is associated with, as in:
+ if (len % (BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR
+ * sizeof(VECTYPE)) == 0
+ && ((uintptr_t) buf) % sizeof(VECTYPE) == 0) {
But since checkpatch.pl didn't complain, and since I'm not sure if there
is a codified qemu indentation style, and since I _am_ sure that not
everyone uses emacs [hi, vi guys], it's not worth respinning. A
maintainer can touch it up if desired.
> +
> +size_t buffer_find_nonzero_offset(const void *buf, size_t len)
> +{
> + VECTYPE *p = (VECTYPE *)buf;
> + VECTYPE zero = ZERO_SPLAT;
> + size_t i;
> +
> + assert(len % (BUFFER_FIND_NONZERO_OFFSET_UNROLL_FACTOR
> + * sizeof(VECTYPE)) == 0);
> + assert(((uintptr_t) buf) % sizeof(VECTYPE) == 0);
I would have written this:
assert(can_use_buffer_find_nonzero_offset(buf, len));
But that's cosmetic, and compiles to the same code, so it's not worth a
respin.
You've addressed my concerns on v3.
Reviewed-by: Eric Blake <ebl...@redhat.com>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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