Replace some x86_64 specific inline assembly with something that
all 64-bit hosts ought to optimize well. At worst this becomes
a call to the gcc __multi3 routine, which is no worse than our
implementation in util/host-utils.c.
With gcc 4.7, we get identical code generation for x86_64. We
now get native multiplication on ia64 and s390x hosts. With minor
improvements to gcc we can get it for ppc64 as well.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Add function comments to the routines, documenting the corner
cases upon which we are standardizing. Fix the few instances
of non-standard coding style.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
We will standardize on these names, rather than the similar routines
currently residing in qemu/bitops.h.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
We had two copies of a ffs function for longs with subtly different
semantics and, for the one in bitops.h, a confusing name: the result
was off-by-one compared to the library function ffsl.
Unify the functions into one, and solve the name problem by calling
the 0-based functions "bitops_ctzl" and "bitops_ctol" respectively.
This also fixes the build on platforms with ffsl, including Mac OS X
and Windows.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Andreas Färber <afaerber@suse.de>
Tested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
We can provide fast versions based on the other functions defined
by host-utils.h. Some care is required on glibc, which provides
ffsl already.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Richard Henderson