From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54710) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1etYZN-0004bt-HJ for qemu-devel@nongnu.org; Wed, 07 Mar 2018 07:53:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1etYZK-0000W7-3l for qemu-devel@nongnu.org; Wed, 07 Mar 2018 07:53:21 -0500 Received: from mga14.intel.com ([192.55.52.115]:58183) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1etYZJ-0000VH-QK for qemu-devel@nongnu.org; Wed, 07 Mar 2018 07:53:18 -0500 From: Wei Wang Date: Wed, 7 Mar 2018 20:34:22 +0800 Message-Id: <1520426065-40265-2-git-send-email-wei.w.wang@intel.com> In-Reply-To: <1520426065-40265-1-git-send-email-wei.w.wang@intel.com> References: <1520426065-40265-1-git-send-email-wei.w.wang@intel.com> Subject: [Qemu-devel] [PATCH v4 1/4] bitmap: bitmap_count_one_with_offset List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, mst@redhat.com, quintela@redhat.com, dgilbert@redhat.com Cc: pbonzini@redhat.com, wei.w.wang@intel.com, liliang.opensource@gmail.com, yang.zhang.wz@gmail.com, quan.xu0@gmail.com, nilal@redhat.com, riel@redhat.com Count the number of 1s in a bitmap starting from an offset. Signed-off-by: Wei Wang CC: Dr. David Alan Gilbert CC: Juan Quintela CC: Michael S. Tsirkin --- include/qemu/bitmap.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h index 509eedd..e3f31f1 100644 --- a/include/qemu/bitmap.h +++ b/include/qemu/bitmap.h @@ -228,6 +228,19 @@ static inline long bitmap_count_one(const unsigned long *bitmap, long nbits) } } +static inline long bitmap_count_one_with_offset(const unsigned long *bitmap, + long offset, long nbits) +{ + long aligned_offset = QEMU_ALIGN_DOWN(offset, BITS_PER_LONG); + long redundant_bits = offset - aligned_offset; + long bits_to_count = nbits + redundant_bits; + const unsigned long *bitmap_start = bitmap + + aligned_offset / BITS_PER_LONG; + + return bitmap_count_one(bitmap_start, bits_to_count) - + bitmap_count_one(bitmap_start, redundant_bits); +} + void bitmap_set(unsigned long *map, long i, long len); void bitmap_set_atomic(unsigned long *map, long i, long len); void bitmap_clear(unsigned long *map, long start, long nr); -- 1.8.3.1