From 6f274444c579305d14d355bab24af31ea2bef224 Mon Sep 17 00:00:00 2001 From: Zhenzhong Duan Date: Wed, 5 Jun 2024 16:30:31 +0800 Subject: [PATCH] range: Introduce range_get_last_bit() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This helper get the highest 1 bit position of the upper bound. If the range is empty or upper bound is zero, -1 is returned. Suggested-by: Cédric Le Goater Signed-off-by: Zhenzhong Duan Reviewed-by: Eric Auger Reviewed-by: Michael S. Tsirkin --- include/qemu/range.h | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/include/qemu/range.h b/include/qemu/range.h index 205e1da76d..4ce694a398 100644 --- a/include/qemu/range.h +++ b/include/qemu/range.h @@ -20,6 +20,8 @@ #ifndef QEMU_RANGE_H #define QEMU_RANGE_H +#include "qemu/bitops.h" + /* * Operations on 64 bit address ranges. * Notes: @@ -217,6 +219,15 @@ static inline int ranges_overlap(uint64_t first1, uint64_t len1, return !(last2 < first1 || last1 < first2); } +/* Get highest non-zero bit position of a range */ +static inline int range_get_last_bit(Range *range) +{ + if (range_is_empty(range)) { + return -1; + } + return 63 - clz64(range->upb); +} + /* * Return -1 if @a < @b, 1 @a > @b, and 0 if they touch or overlap. * Both @a and @b must not be empty. -- 2.11.4.GIT