svn commit: r320939 - in stable/11: share/man/man9 sys/sys
Konstantin Belousov
kib at FreeBSD.org
Thu Jul 13 08:29:02 UTC 2017
Author: kib
Date: Thu Jul 13 08:29:01 2017
New Revision: 320939
URL: https://svnweb.freebsd.org/changeset/base/320939
Log:
MFC r320755,r320762,r320893:
BIT_FLS(9).
Modified:
stable/11/share/man/man9/bitset.9
stable/11/sys/sys/bitset.h
Directory Properties:
stable/11/ (props changed)
Modified: stable/11/share/man/man9/bitset.9
==============================================================================
--- stable/11/share/man/man9/bitset.9 Thu Jul 13 08:23:37 2017 (r320938)
+++ stable/11/share/man/man9/bitset.9 Thu Jul 13 08:29:01 2017 (r320939)
@@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd May 24, 2017
+.Dd July 7, 2017
.Dt BITSET 9
.Os
.Sh NAME
@@ -43,6 +43,7 @@
.Nm BIT_EMPTY ,
.Nm BIT_ISFULLSET ,
.Nm BIT_FFS ,
+.Nm BIT_FLS ,
.Nm BIT_COUNT ,
.Nm BIT_SUBSET ,
.Nm BIT_OVERLAP ,
@@ -85,6 +86,8 @@
.Ft int
.Fn BIT_FFS "const SETSIZE" "struct STRUCTNAME *bitset"
.Ft int
+.Fn BIT_FLS "const SETSIZE" "struct STRUCTNAME *bitset"
+.Ft int
.Fn BIT_COUNT "const SETSIZE" "struct STRUCTNAME *bitset"
.\"
.Ft bool
@@ -282,6 +285,23 @@ index parameter to any other
macro, you must subtract one from the result.
.Pp
The
+.Fn BIT_FLS
+macro returns the 1-index of the last (highest) set bit in
+.Fa bitset ,
+or zero if
+.Fa bitset
+is empty.
+Like with
+.Xr fls 3 ,
+to use the non-zero result of
+.Fn BIT_FLS
+as a
+.Fa bit
+index parameter to any other
+.Nm
+macro, you must subtract one from the result.
+.Pp
+The
.Fn BIT_COUNT
macro returns the total number of set bits in
.Fa bitset .
@@ -499,4 +519,6 @@ argument to all of these macros must match the value g
.Pp
Unlike every other reference to individual set members, which are zero-indexed,
.Fn BIT_FFS
-returns a one-indexed result (or zero if the set is empty).
+and
+.Fn BIT_FLS
+return a one-indexed result (or zero if the set is empty).
Modified: stable/11/sys/sys/bitset.h
==============================================================================
--- stable/11/sys/sys/bitset.h Thu Jul 13 08:23:37 2017 (r320938)
+++ stable/11/sys/sys/bitset.h Thu Jul 13 08:29:01 2017 (r320939)
@@ -213,6 +213,21 @@
__bit; \
})
+#define BIT_FLS(_s, p) __extension__ ({ \
+ __size_t __i; \
+ int __bit; \
+ \
+ __bit = 0; \
+ for (__i = __bitset_words((_s)); __i > 0; __i--) { \
+ if ((p)->__bits[__i - 1] != 0) { \
+ __bit = flsl((p)->__bits[__i - 1]); \
+ __bit += (__i - 1) * _BITSET_BITS; \
+ break; \
+ } \
+ } \
+ __bit; \
+})
+
#define BIT_COUNT(_s, p) __extension__ ({ \
__size_t __i; \
int __count; \
More information about the svn-src-stable-11
mailing list