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| author | kib <kib@FreeBSD.org> | 2017-07-13 08:29:01 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2017-07-13 08:29:01 +0000 |
| commit | 55a89eef51d5a91be65f136631688b2c5b3371ab (patch) | |
| tree | 6c1a66bbab73eccac2efaf32a53afccfb297ba2b | |
| parent | b40b0a78a3a319b57d7920f57f798e7932eece16 (diff) | |
| download | FreeBSD-src-55a89eef51d5a91be65f136631688b2c5b3371ab.zip FreeBSD-src-55a89eef51d5a91be65f136631688b2c5b3371ab.tar.gz | |
MFC r320755,r320762,r320893:
BIT_FLS(9).
| -rw-r--r-- | share/man/man9/bitset.9 | 26 | ||||
| -rw-r--r-- | sys/sys/bitset.h | 15 |
2 files changed, 39 insertions, 2 deletions
diff --git a/share/man/man9/bitset.9 b/share/man/man9/bitset.9 index d4060ac..1d02eee 100644 --- a/share/man/man9/bitset.9 +++ b/share/man/man9/bitset.9 @@ -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 given to .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). diff --git a/sys/sys/bitset.h b/sys/sys/bitset.h index 8bc9e3d..566d944 100644 --- a/sys/sys/bitset.h +++ b/sys/sys/bitset.h @@ -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; \ |
