diff options
| author | Eric Joyner <erj@FreeBSD.org> | 2019-11-21 19:57:56 +0000 |
|---|---|---|
| committer | Eric Joyner <erj@FreeBSD.org> | 2019-11-21 19:57:56 +0000 |
| commit | 52e8f6a3312e630193a2b9d67d83c2f7a6032145 (patch) | |
| tree | 03dcefa12c475ab40631c872731a68664401a7a4 /share | |
| parent | c3bd3d1cc7b7e3142e7fd982f3c76485ee3e3ef6 (diff) | |
bitstring: add functions to find contiguous set/unset bit sequences
Add bit_ffs_area_at and bit_ffc_area_at functions for searching a bit
string for a sequence of contiguous set or unset bits of at least the
specified size.
The bit_ffc_area function will be used by the Intel ice driver for
implementing resource assignment logic using a bitstring to represent
whether or not a given index has been assigned or is currently free.
The bit_ffs_area, bit_ffc_area_at and bit_ffs_area_at functions are
implemented for completeness.
I'd like to add further test cases for the new functions, but I'm not
really sure how to add them easily. The new functions depend on specific
sequences of bits being set, while the bitstring tests appear to run for
varying bit sizes.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Submitted by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed by: asomers@, erj@
MFC after: 1 week
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D22400
Notes
Notes:
svn path=/head/; revision=354977
Diffstat (limited to 'share')
| -rw-r--r-- | share/man/man3/bitstring.3 | 90 |
1 files changed, 89 insertions, 1 deletions
diff --git a/share/man/man3/bitstring.3 b/share/man/man3/bitstring.3 index 3db5be78dfb0..b783468fb462 100644 --- a/share/man/man3/bitstring.3 +++ b/share/man/man3/bitstring.3 @@ -58,7 +58,7 @@ .\" @(#)bitstring.3 8.1 (Berkeley) 7/19/93 .\" $FreeBSD$ .\" -.Dd May 23, 2016 +.Dd Nov 18, 2019 .Dt BITSTRING 3 .Os .Sh NAME @@ -70,6 +70,10 @@ .Nm bit_ffs , .Nm bit_ffc_at , .Nm bit_ffs_at , +.Nm bit_ffc_area , +.Nm bit_ffs_area , +.Nm bit_ffc_area_at , +.Nm bit_ffs_area_at , .Nm bit_nclear , .Nm bit_nset , .Nm bit_set , @@ -95,6 +99,14 @@ .Ft void .Fn bit_ffs_at "bitstr_t *name" "int start" "int nbits" "int *value" .Ft void +.Fn bit_ffc_area "bitstr_t *name" "int nbits" "int size" "int *value" +.Ft void +.Fn bit_ffs_area "bitstr_t *name" "int nbits" "int size" "int *value" +.Ft void +.Fn bit_ffc_area_at "bitstr_t *name" "int start" "int nbits" "int size" "int *value" +.Ft void +.Fn bit_ffs_area_at "bitstr_t *name" "int start" "int nbits" "int size" "int *value" +.Ft void .Fn bit_nclear "bitstr_t *name" "int start" "int stop" .Ft void .Fn bit_nset "bitstr_t *name" "int start" "int stop" @@ -229,6 +241,82 @@ the location referenced by is set to \-1. .Pp The +.Fn bit_ffc_area +function stores in the location referenced by +.Fa value +the zero-based number of the first bit beginning a sequence of unset bits of +at least +.Fa size +unset bits in the array of +.Fa nbits +bits referenced by +.Fa name . +If no sequence of contiguous unset bits of the specified +.Fa size +can be found, the location referenced by +.Fa value +is set to \-1. +.Pp +The +.Fn bit_ffs_area +function stores in the location referenced by +.Fa value +the zero-based number of the first bit beginning a sequence of set bits of +at least +.Fa size +set bits in the array of +.Fa nbits +bits referenced by +.Fa name . +If no sequence of contiguous set bits of the specified +.Fa size +can be found, the location referenced by +.Fa value +is set to \-1. +.Pp +The +.Fn bit_ffc_area_at +function stores in the location referenced by +.Fa value +the zero-based number of the first bit beginning a sequence of unset bits of +at least +.Fa size +unset bits in the array of +.Fa nbits +bits referenced by +.Fa name , +at or after the zero-based bit index +.Fa start . +If no sequence of contiguous unset bits of the specified +.Fa size +can be found at or after +.Fa start , +the location referenced by +.Fa value +is set to \-1. +.Pp +The +.Fn bit_ffs_area_at +function stores in the location referenced by +.Fa value +the zero-based number of the first bit beginning a sequence of set bits of +at least +.Fa size +set bits in the array of +.Fa nbits +bits referenced by +.Fa name , +at or after the zero-based bit index +.Fa start . +If no sequence of contiguous set bits of the specified +.Fa size +can be found at or after +.Fa start , +the location referenced by +.Fa value +is set to \-1. +.Pp +The .Fn bit_count function stores in the location referenced by .Fa value |