'\" t
.\"     Title: bitmap_bitremap
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: January 2017
.\"    Manual: Basic Kernel Library Functions
.\"    Source: Kernel Hackers Manual 4.8.15
.\"  Language: English
.\"
.TH "BITMAP_BITREMAP" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "Basic Kernel Library Functions"
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.SH "NAME"
bitmap_bitremap \- Apply map defined by a pair of bitmaps to a single bit
.SH "SYNOPSIS"
.HP \w'int\ bitmap_bitremap('u
.BI "int bitmap_bitremap(int\ " "oldbit" ", const\ unsigned\ long\ *\ " "old" ", const\ unsigned\ long\ *\ " "new" ", int\ " "bits" ");"
.SH "ARGUMENTS"
.PP
\fIoldbit\fR
.RS 4
bit position to be mapped
.RE
.PP
\fIold\fR
.RS 4
defines domain of map
.RE
.PP
\fInew\fR
.RS 4
defines range of map
.RE
.PP
\fIbits\fR
.RS 4
number of bits in each of these bitmaps
.RE
.SH "DESCRIPTION"
.PP
Let
\fIold\fR
and
\fInew\fR
define a mapping of bit positions, such that whatever position is held by the n\-th set bit in
\fIold\fR
is mapped to the n\-th set bit in
\fInew\fR\&. In the more general case, allowing for the possibility that the weight \*(Aqw\*(Aq of
\fInew\fR
is less than the weight of
\fIold\fR, map the position of the n\-th set bit in
\fIold\fR
to the position of the m\-th set bit in
\fInew\fR, where m == n % w\&.
.PP
The positions of unset bits in
\fIold\fR
are mapped to themselves (the identify map)\&.
.PP
Apply the above specified mapping to bit position
\fIoldbit\fR, returning the new bit position\&.
.PP
For example, lets say that
\fIold\fR
has bits 4 through 7 set, and
\fInew\fR
has bits 12 through 15 set\&. This defines the mapping of bit position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other bit positions unchanged\&. So if say
\fIoldbit\fR
is 5, then this routine returns 13\&.
.SH "COPYRIGHT"
.br