ddi_ffs(9F) Kernel Functions for Drivers ddi_ffs(9F)NAME
ddi_ffs, ddi_fls - find first (last) bit set in a long integer
SYNOPSIS
#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
intddi_ffs(long mask);
int ddi_fls(long mask);
INTERFACE LEVEL
Solaris DDI specific (Solaris DDI).
PARAMETERS
mask A 32-bit argument value to search through.
DESCRIPTION
The function ddi_ffs() takes its argument and returns the shift count
that the first (least significant) bit set in the argument corresponds
to. The function ddi_fls() does the same, only it returns the shift
count for the last (most significant) bit set in the argument.
RETURN VALUES
0 No bits are set in mask.
N Bit N is the least significant (ddi_ffs) or most significant
(ddi_fls) bit set in mask. Bits are numbered from 1 to 32,
with bit 1 being the least significant bit position and bit 32
the most significant position.
CONTEXT
This function can be called from user, interrupt, or kernel context.
SEE ALSO
Writing Device Drivers
SunOS 5.10 16 Jan 2006 ddi_ffs(9F)