opensolaris man page for ddi_ffs

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 corre-
       sponds 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 5.11							    16 Jan 2006 						       ddi_ffs(9F)