ddi_fls(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 sig-
           nificant  (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 or interrupt context.

SEE ALSO

     Writing Device Drivers