2011-07-20 15:32:52 +00:00
/*
Copyright 2011 Jun Wako < wakojun @ gmail . com >
This program is free software : you can redistribute it and / or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation , either version 2 of the License , or
( at your option ) any later version .
This program is distributed in the hope that it will be useful ,
but WITHOUT ANY WARRANTY ; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE . See the
GNU General Public License for more details .
You should have received a copy of the GNU General Public License
along with this program . If not , see < http : //www.gnu.org/licenses/>.
*/
2010-10-27 11:51:45 +00:00
# include "util.h"
2012-10-05 17:23:12 +00:00
// bit population - return number of on-bit
uint8_t bitpop ( uint8_t bits )
2010-10-27 11:51:45 +00:00
{
2012-10-05 17:23:12 +00:00
uint8_t c ;
2010-10-27 11:51:45 +00:00
for ( c = 0 ; bits ; c + + )
2012-11-24 07:34:59 +00:00
bits & = bits - 1 ;
2010-10-27 11:51:45 +00:00
return c ;
2012-10-05 17:23:12 +00:00
/*
const uint8_t bit_count [ ] = { 0 , 1 , 1 , 2 , 1 , 2 , 2 , 3 , 1 , 2 , 2 , 3 , 2 , 3 , 3 , 4 } ;
return bit_count [ bits > > 4 ] + bit_count [ bits & 0x0F ]
*/
2010-10-27 11:51:45 +00:00
}
2012-11-24 07:34:59 +00:00
uint8_t bitpop16 ( uint16_t bits )
{
uint8_t c ;
for ( c = 0 ; bits ; c + + )
bits & = bits - 1 ;
return c ;
}
2012-10-05 17:23:12 +00:00
// most significant on-bit - return highest location of on-bit
2013-02-15 19:05:58 +00:00
// NOTE: return 0 when bit0 is on or all bits are off
2012-10-05 17:23:12 +00:00
uint8_t biton ( uint8_t bits )
2010-10-27 11:51:45 +00:00
{
2012-10-05 17:23:12 +00:00
uint8_t n = 0 ;
2010-10-27 11:51:45 +00:00
if ( bits > > 4 ) { bits > > = 4 ; n + = 4 ; }
if ( bits > > 2 ) { bits > > = 2 ; n + = 2 ; }
if ( bits > > 1 ) { bits > > = 1 ; n + = 1 ; }
return n ;
}
2013-02-15 19:05:58 +00:00
uint8_t biton16 ( uint16_t bits )
{
uint8_t n = 0 ;
if ( bits > > 8 ) { bits > > = 8 ; n + = 8 ; }
if ( bits > > 4 ) { bits > > = 4 ; n + = 4 ; }
if ( bits > > 2 ) { bits > > = 2 ; n + = 2 ; }
if ( bits > > 1 ) { bits > > = 1 ; n + = 1 ; }
return n ;
}