qmk-firmware/common/util.c

38 lines
1018 B
C

/*
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/>.
*/
#include "util.h"
// bit population
int bitpop(uint8_t bits)
{
int c;
for (c = 0; bits; c++)
bits &= bits -1;
return c;
}
// most significant on-bit
int biton(uint8_t bits)
{
int n = 0;
if (bits >> 4) { bits >>= 4; n += 4;}
if (bits >> 2) { bits >>= 2; n += 2;}
if (bits >> 1) { bits >>= 1; n += 1;}
return n;
}