linux-imx

// SPDX-License-Identifier: GPL-2.0

#include <linux/export.h>

#include <linux/bitops.h>

#include <asm/types.h>

​

/**

 * hweightN - returns the hamming weight of a N-bit word

 * @x: the word to weigh

 *

 * The Hamming Weight of a number is the total number of bits set in it.

 */

​

unsigned int __sw_hweight32(unsigned int w)

{

#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER

    w -= (w >> 1) & 0x55555555;

    w =  (w & 0x33333333) + ((w >> 2) & 0x33333333);

    w =  (w + (w >> 4)) & 0x0f0f0f0f;

    return (w * 0x01010101) >> 24;

#else

    unsigned int res = w - ((w >> 1) & 0x55555555);

    res = (res & 0x33333333) + ((res >> 2) & 0x33333333);

    res = (res + (res >> 4)) & 0x0F0F0F0F;

    res = res + (res >> 8);

    return (res + (res >> 16)) & 0x000000FF;

#endif

}

EXPORT_SYMBOL(__sw_hweight32);

​

unsigned int __sw_hweight16(unsigned int w)

{

    unsigned int res = w - ((w >> 1) & 0x5555);

    res = (res & 0x3333) + ((res >> 2) & 0x3333);

    res = (res + (res >> 4)) & 0x0F0F;

    return (res + (res >> 8)) & 0x00FF;

}

EXPORT_SYMBOL(__sw_hweight16);

​

unsigned int __sw_hweight8(unsigned int w)

{

    unsigned int res = w - ((w >> 1) & 0x55);

    res = (res & 0x33) + ((res >> 2) & 0x33);

    return (res + (res >> 4)) & 0x0F;

}

EXPORT_SYMBOL(__sw_hweight8);

​

unsigned long __sw_hweight64(__u64 w)

{

#if BITS_PER_LONG == 32

    return __sw_hweight32((unsigned int)(w >> 32)) +

           __sw_hweight32((unsigned int)w);

#elif BITS_PER_LONG == 64

#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER

    w -= (w >> 1) & 0x5555555555555555ul;

    w =  (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul);

    w =  (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful;

    return (w * 0x0101010101010101ul) >> 56;

#else

    __u64 res = w - ((w >> 1) & 0x5555555555555555ul);

    res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);

    res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;

    res = res + (res >> 8);

    res = res + (res >> 16);