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Revision b11e7b81bf94f633ae44f12a3d2e198277781952 authored by Linus Torvalds on 27 September 2015, 00:56:50 UTC, committed by Linus Torvalds on 27 September 2015, 00:56:50 UTC 
Merge tag 'staging-4.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
 
Pull staging driver fixes from Greg KH:
 "Here are some tiny staging driver and documentation fixes for 4.3-rc3.

  All of these resolve reported issues that people have found and have
  been in the linux-next tree for a while with no problems"

* tag 'staging-4.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  MAINTAINERS: Update email address for Martyn Welch
  staging: ion: fix corruption of ion_import_dma_buf
  staging: dgap: Remove myself from the MAINTAINERS file
  staging: most: Add dependency to HAS_IOMEM
  staging: unisys: remove reference of visorutil
  staging: unisys: visornic: handle error return from device registration
  staging: unisys: stop device registration before visorbus registration
  staging: unisys: visorbus: Unregister driver on error
  staging: unisys: visornic: Fix receive bytes statistics
  staging: unisys: unregister netdev when create debugfs fails
  staging: fbtft: replace master->setup() with spi_setup()
  staging: fbtft: fix 9-bit SPI support detection
  staging/lustre: change Lustre URLs and mailing list
  staging/android: Update ION TODO per LPC discussion
  Staging: most: MOST and MOSTCORE should depend on HAS_DMA
  staging: most: fix HDM_USB dependencies and build errors
2 parent s 7c1efea + 74c600e
Raw File
hweight.c 
#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);
	return (res + (res >> 32)) & 0x00000000000000FFul;
#endif
#endif
}
EXPORT_SYMBOL(__sw_hweight64);
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