cregit-Linux how code gets into the kernel

Release 4.16 lib/hweight.c

Directory: lib
// 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.
 */

#ifndef __HAVE_ARCH_SW_HWEIGHT

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 }

Contributors

PersonTokensPropCommitsCommitProp
Akinobu Mita13798.56%360.00%
Borislav Petkov10.72%120.00%
Linus Torvalds10.72%120.00%
Total139100.00%5100.00%

EXPORT_SYMBOL(__sw_hweight32); #endif
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; }

Contributors

PersonTokensPropCommitsCommitProp
Akinobu Mita7098.59%266.67%
Borislav Petkov11.41%133.33%
Total71100.00%3100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Akinobu Mita5698.25%266.67%
Borislav Petkov11.75%133.33%
Total57100.00%3100.00%

EXPORT_SYMBOL(__sw_hweight8); #ifndef __HAVE_ARCH_SW_HWEIGHT
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 }

Contributors

PersonTokensPropCommitsCommitProp
Akinobu Mita12166.48%240.00%
Andi Kleen5731.32%120.00%
Borislav Petkov31.65%120.00%
Linus Torvalds10.55%120.00%
Total182100.00%5100.00%

EXPORT_SYMBOL(__sw_hweight64); #endif

Overall Contributors

PersonTokensPropCommitsCommitProp
Akinobu Mita40582.65%330.00%
Andi Kleen5912.04%110.00%
Borislav Petkov204.08%220.00%
Linus Torvalds20.41%110.00%
Jiri Slaby20.41%110.00%
Greg Kroah-Hartman10.20%110.00%
Paul Gortmaker10.20%110.00%
Total490100.00%10100.00%
Directory: lib
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