cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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hweight.c (1812B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/bitops.h>
      3#include <asm/types.h>
      4
      5/**
      6 * hweightN - returns the hamming weight of a N-bit word
      7 * @x: the word to weigh
      8 *
      9 * The Hamming Weight of a number is the total number of bits set in it.
     10 */
     11
     12unsigned int __sw_hweight32(unsigned int w)
     13{
     14#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
     15	w -= (w >> 1) & 0x55555555;
     16	w =  (w & 0x33333333) + ((w >> 2) & 0x33333333);
     17	w =  (w + (w >> 4)) & 0x0f0f0f0f;
     18	return (w * 0x01010101) >> 24;
     19#else
     20	unsigned int res = w - ((w >> 1) & 0x55555555);
     21	res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
     22	res = (res + (res >> 4)) & 0x0F0F0F0F;
     23	res = res + (res >> 8);
     24	return (res + (res >> 16)) & 0x000000FF;
     25#endif
     26}
     27
     28unsigned int __sw_hweight16(unsigned int w)
     29{
     30	unsigned int res = w - ((w >> 1) & 0x5555);
     31	res = (res & 0x3333) + ((res >> 2) & 0x3333);
     32	res = (res + (res >> 4)) & 0x0F0F;
     33	return (res + (res >> 8)) & 0x00FF;
     34}
     35
     36unsigned int __sw_hweight8(unsigned int w)
     37{
     38	unsigned int res = w - ((w >> 1) & 0x55);
     39	res = (res & 0x33) + ((res >> 2) & 0x33);
     40	return (res + (res >> 4)) & 0x0F;
     41}
     42
     43unsigned long __sw_hweight64(__u64 w)
     44{
     45#if BITS_PER_LONG == 32
     46	return __sw_hweight32((unsigned int)(w >> 32)) +
     47	       __sw_hweight32((unsigned int)w);
     48#elif BITS_PER_LONG == 64
     49#ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
     50	w -= (w >> 1) & 0x5555555555555555ul;
     51	w =  (w & 0x3333333333333333ul) + ((w >> 2) & 0x3333333333333333ul);
     52	w =  (w + (w >> 4)) & 0x0f0f0f0f0f0f0f0ful;
     53	return (w * 0x0101010101010101ul) >> 56;
     54#else
     55	__u64 res = w - ((w >> 1) & 0x5555555555555555ul);
     56	res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
     57	res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
     58	res = res + (res >> 8);
     59	res = res + (res >> 16);
     60	return (res + (res >> 32)) & 0x00000000000000FFul;
     61#endif
     62#endif
     63}