Quelle  arch_hweight.h   Sprache: C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_HWEIGHT_H
#define _ASM_X86_HWEIGHT_H

#include <asm/cpufeatures.h>

#ifdef CONFIG_64BIT
#define REG_IN "D"
#define REG_OUT "a"
#else
#define REG_IN "a"
#define REG_OUT "a"
#endif

static __always_inline unsigned int __arch_hweight32(unsigned int w)
{
 unsigned int res;

 asm_inline (ALTERNATIVE("call __sw_hweight32",
    "popcntl %[val], %[cnt]", X86_FEATURE_POPCNT)
    : [cnt] "=" REG_OUT (res), ASM_CALL_CONSTRAINT
    : [val] REG_IN (w));

 return res;
}

static inline unsigned int __arch_hweight16(unsigned int w)
{
 return __arch_hweight32(w & 0xffff);
}

static inline unsigned int __arch_hweight8(unsigned int w)
{
 return __arch_hweight32(w & 0xff);
}

#ifdef CONFIG_X86_32
static inline unsigned long __arch_hweight64(__u64 w)
{
 return  __arch_hweight32((u32)w) +
  __arch_hweight32((u32)(w >> 32));
}
#else
static __always_inline unsigned long __arch_hweight64(__u64 w)
{
 unsigned long res;

 asm_inline (ALTERNATIVE("call __sw_hweight64",
    "popcntq %[val], %[cnt]", X86_FEATURE_POPCNT)
    : [cnt] "=" REG_OUT (res), ASM_CALL_CONSTRAINT
    : [val] REG_IN (w));

 return res;
}
#endif /* CONFIG_X86_32 */

#endif