1 #ifndef _ASM_X86_HWEIGHT_H
2 #define _ASM_X86_HWEIGHT_H
4 #include <asm/cpufeatures.h>
7 /* popcnt %edi, %eax -- redundant REX prefix for alignment */
8 #define POPCNT32 ".byte 0xf3,0x40,0x0f,0xb8,0xc7"
9 /* popcnt %rdi, %rax */
10 #define POPCNT64 ".byte 0xf3,0x48,0x0f,0xb8,0xc7"
14 /* popcnt %eax, %eax */
15 #define POPCNT32 ".byte 0xf3,0x0f,0xb8,0xc0"
21 * __sw_hweightXX are called from within the alternatives below
22 * and callee-clobbered registers need to be taken care of. See
23 * ARCH_HWEIGHT_CFLAGS in <arch/x86/Kconfig> for the respective
26 static __always_inline unsigned int __arch_hweight32(unsigned int w)
30 asm (ALTERNATIVE("call __sw_hweight32", POPCNT32, X86_FEATURE_POPCNT)
37 static inline unsigned int __arch_hweight16(unsigned int w)
39 return __arch_hweight32(w & 0xffff);
42 static inline unsigned int __arch_hweight8(unsigned int w)
44 return __arch_hweight32(w & 0xff);
48 static inline unsigned long __arch_hweight64(__u64 w)
50 return __arch_hweight32((u32)w) +
51 __arch_hweight32((u32)(w >> 32));
54 static __always_inline unsigned long __arch_hweight64(__u64 w)
56 unsigned long res = 0;
58 asm (ALTERNATIVE("call __sw_hweight64", POPCNT64, X86_FEATURE_POPCNT)
64 #endif /* CONFIG_X86_32 */