#ifndef _ASM_X86_HWEIGHT_H #define _ASM_X86_HWEIGHT_H #ifdef CONFIG_64BIT /* popcnt %edi, %eax -- redundant REX prefix for alignment */ #define POPCNT32 ".byte 0xf3,0x40,0x0f,0xb8,0xc7" /* popcnt %rdi, %rax */ #define POPCNT64 ".byte 0xf3,0x48,0x0f,0xb8,0xc7" #define REG_IN "D" #define REG_OUT "a" #else /* popcnt %eax, %eax */ #define POPCNT32 ".byte 0xf3,0x0f,0xb8,0xc0" #define REG_IN "a" #define REG_OUT "a" #endif /* * __sw_hweightXX are called from within the alternatives below * and callee-clobbered registers need to be taken care of. See * ARCH_HWEIGHT_CFLAGS in <arch/x86/Kconfig> for the respective * compiler switches. */ static inline unsigned int __arch_hweight32(unsigned int w) { unsigned int res = 0; asm (ALTERNATIVE("call __sw_hweight32", POPCNT32, X86_FEATURE_POPCNT) : "="REG_OUT (res) : 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); } static inline unsigned long __arch_hweight64(__u64 w) { unsigned long res = 0; #ifdef CONFIG_X86_32 return __arch_hweight32((u32)w) + __arch_hweight32((u32)(w >> 32)); #else asm (ALTERNATIVE("call __sw_hweight64", POPCNT64, X86_FEATURE_POPCNT) : "="REG_OUT (res) : REG_IN (w)); #endif /* CONFIG_X86_32 */ return res; } #endif