1 #ifndef _ASM_X86_HWEIGHT_H 2 #define _ASM_X86_HWEIGHT_H 3 4 #ifdef CONFIG_64BIT 5 /* popcnt %edi, %eax -- redundant REX prefix for alignment */ 6 #define POPCNT32 ".byte 0xf3,0x40,0x0f,0xb8,0xc7" 7 /* popcnt %rdi, %rax */ 8 #define POPCNT64 ".byte 0xf3,0x48,0x0f,0xb8,0xc7" 9 #define REG_IN "D" 10 #define REG_OUT "a" 11 #else 12 /* popcnt %eax, %eax */ 13 #define POPCNT32 ".byte 0xf3,0x0f,0xb8,0xc0" 14 #define REG_IN "a" 15 #define REG_OUT "a" 16 #endif 17 18 /* 19 * __sw_hweightXX are called from within the alternatives below 20 * and callee-clobbered registers need to be taken care of. See 21 * ARCH_HWEIGHT_CFLAGS in <arch/x86/Kconfig> for the respective 22 * compiler switches. 23 */ 24 static inline unsigned int __arch_hweight32(unsigned int w) 25 { 26 unsigned int res = 0; 27 28 asm (ALTERNATIVE("call __sw_hweight32", POPCNT32, X86_FEATURE_POPCNT) 29 : "="REG_OUT (res) 30 : REG_IN (w)); 31 32 return res; 33 } 34 35 static inline unsigned int __arch_hweight16(unsigned int w) 36 { 37 return __arch_hweight32(w & 0xffff); 38 } 39 40 static inline unsigned int __arch_hweight8(unsigned int w) 41 { 42 return __arch_hweight32(w & 0xff); 43 } 44 45 static inline unsigned long __arch_hweight64(__u64 w) 46 { 47 unsigned long res = 0; 48 49 #ifdef CONFIG_X86_32 50 return __arch_hweight32((u32)w) + 51 __arch_hweight32((u32)(w >> 32)); 52 #else 53 asm (ALTERNATIVE("call __sw_hweight64", POPCNT64, X86_FEATURE_POPCNT) 54 : "="REG_OUT (res) 55 : REG_IN (w)); 56 #endif /* CONFIG_X86_32 */ 57 58 return res; 59 } 60 61 #endif 62