1 #ifndef _ASM_X86_HWEIGHT_H 2 #define _ASM_X86_HWEIGHT_H 3 4 #include <asm/cpufeatures.h> 5 6 #ifdef CONFIG_64BIT 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" 11 #define REG_IN "D" 12 #define REG_OUT "a" 13 #else 14 /* popcnt %eax, %eax */ 15 #define POPCNT32 ".byte 0xf3,0x0f,0xb8,0xc0" 16 #define REG_IN "a" 17 #define REG_OUT "a" 18 #endif 19 20 /* 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 24 * compiler switches. 25 */ 26 static __always_inline unsigned int __arch_hweight32(unsigned int w) 27 { 28 unsigned int res = 0; 29 30 asm (ALTERNATIVE("call __sw_hweight32", POPCNT32, X86_FEATURE_POPCNT) 31 : "="REG_OUT (res) 32 : REG_IN (w)); 33 34 return res; 35 } 36 37 static inline unsigned int __arch_hweight16(unsigned int w) 38 { 39 return __arch_hweight32(w & 0xffff); 40 } 41 42 static inline unsigned int __arch_hweight8(unsigned int w) 43 { 44 return __arch_hweight32(w & 0xff); 45 } 46 47 #ifdef CONFIG_X86_32 48 static inline unsigned long __arch_hweight64(__u64 w) 49 { 50 return __arch_hweight32((u32)w) + 51 __arch_hweight32((u32)(w >> 32)); 52 } 53 #else 54 static __always_inline unsigned long __arch_hweight64(__u64 w) 55 { 56 unsigned long res = 0; 57 58 asm (ALTERNATIVE("call __sw_hweight64", POPCNT64, X86_FEATURE_POPCNT) 59 : "="REG_OUT (res) 60 : REG_IN (w)); 61 62 return res; 63 } 64 #endif /* CONFIG_X86_32 */ 65 66 #endif 67