Borislav Petkov | d61931d | 2010-03-05 17:34:46 +0100 | [diff] [blame] | 1 | #ifndef _ASM_X86_HWEIGHT_H |
| 2 | #define _ASM_X86_HWEIGHT_H |
| 3 | |
| 4 | #ifdef CONFIG_64BIT |
| 5 | /* popcnt %rdi, %rax */ |
| 6 | #define POPCNT ".byte 0xf3,0x48,0x0f,0xb8,0xc7" |
| 7 | #define REG_IN "D" |
| 8 | #define REG_OUT "a" |
| 9 | #else |
| 10 | /* popcnt %eax, %eax */ |
| 11 | #define POPCNT ".byte 0xf3,0x0f,0xb8,0xc0" |
| 12 | #define REG_IN "a" |
| 13 | #define REG_OUT "a" |
| 14 | #endif |
| 15 | |
| 16 | /* |
| 17 | * __sw_hweightXX are called from within the alternatives below |
| 18 | * and callee-clobbered registers need to be taken care of. See |
| 19 | * ARCH_HWEIGHT_CFLAGS in <arch/x86/Kconfig> for the respective |
| 20 | * compiler switches. |
| 21 | */ |
| 22 | static inline unsigned int __arch_hweight32(unsigned int w) |
| 23 | { |
| 24 | unsigned int res = 0; |
| 25 | |
| 26 | asm (ALTERNATIVE("call __sw_hweight32", POPCNT, X86_FEATURE_POPCNT) |
| 27 | : "="REG_OUT (res) |
| 28 | : REG_IN (w)); |
| 29 | |
| 30 | return res; |
| 31 | } |
| 32 | |
| 33 | static inline unsigned int __arch_hweight16(unsigned int w) |
| 34 | { |
| 35 | return __arch_hweight32(w & 0xffff); |
| 36 | } |
| 37 | |
| 38 | static inline unsigned int __arch_hweight8(unsigned int w) |
| 39 | { |
| 40 | return __arch_hweight32(w & 0xff); |
| 41 | } |
| 42 | |
| 43 | static inline unsigned long __arch_hweight64(__u64 w) |
| 44 | { |
| 45 | unsigned long res = 0; |
| 46 | |
| 47 | #ifdef CONFIG_X86_32 |
| 48 | return __arch_hweight32((u32)w) + |
| 49 | __arch_hweight32((u32)(w >> 32)); |
| 50 | #else |
| 51 | asm (ALTERNATIVE("call __sw_hweight64", POPCNT, X86_FEATURE_POPCNT) |
| 52 | : "="REG_OUT (res) |
| 53 | : REG_IN (w)); |
| 54 | #endif /* CONFIG_X86_32 */ |
| 55 | |
| 56 | return res; |
| 57 | } |
| 58 | |
| 59 | #endif |