| Eric Biederman | 8ca8d76 | 2003-04-22 19:02:15 +0000 | [diff] [blame] | 1 | #ifndef I386_BITOPS_H |
| 2 | #define I386_BITOPS_H | ||||
| 3 | |||||
| 4 | /** | ||||
| 5 | * log2 - Find the truncated log base 2 of x | ||||
| 6 | */ | ||||
| 7 | |||||
| 8 | static inline unsigned long log2(unsigned long x) | ||||
| 9 | { | ||||
| 10 | unsigned long r = 0; | ||||
| 11 | __asm__( | ||||
| 12 | "bsrl %1, %0\n\t" | ||||
| 13 | "jnz 1f\n\t" | ||||
| 14 | "movl $-1, %0\n\t" | ||||
| 15 | "1:\n\t" | ||||
| 16 | : "=r" (r) : "r" (x)); | ||||
| 17 | return r; | ||||
| Stefan Reinauer | 14e2277 | 2010-04-27 06:56:47 +0000 | [diff] [blame] | 18 | |
| Eric Biederman | 8ca8d76 | 2003-04-22 19:02:15 +0000 | [diff] [blame] | 19 | } |
| 20 | #endif /* I386_BITOPS_H */ | ||||