diff options
Diffstat (limited to 'src/arch/x86/include/bitops.h')
| -rw-r--r-- | src/arch/x86/include/bitops.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/src/arch/x86/include/bitops.h b/src/arch/x86/include/bitops.h new file mode 100644 index 0000000000..9206465c77 --- /dev/null +++ b/src/arch/x86/include/bitops.h @@ -0,0 +1,20 @@ +#ifndef I386_BITOPS_H +#define I386_BITOPS_H + +/** + * log2 - Find the truncated log base 2 of x + */ + +static inline unsigned long log2(unsigned long x) +{ + unsigned long r = 0; + __asm__( + "bsrl %1, %0\n\t" + "jnz 1f\n\t" + "movl $-1, %0\n\t" + "1:\n\t" + : "=r" (r) : "r" (x)); + return r; + +} +#endif /* I386_BITOPS_H */ |