File: /usr/src/linux/include/linux/compiler.h

1     #ifndef __LINUX_COMPILER_H
2     #define __LINUX_COMPILER_H
3     
4     /* Somewhere in the middle of the GCC 2.96 development cycle, we implemented
5        a mechanism by which the user can annotate likely branch directions and
6        expect the blocks to be reordered appropriately.  Define __builtin_expect
7        to nothing for earlier compilers.  */
8     
9     #if __GNUC__ == 2 && __GNUC_MINOR__ < 96
10     #define __builtin_expect(x, expected_value) (x)
11     #endif
12     
13     #define likely(x)	__builtin_expect((x),1)
14     #define unlikely(x)	__builtin_expect((x),0)
15     
16     #endif /* __LINUX_COMPILER_H */
17