Access to timer registers in PowerPC systems
The PowerPC® architecture includes a 64-bit TimeBase register, which is logically divided into 32-bit upper and lower fields (TBU and TBL).
The TimeBase register is incremented at a frequency that is hardware-implementation and software-implementation dependent and can vary from time to time. Transforming the values from TimeBase into seconds is a more complex task than in the POWER® processor-based architecture. To obtain time values in PowerPC systems, use the read_real_time(), read_wall_time() and time_base_to_time() interfaces.