@node Platform, Contributors, Maintenance, Top
@c %MENU% Describe all platform-specific facilities provided
@appendix Platform-specific facilities

@Theglibc{} can provide machine-specific functionality.

@menu
* PowerPC::           Facilities Specific to the PowerPC Architecture
@end menu

@node PowerPC
@appendixsec PowerPC-specific Facilities

Facilities specific to PowerPC that are not specific to a particular
operating system are declared in @file{sys/platform/ppc.h}.

@deftypefun {uint64_t} __ppc_get_timebase (void)
Read the current value of the Time Base Register.

The @dfn{Time Base Register} is a 64-bit register that stores a monotonically
incremented value updated at a system-dependent frequency that may be
different from the processor frequency.  More information is available in
@cite{Power ISA 2.06b - Book II - Section 5.2}.

@code{__ppc_get_timebase} uses the processor's time base facility directly
without requiring assistance from the operating system, so it is very
efficient.
@end deftypefun