These functions perform low-level processor synchronization.
void
__eieio(void) - Enforce in-order execution of I/O
void
__sync(void) - Synchronize
void
__isync(void) - Instruction synchronize
For more information on these functions, see the instructions
eieio ,
sync , and
isync in PowerPC Microprocessor Family: The Programming Environments by Freescale.