This intrinsic inserts an
ISB or equivalent instruction into the instruction stream generated by the compiler.
ISB instruction flushes the processor pipeline fetch buffers, so that
subsequent instructions are fetched from cache or memory.
If the target does not support the
instruction, the compiler treats this intrinsic as an optimization barrier.
void __isb(unsigned int
is a numeric argument indicating the scope and access type of the barrier. The only
supported value for the
__isb intrinsic is
15. See ARM C Language Extensions for more information.