You can use this instruction to execute special coprocessor
instructions such as cache, branch predictor, and TLB operations.
The instructions operate by writing to special write-only coprocessor
registers. The instruction names are the same as the write-only
coprocessor register names and are listed in the ARMv7-AR
Architecture Reference Manual. For example:
SYS ICIALLUIS ; invalidates all instruction caches Inner Shareable to Point
; of Unification and also flushes branch target cache.