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SYS

Execute system coprocessor instruction.

Syntax

SYS{cond} instruction{, Rn}

where:

cond

is an optional condition code.

instruction

is the coprocessor instruction to execute.

Rn

is an operand to the instruction. For instructions that take an argument, Rn is compulsory. For instructions that do not take an argument, Rn is optional and if it is not specified, R0 is used. Rn must not be PC.

Usage

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.

Architectures

The SYS ARM instruction is available in ARMv7-A and ARMv7-R.

The SYS 32-bit Thumb instruction is available in ARMv7-A and ARMv7-R.

There are no 16-bit Thumb versions of these instructions.

See also

Reference
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