ARM ARM926EJ-S Technical Reference Manual page 174

Instruction Memory Barrier
9.2.4 Invalidate the ICache
9.2.5 Flush the prefetch buffer
9-4
The ICache must be invalidated to remove any stale copies of instructions that are no
longer valid. If the ICache is not being used, or the modified regions are not in cachable
areas of memory, then this might not be required.
To ensure consistency, the prefetch buffer should be flushed before self-modifying code
is executed. See Self modifying code on page 7-2.
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