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8.2.3. Write full line of zeros

When this feature is enabled, the Cortex-A9 processor can write entire non-coherent cache lines full of zero to the L2C-310 cache controller with a single request. This provides a performance improvement and some power savings. This feature can optimize the performance of the processor, but it requires a slave that is optimized for this special access. The requests are marked as write full line of zeros by having the associated AWUSERM0[7] bit set.

Setting bit [3] of the ACTLR enables this feature. See Auxiliary Control Register.

You must program the L2C-310 Cache Controller first, prior to enabling the feature in the Cortex-A9 processor, to support this feature. See the CoreLink Level 2 Cache Controller (L2C-310) Technical Reference Manual.