UAV behavior with non-mapped tiles
Behavior of unordered access view (UAV) reads and writes depends on the level of hardware support. For a breakdown of requirements, see overall read and write behavior for Tiled resources features tiers. This section summarizes the ideal behavior.
Shader operations that read from a non-mapped tile in a UAV return 0 in all non-missing components of the format, and the default for missing components.
Shader operations that attempt to write to a non-mapped tile cause nothing to be written to the non-mapped area (while writes to a mapped area proceed). This ideal definition for write handling is not required by Tier 2; writes to non-mapped tiles can end up in a cache that subsequent reads could pick up.