D910 - A fetch from a later layer reads the array whole

Status: decided Date: 2026-10-20

A dispatch may address a view of a 2D array that starts past its first layer. A view of one later layer L alone is that layer's level, placed as a colour target's slice is (D859, D899): L chains on from the base, and in a 64 KiB _X mode with the layer's pipe-bank XOR. 64KB_S has no layer terms (tools/addrlib/equation 64KB_S 4 32 array). Both a fetch and a store take it.

A view of several layers from a later one is fetched by reading the array from its first layer and dropping the layers before the view. A store to such a view is refused.

Why: Grand Theft Auto V's loading-screen program fetches layer one of a two-layer colour array and stores to layer one of its 10_11_11_FLOAT cube.