SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The page-grained translation is named the indirect access. In this mode the translation vector is found in the internal 32-k entry physical address translation vector table at the index given by bits [26:12] of the input virtual address, and the DMM_PAT_VIEW_MAP_i CONT_x bit field references the internal physical address translation table to use. Because the DMM uses only one such table, in this mode the CONT_x bit field must be written as 0. See Figure 15-7.
Each entry of the PAT lookup table (LUT) is a 19-bit vector that replaces bits [30:12] of the input virtual address. The PAT index aimed at selecting the vector in the table consists of bits [26:12] of the input virtual address.
The mode associated to the transaction is used to define if the upper or lower half of the LUT is effectively used:
This means the PAT index used is the concatenation of 0 and address bits 12 to 26 in 8-, 16- or 32-bit mode, and the concatenation of 1 and address bits 12 to 26 in page mode.
Using different LUT indexes depending on the mode enables the user to define a larger tiled space, with the constraint that half of the space can be used only in 8-, 16- or 32-bit mode and the other half only in page mode. If the user wishes to preserve software compatibility with the case CONT_HGHT = 128, it is required to mirror the configuration for the lower half of the LUT on the upper half of the LUT. In that way, all views see the same address decoding through PAT.