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== VRAM management ==
The kernel is in charge of allocating, caching, and displaying in Video RAM. The In the case if of the PSX, port, the Playstation only has 1 megabyte of VRAM which makes this task a little complex. This is alleviated somewhat by using the PSX's VRAM caching system.
The PSX video memory can best be seen as a rectangular "surface" made up of 2048x512 pixels. A slight caveat to this model is that the PSX can hold multiple color depths in VRAM at the same time. To make the VRAM a little easier to visualize, This document represents VRAM as a 1024x512 matrix to allow for some color depth in either direction and to minimize some extreme skewing of the video buffers.
Here the sections of VRAM are much more visible. The large cyan areas are the video frame buffers. The PSX uses a standard double page buffer to animate the game. The blank areas above and below the frame buffers are blank to allow for a correct V-sync. The dark blue areas to the right of the frame buffers are when the game plays 24 bit movies. This requires a slightly larger display and the first two texture caches are overwritten. During times in the game where no movies can take place, such as Battle, textures are commonly placed here.
The magenta area under the video buffers is the Color Look Up Tables (CLUT). This is where the texture palettes are stored. This is also allows the PSX to display multiple color depths at the same time. The red area to the right is extra CLUT space when it is needed and there are no textures cached there.
The green area on the right is the permanent menu textures and the yellow is where the menu font is located.
