Circuits, systems and methods for graphics and video window/display data block transfer via dedicated memory control

摘要

Display control circuitry is provided which includes a frame buffer 104 having a plurality of memory spaces 301 each for storing a block of display data. Circuitry 200 is provided for generating display position data representing a position on a display screen corresponding to a current display pixel being generated. For each memory space 301, a window control circuit 201 is provided for controlling the transfer of a block of data from the given memory space 301 to a selected window on the display screen. Each window control circuit 201 includes first registers 205, 206 for storing data defining horizontal boundaries of the window, second registers 210, 211 for storing data defining vertical boundaries of the window, and circuitry 207, 208, 209, 212, 213, 214 for comparing the display position data with data stored in the first and second registers and generate an enable signal when the position on the screen of the current pixel is within the window boundaries. Memory control circuitry 300, 302 is provided for retrieving data from the memory space 301 selected in response to the enable signals received from the window control circuits 201.