Display managing arrangement with a display memory divided into a matrix of memory blocks, each serving as a unit for display management

摘要

In a display managing arrangement comprising a display memory and a display memory controller for accessing the display memory to display a selected area of an image datum with the selected area scrolled on the image datum or otherwise subjected to management, the display memory is divided into memory blocks arranged as an N-row M-column matrix. Each memory block is for use as a unit of the management and is divisible into memory elements arranged as an n-row m-column matrix. When the memory elements of the display memory are assigned with serial memory element addresses along each row of the memory elements of the display memory and then along a next column-wise downward row, the memory controller may access the memory elements of selected ones of the memory blocks in block parallel by specifying the serial memory element addresses for each memory block on the one hand from a least memory element address in the memory block under consideration consecutively to the serial memory element address which is equal to the least memory element address plus the number m less one. On the other hand, the serial memory element addresses are specified discretely along one of the m columns by adding products of a step value mM and multipliers variable from zero to the number n less one to one of the serial memory element addresses that is congruent with the least memory element address modulo the step value. On storing the selected area in the display memory, the image datum may likewise be accessed.