Abstract: A method of correcting out-of-range 8-bit pixel values, which should range from 0 to 255 by successively finding an out-of-range pixel, correcting it by adding (subtracting) an amount to restore that value to 0 (255), and then subtracting (adding) an equal amount to an adjacent pixel or pixels. An alternative, most useful for text, is to find an out-of-range pixel, and then replace it, and all adjacent pixels that are within a predetermined limit of 0 (255), with 0 (255).

Abstract: A circuit for performing high-speed 90 and 270 degree rotations of an uncompressed image in a page buffer. The rotation is performed as the data is written into and read from the page buffer, thus requiring no additional time. A special memory mapping technique is used to make efficient use of the page buffer memory.

Abstract: A single queue for controlling a plurality of FIFO registers in a bus to bus interface. Assume that there are a number of FIFO's and that each FIFO has a number of packet sized locations. Then, the queue for controlling these FIFO's can be implemented from memory and pointers. The queue will have a number of slots, one for each packet location in a FIFO, each slot having one number of bits identifying the originating device and another number of bits identifying the set of pointers involved. The result is that a single queue will have a number of pointers to control a number of FIFO's. For a numerical example, assume two FIFO's connecting two data busses, eight devices connected to one bus, and a capacity of sixteen packets for each FIFO. In this case the queue will have sixteen slots and two sets of pointers. Each set has one pointer to identify the place at which data can be entered into the FIFO, and one pointer to identify the place at which data can be read from the FIFO.