Device for giving a pattern a rotation of an integral multiple of 90.degree. with the pattern read from a memory on a block by block basis

Abstract

An original pattern stored in a first memory, is read out in read-out blocks. A rotated pattern, namely, the original pattern given a rotation of one of 0.degree., 90.degree., 180.degree., and 270.degree. that is selected by a selection signal, is written in a second memory in write-in blocks. Each of the read-out and write-in blocks consists preferably of N N-bit words, where N represents a predetermined integer. The write-in block in which a read-out block should be written with the rotation, is selected by the selection signal. Each read-out block is stored in an array of shift registers for the respective words of the block and successively read out stage by stage into a loading circuit for the second memory as words of one of the write-in blocks when the rotation is 90.degree. or 270.degree.. Words of each read-out block may directly be transferred to the loading circuit when the rotation is 0.degree. or 180.degree.. The loading circuit is controlled by the selection signal on loading the second memory with each word of the write-in block. The second memory may be the memory used as the first memory. In this case, a buffer memory should be used in temporarily keeping the read-out block in which one of the write-in blocks should be written. The buffer memory is preferably another shift register array which is alternatingly used in combination with the first-mentioned shift register array.

Dependencies are inferred from the claim text.