| 摘要 |
PURPOSE:To make high speed access in vertical, horizontal and oblique directions as well possible by providing a register that sets access address, a register to which the displacement of address is set and a data width register to which access unit of one time is set. CONSTITUTION:Before accessing, two-dimensional start addresses X, Y and the displacement of addresses DELTAX, DELTAY, and data width in one access are set respectively to registers 31-34 and a register 38. Then, a bit map memory 3 is accessed based on set address. When the data width is 8 bits,addresses of X, Y are renewed by DELTAX, DELTAY eight times from the first X, Y addresses, and exchange is made between the data register 38 and a memory cell 39 at every time. In former memory constitution, the number of times of bit length in the vertical direction was necessary in case of accessing in the vertical direction (Y), and in this method, the number of times of (bit length/access data for one time) becomes sufficient.
|
