| 摘要 |
PURPOSE:To enable writing on plural picture memories efficiently by executing the arithmetic of contents of the picture memory and modification data simultaneously to write them at the time of writing on plural picture memories for controlling display. CONSTITUTION:When a picture display mode is modified, a CPU issues action information to an action information memory circuit 11 and readout instructions to an address of a picture memory to be rewritten. At this time a control circuit 10 generates a control signal with respect to data holding circuits 5, 7 and 9 so that values of the picture memory outputted to memory buses 1a, 2a and 3a will be held. Moreover, the circuit 10 gives instructions that arithmetic circuits 4 and 6 take an OR of a value of data bus 20a and that of data lines 5a and 7a and output it. The circuit 10 medicates that an arithmetic circuit 8 takes an AND of inversion of the value of the bus 20a and that of a data line 9a and outputs it to the bus 3a. Picture memories 1, 2 and 3 receive the value; therefore writing on plural picture memories can be efficiently executed. |
