| 摘要 |
PURPOSE:To remove a useless cycle which is generated for each loop and to increase the speed of operation by discontinuing the control using a loop end sentence but using a loop declaring sentence. CONSTITUTION:An address N-1 of an instruction ROM2 is designated by a program counter PC1', and the contents of instruction of the address N-1 are sent to an instruction register 3. Then the loop frequency is set to a loop counter 5 via a decoder 4. Then the OC1' designates an address N of the ROM2, and both the loop declaring sentence of the contents of the address N and an address N+2 of a loop end are sent to the register 3. The value of the address N+1 of the PC1' of that time point is loaded to a stack 8 by said loop declaring sentence and an indication of a decoder 4'. Thus the address N+1 is used as the head address. At the same time, the last address N+1 of the loop is loaded to an end address setting register 9 by a command of the decoder 4'. The PC1' designates successively subsequent addresses N+1 and N+2 of the ROM2. |
