| 摘要 |
PURPOSE:To detect easily the intermittent failure of a hardware and to minimizing the reduction of the processing ability of a computer system, by providing the titled device with a microinstruction starting the self-diagnosis test of a CPU during the idle time of the CPU. CONSTITUTION:A selector circuit 12 is used as a gate to access a control memory (CS 19) in accordance with the contents of a microinstruction register 11 and a selector circuit 13 functions as a circuit to access the control memory 19 in accordance with the contents of an output register (microdata register MDR20) of the control memory 19. The control memory 19 stores a microprogram to execute a microprogram instruction for self-diagnosis. When a SST (start self- test) instruction is read out in the microinstruction register 11, the control memory 19 is accessed through the selector circuit 12 to execute various diagnosis. |
