| 摘要 |
PURPOSE:To reduce erroneous processing due to a difference between an instruction address and an instruction code by storing a couple of the instruction address and instruction code in adjacent addresses by a history storage system which achieves circulating storage. CONSTITUTION:An instruction of a logical device 1 has one instruction cycle Lop consisting normally of several machine cycles i0-i4, so when some instruction is executed, an instruction address signal is selected and sent out in the starting machine cycle i0, and is stored in the address #n of a storage device 7. In the next machine cycle i1, an instruction code signal 12 is selected and stored in the address #n+1. Thus, a couple of the instruction address signal 11 and instruction code signal 12 having a correlation with respect to history information are stored in adjacent addresses of the storage circuit 7, and consequently pieces of analysis information are obtained from invariably adjacent addresses during an analysis of a fault such as malfunction, thereby reducing erroneous processing whose cause is unclear due to a difference between the instruction address and instruction code. |
