| 摘要 |
PURPOSE:To control or monitor externally an operation related to a microprogram instruction by providing a microprogram instruction control means on a microprogram instruction operating means. CONSTITUTION:In case when an enable bit of a breakpoint register 11 is '1' and executes control externally, an address related to a microprogram to be controlled is loaded in advance in an FIFO memory 19. This address is applied to one terminal of an ENOR gate 13, an output of a register 11 is applied to the other terminal, and when addresses of both of them have coincided, an FF 14 is set. Accordingly, an output of an NAND gate 15 becomes a low level, an output buffer 18 is selected, and an output buffer 17 is inhibited. As a result, the address which has been loaded in the memory 19 is applied to a decoder 3 instead of an address from a microaddress register 2. Therefore, based on the address which has been loaded in the memory 19, each operation of the microprogram instruction can be executed.
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