| 摘要 |
PURPOSE:To add or change a microprogram even in case of an operation by providing a control register for shifting it to other flow, when it is shown that a flag bit of a processing flow of the microprogram is ineffective. CONSTITUTION:When an operation request is set to external control register ECTR8 from a CPU1, a control processor 4 decodes it, and it is made to branch to a processing flow of a microprogram. In a branch destination flow, an effective flag is decided by referring to an external microprogram control register EMCTR5. When it is shown to be ineffective, it is made to branch to a microprogram store area ROMCS6 or RAMCS7 in which a processing flow shown by a replacement address is stored. The EMCTR5 and the RAMCS7 can read and write at any time from and to the CPU1, and the contents of the operation request from the CPU1 can be changed by rewriting suitably the EMCTR5 and the RAMCS7. |
