| 摘要 |
PURPOSE:To scale down an instruction decoding programmable logic array (PLA) and to simplify coding by converting the output of the PLA into an access address to a control memory with the use of an address conversion table. CONSTITUTION:In order to specify each micro instruction string in functional units, which is stored in the control memory 4, the instruction decoding PLA2 outputs the number of a micro instruction module. With said number outputted by the instruction decoding PLA2 as a pointer input, the address conversion table 8 outputs a top address stored in the control memory 4 of the corresponding micro instruction module. Namely, the instruction decoding PLA2 does not directly output an access address to the control memory, but executes the pointer output, while the address conversion table 8 converts the access address to the control memory 4. With respect to the address conversion table 8 the instruction decoding PLA2 merely executes the pointer output, thereby scaling down the PLA. |
