Microprogram control system

Abstract

Abstract PURPOSE:To execute a non-operation (NOP) instruction with a microprogram without increasing the capacity of a control memory, by inserting the NOP instruction for timing control to a data register of the control memory at a desired time point. CONSTITUTION:A microprogram address obtained by decoding the operation part of a microinstruction is set to a control memory address register 1 through a next address control circuit 4. An access is given to a control memory 2, and the microinstruction is read out to a data register 3. Then this read-out instruction is decoded by a decoder 7 and latched by a controller 8 for execution of an instruction action. In this case, an NOP control field 31 is decoded by a decoder 5 and then latched by an NOP command insertion control latch 6 after it is detected that the insertion of an NOP instruction is indicated in the next machine cycle. The output NOPC of the latch 6 controls a selection circuit 21, and the NOP code is set to the operation part of the register 3. Then the NOP instruction is executed and the next address of the register 1 is executed.

Inventors

• 👤 Hisajiro Sagara
• 👤 相良　久次郎
• 👤 Koichi Inoue
• 👤 浩一 井上
• 👤 Katsuyuki Iwata
• 👤 勝行 岩田

Bibliographic Details