Control system of microprogram

Abstract

Abstract PURPOSE:To avoid the waste of the memory capacity by holding plural microinstruction groups of different bits at a register after storing those instruction groups to each memory and supplying an invalid bit to a control subject after adding is to the pat of microinstruction which is less than the maximum number of bits of the register. CONSTITUTION:A microprogram memory 1 consists of microinstruction group memories 1a and 1b of short and long word lengths. The microinstruction read out of the memory 1 is stored to a register 3. Then the application of addressing is possible via a register 3 to a memory 1a or 1b storing the microinstruction to be read next. The upper bits of an address delivered from the register 2 are retrieved by a word length detecting circuit 4 for detection of a microinstruction of the long or short word length. Then a transmission gate 5 is opened and closed. The gate 5 is closed with an instruction of the short word length and an invalid field NOP is added to a control subject.

Inventors

• 👤 Noriyuki Tachibana
• 👤 橘　則行

Bibliographic Details