Microinstruction

A microinstruction is a vector of bits, where each bit is a control signal, condition code, or the address of the next microinstruction .

A microinstruction cycle can be executed faster than an instruction cycle, since microinstructions are stored within the CPU, whereas instructions must be fetched from an external memory. Microinstructions also normally require less decoding than instructions.

Sources:

Mostafa Abd-El-Barr, Hesham El-Rewini Fundamentals of Computer Organization and Architecture, 2005 – 288p. – 100

A.P.Godse, D.A.Godse Computer Architecture. Published by Technical Publications, 2010 – 496p. – 54