In the original proposal byWilkes [

In the original proposal byWilkes [WILK51], each bit of a microinstruction either
directly produced a control signal or directly produced one bit of the next address.
We have seen, in the preceding section, that more complex address sequencing
schemes, using fewer microinstruction bits, are possible. These schemes require a
more complex sequencing logic module.A similar sort of trade-off exists for the portion
of the microinstruction concerned with control signals. By encoding control information,
and subsequently decoding it to produce control signals, control word bits
can be saved.