The microinstructions stored in the control memory of a processor have a width of 26 bits. Each microinstruction is divided into three fields: a micro-operation field of 13 bits, a next address field (X), and a MUX select field (Y). There are 8 status bits in the inputs of the MUX.
How many bits are there in the X and Y fields, and what is the size of the control memory in number of words?
(A) 10, 3, 1024
(B) 8, 5, 256
(C) 5, 8, 2048
(D) 10, 3, 512
Answer: (A)
Explanation: MUX has 8 states bits as input lines so we require 3 select inputs to select and input lines.
No. of bits in control memory next address field=26-13-3Â =10
10 bit addressing .we have 2 10 memory size
So X,Y size=10,3
So (A) is correct option.
Quiz of this Question