Question

Assume that the control memory is 30-bits wide. the micro instruction format is divided into 3 fields. A micro-operation field of 15-bits specifies the micro-operations to be performed. An address selection field specifies a condition based on flags; and a control memory address field. There are 8 flags to be selected. Number of bits in address selection field, number of bits in address field and size of control memory in words respectively.

• A. 3, 10, 1024
• B. 3, 10, 2048
• C. 3, 12, 4096
• D. 3, 12, 2048

Answer 1

The correct option is C 3, 12, 4096

option (c)

No. of flags = 8 = $2^3$

No. of bits for address selection field = 3- bits


bits in address field = 30-(15 + 3) = 12-bits

No. of addresses = $2^{12}$ = 4096 [ Size of memory]