12,987 views
4 votes
4 votes
A computer has 256 K word memory. The instruction format has 4 fields i.e., Opcode, register field to represent one of the 60 processor registers, mode field represent one of 7 addressing modes and memory address field. How many instructions the system supports when a 32- bit instruction is placed in the one memory cell.

1 Answer

7 votes
7 votes

 

instruction format (32- bit instruction):

Opcode Register Addressing Mode Memory Address

A computer has 256 K word memory i.e. memory is word addressable.

 60 processor registers will require 6 bits (60 < 26)

7 addressing modes will require 3 bits (7 < 23)

memory address field will require 18 bits

so opcode will have 32 -(6+3+18) = 5

so maximum instructions the system supports = 32

Related questions

4 votes
4 votes
3 answers
2