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