A digital computer has a memory unit with 64 bits per word and 32G memory. The instruction set consists of 400 different operations. All instructions have an opcode, general register, index register, mode, future and address fields. This particular system includes 64 general-purpose registers, 16 index register,8 modes, future and address. a) How many bits are needed for the opcode? b) How many bits are needed to specify the general and index registers? c) How many bits are needed to specify the mode and the future? d) How many bits are needed to specify the address? e) What is the largest unsigned binary number that can be accommodated in one word of memory?