A digital computer has 32 bit instructions. There are a number of different inst

Question

A digital computer has 32 bit instructions. There are a number of different instruction formats and the number of bits in each format used for opcodes varies depending on the bits need for the other fields

If the 1st bit of the opcode is 0, there are 5 opcode bits

if the 1st bit of the opcode is 1 and the 2nd bit of the opcode is 0, then there 7 opcode bits

if the 1st bit of the opcode is 1 and the 2nd bit of the opcode is 1, then there 8 opcode bits

1. How many distinct opcodes are there for this computer? Show all work, if you just write a number and it is wrong you get 0 point.

2. Is this a RISC or CISC architecture? Justify you answer.

Explanation / Answer

1) 1st bit 0: No of Opcodes = 2^(5-1) = 16

1st bit of the opcode is 1 and the 2nd bit of the opcode is 0No of Opcodes = 2^(7-2) = 32

1st bit of the opcode is 1 and the 2nd bit of the opcode is 1No of Opcodes = 2^(8-2) = 64

Total = 112 opcodes

2) Here there is not much information but based in fixed size instruction and low number of opcodes this is a RISC architecture.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.