Part 2 - Topic 1 - MIPS Architecture

Question 1

What does MIPS stand for?

Answer 1

Microprocessor without Interlocked Pipelined Stages

Question 2

What is this in MIPS assembly code?

a = b + c

Answer 2

add a, b, c

Question 3

What is the answer of this C expression in MIPS assembly code?

Answer 3

add t, b, c #t = b + c

sub a, t, d #a = t - d

Question 4

What is lw?

Load a word ( = 4 bytes) of data at memory address 4 into $s3.

Answer 4

lw = load word

use 2 register operands and a constant

lw $s3, 4($0)

reads word at address 4 into $s3

Question 5

If opcode is 0 what does that mean?

Answer 5

That it is a R-type instruction and function bits tell operation.

Otherwise opcode tells operation

Question 6

MIPS: 32 × 32 multiplication

result and registers used

Answer 6

64 bit result

{hi,lo}

Question 7

MIPS: 32-bit division

Output and register format

Answer 7

32-bit quotient, remainder

Quotient in lo

Remainder in hi

Question 8

Moves from lo/hi special registers

Answer 8

• *mflo** $s2
• *mfhi** $s3

Question 9

What is this in MIPS assembly code?

Answer 9

Not ‘j done’ sends the code to ‘done:’ and prevents code from going to ‘else’ clause after ‘if’ statement completion

Question 10

How can this be written in assembly code?

Answer 10

sll: Shift Left Logical

One shift is the equivalent to raising value to power of 2.
In this case the 1 is the shift raising the value to a power of 2.

Question 11

What are R-type instructions?

Answer 11

and, or, add, sub, slt

Question 12

How do you calculate PC’?

Answer 12

(sign-extended immediate << 2) + (PC+4)

Question 13

How do you convert Imm to signImm?

Answer 13

16 bits need to be added in front of the 16 bits of Imm,

This comes to 4 zeros added in hexadecimal