machine language into hex

Question

Convert following four instructions of the MIPS assembly code into machine code and express machine code in hexadecimal representation.

sll $t0, $s1, 10

j jtarget

sw $t3, 0x24($s2)

addi $t4, $0, -10

...

jtarget: 

...

Assume that label mycode: is stored at memory address 0x00444400 and label jtarget: is stored at memory address 0x045678F0.

Answer 1

2. j jtarget

j is a J-type instruction:

opcode | target

The opcode for j is 000010 (decimal 2).

The target address is:

0x045678F0

For a MIPS jump, the 26-bit target field is obtained from:

address >> 2

So:

0x045678F0 >> 2 = 0x01159E3C

Then combine with the opcode:

0x08159E3C

So:

j jtarget = 0x08159E3C

3. sw $t3, 0x24($s2)

sw is an I-type instruction:

opcode | rs | rt | immediate

1. sw opcode = 101011 = 0x2B
2. $s2 = register 18 → 10010
3. $t3 = register 11 → 01011
4. 0x24 = 36 → 0x0024

Therefore:

0xAE4B0024

4. addi $t4, $0, -10

addi is also I-type:

opcode | rs | rt | immediate

1. addi opcode = 001000 = 0x08
2. $0 = register 0
3. $t4 = register 12
4. -10 represented as a 16-bit two's-complement value = 0xFFF6

Therefore:

0x200CFFF6

Final answers

MIPS instructionMachine code (hex)
sll $t0, $s1, 10	0x00284140
j jtarget	0x08159E3C
sw $t3, 0x24($s2)	0xAE4B0024
addi $t4, $0, -10	0x200CFFF6