Question

How does one find the binary and hex for MIPS instructions. Such as, sub $s1, $t7, $t8 or lw $s1, 400($s5) ???

Answer 1

Greetings!!

Q1:sub $s1, $t7, $t8

Step 1: Identify the instruction format. Example:sub instruction is R-format.

Step 2: Get the instruction syntax Example: sub rd,rs,rt

Step 3: Get the instruction encoding format:

Opcode	rs	rt	rd	shamt	func
6 bits	5 bits	5 bits	5 bits	5 bits	6 bits

Step 4:Add the binaries of the respective opcode and register numbers into the encoding format

Opcode	rs	rt	rd	shamt	func
6 bits	5 bits	5 bits	5 bits	5 bits	6 bits
000000	00111	01000	00001	00000	100010

Step 5: Arrange the bits in group of 4 and write the hex equivalent. 0000 0000 1110 1000 0000 1000 0010 0010

0x00E8082

Q2:lw $s1, 400($s5)

Step 1: Identify the instruction format. Example:sub instruction is I-format.

Step 2: Get the instruction syntax Example: lw rt,imm(rs)

Step 3: Get the instruction encoding format:

Opcode	rs	rt	imm
6 bits	5 bits	5 bits	16 bits

Step 4:Add the binaries of the respective opcode and register numbers into the encoding format

Opcode	rs	rt	imm
6 bits	5 bits	5 bits	16 bits
100011	00101	00001	000000110010000

Step 5: Arrange the bits in group of 4 and write the hex equivalent. 1000 1100 1010 0001 0000 0001 1001 0000

0x8CA10190

Hope this helps