Question

Represent following LEGv8 assembly instruction into machine code (use hexa decimal format).
STUR X1, [X1, #8]

Answer 1

Solution :

LEGv8 assembly instruction STUR X1,[X1,#8] have following format,

Opcode	address	Op2	Rn	Rt
11 bits	9 bits	2 bits	5 bits	5 bits

Where, Opcode = Operation Code, Address = constant offset from content of base register, Op2 = any other operand, Rn = Base register, Rt = Destination or source register

So for translation we need to write instruction in above format using equivalent binary form and then covert into hexadecimal format, Opcode for STUR is 1984

Opcode(11 bits)	Address(9 bits)	Op2(2 bits)	Rn(5 bits)	Rt(5 bits)
1984	8	0	1	1
Equivalent binary form of each field in required bits
11111000000	000001000	00	00001	0001

Now we are going to make group of 4 bits from above resulted binary string, 1111 1000 0000 0000 1000 0000 0010 0001_two = F8008021₁₆ Therefore instruction STUR X1,[X1,#8] is converted to (F8008021)₁₆ machine code.