Question

Computer Architecture problem

Consider the following number 5 Digits Depending on the given number, convert the assembly instruction into machine code in hexadecimal. Register (F)fopl opcode funct(C)Irs! Number Even and 0x0 0x24 Even $a0 Odd or Ox0 0x25 Odd $al Number Even $s6 22 5 Odd $s7 23 Write out your assembly instruction f irst. Convert it into machine code in hexadecimal. If the content of the registers are as follows, determine the value of $vO after your instruction has been executed. (You can use the right table for your calculation, but not required.) Binary $a0 0x12345678 $al 0xFEDCAB98 $s6 0x 30502060 $7 0xF3F5F2F6 (rs) (rt) and/or $v0

Answer 1

Answe is as follows :

As we see that we have to identify the instruction first i.e. according to {op} , v0 {rs} {rt}

where op s opcode, v0 is destination register , rs and rt are source registers.

so as per given scenario

we have F = 1 i.e. odd so instruction is OR with opcode 0x0 and funct is 0x25

we have G = 5 i.e. odd so rs is $a1 i.e. register number 5

we have H = 8 i.e. even so rt is $s6 i.e. register number 22

here $v0 is register number 2

So our final instruction is

OR $v0 , $a1 , $s6

So equivalent instruction is OR $2 , $5 , $22

so the machine instruction is :

opcode = 6 bits = 000000

rs = 5 bits = $5 = 00101

rt = 5 bits = $22 = 10110

rd = 5 bits = $2 = 00010

funct = 11 bits = 00000011001

So complete binary instruction is :

000000 00101 10110 00010 00000011001

= 0000 0000 101 0110 0001 0000 0001 1001

So we have

OR $v0 , $a1 , $s6

where $a1 = 0xFEDCAB98 = 1111 1110 1101 1100 1010 1011 1001 1000

and $s6 = 0x30502060 = 0011 0000 0101 0000 0010 0000 0110 0000

So after ORing both we get = 1111 1110 1101 1100 1010 1011 1111 1000 = FEDCABF8

So $v0 contains 0xFEDCABF8

if there is any query please ask in comments....