Converting Assembly to Machine Code

Question

I'm taking a course now about computer organization and architecture. We've been given some exercises to do. One of them is to convert assembly code into machine instructions.

I'm stuck on converting movia into a machine instruction.

I know it consists of 2 operations, orhi and addi.

This is the code in assembly:

movia r8, 50000 

The exercise states that r0 is 0x0, and r8 is 0x8.

So, the orhi would be: orhi r8, r0, %hiadj(50000) and the add would be: addi r8, r8,%lo(50000)

I've gotten the orhi to:

    00000 01000 1100001101010000 110100    
___________________r0____r8_______50000________0x34(opcode)

But I have to use the %hiadj on the 50000! I don't know how to? I've searched around for it a bit but haven't found an answer clear enough.

I'm very new at this but really want to understand! So, how do you use the %hiadj? Sorry if the question isn't clear, but if you'd like to help, I'll try and explain more.

Answer 1

%hiadj is the 16 most significant bits of its operand, with an adjustment if the 16 least significant bits would be sign-extended by the movia. In the case of 50000, the 16 most significant bits are 0, and there is no sign extension.

So %hiadj(50000) would simply be 0.