Converting C to MIPS?

Hi,

I've just started looking at MIPS assembly and one of the questions in my book asks to convert C to MIPS:

Code:

---

for (i = 1; i <= 25; i += 2) {
        A[i] = A[i-1] - B[i-1];
}

---

Where A and B are both arrays of integers, an addressed at $s2 and $s4 respectively.

I'm not sure how to approach this as I've never really coded in C and very new to MIPS. Would I store i to a temporary register like say $t0? Also would I need to rewrite this as a while loop for MIPS? I'm not really sure how to write it as a For loop in MIPS. I would use a "Break" if it were an if/then loop, but like I said I'm not sure how to handle the for loop.

Any info or starting tips would be greatly appreciated.

Yes, you'll need to store 'i' in some temporary register. As you said $t0 is a good place.

Just keep looping, but branch when 'i' ($t0) is greater than 25. Your loop may look something like:

Code:

---

addi $t0, $0, 1
addi $t1, $0, 25

loop:
  # i <= 25
  bgt $t0, $t1, end

  # ... stuff in the loop

  # i += 2
  addi $t0, $t0, 2

  # go to the next iteration
  j loop

end:
  # ... stuff after the loop ...

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Don't get caught up in the while/do-while/for loops, they all can be written as for loops, while loops or do-while loops.