question on mips code

[gdarian216]

the following program is trying to copy words from the address in register $a0 to the address in register $a1, counting the number of words copied in register $v0. It will then stop copying when it finds a word equal to 0. i wasnt tring to preserve the contents of register $v1,$a0,$a1. the terminating word should be copied but not counted.

this is what i have so far can anyone show me the buggs

        addi $v0, $zero, 0          #initialize count
loop: lw    $v1, 0($a0)             #read next word from source
        sw   $v1, 0($a1)             #write to destination
        addi $a0, $a0, 4            #advance pointer to next source
        addi $a1, $a1, 4            #advance pointer to next destination
        beq  $v1, $zero, loop     #loop if word copied != zero

[Banfa]

this is what i have so far can anyone show me the buggs

What makes you think it is buggy? What behaviour do you get, and how does this differ from what you expect?

The only obvious error I see is that you never do anything with $v0 so you do not record the number of words copied.

[gdarian216]

i wasn't sure Is there a simulator that I can test out my code because it was done in my head and when i handed it in my teacher said it had some bugs in it but didn't tell me where

[kaioshin00]

i wasn't sure Is there a simulator that I can test out my code because it was done in my head and when i handed it in my teacher said it had some bugs in it but didn't tell me where

There is a simulator called PC Spim

It's available here

[kaioshin00]

Also ..

beq  $v1, $zero, loop     #loop if word copied != zero

Shouldn't that be

bne  $v1, $zero, loop     #loop if word copied != zero

?