Question

I am trying copy some words from memory and saving it to another memory address using assembly.
I am trying to write the code for it but I am not sure about some of the parts. I will briefly describe what I want to do.

The source address, destination address and the number of words to copy are input arguments of the function.

Answer 1

From your description it sounds like a regular memcpy, except that you specify the number of words to copy rather than the number of bytes. Not sure where the whole stack buffer idea comes from(?).

Something like this would copy the words from the source to the destination address:

sll $a2,$a2,2
addu $a2,$a1,$a2  ; $a2 = address of first byte past the dest buffer
Loop:
    lw $t0,0($a0)
    sw $t0,0($a1)
    addiu $a0,$a0,4
    addiu $a1,$a1,4
    bne $a1,$a2,Loop
    nop

EDIT: If your source and destination buffers are not aligned on word boundaries you need to use lb/sb instead to avoid data alignment exceptions.