Epilog

It is OK if the return value is already in $v0 when the epilog is reached. Here is the complete subroutine:

## maxInt -- compute the maximum of two integer arguments
##
## Input:
## $a0 -- a signed integer
## $a1 -- a signed integer
##
## Returns:
## $v0 -- maximum

         .text
         .globl maxInt

maxInt:
          # body
          move   $v0,$a0          # max = $a0
          bgt    $a0,$a1,endif    # if $a1 > $a0  
          nop
          move   $v0,$a1          #    max = $a1
endif:                            # endif 
          # epilog
          jr     $ra              # return to caller
          nop

This subroutine could be put in its own file, perhaps maxInt.asm, and separately assembled. Later on it could be used with programs we don't even know about, as long as they follow the Stack-based Linkage Convention.

With QtSPIM, main and each subroutine can be placed in a separate file and separately loaded. Use the "File" menu. Use the "Reinitialize and Load File" menu choice for main, and use "Load File" with the subroutines.