Complete fact()

Here is the complete code for fact():

#  int fact( int n )
#  {
#    if ( n<=1)
#      return 1;
#    else
#      return n*fact(n-1);
#  }
         .text
         .globl  fact
fact:
                                  # prolog        
         sub     $sp,$sp,4        #   1. Push return address
         sw      $ra,($sp)
         sub     $sp,$sp,4        #   2. Push caller's frame pointer
         sw      $fp,($sp)
         sub     $sp,$sp,4        #   3. Push register $s1
         sw      $s1,($sp)
         sub     $fp,$sp,0        #   4. $fp = $sp - space_for_variables (==0)
         move    $sp,$fp          #   5. $sp = $fp
         
                                  # body of subroutine
         move    $s1,$a0          # save argument in $s1
         li      $t1,1            # get a 1
         bgt     $s1,$t1,recurse  # if ( n<=1)
         li      $v0,1            #   return 1
         b       epilog    

recurse:                          # else
                                  #  return n*fact(n-1)
         sub     $a0,$s1,1        #     n-1
                       
                                  # subroutine call
                                  #   1. No T registers to push
                                  #   2. Argument is in $a0 
         jal     fact             #   3. Jump and link to subroutine

         mul     $v0,$v0,$s1      # n*fact(n-1)
                            
epilog:                           # epilog
                                  #   1. Return value is already in $v0        
         add     $sp,$fp,0        #   2. $sp = $fp + space_for_variables (==0)
         lw      $s1,($sp)        #   3. Pop register $s1
         add     $sp,$sp,4        #          
         lw      $fp,($sp)        #   4. Pop $fp
         add     $sp,$sp,4        #           
         lw      $ra,($sp)        #   5. Pop $ra
         add     $sp,$sp,4        #            
         jr      $ra              #   6. return to caller