It would be useful to have a read integer subroutine.
The subroutine prompts the user for an integer and reads it in. The integer is returned in $v0. Here is a start on the subroutine:
# pread -- prompt for and read an integer
#
# on entry:
# $ra -- return address
#
# on exit:
# $v0 -- the integer
pread:
la $a0,prompt # print string
li $v0,4 # service 4
syscall
li $v0,5 # read int into $v0
syscall # service 5
____ ____ # return
nop # branch delay slot
.data
prompt:
.asciiz "Enter an integer"