jalr     $t0                # call the object's method

This instruction transfers control to the address in register $t0.

Implementation of an Object

After the print method runs control returns to the instruction after the jalr (if delays are set to off in SPIM).

Now look at the implementation of object1. It follows this plan:

byte 0-3: address of print()                # single-entry jump table
byte 4- : null terminated string            # as many bytes as needed

Here is the actual code:

          .data
object1:
          .word    print                    # Jump Table
          .asciiz  "Hello World\n"          # This object's data

A larger object, with more methods, would have more entries in its jump table.

Complete the declaration for object2:

object2:
          .word              # Jump Table 
 
          .asciiz            # This object's data