Here's what the listing file looks like for simple.as:

   0:          LOD    A
   1:          ADD    B
   2:          STD    C
   3:          HLT
   4:  A:      NUM    5
   5:  B:      NUM    7
   6:  C:      NUM

This tells us that variable A resides at memory address 4, B at 5 and C at 6. All object programs in the CSC-1 start at location 0 (which is true of most real-world systems, too).