68000 cpu
   add.l    D0,D1   ;Source listed first. Add D0 to D1 - 38 bits wide.
                    ; Uses 8 GP registers, either accumulator or index
                    ; Regsiter 32 bits but can be treated as 8, 16, or 32
                    ; by appending .b, .w, or .l, 
   subq     #1,D0   ;Immediate  - subtract quick.  bits normally used to 
                    ; to store the data modifiers, .b, .w, or .l are used 
                    ; instead to store value between 1 and 8.