MOV  AX, VARIABLE    ; 3 bytes, 14 clocks
   MOV  CL, 4           ; 2 bytes,  4 clocks
   SHL  AX, CL          ; 2 bytes, 24 clocks
   MOV  BX, AX          ; 2 bytes,  2 clocks
   SHL  AX, 1           ; 2 bytes,  2 clocks
   SHL  AX, 1           ; 2 bytes, 6 clocks -- prefetch queue
                        ; is empty before the instruction
                        ; is executed
   ADD  AX, BX          ; 2 bytes, 14 clocks -- 4 clocks/byte
                        ; for the BIU to put the instruction
                        ; in the queue plus 2 clocks to
                        ; execute it