ADDRES    START    100                               
. tests pc forward addressing
. tests base addressing
. tests pc backward addressing
NOW      +LDB     #BEGIN              load base register 
XXX       BASE     BEGIN              tell assembler  
YYY       LDA      BE                 A <- (m..m+2)    
EN        RESW     4                  
BE        WORD     2                              
BEGIN     RESW     1
JUNK      RESW     2200                              
THERE     RESW     1                              
ZZZ       LDA      JUNK                               
MMM       STA      THERE                              
          END      NOW