MAIN1  PC=PC+1; fetch; goto(MBR)

PC = PC+1; fetch    
MAR=MBRU; rd
H=MBRU
MDR=MDR<<8
TOS=MDR=H OR MDR 
MAR=SP=SP+1; wr 
PC=PC+1; fetch;goto MAIN1  
MAIN1 GOTO (MBR)