LXI H 4200h
MOV C M
DCR C
REPEAT: MOV D C
LXI H 4201h
LOOP: MOV A M
INX H
CMP M
JC SKIP
MOV B M
MOV M A
DCX H
MOV M B
INX H
SKIP: DCR D
JNZ LOOP
DCR C
JNZ REPEAT
HLT