Once checking the program, i created the main program through which i send two 8 bits here the check is different, i used Accumulator registor A 's value as a check to decide MSBYTE AND LSBYTE

ORG 000H
        JMP     MAIN
ORG 023H
        JMP     SERIAL
ORG 030H
MOV DPTR,#0000H
MAIN:
        INC DPTR
        MOV     SCON,#50H
        MOV     TMOD,#20H
        MOV     TH1,#-24
        SETB    TR1
        SETB    EA
        SETB    ES
        MOV A,#00
        MOV SBUF,'B'
        JZ $
        MOV TMOD,#00
        CLR TR1
        CLR EA
        CLR ES
        JMP$

SERIAL:
        CLR     TI
 
        MOV A,#01
        MOV SBUF,'C'
        RETI

SKIP:
        MOV     SBUF,DPH
RETI
FINISH: RETI
END


 

Now what problem did i faced
As you can see that i have moved B as my first value and C as my second value to check the program.
But when i run it i just get U on the screen.
I run this proram through the edsim51 simulator, sim535 and JISM simulator, edsim didnt work for any code, sim535 and JISM worked correctly for the first two codes but were not displaying the U for the third code so i guessed that when they are not giving the correct display how could i use them to debug my program.
Wel i think that it wont be difficult for you people to anwer it.