To perform MESSAGE PASSING in 8051 Programming

MOV TMOD,#20H
MOV TH1,#0faH
MOV SCON,#050H
SETB TR1
START: MOV A,#'M'
ACALL F1
MOV A,#'e'
ACALL F1
MOV A,#'s'
ACALL F1
MOV A,#'s'
ACALL F1
MOV A,#'a'
ACALL F1
MOV A,#'g'
ACALL F1
MOV A,#'e' 
ACALL F1
SJMP START

F1: MOV SBUF,A
HERE:JNB TI,HERE
CLR TI
RET

Check if 5AH is located is located in any one of the locations.If yes load acc. by 5AH.

START: MOV R0,#5FH
 MOV R7,#10H
 COMPIT: CJNE @R0,#5AH,NEXT
 MOV A,#5AH
 SJMP FOUND
NEXT: DEC R0
DJNZ R7,COMPIT
NOMATCH : MOV A,#00H
FOUND : SJMP FOUND

Copy a block of 20bytes of data from 60h to 73h to the location starting from 40h.

START: MOV R0,#60H
 MOV R1,#40H
 MOV R7,#14H
COPYIT: MOV A,@R0
 MOV @R1,A
 INC R0
 INC R1
 DJNZ R7,COPYIT
 OVER: SJMP OVER

Program to shift a block of 8 bytes data,from 50h to 57h,1 byte up data is available from 51H to 58H

START: MOV R0,#57H
 MOV R1,#58H
 MOV R7,#08H
 SHIFT: MOV A,@R0
 MOV @R1,A
 DEC R0
 DEC R1
 DJNZ R7,SHIFT
 OVER :SJMP OVER