8051 Program – largest element in an array

; largest element in an array
; array: 4000H - 4009H
; result: 4010H
	ORG 0H
	ARRAY_ADDR EQU 4000H
	RESULT_ADDR EQU 4010H
	ELEMENT_COUNT EQU 10
	TEMP EQU 40H
MAIN:
	MOV DPTR,#ARRAY_ADDR	; fill memory
	MOV A, #05H
	MOVX @DPTR,A
	INC DPTR
	MOV A, #09H
	MOVX @DPTR,A
	INC DPTR
	MOV A, #06H
	MOVX @DPTR,A
	INC DPTR
	MOV A, #05H
	MOVX @DPTR,A
	INC DPTR
	MOV A, #03H
	MOVX @DPTR,A
	INC DPTR
	MOV A, #07H
	MOVX @DPTR,A
	INC DPTR
	MOV A, #0AH
	MOVX @DPTR,A
	INC DPTR
	MOV A, #0BH
	MOVX @DPTR,A
	INC DPTR
	MOV A, #07FH
	MOVX @DPTR,A
	INC DPTR
	MOV A, #04H
	MOVX @DPTR,A
	LCALL LARGE
	SJMP MAIN
LARGE:
	MOV DPTR,#ARRAY_ADDR
	MOV TEMP,#00
	MOV R5,#ELEMENT_COUNT
loop2:	MOVX A,@DPTR
	CJNE A,TEMP,loop1
loop3:	INC DPTR
	DJNZ R5,loop2
	MOV A,TEMP
	MOVX @DPTR,A
	RET
loop1:	JC loop3
	MOV TEMP,A
	SJMP loop3
	RET
	END

; largest element in a given array
; external memory
	ORG 0H
START:
	MOV R0,#10H	;count
	MOV DPTR,#9000H
LOOP:	CLR C	;Carry=0
	MOVX A,@DPTR
	MOV R2,A	;R2=first no
	INC DPTR
	MOVX A,@DPTR	;Acc=second no
	MOV R3,A
	SUBB A,R3	;Compare
	JNC SKIP
	XCH A,R2	;Exchange
SKIP:	MOVX @DPTR,A	;Big no -> mem
	DEC 82H	;DPL=DPL-1
	MOV A,R2
	MOVX @DPTR,A	;Small no -> mem
	INC DPTR
	DEC R0
	CJNE R0,#01H,LOOP
	INC DPTR
	MOVX A,@DPTR	;A=largest no
	SJMP $
	END

; largest element in a given string
; external memory
	ORG 9000H
	MOV R3,#05H
	MOV DPTR,#8000H
	MOVX A,@DPTR
	MOV R1,A
NEXTBYTE:	INC DPTR
	MOVX A,@DPTR
	CLR C
	MOV R2,A
	SUBB A,R1
	JC SKIP
	MOV A,R2
	MOV R1,A
SKIP:	DJNZ R3,NEXTBYTE
	MOV DPL,#62H
	MOV A,R1
	MOVX @DPTR,A
	SJMP $
	ORG 8000H
	DB 04,05,06,07,08,02
	END
;Result: 8062 -> 08

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Related topics:
8051 Program - smallest element in an array   |   8051 Program - factorial of a given number   |   8051 Program - fibonacci series   |   8051 Program - lcm of two numbers   |   8051 Program - gcf of two numbers   |   8051 Program - memory subroutines   |   8051 Program - math subroutines   |   8051 Program - conversion subroutines

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List of topics: 8051

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