8051 Program – exchange content of two ram locations

; exchange content of two ram locations
	ORG 0H
	MEM1_ADDR EQU 40H
	MEM2_ADDR EQU 60H
	BYTE_COUNT EQU 10
MAIN :
	MOV R0,#MEM1_ADDR
	MOV R7,#BYTE_COUNT
	MOV A, #0
mem1fill:	MOV @R0,A
	INC A
	INC R0
	DJNZ R7,mem1fill
	MOV R0,#MEM2_ADDR
	MOV R7,#BYTE_COUNT
	MOV A, #10H
mem2fill:	MOV @R0,A
	INC A
	INC R0
	DJNZ R7,mem2fill
	MOV R0,#MEM1_ADDR
	MOV R1,#MEM2_ADDR
	MOV R7,#BYTE_COUNT
	LCALL XCHANGE
	SJMP MAIN
XCHANGE:
	MOV A, #0
loop:	MOV A, @R0
	MOV B, @R1
	MOV @R1, A
	MOV @R0, B
	INC R0
	INC R1
	DJNZ R7, loop
	RET
	END

; exchange block of data
; using XCH instruction
	ORG 0H
	SJMP 30H
	ORG 30H
	MOV R0,#27H	;source address
	MOV R1,#41H	;destination address
	MOV R3,#05H	;count
BACK:
	MOVX A,@r0
	MOV r2,a
	MOVX a,@r1
	XCH a, r2
	MOVX @r1,a
	XCH a, r2
	MOVX @r0,a
	INC R0
	INC R1
	DJNZ R3, BACK
HERE:	SJMP HERE
	END

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Related topics:
8051 Program - move block of data without overlap   |   8051 Program - move block of data with overlap   |   8051 Program - move block of data external memory   |   8051 Program - exchange block of data external memory   |   8051 Program - memory compare   |   8051 Program - swap nibbles   |   8051 Program - memory subroutines   |   8051 Program - math subroutines   |   8051 Program - conversion subroutines

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List of topics: 8051

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