8051 Program - copy xram to xram

; Description:

; Copy Bytes From External Memory To External Memory

;

; Entry Requirements:

; DPTR Points To Destination In External Memory

; R6/7 Points To Source In External Memory

; R0/1 Contains The Length

;

; On Exit:

; DPTR = Points To End Of Destination + 1

; R6/7 = Points To End Of Source + 1

; R0/1 = 0

;

; Affected:

; PSW.Z, PSW.P, Acc, DPTR, R0, R1, R6, R7

;

; Stack:

; 2 Bytes, Not Including Space Used By Called Routines

;

; Comments:

; None

;

UTIL_COPYDTODL:
	call UTIL_DPTRR01	; DPTR=Len, R01=Src
	call UTIL_DPTR2C	; 2's Complement
	call UTIL_DPTRR01	; DPTR=Src, R01=Len
		;
loop1:	call UTIL_DPTRR67	; DPTR=Src, R67=Dest
	movx a,@dptr	; Get Character
	inc dptr	; Next Source Location
	call UTIL_DPTRR67	; DPTR=Dest, R67=Src
	movx @dptr,a	; Store It
	inc dptr	; Next Destination Location
	call UTIL_DPTRR01	; DPTR=Len, R01=Dest
	inc dptr	; Increment Length
	mov a,dph	; Get High
	orl a,dpl	; OR In Low
	call UTIL_DPTRR01	; DPTR=Dest, R01=Len
	jnz loop1	; Repeat Until 0
	ret	; Return To Caller

Source: Assorted Utilities, John C. Wren 11/23/96

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List of topics: 8051

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