Intel 210200-002 manual Move 50 bytes between two overlapping strings

ARCHITECTURE AND INSTRUCTIONS

Sample Four:

Move 50 bytes between two overlapping strings.

MY _DATA	SEGMENT
STRING	DB	1000 DUP (?)
STRING _1	EQU	STRING+?
STRING_2	EQU	STRING+25
MY_DATA	ENDS
MY_CODE	SEGMENT
	ASSUME	CS:MY _CODE, DS:MY _DATA
STRING_SIZE	EQU	50
GO:	MOV	AX,MY_DATA
	MOV	DS,AX
	MOV	ES,AX
	MOV	CX,STRING_SIZE
	MOV	SI,OFFSET STRING_1
	MOV	DI,OFFSET STRING_2
	CLD
	CMP	SI,DI
	JLT	OK
	STD
	ADD	SI,STRING_SIZE-1
	ADD	DI,STRING_SIZE-1
OK:	REPEAT MOVS	STRING_2,STRING_1
	HLT
MY_CODE	ENDS
	END	GO

;number of bytes to move ;establish data segment

;source string ;destination string ;assume a forward move ;if source string comes first

;...we need backwards move ;set SI and 01 to

;... end of stri ngs ;move the string

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