Block movement without overlap in Z-80

Microprocessor 8085

In this section, we will see how we can use the Zilog Z-80 Microprocessor to move a block of data to another location. There is one assumption, there is sufficient distance between source and destination. So blocks are non-overlapping. Basically the block movement is not exact moving, it is copying the data to other locations.

The number of items in the block is given at location 5000H, and the block is located at position 5050H.

So before movement, the items in the memory is looking like this.

Address	Value
5000H	04H
	. . .
5050H	89H
5051H	7AH
5052H	2FH
5053H	56H
	. . .

Now, we are writing a program at location 8000H to move the block contents to other locations.

Program

Address	Hex Codes	Labels	Mnemonics	Comments
8000	21 00 50		LD HL, 5000H	Load the HL pair with 5000H
8003	DD 21 50 50		LD IX, 5050H	Set the index register with 5050H
8007	DD 7E 00	LOOP	LD A, (IX+00H)	Load Acc with IX + 00H
800A	DD 77 20		LD (IX+20H), A	Load content of Acc at IX + 20H
800D	DD 23		INC IX	Increase the Index Register
800F	35		DEC (HL)	Decrease the content of memory location, pointed with HL pair
8010	C2 07 80		JP NZ, LOOP	Jump to Loop, when Zero flag is off
8013	76		HALT	Stop the program

Output

Address	Value
5000H	04H
	. . .
5050H	89H
5051H	7AH
5052H	2FH
5053H	56H
	. . .
5070H	89H
5071H	7AH
5072H	2FH
5073H	56H
	. . .

Ankith Reddy

Updated on: 26-Jun-2020

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