8085 Program to Add N numbers, of size 8 bits

In this program, we will see how to add a block of data using the 8085 microprocessor.

Problem Statement

Write 8085 Assembly language program to add N 1-byte numbers. The value of N is provided.

Discussion

In this problem, we are using location 8000H to hold the length of the block. The main block is stored from address 8010H. We are storing the result at location 9000H and 9001H. The 9000H holding the lower byte, and 9001H is holding the upper byte.

Repeatedly we are taking the number from the memory, then adding it with the accumulator and increase the register E content when carry flag is set. Initially, Eis cleared.

Input

Address	Data
. . .	. . .
8000	08
. . .	. . .
8010	AF
8011	2E
8012	7C
8013	81
8014	2C
8015	BF
8016	FB
8017	1C
. . .	. . .

Flow Diagram

Program

Address		Labels	Mnemonics	Comments
F000	21, 00, 80		LXI H, 8000H	Load the address to get a count of numbers
F003	4E		MOV C, M	Load C with the count value
F004	21,10, 80		LXI H, 8010H	Load HL with the starting address
F007	AF		XRA A	Clear Accumulator
F008	5F		MOV E, A	Clear the E register also
F009	86	LOOP	ADD M	Add Memory content with Accumulator
F00A	D2, 0E, F0		JNC SKIP	When the carry is false, skip next task
F00D	1C		INR E	Increase E, when the C flag is set
F00E	0D	SKIP	DCR C	Decrease C register by 1
F00F	23		INX H	Point to next location
F010	C2, 09, F0		JNZ LOOP	When Zero is false, go to LOOP
F013	21, 00, 90		LXIH, 9000H	Load address to store the result
F016	77		MOV M, A	Save accumulator content
F017	23		INX H	Increase HL pair
F018	73		MOV M, E	Store carry
F019	76		HLT	Terminate the program