Program to add two 8-bit numbers & show result in Decimal Number System

Q. Write an 8085 program and draw a flowchart to add two 8-bit numbers & show the result in the decimal number system.(8085 Microprocessor Program)

Flowchart/Algorithm

Program

Address	Mnemonics	Operand	Opcode	Comments
2000	LXI	H, 3000H	21	Load H-L pair with address 3000H.
2001			00
2002			30
2003	MOV	A, M	7E	Move the 1^st operand from memory to reg. A.
2004	INX	H	23	Increment H-L pair.
2005	MOV	B, M	46	Move the 2^nd operand from memory to reg. B.
2006	MVI	C, 00H	0E	Initialize reg. C with 00H.
2007			00
2008	ADD	B	80	Add B with A.
2009	DAA		27	Convert the result to decimal.
200A	JNC	200EH	D2	Jump to address 200EH if there is no carry.
200B			0E
200C			20
200D	INR	C	0C	Increment reg. C.
200E	INX	H	23	Increment H-L pair.
200F	MOV	M, A	77	Move the result from reg. A to memory.
2010	INX	H	23	Increment H-L pair.
2011	MOV	M, C	71	Move carry from reg. C to memory.
2012	HLT		76	Halt

Output

Before Execution:

3000H: 08H

3001H: 05H

After Execution:

3002H: 13

3003H: 00H

Program Explanation

This program adds two operands stored in memory location 3000H and 3001H and shows the result in decimal number system.
Let us assume that the operands stored at memory location 3000H are 08H and 3001H is 05H.
After addition, instead of showing the result in hexadecimal as 0DH, it shows the result in decimal as 13.
Initially, H-L pair is loaded with the address of first memory location.
The first operand is moved to accumulator from memory location 3000H and H-L pair is incremented to point to next memory location.
The second operand is moved to register B from memory location 3001H.
Register C is initialized to 00H. It stores the carry (if any).
The two operands stored in register A and B are added and the result is stored in the accumulator.
The result is converted to decimal by using the DAA instruction.
H-L pair is again incremented and carry (either 0 or 1) is moved from register C to memory location 3003H.