Program to Add two 8-bit numbers along with Carry

Q. Write an 8085 program and draw a flowchart to add two 8-bit numbers along with considering the carry.(8085 Microprocessor Program)

Flowchart/Algorithm

Program

Address	Mnemonics	Operand	Opcode	Comments
2000	LXI	H, 300H	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	JNC	200D	D2	Jump to address 200DH if there is no carry.
200A			0D
200B			20
200C	INR	C	0C	Increment reg. C.
200D	INX	H	23	Increment H-L pair.
200E	MOV	M, A	77	Move the result from reg. A to memory.
200F	INX	H	23	Increment H-L pair.
2010	MOV	M, C	71	Move carry from reg. C to memory.
2011	HLT		76	HALT

Output

Before Execution:

3000H: FAH

3001H: 28H

After Execution:

3002H: 22H

3003H: 01H

Program Explanation

This program adds two operands stored in memory location 3000H and 3001H, along with considering the carry produced (if any).
Let us assume that the operands stored at memory location 3000H is FAH and 3001H is 28H.
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.
Then, carry flag is checked for carry. If there is a carry, C register is incremented.
H-L pair is incremented and the result is moved from the accumulator to memory 3002H.
H-L pair is again incremented and carry (either 0 or 1) is moved from register C to memory location 3003H.

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