1.b. 8-BIT SUBTRACTION

1.b. 8-BIT SUBTRACTION

AIM:

            To write a assembly language program for the subtraction of two 8-bit numbers

APPARATUS REQUIRED:

                                    8085 kit, power chord

ALGORITHM:

1. Start the program

            2. Load the HL pair with 8-bit numbers

            3. Move the content of HL to accumulator

            4. Increment the address of Hl pair

            5. Subtract the content of memory from accumulator

            6. Jump on no carry to step

            7. Increment the C-register

            8. Store the content of accumulator and C-register

9. Stop the program

PROGRAM:

ADDRESS	LABEL	OPCODE	MNEMONICS	OPERAND	COMMENTS
4100		21,50,41	LXI	H, 4150	Load data to HL Register
4103		7E	MOV	A, M	Move data to accumulator
4104		0E, 00	MVI	C, 00	Clear c register.
4106		23	INX	H	Increment address.
4107		9E	SBB	M	Subtract with borrow
4108		D2, 0C, 41	JNC	REPET	Jump on no carry.
410B		0C	INR	C	Increment c register
410C	REPET	32,52,41	STA	4152	Store the result
410F		79	MOV	A, C	Move carry to acc
4110		32,53,41	STA	4153	Store the carry
4113		76	HLT		Stop the program

INPUT:                                             OUTPUT:

4150 = 57, 4151 = 66                      4152 – f1 (Result), 4153 – 01 (carry)

RESULT:

            Thus the assembly language program for 8-bit subtraction is executed and the results are verified.