8085 Program to do an operation on two numbers based on the contents of X

Now let us see a program of Intel 8085 Microprocessor. In this program we will see how to do different operations based on choice.

Problem Statement:

Write 8085 Assembly language program to perform some operations on two 8-bit binary numbers base on choice.

Discussion:

In this program we are taking a choice. The choice value is stored at memory location 8000H (named as X). And the numbers are stored at location 8001H and 8002H. We are storing the result at location 8050H and 8051H.

Here if the choice is 00H, then it will perform addition, for 01H, it will perform subtraction, and for 02H, it will do the multiplication operation.

Input:

First input

Address	Data
. . .	. . .
8000	00
8001	97
8002	88
. . .	. . .

Second input

Address	Data
. . .	. . .
8000	01
8001	97
8002	88
. . .	. . .

Third input

Address	Data
. . .	. . .
8000	02
8001	05
8002	04
. . .	. . .

Flow Diagram:

Program:

Address	HEX Codes	Labels	Mnemonics	Comments
F000	21, 00, 80		LXI H,8000H	Point to get the choice
F003	7E		MOV A,M	Load choice into A
F004	FE, 00		CPI 00H	Compare for ADD
F006	CA,14, F0		JZ ADD	Jump to do Addition
F009	FE, 01		CPI 01H	Compare for SUB
F00B	CA,26, F0		JZ SUB	Jump to do Subtraction
F00E	FE, 02		CPI 02H	Compare for MUL
F010	CA, 38, F0		JZ MUL	Jump to do Multiplication
F013	76		HLT	Terminate the program
F014	23	ADD	INX H	Point to first operand
F015	7E		MOV A,M	Load operand to A
F016	23		INX H	Point to next operand
F017	86		ADD M	Add M with A
F018	6F		MOV L,A	Store A to L
F019	D2, 21, F0		JNC SKP1	If CY = 0, jump to SKP1
F01C	26, 01		MVI H,01H	Load H with 01H
F01E	C3, 49, F0		JMP STORE	Store result
F021	26, 00	SKP1	MVI H,00H	Clear HL
F023	C3, 49, F0		JMP STORE	Store HL as result
F026	23	SUB	INX H	Point to first operand
F027	7E		MOV A,M	Load operand to A
F028	23		INX H	Point to next operand
F029	96		SUB M	Subtract second operand from A
F02A	6F		MOV L,A	Store A to L
F02B	D2, 33, F0		JNC SKP2	If CY = 0, jump to SKP2
F02E	26, FF		MVI H,FFH	Load H with FFH
F030	C3, 49, F0		JMP STORE	Store result
F033	26, 00	SKP2	MVI H,00H	Clear HL
F035	C3, 49, F0		JMP STORE	Store HL as result
F038	23	MUL	INX H	Point to first operand
F039	5E		MOV E,M	Load operand to E
F03A	16, 00		MVI D,00H	Clear D register
F03C	23		INX H	Point to next operand
F03D	4E		MOV C,M	Load the second operand
F03E	21, 00, 00		LXI H,0000H	Clear HL pair
F041	19	LOOP	DAD D	Add first operand to HL
F042	0D		DCR C	Decrease C
F043	C2, 41, F0		JNZ LOOP	Jump to LOOP if Z = 0
F046	C3, 49, F0		JMP STORE	Store result
F049	22, 50, 80	STORE	SHLD 8050H	Store result from HL
F04C	76		HLT	Terminate the program