Program to find the HCF of two given bytes in 8085 Microprocessor

Here we will see how to find the HCF or GCD of two given bytes using 8085. The numbers are 8-bit numbers, nor larger than that.

Problem Statement−

Write an 8085 Assembly language program to find the HCF or GCD of two numbers stored at memory location 8000H and 8001H.

Discussion−

Here we will use the Euclidean algorithm to find HCF. This algorithm is very simple. We have to follow these steps−

Else if first number < second number, the
b) exchange no1 and no2.

The values are stored at location 8000H and 8001H, and the result will be stored at location 8050H.

Input

First Input

Second Input

Address	HEX Codes	Labels	Mnemonics	Comments
F000	21, 00, 80		LXI H,8000H	Point to the first number
F003	7E		MOV A,M	Load the first number into Acc
F004	23		INX H	Point to next location
F005	46		MOV B,M	Load the second number
F006	B8	LOOP	CMP B	Compare B with A
F007	CA, 17, F0		JZ STORE	When A and B are same, store the result
F00A	DA, 11, F0		JC EXG	If B > A, then exchange B and A
F00D	90		SUB B	if B < A, subtract B from A
F00E	C3, 06, F0		JMP LOOP	Jump to LOOP
F011	48	EXG	MOV C,B	Load C with B
F012	47		MOV B,A	Move A to B
F013	79		MOV A,C	Move C to A
F014	C3, 06, F0		JMP LOOP	Jump to LOOP
F017	32, 50, 80	STORE	STA 8050H	Store the value into memory
F01A	76		HLT	Terminate the program

First Output

Second Output

Updated on: 06-Jul-2020

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