8085 is a Microprocessor which was developed by Intel in 1970s. All the instructions in this microprocessor are encoded in a single byte. Some of the instructions are followed by one or two bytes of data, which can be a memory address, an immediate operand or a port number.

In this post, we will write a program in 8085 to find the HCF of two numbers.

### Algorithm

Start Read count(C) Read first number(A) C <- C - 1 Read the next number(B) Compare A and B If A - B = 0 go to 13 If A - B < 0 go to 11 A <- A - B go to 6 Swap A and B go to 6 C <- C - 1 If CS != 1 go to 5 Store A Stop

### Flow Chart

### Program

LXI H, 2100H MOV C, M DCR C INX H MOV A, M LOOP2: INX H MOV B, M LOOP1: CMP B JZ NEXT JC EXG SUB B JMP LOOP1 EXG: MOV C, B MOV B, A MOV A, C JMP LOOP1 NEXT: DCR C JNZ LOOP2 INX H MOV M, A RST-5

### Example

2100H: 04 2101H: 06 2102H: 08 2103H: 10 2104H: 12 2105H: 02 -> output

#### Check out our other 8085 programs

- Program to Calculate 8-bit Sum of N 8-bit Numbers
- Program to Find the Maximum of N Numbers
- Program to Find the Minimum of N Numbers
- Program to multiply two 8-bit numbers without using shifting multiplicand
- Program to multiply two 8-bit numbers using shifting multiplicand
- Program to divide a 16-bit number with an 8-bit number
- Program to find the HCF of two numbers
- Program to find the HCF of N numbers
- Program to convert binary number to decimal
- Program to convert binary number to decimal without using DAA
- Program to convert decimal to binary

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