8051 Program to Divide Two 8-Bit Numbers

Now we will see another arithmetic operation. The divide operation to divide two 8-bit numbers using this 8051 microcontroller. The register A and B will be used in this operation. No other registers can be used for division. The result of the division has two parts. The quotient part and the remainder part. Register A will hold Quotient, and register B will hold Remainder.

We are taking two number0EH and 03H at location 20H and 21H, After dividing the result will be stored at location 30H and 31H.  

Program

MOV R0, #20H;set source address 20H to R0
MOV R1, #30H;set destination address 30H to R1

MOV A, @R0;take the first operand from source to register A
INC R0; Point to the next location
MOV B, @R0; take the second operand from source to register B

DIV AB ; Divide A by B

MOV @R1, A; Store Quotient to 30H
INC R1; Increase R1 to point to the next location
MOV @R1, B; Store Remainder to 31H
HALT:   SJMP HALT ;Stop the program

8051 provides DI VAB instruction. By using this instruction, the division can be done. In some other microprocessors like 8085, there was no DIV instruction. In that microprocessor, we need to use repetitive Subtraction operations to get the result of the division. 

When the denominator is00H, the overflow flag OV will be 1. otherwise it is 0 for the division.

Output