Addition program of 8051

During the DIV operation, the numerator is stored in the accumulator, and the denominator is stored in register B. Once the operation is performed, the quotient is placed in A, and the remainder is stored in B. You might be familiar with the binary and hexadecimal formats of numbering, but there is another format that is widely used; the binary coded decimal or BCD.

This format represents numbers in a different manner. For example, 11 in binary is , but in BCD, it is In BCD code, counting resets after When it comes to adding BCD numbers in microcontrollers, normal binary addition will give the wrong results. So to solve this issue, microcontrollers use the DA command, which converts the binary results to BCD. The DA command can take only one operand; A.

We hope that reading this article has helped you understand the arithmetic instructions in the microcontroller. If you have any issues with any of the examples, feel free to ask them in the comments, and we will get back to you in a jiffy. An Engineering Graduate with a specialization in Embedded systems, who loves to dabble with IoT automation cause switching lights on with switches is to mainstream.

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Operation Opcode Operand Description Addition. Memory to memory arithmetic operations cannot be performed in the There are two conditions when the overflow flag is set When there is carry from D6 to D7, but no carryout from D7.

When there is a carryout from D7, but no carry from D6 to D7. They use the circuitry meant for addition to perform the subtraction operation. In the multiplication operation, the carry flag is always cleared, and the overflow flag is set to 1 if the value is out of range.

The division operation always sets CY flag to 0 and overflow flag to 0 if the denominator is not 0. Now lets come to instruction sets of micro controller. The instruction set can be classified as shown below. Follow the given link, where you can access the complete list of instructions for micro controller — Instruction Set see the heading Alphabetical order below first table. Note:- micro controller belongs to the MCS family of micro controllers.

This basically means,any variant micro controller that comes under the MCS family made by any other manufacturer must use the same set of instructions made for MCS So a program written for Intel can be used to run AT89C too you may have to make slight modifications to match hardware disparities. You may learn about all instructions in detail by following that link given above.

There are 44 instructions in or MCS instruction set. Now lets write a very simple program. Natural numbers generated from 0 to N must be stored from location 55H. The sum of natural numbers must be stored in location 36H. Analyzing the program description, we need 3 registers.

R5 is used to save the value of first storage location of natural numbers and then R5 is incremented by one each to store each newly generated natural number. R7 is initiated as 0 and is incremented by 1 to generate natural numbers. Note: '0' is not a natural number. It is not possible to transfer data from one register to another register directly. Instead we use the direct address 07 of register R7 of register bank 00 to transfer the generated natural number to it's storage location in register R5.

Indirect addressing is used as we need to save the generated natural number directly to memory address. R5 holds the starting location address of the storage area as its value i. By indirectly addressing, we can save what ever value in R7 directly to location 55H. It is checked against stopping condition zero. When R0 is equal to zero, program control will exit the loop and move to next instruction given below.

Solution: — here we shall compare each byte one by one from both blocks. Increase the count every time when equal bytes are found. Mov r0, 10h ; get initial location of block1. Mov r1, 20h ; get initial location of block2. Mov r6, 00h ; equal byte counter. Starts from zero. Nxt: Mov a, r0 ; get content of block 1 in acc. Mov a, r1 ; get content of block 2 in acc. Cjne a, b, nomatch ; compare both if equal. Inc r6 ; increment the counter. Nomatch: inc r0 ; otherwise go for second number.

Inc r1. Statement 7: — given block of h to h. Find out how many bytes from this block are greater then the number in r2 and less then number in r3. Store the count in r4. Solution: — in this program, we shall take each byte one by one from given block. Now here two limits are given higher limit in r3 and lower limit in r2. So we check first higher limit and then lower limit if the byte is in between these limits then count will be incremented.

Mov dptr, h ; get initial location. Mov r7, 0FFh ; counter. Mov r4, 00h ; number counter. Mov 20h, r2 ; get the upper and lower limits in. Mov 21h, r3 ; 20h and 21h. Nxt: Movx a, dptr ; get the content in acc. Cjne a, 21h, lower ; check the upper limit first. Sjmp out ; if number is larger. Lower: jnc out ; jump out. Cjne a, 20h, limit ; check lower limit. Sjmp out ; if number is lower.

Limit: jc out ; jump out. Inc r4 ; if number within limit increment count. Out: inc dptr ; get next location. Djnz r7, nxt ; repeat until block completes. Statement the crystal frequency is given as 12 MHz. Comments are statements included by the developer for easier understanding of the code and is used for proper documentation of the Program. The following statements will show a few possible ways of using Label, Instruction and Comments. Assembly Language Directives are not the instructions to the Microcontroller Assembler even though they are written in the Mnemonic field of the program.

Assembly Language Directives are actually instructions to the Assembler and directs the Assembler Program what to do during the process of Assembling. We will now see about few of the important and frequently used Assembly Language Directives.

This is also the address from which the Microcontroller will start executing the code. Jump to MAIN. MAIN starts here. The DB Directive is used to define a Byte type variable. Only lower byte is. The END Directive is used to stop the assembling process. This should be the last statement in the program.