ASSEMBLY LANGUAGEFor 8051

By:

AMIT GODRE

OUTLINE:

• INTRODUCTION TO ASSEMBLY LANGUAGE.• INSTRUCTION SETS.• EXAMPLES.• ADVANTAGE.• DISADVANTAGE .

Programming language:“A Program is a group of instructions.

There are two type of programming language.”

1.High level Programming language.(Similar to English)

Example: C, C++, java, etc.

2.Low level Programming language.(Symbolic format)

Example: Assembly language.

Assembly Language

ORG 0HMOV R5,#25HMOV A,#25H

ADD A,R5END

C Language

#include<stdio.h>

Void main()

{

Printf(“ AMIT GODRE”);

}

MOV INSTRUCTION

D SMOV A, #55H

MOV R0,AMOV A,#9

In MOV (MOVE) instruction the data is moved from Source(S) to Destination(D).

# (Pound sign shows immediate value)

ADD INSTRUCTION

MOV R0,#25HMOV A,#25H

ADD R0,A // ErrorADD A,R0

If we want to perform any Arithmetic Operation than we have to use Accumulator (A) Register. Result will be stored in Destination(D) so, Accumulator will we at the destination place only otherwise it will give the error.

Now you will see three back to back program and you will understand the way how to reduce the number of steps but you will get the same answer.

MOV R5,#25HMOV R7,#26H

MOV A,#0ADD A,R5ADD A,R7

A = 51H

MOV A,#25HMOV R7,#26H

ADD A,R7

A = 51H

MOV A,#25HADD A,#26H

A = 51H

PROGRAMMING

ORG 0H // Starting of the program

(Body of the Program)

END // End of the program

ORG 0HMOV R5,#30HMOV R7,#20H

MOV A,#0ADD A,R5ADD A,R7

ADD A,#10HEND

A = 60H

LOOPRepeating a sequence of instruction a

Certain number of times.

ORG 0H MOV A,#0

MOV R2,#10

ADD A,#03AGAIN:

DJNZ R2,AGAIN

MOV R5,A

Write a program to(a) Clear ACC, then(b) add 3 to the ACC ten times

END

DJNZ = Decrement and jump if A != 0

Conditional Jump

JZ = jump if A = 0

JNZ = jump if A != 0

ORG 0H MOV A,R5

JNZ NEXT

MOV R5,#55H

….

Write a program to determine if R5 Contain the value 0. If so, put 55H in it.

NEXT :

JNZ = jump if A != 0

Addressing Modes:

• Immediate • Register• Direct• Register indirect

Immediate

MOV A,#25HMOV R4,#62MOV B,#40H

Notice that the immediate data must be preceded by the sign, ”#”

Register

MOV A,R0MOV R2,AADD A,R5

MOV DPTR,A //ERRORMOV R4,R7 //ERROR

Direct

MOV R0,40HMOV 56H,AMOV R4,7FH

“#” Sign is not used.40H is the RAM location

Register indirect

MOV A,@R0MOV @R1,B

R0-R1 are usedR2-R7 are not used.

MOV A,@R0 move the content of RAM location

DISADVANTAGE:1. If we are using Assembly level

programing we have to learn different instruction set for

different micro controller family.

2. Program written on one computer Will not run in other computer

With different hardware configuration.

THANK YOU