8085 Program to check for palindrome

Now let us see a program of Intel 8085 Microprocessor. This program will convert ASCII to binary values.

Problem Statement

Write 8085 Assembly language program to check whether a bit pattern is palindrome or not.

Discussion

In this program we are taking the number from location 8000H. The program will return 00H if the number is not palindrome, otherwise it will return FFH.

Let the Input is 18H so the binary value is (0001 1000) this is a palindrome. The number 52H(0101 0010) it is not a palindrome.

In this problem we are taking the first number into accumulator, then shifting it to the left. When it is left shifted the MSb will be placed at LSb and also in the carry flag. This carry flag is inserted into the D register by right shifting. Thus the bit pattern will be reversed, now by checking the values of actual number and the reversed number we can determine it is palindrome or not. 

Input

first input

Address	Data
. . .	. . .
8000	BD
. . .	. . .

second input

Address	Data
. . .	. . .
8000	52
. . .	. . .

third input

Address	Data
. . .	. . .
8000	18
. . .	. . .

Flow Diagram

Program

Address	HEX Codes	Labels	Mnemonics	Comments
F000	3A, 00, 80		LDA 8000H	Load the number into A
F003	67		MOV H, A	Move Acc to H
F004	0E, 08		MVI C,08H	InitializeCounter
F006	7C	LOOP	MOV A, H	Load H to Acc
F007	07		RLC	Rotate Left
F008	67		MOV H, A	Get back Accto H
F009	7A		MOV A, D	Load D content into Acc
F00A	1F		RAR	Rotate Right through carry
F00B	57		MOV D, A	Get back Acc to D
F00C	0D		DCR C	Decrease C
F00D	C2, 06, F0		JNZ LOOP	Jump to LOOPif Z = 0
F010	7C		MOV A, H	Load H data to Acc
F011	BA		CMP D	Compare D with Acc
F012	CA, 1A, F0		JZ TRUE	If both are same, it is palindrome
F015	3E, 00		MVI A, 00H	Load 00H intoA
F017	C3, 1C, F0		JMP EXIT	Jump to Exit
F01A	3E, FF	TRUE	MVI A, FFH	Load FFH into A
F01C	32, 50, 80	EXIT	STA 8050H	Store the result into memory
F01F	76		HLT	Terminate the program

Output

first output

Address	Data
. . .	. . .
8050	FF
. . .	. . .

second output

Address	Data
. . .	. . .
8050	00
. . .	. . .

third output

Address	Data
. . .	. . .
8050	FF
. . .	. . .