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
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.
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 .
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8000 BD
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.
 .
.
.

second input

Address Data
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.
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 .
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8000 52
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 .
.
.

third input

Address Data
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 .
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8000 18
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.
.
 .
.
.

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
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 .
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8050 FF
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 .
.
.

second output

Address Data
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 .
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8050 00
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 .
.
.

third output

Address Data
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 .
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8050 FF
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.
.
 .
.
.
Updated on: 2019-07-30T22:30:24+05:30

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