8085 program to unpack 16-bit BCD, and store consecutive locations

Here we will see we can take 16-bit BCD data from memory and unpack it, then store into memory using 8085.

Problem Statement

Write 8085 program to take 16-bit BCD number from memory then store each digit by unpacking into different locations.

Discussion

To solve this problem, we will create one subroutine, that can unpack 1-byte BCD number and store into memory, then we will use that subroutine for two times to store 16-bit data. The subroutine will cut the numbers by masking upper nibble and lower nibble, and store into memory.

Input

1234 in the DE register pair

Flow Diagram

Program

Address	HEX Codes	Labels	Mnemonics	Comments
F000	31, 00, FC		LXI SP,FC00	Initialize stack pointer
F003	11, 34, 12		LXI D,ABCD	load 16-bit number
F006	21, 00, 90		LXI H,9000	point to destination address
F009	7B		MOV A,E	take E into A
F00A	CD, 13, F0		CALL UNPACK	Unpack lower byte and store
F00D	23		INX H	point to next location
F00E	7A		MOV A,D	take upper byte
F00F	CD, 13, F0		CALL UNPACK	unpack upper byte and store
F012	76		HLT	Terminate the program
F013	D5	UNPACK	PUSH D	push DE into stack
F014	57		MOV D,A	store number into D
F015	E6, F0		ANI 0FH	mask upper nibble
F017	77		MOV M,A	store lower nibble
F018	7A		MOV A,D	take the number again
F019	E6, F0		ANI F0H	mask lower nibble
F01B	07		RLC	rotate left
F01C	07		RLC	rotate left
F01D	07		RLC	rotate left
F01E	07		RLC	rotate left
F01F	23		INX H	point to next location
F020	77		MOV M,A	store upper nibble into memory
F021	D1		POP D	pop DE from stack
F022	C9		RET	Return from subroutine

Output

Address	Data
…	…
9000	04
9001	03
9002	02
9003	01
…	…

Ankith Reddy

Updated on: 30-Jul-2019

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