8085 program to find sum of digits of 8 bit number

In this program we will see how to add the digits of an 8-bit number.

Problem Statement

Write 8085 Assembly language program to add the digits of an 8-bit number stored in memory location 8000H.

Discussion

To get the digits of an 8-bit number, we can use the masking operation. At first we will mask the upper nibble, and then the lower nibble. After masking the lower nibble, we have to rotate it to the right to make it least significant nibble. Then we can simply add it to the stored nibble to get the sum.

Input

Address	Data
...	...
8000	8A
...	...

Program

Address	HEX Codes	Mnemonics	Comments
F000	3A, 00, 80	LDA 8000H	Load the number into A
F003	4F	MOV C, A	Copy the number to C
F004	E6, 0F	ANI 0FH	Take the lower nibble
F006	47	MOV B, A	Store the result into B
F007	79	MOV A, C	Restore the actual number
F008	E6, F0	ANI F0	Take the upper nibble
F00A	0F	RRC	Rotate the bits four times
F00B	0F	RRC
F00C	0F	RRC
F00D	0F	RRC
F00E	80	ADD B	Add A with B
F00F	32, 50, 80	STA 8050H	Store the result at 8050H
F012	76	HLT	Terminate the program