8085 program to convert binary numbers to gray

In this program we will see how to find the gray code from an 8-bit number.

Problem Statement

Write 8085 Assembly language program to convert an 8-bit number stored at 8000H to its equivalent gray code. The result will be stored at 8050H.

Discussion

In this program we are converting binary to gray code. The procedure is simple. At first we have to shift the content to the right, then perform XOR operation with the sifted content and the actual content. Thus we will get the gray code. For an example if the number is ABH, then the binary value will be (1010 1011), after shifting the value will be (0101 0101) = 55H, now by XORing ABH and 55H, the result will be (1111 1110) = FEH

Input

first input

Address	Data
...	...
8000	AB
...	...

second input

Address	Data
...	...
8000	77
...	...

third input

Address	Data
...	...
8000	CD
...	...

Flow Diagram

Program

Address	HEX Codes	Mnemonics	Comments
F000	21, 00, 80	LXI H,8000H	Point to the source address
F003	7E	MOV A, M	Take the number from memory to Acc
F004	37	STC	Set carry flag
F005	3F	CMC	Complement carry flag
F006	1F	RAR	Rotate right Acc content
F007	AE	XRA M	XOR memory content with A
F008	32, 50, 80	STA 8050H	Store the gray code
F00B	76	HLT	Terminate the program