Experiment-4: Write a program to find 1‘s complement of an 8 bit number.

Objective:

• To understand the complement process
• To write the algorithm for 1’s complement
• To develop the assembly program
• To analyze the program and interpret errors and result

Requirement:

• Operating System – Windows, Linux
• 8085 Simulator

Theory:

1’s complement of a number is found in the following ways:

• • By complementing each bit of the number

OR

• • By subtracting the number from all 1’s

Eg.

1’s complement of binary number 10101100 is 01010011

OR

1’s complement of binary number 10101100

  1 11 11 111

-10101100

——————

 01010011

Algorithm:

• Input the number into the accumulator
• Complement using instruction CMA, Result in accumulator
• Save the result

Program:

Address	OP-CODE	Label	Mnemonic	Comments
	C9 05 042		JMP start
4203	45H	X:
4204	00	Y
4205		start:	NOP
4206	21,03,42		LXI H, X
4209	7E		MOV A,M
421A	2F		CMA
421B	76		HLT

Viva Questions