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Arithmetic instructions in 8085 microprocessor

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Arithmetic Instructions are the instructions which perform basic arithmetic operations such as addition, subtraction and a few more. In 8085 microprocessor, the destination operand is generally the accumulator. Following is the table showing the list of arithmetic instructions:

OpcodeOperandExplanationExample
ADDRA = A + RADD B
ADDMA = A + McADD 2050
ADI8-bit dataA = A + 8-bit dataADI 50
ADCRA = A + R + prev. carryADC B
ADCMA = A + Mc + prev. carryADC 2050
ACI8-bit dataA = A + 8-bit data + prev. carryACI 50
SUBRA = A – RSUB B
SUBMA = A – McSUB 2050
SUI8-bit dataA = A – 8-bit dataSUI 50
SBBRA = A – R – prev. carrySBB B
SBBMA = A – Mc -prev. carrySBB 2050
SBI8-bit dataA = A – 8-bit data – prev. carrySBI 50
INRRR = R + 1INR B
INRMM = Mc + 1INR 2050
INXr.p.r.p. = r.p. + 1INX H
DCRRR = R – 1DCR B
DCRMM = Mc – 1DCR 2050
DCXr.p.r.p. = r.p. – 1DCX H
DADr.p.HL = HL + r.p.DAD H

1 Add)  – The content of operand are added to the content of the accumulator and the result is stored in accumulator .

with the addition  instruction , the following  3 operations can be done.

1) any 8 bit number can be added to the contents of the accumulator and the result is stored in the accumulator.

2) The contents of a register can be added to the contents of the accumulator and result is stored in the accumulator .

 3) The contents of a memory location can be added to the contents of the accumulator and result is stored in accumulator. 

this 1 byte instruction.

example – addb c it adds  the content of accumulator to the content of the register b 

2) SUB    Any 8 bit data or the contents of a register or contents of a memory location can be subtracted from the contents of the accumulator.

with the subtraction instruction the following 3 operator can be done . 

1) any 8 bit number can be subtracted from the contents of the accumulator . The result is stored in the accumulator.

In the table, R stands for register M stands for memory Mc stands for memory contents r.p. stands for register pair

 

Applications:

Data processing: The arithmetic instructions in the 8085 microprocessor are used to perform mathematical operations on data stored in memory or registers. This allows the microprocessor to manipulate and process data in various ways, such as performing calculations, generating checksums, and processing sensor data.

Control systems: The arithmetic instructions are used to perform complex calculations in control systems. These calculations are used to make decisions based on sensor data and other inputs, and to generate control signals that regulate the behavior of the system.

Signal processing: The arithmetic instructions in the 8085 microprocessor are used in digital signal processing applications, such as audio and image processing. These instructions are used to perform various operations on the digital signal data, such as filtering, compression, and encryption.

Communication systems: The arithmetic instructions are used to perform various operations in communication systems, such as signal modulation and demodulation, error correction, and encryption/decryption.

Gaming: The arithmetic instructions are used to perform various operations in gaming applications, such as calculating the trajectory of projectiles, simulating physics, and rendering graphics.

Advantages: 

Efficient arithmetic operations: The arithmetic instructions in the 8085 microprocessor can perform a variety of arithmetic and logical operations quickly and efficiently, making it suitable for applications that require fast arithmetic operations.

Reduced memory access: The use of registers and the accumulator in the 8085 microprocessor can help reduce the number of memory accesses required during arithmetic operations, which can improve the overall performance of the system.

Supports a wide range of operations: The arithmetic instructions in the 8085 microprocessor support a wide range of operations, including addition, subtraction, logical AND/OR/XOR, and shifting/rotating operations.

Simplifies programming: The arithmetic instructions in the 8085 microprocessor simplify programming by providing a set of dedicated instructions for performing arithmetic and logical operations.

Disadvantages:

Limited precision: The 8085 microprocessor uses 8-bit registers and arithmetic operations, which limits the precision of calculations that can be performed. This can be a disadvantage for applications that require high precision arithmetic.

Limited range of operations: Although the 8085 microprocessor supports a wide range of arithmetic and logical operations, it does not support advanced operations such as trigonometric functions or complex numbers.

Limited memory access: Although the use of registers can reduce the number of memory accesses required, the limited number of registers in the 8085 microprocessor can restrict the amount of data that can be manipulated at any given time.

Complex addressing modes: The addressing modes used in the arithmetic instructions can be complex, which can make programming more difficult.


Last Updated : 07 May, 2023
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