Program 2: Basic Arithmetic Operation (Addition) - 4.2 | EXPERIMENT NO. 1:Introduction to 8085 Microprocessor - Architecture and Basic Operations | Microcontroller Lab
K12 Students

Academics

AI-Powered learning for Grades 8–12, aligned with major Indian and international curricula.

Professionals

Professional Courses

Industry-relevant training in Business, Technology, and Design to help professionals and graduates upskill for real-world careers.

Games

Interactive Games

Fun, engaging games to boost memory, math fluency, typing speed, and English skills—perfect for learners of all ages.

Typing
Memory
Math
English Adventures
Knowledge

4.2 - Program 2: Basic Arithmetic Operation (Addition)

Practice

Interactive Audio Lesson

Listen to a student-teacher conversation explaining the topic in a relatable way.

Understanding Basic Addition Using 8085

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

0:00
Teacher
Teacher

Today we're going to discuss how to perform addition using the 8085 microprocessor. Can anyone tell me what we need to do before we can add two numbers?

Student 1
Student 1

Do we need to load the numbers into registers first?

Teacher
Teacher

Exactly! We use the `MVI` instruction to move immediate data into the Accumulator and another register. For example, `MVI A, 05H` loads 05H into the Accumulator.

Student 2
Student 2

What happens after we move the values?

Teacher
Teacher

Next, we use the `ADD` instruction. It adds the contents of the specified register to the Accumulator. So, if we add B to A, the instruction will look like `ADD B`.

Student 3
Student 3

And how do we see the result?

Teacher
Teacher

We can save the result back to memory using `STA`, which stands for Store Accumulator. After running the program, we can check the specific memory location to see the result.

Student 4
Student 4

What about the flags? Do they change?

Teacher
Teacher

Great question! The flags will update based on the result of the addition. For example, if the result is zero, the Zero flag is set.

Teacher
Teacher

To recap, we load numbers, add them using the ADD instruction, and store the result. And don’t forget to check the flag statuses!

Assembly Code for Addition

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

0:00
Teacher
Teacher

Now, let’s write an assembly code for our addition operation. First, what will our starting address be?

Student 1
Student 1

We will start at 2000H?

Teacher
Teacher

Correct! We'll use `ORG 2000H` as our starting address. Next, how do we move the first number into the Accumulator?

Student 2
Student 2

We use `MVI A, 05H` for that.

Teacher
Teacher

Exactly! For the second number, what should we write?

Student 3
Student 3

We write `MVI B, 03H` to load it into register B.

Teacher
Teacher

Perfect! After we add, we will store the result using `STA` followed by the memory location where we want to save it.

Student 4
Student 4

So, the complete code will look something like this?

Teacher
Teacher

Right! It should include the MVI commands, the ADD command, and finally STA to store the result. Great job recalling that!

Understanding Flag Changes

Unlock Audio Lesson

Signup and Enroll to the course for listening the Audio Lesson

0:00
Teacher
Teacher

Adding two binary numbers impacts the Flag register. Can anyone tell me which flags are affected when we perform addition?

Student 1
Student 1

The Sign flag, Zero flag, Auxiliary Carry flag, Parity flag, and Carry flag.

Teacher
Teacher

Exactly! Let's talk about the Carry flag. When does it get set?

Student 2
Student 2

It gets set when there is an overflow, right?

Teacher
Teacher

Yes! And what about the Zero flag?

Student 3
Student 3

It gets set when the result of the operation is zero.

Teacher
Teacher

Great! Finally, why is understanding these flags important?

Student 4
Student 4

Because they tell us about the outcome of our calculations and help us make decisions in programming.

Teacher
Teacher

Exactly! Understanding how the flags affect our program is crucial for debugging and efficient coding.

Introduction & Overview

Read a summary of the section's main ideas. Choose from Basic, Medium, or Detailed.

Quick Overview

This section focuses on the addition operation within the 8085 microprocessor architecture, demonstrating basic arithmetic commands and their effects on registers and flags.

Standard

In this section, students will explore the addition operation facilitated by the 8085 microprocessor. They will learn how to create assembly programs to perform addition of two numbers, analyze the outcomes stored in registers, and observe the status of flags post-operation.

Detailed

Program 2: Basic Arithmetic Operation (Addition)

This section educates students about performing addition using the 8085 microprocessor, expanding on basic arithmetic operations relevant to the microprocessor's instruction set. The 8085 architecture allows for direct interaction with registers to execute arithmetic commands.

Objectives

  • To understand how to utilize the 8085 microprocessor for addition operations.
  • To analyze the results of these operations, specifically noting the registers and flags affected.
  • To practice creating assembly code that accomplishes these tasks and observe memory states before and after execution.

Key Concepts

  1. Loading Data: The MVI instruction is used to load immediate values into the registers before performing the addition.
  2. Adding Values: The ADD instruction adds the content of one register to the Accumulator and updates its value.
  3. Storing Results: The STA instruction stores the result of the addition in a specified memory location.
  4. Flag Register Status: Students will learn how the arithmetic operations affect the Sign, Zero, Auxiliary Carry, Parity, and Carry flags, which indicate the outcome of the arithmetic operations performed.

Through practical assembly programs, students observe the interplay between the registers, memory, and the processor's flag status, which provides insights into microprocessor functionality.

Audio Book

Dive deep into the subject with an immersive audiobook experience.

Objective of the Program

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Objective: To add two 8-bit numbers (05H and 03H), store the result in the Accumulator, then save it to a memory location (2060H), and observe the flag status.

Detailed Explanation

The objective of this program is to demonstrate how to perform a basic addition operation using the 8085 microprocessor. The program will add two values, 05H and 03H, together. The result of this addition will be stored in the Accumulator, which is a special register in the microprocessor used to hold intermediate results of operations. After performing the addition, the result will be saved in a specific memory location (2060H) for later use or verification. Additionally, the program aims to observe the status of various flags in the microprocessor that indicate the outcome of the arithmetic operation.

Examples & Analogies

Think of the Accumulator as a large basket (the microprocessor's temporary storage) where you put numbers (values) for quick operations. After adding two bags of apples (05H and 03H) and getting a total (the sum), you're putting that total back into your basket while also writing it down separately for later use.

Assembly Code Explanation

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Assembly Code:

; Program to demonstrate addition and flag changes
; Starting Address: 2000H
ORG 2000H
MVI A, 05H ; Load Accumulator A with immediate data 05H (A = 05H)
MVI B, 03H ; Load Register B with immediate data 03H (B = 03H)
ADD B ; Add content of Register B to Accumulator A (A = A + B)
STA 2060H ; Store content of Accumulator A into memory location 2060H
HLT ; Halt processor execution

Detailed Explanation

This section shows the assembly code used for the addition operation. It starts by defining where the program will begin in memory (2000H). The first command 'MVI A, 05H' loads the value 05H directly into the Accumulator (A). The next command 'MVI B, 03H' loads the value 03H into another register (B). Following that, the instruction 'ADD B' adds the content of Register B to the Accumulator, effectively performing 05H + 03H. The sum of these numbers is stored back into A. The instruction 'STA 2060H' then saves this resulting value from the Accumulator into memory location 2060H. Finally, the program ends with 'HLT', which stops execution.

Examples & Analogies

Imagine you have a recipe where you need to add 5 apples and 3 bananas (adding 05H and 03H). First, you gather your apples and place them in a bowl (load into the Accumulator). Then, you do the same with the bananas. To complete the recipe, you mix (add them together) and finally note the total number of fruits you have in a notebook (store the result in memory). At the end of the task, you put the notebook away (stop the process with HLT).

Memory Layout

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Memory Layout:
| Address | Hex Code | Instruction |
| :------ | :------- | :------------------ |
| 2000H | 3E | MVI A, 05H |
| 2001H | 05 | |
| 2002H | 06 | MVI B, 03H |
| 2003H | 03 | |
| 2004H | 80 | ADD B |
| 2005H | 32 | STA 2060H |
| 2006H | 60 | |
| 2007H | 20 | |
| 2008H | 76 | HLT |

Detailed Explanation

The memory layout outlines how the assembly instructions are stored in the 8085 microprocessor memory. Each row lists the memory address, the corresponding hexadecimal code (which the microprocessor understands), and the specific assembly instruction. For instance, at address 2000H, the instruction 'MVI A, 05H' has a hex code of 3E. The instruction to add is located at 2004H with hex code 80, showing that each operation in assembly is translated into a unique hexadecimal representation that tells the microprocessor what to do.

Examples & Analogies

Think of the memory layout like a series of labeled drawers (memory addresses) in a filing cabinet (computer memory). Each drawer contains a specific instruction (the hex code corresponding to the assembly code). Just like you would refer to each drawer by its number to find the instructions (in this case, hex codes) for creating a dish, the microprocessor uses the memory address to pull out the necessary instruction to execute step by step.

Expected Register and Memory States

Unlock Audio Book

Signup and Enroll to the course for listening the Audio Book

Expected Register and Memory States (After Execution of HLT):
● A Register: 08H (05H + 03H)
● B Register: 03H
● Memory Location 2060H: 08H
● Program Counter (PC): 2009H
● Flag Register Status (after ADD B where A=05H, B=03H, Result A=08H):
○ S (Sign Flag): 0 (Result 08H is positive)
○ Z (Zero Flag): 0 (Result 08H is not zero)
○ AC (Auxiliary Carry Flag): 0 (No carry from bit 3 to bit 4)
○ P (Parity Flag): 0 (Result 08H = 00001000b, has one '1' bit, which is odd parity)
○ C (Carry Flag): 0 (No carry out from bit 7)

Detailed Explanation

After running the addition program, we can expect specific values to be found in certain registers and memory. The A Register will hold 08H, the result of adding 05H and 03H. The B Register will still hold 03H, as it wasn't changed during the addition. The value stored in memory location 2060H will also be 08H, reflecting the same sum. The Program Counter will increment to 2009H, as it points to the next instruction after HLT. Additionally, we look at the state of the flags after the addition operation. The Sign flag will be 0 because the result is positive. The Zero flag will also be 0, indicating that the result is not zero. The Carry flag will be 0, meaning there was no overflow in addition, confirming that the numbers added fit within the 8-bit limit.

Examples & Analogies

You could think of this step as checking your homework after adding up numbers. You expect your final answer (in the A Register) to be 8 apples, confirming that you only added correctly without any borrowing (flags showing no carry). The memory holds the same total as a backup, just like writing it down to remember later. Each flag tells you about the calculation condition, helping you ensure everything looks good (e.g., whether you went over your basket capacity).

Definitions & Key Concepts

Learn essential terms and foundational ideas that form the basis of the topic.

Key Concepts

  • Loading Data: The MVI instruction is used to load immediate values into the registers before performing the addition.

  • Adding Values: The ADD instruction adds the content of one register to the Accumulator and updates its value.

  • Storing Results: The STA instruction stores the result of the addition in a specified memory location.

  • Flag Register Status: Students will learn how the arithmetic operations affect the Sign, Zero, Auxiliary Carry, Parity, and Carry flags, which indicate the outcome of the arithmetic operations performed.

  • Through practical assembly programs, students observe the interplay between the registers, memory, and the processor's flag status, which provides insights into microprocessor functionality.

Examples & Real-Life Applications

See how the concepts apply in real-world scenarios to understand their practical implications.

Examples

  • Using the MVI A, 05H to load the value 5 into the Accumulator.

  • Using the ADD B instruction to add the content of Register B to the Accumulator.

  • Using the STA 2060H instruction to store the result at memory location 2060.

Memory Aids

Use mnemonics, acronyms, or visual cues to help remember key information more easily.

🎵 Rhymes Time

  • MVI MVI, ADD then STA, store it away—results on display!

📖 Fascinating Stories

  • Imagine two friends, A and B. They want to share their candies. A has 5, and B has 3. They add them together to see how many candies they can share in a box.

🧠 Other Memory Gems

  • Remember: MVI - Move Values Immediately, A - Accumulator, D - Do the operation, STA - Store Action.

🎯 Super Acronyms

MAS - Move, Add, Store, a simple acronym to remember our steps in arithmetic.

Flash Cards

Review key concepts with flashcards.

Glossary of Terms

Review the Definitions for terms.

  • Term: 8085 Microprocessor

    Definition:

    An 8-bit microprocessor that handles arithmetic operations and data processing tasks.

  • Term: ADD Instruction

    Definition:

    An instruction used to add the content of a specified register to the Accumulator.

  • Term: STA Instruction

    Definition:

    An instruction to store the content of the Accumulator into a specific memory location.

  • Term: Flags

    Definition:

    Bits in the Flag Register that indicate the status of the previous arithmetic or logical operations.

  • Term: Zero Flag

    Definition:

    A flag that is set if the result of an operation is zero.

  • Term: Carry Flag

    Definition:

    A flag that is set when there is a carry out from the most significant bit during an arithmetic operation.