🖥️ 8086 Assembly Mini Projects

Four little programs, one old-school CPU, zero high-level luxuries.

Welcome to my dive into 8086 Assembly using EMU8086. No frameworks, no garbage collector, no print(); just registers, flags, and the raw satisfaction of making a 40-year-old architecture do something useful. If you've never written Assembly before: it's like cooking a five-course meal using only a lighter and a spoon. Painful at first, weirdly addictive once it clicks.

This repo contains 4 mini-projects, each solving a real (if small) problem end to end in pure .asm.

📁 What's Inside

#	Project	File	What it does
1	🎓 Student Result Calculator	242_115_013_project1.asm	Totals, averages, and grades a student's marks
2	➗ Menu-Driven Calculator	242_115_013_project2.asm	A loop-driven CLI calculator (Add / Sub / Mul / Exit)
3	🛒 Shopping / Billing System	242_115_013_project3.asm	A tiny POS system — pick items, checkout, get a bill
4	🔐 Password Verification System	242_115_013_project4.asm	3 attempts to guess the right digit, or you're locked out

🎓 Project 1 — Student Result Calculator

Takes three hardcoded subject marks, does the math a calculator would do in your head, and prints a report card.

Input (stored in memory):

Mathematics   = 78
Physics       = 82
Programming   = 91

Logic:

1. Total = Math + Physics + Programming
2. Average = Total / 3
3. Grade is decided by comparing Average against thresholds:

Average	Grade
≥ 80	A
≥ 70	B
≥ 60	C
< 60	F

Sample Output:

➗ Project 2 — Menu-Driven Calculator

A classic looping menu — the "Hello World" of interactive Assembly programs. Two numbers are predefined in memory, and the user just picks what to do with them.

SIMPLE CALCULATOR
1. Addition
2. Subtraction
3. Multiplication
4. Exit

Pick a number, get the result, and the menu reappears — because real programs don't quit after one operation. Choose 4 when you're done playing calculator.

Sample Output:

🛒 Project 3 — Shopping / Billing System

The most "real-world" of the bunch — a mini point-of-sale system for a tiny grocery stand.

Price List:

Item	Price (Tk)
🍎 Apple	40
🍊 Orange	30
🥭 Mango	60

SHOP MENU
1. Apple
2. Orange
3. Mango
4. Checkout
5. Exit

Every time you pick an item, its quantity ticks up by 1 and the running bill updates behind the scenes. Hit Checkout and it prints an itemized receipt:

Apple    Quantity : x
Orange   Quantity : x
Mango    Quantity : x
Total Bill        : xxx

Then it's back to the menu — because the shop doesn't close after one sale. Sample Output:

🔐 Project 4 — Password Verification System

Simple, strict, unforgiving — exactly how security should be.

• A single-digit password lives in memory.
• You get 3 attempts. That's it.
• Get it right → Access Granted, program exits.
• Get it wrong → Wrong Password, and it tells you how many tries you have left.
• Burn through all 3 → Access Denied, and the door stays shut.

Enter Password: _
Wrong Password
Attempts Left: 2

🛠️ Tech Stack

• Language: 8086 Assembly (Intel syntax)
• Emulator/IDE: EMU8086
• Core instructions used: MOV, ADD, SUB, MUL, CMP, JMP family, INT 21h (DOS interrupts for I/O), loops via LOOP / conditional jumps

▶️ How to Run

1. Download and install EMU8086.
2. Open any .asm file from this repo in the EMU8086 editor.
3. Hit Compile (F5) then Emulate / Run.
4. Follow the on-screen prompts — type your menu choices or password digit and press Enter.

🧠 What I Actually Learned Building This

• How to move data between memory and registers without losing my mind
• Simulating "if/else" and "switch" logic purely with CMP + conditional jumps
• Building loops that behave like real menus instead of running once and dying
• Basic string/number output via DOS interrupts (INT 21h) — no printf, no mercy
• Appreciating every high-level language I've ever used, immediately after finishing this project

📌 Notes

• All input values (marks, prices, password) are hardcoded in memory per the project requirements — this isn't meant to take dynamic input beyond menu choices and the password digit.
• Each project is self-contained in its own .asm file, so you can compile and run them independently.

🏁 Final Word

Assembly doesn't hold your hand. Every register has a job, every flag matters, and there's no try/catch to bail you out. These four projects were built the hard way — one instruction at a time — and honestly? That's what made them fun.

Built with MOV, CMP, patience, and mild caffeine dependency.