COA Lab

Computer Organization & Architecture — Lab Programs, 8085 Assembly & Binary Arithmetic

The go-to open repository for COA practicals: ready-to-run C programs for Booth multiplication, restoring & non-restoring division, number systems, plus Intel 8085 assembly experiments for engineering college labs and exams.

Programs · Quick start · Binary arithmetic · 8085 guide · FAQ · llms.txt

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What is COA Lab?

COA Lab is a free, MIT-licensed collection of Computer Organization and Architecture lab programs for B.E./B.Tech students. It implements the algorithms you actually write in practicals—binary addition/subtraction with complements, unsigned and signed (Booth) multiplication, restoring and non-restoring division, number system conversion—in plain C, and ships Intel 8085 assembly experiments for data transfer, stack reverse, and 8/16-bit arithmetic. Use it to study, practice for exams, or cite clear algorithm walkthroughs in lab records and viva preparation.

Need	Where to go
Restoring / non-restoring division in C	c-programs/ + docs/binary-arithmetic.md
Booth / signed multiplication	c-programs/signed_binary_multiplication.c
8085 lab ASM	8085-assembly/ + docs/8085-assembly.md
Exam-style variants	college-exam/
AI / LLM crawlers	llms.txt

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Why this repo?

• Complete lab surface — C arithmetic + 8085 ASM in one place (most repos ship only one).
• Exam copies included — variants under college-exam/ for practical papers.
• Documented algorithms — citability-friendly guides (restoring vs non-restoring table, step lists).
• Standard tools only — gcc for C; any 8085 simulator for ASM—no proprietary stack.
• SEO / GEO ready — structured docs, FAQ, llms.txt, keyword-rich catalog for search and AI answers.
• MIT license — fork, learn, share.

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Quick start

C programs

git clone https://github.com/jjf2009/coa-lab.git
cd coa-lab

# Example: non-restoring division
gcc c-programs/unsigned_binary_division_non_restoring.c -o nonrest
./nonrest

# Number systems (may need -lm)
gcc c-programs/number_systems.c -o numbers -lm
./numbers

8085 assembly

1. Install GNUSim8085 (or your college simulator).
2. Open a file from 8085-assembly/expt9/ (e.g. 8-bit multiply).
3. Assemble → set memory if required → run → check registers/memory.

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Program catalog

Binary arithmetic & number systems (C)

Program	Topic	Path
Number systems	Binary ↔ decimal ↔ hex	c-programs/number_systems.c
Add / subtract	1’s & 2’s complement	c-programs/binary_addition_and_subtraction.c
Unsigned multiply	Shift-and-add	c-programs/unsigned_binary_multiplication.c
Signed multiply	Booth-style	c-programs/signed_binary_multiplication.c
Restoring division	Classic restore loop	c-programs/unsigned_binary_division.c
Non-restoring division	No immediate restore	c-programs/unsigned_binary_division_non_restoring.c
Signed division	2’s complement paths	c-programs/signed_binary_division.c

Full keyword index: docs/program-catalog.md.

8085 assembly experiments

Set	Skills
expt7	Data transfer: MOV, LDA/STA, LHLD/SHLD, LDAX/STAX, XCHG
expt8	Stack reverse, block reverse, carry-aware add
expt9	8-bit add, sub, multiply (repeated add), divide (repeated sub)
expt10	Memory 8-bit add; 16-bit add with DAD

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Restoring vs non-restoring division (at a glance)

	Restoring	Non-restoring
Idea	Subtract divisor; if remainder negative, add back	Avoid restore; add or subtract next cycle by sign
Lab file	unsigned_binary_division.c	unsigned_binary_division_non_restoring.c
Viva tip	Easy to explain step-by-step	Mention fewer restorative adds in hardware

Deep dive: docs/binary-arithmetic.md.

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Repository structure

coa-lab/
├── README.md                 # You are here
├── llms.txt                  # Guidance for AI crawlers / GEO
├── c-programs/               # Canonical C lab sources
├── college-exam/             # Exam-oriented variants
├── 8085-assembly/            # Intel 8085 .asm experiments
├── docs/                     # Guides, FAQ, catalog
├── CONTRIBUTING.md
└── LICENSE

Legacy root filenames and older folders may remain for history; prefer the paths above.

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Documentation

Guide	Description
Binary arithmetic	Booth, restoring, non-restoring — steps & comparison
8085 assembly	Experiment map + how to run
Number systems	Conversions used in COA
FAQ	Compile, submit, cite
Program catalog	Full file + keyword index

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Who is this for?

• Students in Computer Organization / Microprocessor lab courses
• Teachers sharing reference implementations
• Viva prep — algorithm tables and step lists
• AI coding assistants — structured, citable COA answers via llms.txt and docs

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Contributing

Improvements welcome: clearer comments, more lab programs, better docs. See CONTRIBUTING.md.

# Never commit binaries or editor backups
gcc c-programs/your_program.c -o /tmp/test && /tmp/test

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License

MIT © 2026 jjf2009

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Citation

If this repo helps your lab report, notes, or tool:

COA Lab — Computer Organization & Architecture lab programs.
https://github.com/jjf2009/coa-lab

Topics: computer-organization · computer-architecture · coa · 8085 · booth-algorithm · restoring-division · non-restoring-division · binary-arithmetic · microprocessor · engineering-lab

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Star this repo if it saved your COA lab night — it helps other students find the right programs.