https://github.com/uggla/asm

Hello world example to play with Rust inline assembly
https://github.com/uggla/asm

Last synced: 25 days ago
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Hello world example to play with Rust inline assembly

• Host: GitHub
• URL: https://github.com/uggla/asm
• Owner: uggla
• License: apache-2.0
• Created: 2022-04-15T00:00:01.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2024-09-05T17:08:54.000Z (4 months ago)
• Last Synced: 2024-10-14T09:11:07.355Z (2 months ago)
• Language: Rust
• Homepage:
• Size: 15.6 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# asm

This is a "hello world" project to play with Rust inline assembly.

[Inline assembly](https://blog.rust-lang.org/2022/02/24/Rust-1.59.0.html#whats-in-1590-stable)

was introduced with Rust 1.59 release (2022-02-24)

and this is an attempt to learn more about it.

Inspiration from this little project also comes from

[@iMilnb](https://twitter.com/iMilnb)

and the C From Scratch video series, mainly this

show https://www.youtube.com/watch?v=F-Ow6-uH6Mc

The goal of the project is to show:

- How to call the `write` and `uname` syscall directly using assembly.

- How to use raw pointers and a bit of FFI (Foreign Fonction Interface)

  to share data.

- Usage of unsafe in such cases.

- Implementation of the From trait to convert data from the C style

  structure to the Rust one. This part is shamefully more or less

  copied from the uname crate.

The asm directory contains a "hello world" example written in

assembly and was used as a reference for the project.

The project uses x86_64 assembly and is targeting a Linux x86_64

operating system. It means that **it will not be able to run** on

another platform or CPU.

Of course, tracing the program with `stace` shows

the syscalls explicitly requested with inline assembly :

```

execve("./target/debug/asm", ["./target/debug/asm"], 0x7fff86007bb0 /* 90 vars */) = 0

...

...

write(1, "Hello from: ", 12Hello from: )            = 12

write(1, "\360\237\246\211 Uggla !!!\n", 15🦉 Uggla !!!

) = 15

uname({sysname="Linux", nodename="ugglalaptop", ...}) = 0

...

...

exit_group(0)                           = ?

+++ exited with 0 +++

```

## Build from the sources

1. Clone the project

```bash

  git clone https://github.com/uggla/asm.git

```

2. Go to the project directory

```bash

  cd asm

```

3. Build and run the program

```bash

cargo build

./target/debug/asm

```

4. Build hello.asm within asm directory (optional)


   Install make, gcc and nasm on your system using your

   system package manager. Then execute :

```bash

cd asm

make

./hello

```

## Program output example

```bash

 🦉 uggla   main  ~  workspace  rust  asm  cargo -V

cargo 1.80.1 (376290515 2024-07-16)

 🦉 uggla   main  ~  workspace  rust  asm  cargo run

    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.00s

     Running `target/debug/asm`

Hello from: 🦉 Uggla !!!

UnameInfo {

    sysname: "Linux",

    nodename: "ugglalaptop",

    release: "6.10.6-200.fc40.x86_64",

    version: "#1 SMP PREEMPT_DYNAMIC Mon Aug 19 14:09:30 UTC 2024",

    machine: "x86_64",

    domainname: "(none)",

}

```