update readme

Author: vytdev

README.md

@@ -1,6 +1,70 @@
 # rvm
 
-A virtual machine.
+A tiny, fast, portable, and embeddable low-level virtual machine.
+
+*`rvm` is now complete!*
+
+## Usage
+
+1. Make sure you have `make` and `gcc`/`clang` installed.
+2. Clone the repo.
+3. Run `make -C'path/to/repo'`
+
+**For the APIs**: Please read the source code. Check out `test/test.c` to see
+how to set it up. I don't plan to write a full documentation, yet. Thanks for
+understanding.
+
+## Benchmarks
+
+I've got no access to a PC. RVM was entirely built on my phone, which has
+these decent specs:
+
+- processor: Unisoc  T603
+- cpu: 8 cores (4x 1.2GHz + 4x 1.8GHz)
+- arch: armv8 (aarch64), little-endian
+- ram: 4GB (+4GB swap)
+
+| Test           | Elapsed time | Inst Count          | Avg TPI | Inst Rate  |
+| :------------: | :----------: | :-----------------: | :-----: | :--------: |
+| `nops`         | 3.651 ms     | 1048576 (1.05 M)    | 3.482ns | 287.2M IPS |
+| `cnt_1bill`    | 9.509 secs   | 1000000006 (1.01 B) | 8.317ns | 105.2M IPS |
+| `naive_fib_40` | 18.662 secs  | 2980442527 (2.98 B) | 6.262ns | 159.7M IPS |
+
+CI benchmarks (GitHub-hosted runner):
+
+| Test           | Elapsed time | Inst Count          | Avg TPI | Inst Rate  |
+| :------------: | :----------: | :-----------------: | :-----: | :--------: |
+| `nops`         | 456.413 μs   | 1048576 (1.05 M)    | 0.435ns | 2.297G IPS |
+| `cnt_1bill`    | 2.904 secs   | 1000000006 (1 B)    | 2.904ns | 344.4M IPS |
+| `naive_fib_40` | 4.459 secs   | 2980442527 (2.98 B) | 1.496ns | 668.4M IPS |
+
+In the naive `fib(40)` test, RVM is ~2.5× slower than LuaJIT — but
+**orders of magnitude faster** than Python!
+
+## Contributing
+
+I'd appreciate any contributions! To contribute:
+
+1. Fork the repo
+2. Clone your fork
+3. Make a new branch:
+
+    ```sh
+    git checkout -b fix/somebug
+    ```
+
+4. Make your changes.
+5. Commit and push.
+
+    ```sh
+    git commit -m "fix bug #123"
+    git push
+    ```
+
+6. Open a pull request.
+
+Then just sit back! I may not respond instantly, but I’m always open to
+contributions. Thanks!
 
 ## License