eddydg / disassembly

What is this

Create your C/C++ app

fibo.c

#include <emscripten.h>

EMSCRIPTEN_KEEPALIVE
int fib(int n) {
int i, t, a = 0, b = 1;
  for (i = 0; i < n; i++) {
    t = a + b;
    a = b;
    b = t;
  }
  return b;
}

Compile C/C++ files to JS modules

https://developer.mozilla.org/fr/docs/WebAssembly/C_to_wasm

git clone https://github.com/juj/emsdk.git
cd emsdk

./emsdk install --build=Release sdk-incoming-64bit binaryen-master-64bit
./emsdk activate --global --build=Release sdk-incoming-64bit binaryen-master-64bit

emcc -O3 -s WASM=1 -s EXTRA_EXPORTED_RUNTIME_METHODS='["cwrap"]' 'fibo.c'

You will obtain the binary a.out.asm and the JS wrapper a.out.js.

On Windows: remove the ./ in the commands.

Note: On Window I had several issues installing all the necessary. I ended up using the Window 10 "Ubuntu Bash" terminal end it worked flawlessly.

Call it in your browser

index.html

<script src="a.out.js"></script>
<script>
  Module.onRuntimeInitialized = _ => {
    const fib = Module.cwrap('fib', 'number', ['number']);
    console.log(fib(12));
  };
</script>

If you try it, you will have a CORS error, so you need to access it from a server.

Emrun

emrun index.html

If your browser is not recognized, you can check what is available with emrun --list_browsers. You can also directly provide the browsers path: emrun --browser=/mnt/c/Program\ Files\ \(x86\)/Google/Chrome/Application/chrome.exe index.html.

Alternatively, the --no_browser flag is also available.

Custom server

npm install http-server -g
http-server

Now you can go to http://127.0.0.1:8080/index.html and see the result in your console.