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diff --git a/README.md b/README.md new file mode 100644 index 000000000..66ca7a0b4 --- /dev/null +++ b/README.md @@ -0,0 +1,43 @@ +# emscripten-wasm + +This repository contains tools to compile C/C++ to WebAssembly s-expressions, using [Emscripten](http://emscripten.org/), by translating Emscripten's asm.js output into WebAssembly. + +This repository contains an asm.js-to-WebAssembly compiler, **asm2wasm**, built on Emscripten's asm optimizer infrastructure. That can directly compile asm.js to WebAssembly. You can use Emscripten to build C++ into asm.js, and together the two tools let you compile C/C++ to WebAssembly. + +## Building asm2wasm + +``` +$ build.sh +``` + +## Running + +Just run + +``` +bin/asm2wasm [input.asm.js file] +``` + +This will print out a WebAssembly module in s-expression format to the console. For example, try + +``` +$ bin/asm2wasm tests/hello_world.asm.js +``` + +On Linux and Mac you should see pretty colors. Set `COLORS=0` in the env to disable colors if you prefer that. Set `COLORS=1` in the env to force colors (useful when piping to `more`, for example). + +Set `ASM2WASM_DEBUG=1` in the env to see debug info, about asm.js nodes as they are parsed, etc. + +## Starting from C/C++ Source + +[Grab Emscripten](http://kripken.github.io/emscripten-site/docs/getting_started/downloads.html), and build + +Limitations: + + * WebAssembly lacks global variables, so `asm2wasm` maps them onto addresses in memory. This requires that you have some reserved space for those variables. You can do that with `emcc -s GLOBAL_BASE=1000`. We still need to write the code to copy the globals there. + * Emscripten emits asm.js and JavaScript, that work together using web APIs to do things like print, render, etc. Not sure if there is a way to test that full output yet. + +## License & Contributing + +Same as Emscripten: MIT license. This code is sync'ed with Emscripten's repo. + |