add doc for WASM

readme.md

@@ -92,6 +92,16 @@ cd build
 cmake .. -A x64
 msbuild mcl.sln /p:Configuration=Release /m
 ```
+## Build for WASM(WebAssembly) (experimental)
+mcl supports emcc (Emscripten) and `test/bn_test.cpp` runs on browers such as Firefox and Chrome.
+Type
+```
+emcc -O3 -I ./include/ -I ../cybozulib/include/ src/fp.cpp test/bn_test.cpp -DNDEBUG -s WASM=1 -o t.html
+emrun --no_browser --port 8080 --no_emrun_detect .
+```
+and open `http://<address>:8080/t.html`.
+The timing of a pairing on `CurveFp254BNb` is 2.8msec on 64-bit Firefox with Skylake 3.4GHz.
+
 ### SELinux
 mcl uses Xbyak JIT engine if it is available on x64 architecture,
 otherwise mcl uses a little slower functions generated by LLVM.
@@ -234,7 +244,7 @@ mcl                                                      | 0.31 | 1.6 |22.6|  4.
 ```
 cmake -DARITH=x64-asm-254 -DFP_PRIME=254 -DFPX_METHD="INTEG;INTEG;LAZYR" -DPP_METHD="LAZYR;OATEP"
 ```
-# 384-bit curve (experimental)
+# 384-bit curve
 see `test/bn384_test.cpp`
 Benchmark on Skylake(3.4GHz)