diff --git a/README.md b/README.md
index 693732d..f513424 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,3 @@
-# wasm-experiments
\ No newline at end of file
+# wasm-experiments
+
+Just some playing around with the new experimental Go WASM arch target
diff --git a/printing/Makefile b/printing/Makefile
new file mode 100644
index 0000000..2cb4239
--- /dev/null
+++ b/printing/Makefile
@@ -0,0 +1,7 @@
+build: clean compile
+
+clean:
+ rm -f ./html/test.wasm
+
+compile:
+ GOOS=js GOARCH=wasm GOROOT=$(GOPATH)/src/github.com/neelance/go/ $(GOPATH)/src/github.com/neelance/go/bin/go build -o ./html/test.wasm main.go
diff --git a/printing/README.md b/printing/README.md
new file mode 100644
index 0000000..7dc8ecf
--- /dev/null
+++ b/printing/README.md
@@ -0,0 +1,13 @@
+# Printing
+
+## Running:
+
+Simply open ./html/index.html in a web browser of your choice (that supports WebAssembly)
+
+## Building
+
+```bash
+$ make build
+```
+
+This requires the WASM Go fork in your $GOPATH, and the compiled Go binary in that fork to be built.
diff --git a/printing/html/index.html b/printing/html/index.html
new file mode 100644
index 0000000..5ccee6f
--- /dev/null
+++ b/printing/html/index.html
@@ -0,0 +1,24 @@
+
+
+
+
+
+ Go wasm
+
+
+
+
+
+
+ Run
+
+
+
diff --git a/printing/html/test.wasm b/printing/html/test.wasm
new file mode 100755
index 0000000..174cc6a
Binary files /dev/null and b/printing/html/test.wasm differ
diff --git a/printing/html/wasm_exec.js b/printing/html/wasm_exec.js
new file mode 100644
index 0000000..b31a627
--- /dev/null
+++ b/printing/html/wasm_exec.js
@@ -0,0 +1,387 @@
+let args = ["js"];
+let trace = false;
+
+if (typeof process !== "undefined") {
+ if (process.argv.length < 3) {
+ process.stderr.write("usage: go_js_wasm_exec [wasm binary]\n");
+ process.exit(1);
+ }
+
+ args = args.concat(process.argv.slice(3));
+ trace = process.env.TRACE === "1";
+ global.require = require;
+
+ global.fs = require("fs");
+
+ const nodeCrypto = require("crypto");
+ global.crypto = {
+ getRandomValues(b) {
+ nodeCrypto.randomFillSync(b);
+ },
+ };
+
+ const now = () => {
+ const [sec, nsec] = process.hrtime();
+ return sec * 1000 + nsec / 1000000;
+ };
+ global.performance = {
+ timeOrigin: Date.now() - now(),
+ now: now,
+ };
+
+ const util = require("util");
+ global.TextEncoder = util.TextEncoder;
+ global.TextDecoder = util.TextDecoder;
+
+ compileAndRun(fs.readFileSync(process.argv[2])).catch((err) => {
+ console.error(err);
+ });
+} else {
+ window.global = window;
+
+ global.process = {
+ env: {},
+ exit(code) {
+ if (code !== 0) {
+ console.warn("exit code:", code);
+ }
+ },
+ };
+
+ let outputBuf = "";
+ global.fs = {
+ constants: {},
+ writeSync(fd, buf) {
+ outputBuf += decoder.decode(buf);
+ const nl = outputBuf.lastIndexOf("\n");
+ if (nl != -1) {
+ console.log(outputBuf.substr(0, nl));
+ outputBuf = outputBuf.substr(nl + 1);
+ }
+ return buf.length;
+ },
+ };
+}
+
+const encoder = new TextEncoder("utf-8");
+const decoder = new TextDecoder("utf-8");
+
+let mod, inst;
+let names = [];
+let prevSP = 0;
+let values = []; // TODO: GC
+
+function mem() {
+ return new DataView(inst.exports.mem.buffer);
+}
+
+function setInt64(addr, v) {
+ mem().setUint32(addr + 0, v, true);
+ if (v >= 0) {
+ mem().setUint32(addr + 4, v / 4294967296, true);
+ } else {
+ mem().setUint32(addr + 4, -1, true); // FIXME
+ }
+}
+
+function getInt64(addr) {
+ const low = mem().getUint32(addr + 0, true);
+ const high = mem().getInt32(addr + 4, true);
+ return low + high * 4294967296;
+}
+
+function loadValue(addr) {
+ const id = mem().getUint32(addr, true);
+ return values[id];
+}
+
+function storeValue(addr, v) {
+ if (v === undefined) {
+ mem().setUint32(addr, 0, true);
+ return;
+ }
+ if (v === null) {
+ mem().setUint32(addr, 1, true);
+ return;
+ }
+ values.push(v);
+ mem().setUint32(addr, values.length - 1, true);
+}
+
+function loadSlice(addr) {
+ const array = getInt64(addr + 0);
+ const len = getInt64(addr + 8);
+ return new Uint8Array(inst.exports.mem.buffer, array, len);
+}
+
+function loadSliceOfValues(addr) {
+ const array = getInt64(addr + 0);
+ const len = getInt64(addr + 8);
+ const a = new Array(len);
+ for (let i = 0; i < len; i++) {
+ const id = mem().getUint32(array + i * 4, true);
+ a[i] = values[id];
+ }
+ return a;
+}
+
+function loadString(addr) {
+ const saddr = getInt64(addr + 0);
+ const len = getInt64(addr + 8);
+ return decoder.decode(new DataView(inst.exports.mem.buffer, saddr, len));
+}
+
+async function compileAndRun(source) {
+ await compile(source);
+ await run();
+}
+
+async function compile(source) {
+ mod = await WebAssembly.compile(source);
+}
+
+async function run() {
+ let importObject = {
+ js: {
+ // func wasmexit(code int32)
+ "runtime.wasmexit": function (sp) {
+ process.exit(mem().getInt32(sp + 8, true));
+ },
+
+ // func wasmwrite(fd uintptr, p unsafe.Pointer, n int32)
+ "runtime.wasmwrite": function (sp) {
+ const fd = getInt64(sp + 8);
+ const p = getInt64(sp + 16);
+ const n = mem().getInt32(sp + 24, true);
+ fs.writeSync(fd, new Uint8Array(inst.exports.mem.buffer, p, n));
+ },
+
+ // func nanotime() int64
+ "runtime.nanotime": function (sp) {
+ setInt64(sp + 8, (performance.timeOrigin + performance.now()) * 1000000);
+ },
+
+ // func walltime() (sec int64, nsec int32)
+ "runtime.walltime": function (sp) {
+ const msec = (new Date).getTime();
+ setInt64(sp + 8, msec / 1000);
+ mem().setInt32(sp + 16, (msec % 1000) * 1000000, true);
+ },
+
+ // func boolVal(value bool) Value
+ "runtime/js.boolVal": function (sp) {
+ storeValue(sp + 16, mem().getUint8(sp + 8) !== 0);
+ },
+
+ // func intVal(value int) Value
+ "runtime/js.intVal": function (sp) {
+ storeValue(sp + 16, getInt64(sp + 8));
+ },
+
+ // func floatVal(value float64) Value
+ "runtime/js.floatVal": function (sp) {
+ storeValue(sp + 16, mem().getFloat64(sp + 8, true));
+ },
+
+ // func stringVal(value string) Value
+ "runtime/js.stringVal": function (sp) {
+ storeValue(sp + 24, loadString(sp + 8));
+ },
+
+ // func (v Value) Get(key string) Value
+ "runtime/js.Value.Get": function (sp) {
+ storeValue(sp + 32, Reflect.get(loadValue(sp + 8), loadString(sp + 16)));
+ },
+
+ // func (v Value) set(key string, value Value)
+ "runtime/js.Value.set": function (sp) {
+ Reflect.set(loadValue(sp + 8), loadString(sp + 16), loadValue(sp + 32));
+ },
+
+ // func (v Value) Index(i int) Value
+ "runtime/js.Value.Index": function (sp) {
+ storeValue(sp + 24, Reflect.get(loadValue(sp + 8), getInt64(sp + 16)));
+ },
+
+ // func (v Value) setIndex(i int, value Value)
+ "runtime/js.Value.setIndex": function (sp) {
+ Reflect.set(loadValue(sp + 8), getInt64(sp + 16), loadValue(sp + 24));
+ },
+
+ // func (v Value) call(name string, args []Value) (Value, bool)
+ "runtime/js.Value.call": function (sp) {
+ try {
+ const v = loadValue(sp + 8);
+ const m = Reflect.get(v, loadString(sp + 16));
+ const args = loadSliceOfValues(sp + 32);
+ storeValue(sp + 56, Reflect.apply(m, v, args));
+ mem().setUint8(sp + 60, 1);
+ } catch (err) {
+ storeValue(sp + 56, err);
+ mem().setUint8(sp + 60, 0);
+ }
+ },
+
+ // func (v Value) invoke(args []Value) (Value, bool)
+ "runtime/js.Value.invoke": function (sp) {
+ try {
+ const v = loadValue(sp + 8);
+ const args = loadSliceOfValues(sp + 16);
+ storeValue(sp + 40, Reflect.apply(v, undefined, args));
+ mem().setUint8(sp + 44, 1);
+ } catch (err) {
+ storeValue(sp + 40, err);
+ mem().setUint8(sp + 44, 0);
+ }
+ },
+
+ // func (v Value) wasmnew(args []Value) (Value, bool)
+ "runtime/js.Value.wasmnew": function (sp) {
+ try {
+ const v = loadValue(sp + 8);
+ const args = loadSliceOfValues(sp + 16);
+ storeValue(sp + 40, Reflect.construct(v, args));
+ mem().setUint8(sp + 44, 1);
+ } catch (err) {
+ storeValue(sp + 40, err);
+ mem().setUint8(sp + 44, 0);
+ }
+ },
+
+ // func (v Value) Float() float64
+ "runtime/js.Value.Float": function (sp) {
+ mem().setFloat64(sp + 16, parseFloat(loadValue(sp + 8)), true);
+ },
+
+ // func (v Value) Int() int
+ "runtime/js.Value.Int": function (sp) {
+ setInt64(sp + 16, parseInt(loadValue(sp + 8)));
+ },
+
+ // func (v Value) Bool() bool
+ "runtime/js.Value.Bool": function (sp) {
+ mem().setUint8(sp + 16, !!loadValue(sp + 8));
+ },
+
+ // func (v Value) Length() int
+ "runtime/js.Value.Length": function (sp) {
+ setInt64(sp + 16, parseInt(loadValue(sp + 8).length));
+ },
+
+ // func (v Value) prepareString() (Value, int)
+ "runtime/js.Value.prepareString": function (sp) {
+ const str = encoder.encode(String(loadValue(sp + 8)));
+ storeValue(sp + 16, str);
+ setInt64(sp + 24, str.length);
+ },
+
+ // func (v Value) loadString(b []byte)
+ "runtime/js.Value.loadString": function (sp) {
+ const str = loadValue(sp + 8);
+ loadSlice(sp + 16).set(str);
+ },
+
+ "trace": function (pcF, pcB, sp) {
+ console.log(
+ `trace`,
+ String(sp).padStart(10),
+ String(pcF).padStart(10),
+ String(pcB).padStart(10),
+ sp <= prevSP ? "->" : "<-",
+ names[pcF],
+ );
+ prevSP = sp;
+ },
+ }
+ };
+
+ const nameSec = new SimpleStream(new Uint8Array(WebAssembly.Module.customSections(mod, "name")[0]));
+ while (!nameSec.atEnd()) {
+ const nameType = nameSec.readByte();
+ const namePayloadLen = nameSec.readUleb128();
+ const namePayloadData = new SimpleStream(nameSec.read(namePayloadLen));
+ if (nameType === 1) { // function names
+ const count = namePayloadData.readUleb128();
+ for (let i = 0; i < count; i++) {
+ const index = namePayloadData.readUleb128();
+ const nameLen = namePayloadData.readUleb128();
+ const nameStr = String.fromCharCode.apply(null, namePayloadData.read(nameLen));
+ names[index] = nameStr;
+ }
+ }
+ }
+
+ inst = await WebAssembly.instantiate(mod, importObject);
+ values = [undefined, null, global, inst.exports.mem];
+
+ let offset = 4096;
+
+ const strPtr = (str) => {
+ let ptr = offset;
+ new Uint8Array(inst.exports.mem.buffer, offset, str.length + 1).set(encoder.encode(str + "\0"));
+ offset += str.length + (8 - (str.length % 8));
+ return ptr;
+ };
+
+ const argc = args.length;
+
+ const argvPtrs = [];
+ args.forEach((arg) => {
+ argvPtrs.push(strPtr(arg));
+ });
+
+ const keys = Object.keys(process.env).sort();
+ argvPtrs.push(keys.length);
+ keys.forEach((key) => {
+ argvPtrs.push(strPtr(`${key}=${process.env[key]}`));
+ });
+
+ const argv = offset;
+ argvPtrs.forEach((ptr) => {
+ mem().setUint32(offset, ptr, true);
+ mem().setUint32(offset + 4, 0, true);
+ offset += 8;
+ });
+
+ try {
+ inst.exports.run(argc, argv, trace);
+ } catch (err) {
+ console.error(err);
+ process.exit(1);
+ }
+}
+
+class SimpleStream {
+ constructor(array) {
+ this.array = array;
+ this.offset = 0;
+ }
+
+ atEnd() {
+ return this.offset >= this.array.length;
+ }
+
+ read(len) {
+ const a = this.array.subarray(this.offset, this.offset + len);
+ this.offset += len;
+ return a;
+ }
+
+ readByte() {
+ const b = this.array[this.offset];
+ this.offset++;
+ return b;
+ }
+
+ readUleb128() {
+ let value = 0;
+ let shift = 0;
+ while (true) {
+ let byte = this.readByte();
+ value |= (byte & 0x7F) << shift;
+ if ((byte & 0x80) === 0) { break; }
+ shift += 7;
+ }
+ return value;
+ }
+}
diff --git a/printing/main.go b/printing/main.go
new file mode 100644
index 0000000..e4f15a3
--- /dev/null
+++ b/printing/main.go
@@ -0,0 +1,11 @@
+package main
+
+import (
+ "fmt"
+ "runtime/js"
+)
+
+func main() {
+ fmt.Println("Test")
+ js.Global.Get("console").Call("log", "yadayada")
+}