all: add WebAssembly backend

2026-08-03 02:27:48 +00:00 · 2018-10-18 15:15:29 +02:00
parent a51e04c550
commit e5e09747f0
15 changed files with 199 additions and 17 deletions
@@ -0,0 +1,9 @@
+package main
+
+func main() {
+}
+
+//go:export add
+func add(a, b int) int {
+	return a + b
+}
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+
+<html>
+	<head>
+		<meta charset="utf-8"/>
+		<title>Go WebAssembly</title>
+		<meta name="viewport" content="width=device-width, initial-scale=1"/>
+		<script src="wasm.js" async></script>
+	</head>
+	<body>
+		<h1>WebAssembly</h1>
+		<p>Add two numbers, using WebAssembly:</p>
+		<input type="number" id="a" value="2"/> + <input type="number" id="b" value="2"/> = <input type="number" id="result" readonly/>
+	</body>
+</html>
@@ -0,0 +1,55 @@
+'use strict';
+
+const WASM_URL = '../../../wasm.wasm';
+
+var wasm;
+var logLine = [];
+var memory8;
+
+var importObject = {
+  env: {
+    io_get_stdout: function() {
+      return 1;
+    },
+    resource_write: function(fd, ptr, len) {
+      if (fd == 1) {
+        for (let i=0; i<len; i++) {
+          let c = memory8[ptr+i];
+          if (c == 13) { // CR
+            // ignore
+          } else if (c == 10) { // LF
+            // write line
+            let line = new TextDecoder("utf-8").decode(new Uint8Array(logLine));
+            logLine = [];
+            console.log(line);
+          } else {
+            logLine.push(c);
+          }
+        }
+      } else {
+        console.error('invalid file descriptor:', fd);
+      }
+    },
+  },
+};
+
+function updateResult() {
+  let a = parseInt(document.querySelector('#a').value);
+  let b = parseInt(document.querySelector('#b').value);
+  let result = wasm.exports.add(a, b);
+  document.querySelector('#result').value = result;
+}
+
+function init() {
+  document.querySelector('#a').oninput = updateResult;
+  document.querySelector('#b').oninput = updateResult;
+
+  WebAssembly.instantiateStreaming(fetch(WASM_URL), importObject).then(function(obj) {
+    wasm = obj.instance;
+    memory8 = new Uint8Array(wasm.exports.memory.buffer);
+    wasm.exports.cwa_main();
+    updateResult();
+  })
+}
+
+init();
@@ -2,6 +2,10 @@

 package runtime

+import (
+	"unsafe"
+)
+
 const GOARCH = "arm"

 // The length type used inside strings and slices.
@@ -9,3 +13,6 @@ type lenType uint32

 // The bitness of the CPU (e.g. 8, 32, 64).
 const TargetBits = 32
+
+//go:extern _heap_start
+var heapStart unsafe.Pointer
@@ -2,6 +2,10 @@

 package runtime

+import (
+	"unsafe"
+)
+
 const GOARCH = "avr"

 // The length type used inside strings and slices.
@@ -9,3 +13,6 @@ type lenType uint16

 // The bitness of the CPU (e.g. 8, 32, 64).
 const TargetBits = 8
+
+//go:extern _heap_start
+var heapStart unsafe.Pointer
@@ -2,6 +2,10 @@

 package runtime

+import (
+	"unsafe"
+)
+
 const GOARCH = "wasm"

 // The length type used inside strings and slices.
@@ -9,3 +13,6 @@ type lenType uint32

 // The bitness of the CPU (e.g. 8, 32, 64).
 const TargetBits = 32
+
+//go:extern __heap_base
+var heapStart unsafe.Pointer
@@ -6,9 +6,6 @@ import (
 	"unsafe"
 )

-//go:extern _heap_start
-var heapStart unsafe.Pointer
-
 var heapptr = uintptr(unsafe.Pointer(&heapStart))

 func alloc(size uintptr) unsafe.Pointer {
@@ -0,0 +1,54 @@
+// +build wasm,!arm,!avr
+
+package runtime
+
+type timeUnit int64
+
+const tickMicros = 1
+
+var timestamp timeUnit
+
+// CommonWA: io_get_stdout
+func _Cfunc_io_get_stdout() int32
+
+// CommonWA: resource_write
+func _Cfunc_resource_write(id int32, ptr *uint8, len int32) int32
+
+var stdout int32
+
+func init() {
+	stdout = _Cfunc_io_get_stdout()
+}
+
+//go:export _start
+func _start() {
+	initAll()
+}
+
+//go:export cwa_main
+func cwa_main() {
+	initAll() // _start is not called by olin/cwa so has to be called here
+	mainWrapper()
+}
+
+func putchar(c byte) {
+	_Cfunc_resource_write(stdout, &c, 1)
+}
+
+func sleepTicks(d timeUnit) {
+	// TODO: actually sleep here for the given time.
+	timestamp += d
+}
+
+func ticks() timeUnit {
+	return timestamp
+}
+
+// Align on word boundary.
+func align(ptr uintptr) uintptr {
+	return (ptr + 3) &^ 3
+}
+
+func abort() {
+	// TODO
+}