1 files changed, 43 insertions, 0 deletions
diff --git a/src/runtime/wincallback.go b/src/runtime/wincallback.go
new file mode 100644
index 000000000..4c0daf17c
--- /dev/null
+++ b/src/runtime/wincallback.go
@@ -0,0 +1,43 @@
+// Copyright 2014 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore
+
+// Generate Windows callback assembly file.
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+)
+
+const maxCallback = 2000
+
+func main() {
+	var buf bytes.Buffer
+
+	buf.WriteString(`// generated by wincallback.go; run go generate
+
+// runtime·callbackasm is called by external code to
+// execute Go implemented callback function. It is not
+// called from the start, instead runtime·compilecallback
+// always returns address into runtime·callbackasm offset
+// appropriately so different callbacks start with different
+// CALL instruction in runtime·callbackasm. This determines
+// which Go callback function is executed later on.
+TEXT runtime·callbackasm(SB),7,$0
+`)
+	for i := 0; i < maxCallback; i++ {
+		buf.WriteString("\tCALL\truntime·callbackasm1(SB)\n")
+	}
+
+	err := ioutil.WriteFile("zcallback_windows.s", buf.Bytes(), 0666)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "wincallback: %s\n", err)
+		os.Exit(2)
+	}
+}