1 files changed, 76 insertions, 0 deletions
diff --git a/src/pkg/runtime/callback_windows.c b/src/pkg/runtime/callback_windows.c
new file mode 100644
index 000000000..88ee53bb5
--- /dev/null
+++ b/src/pkg/runtime/callback_windows.c
@@ -0,0 +1,76 @@
+// Copyright 2009 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.
+
+#include "runtime.h"
+#include "type.h"
+#include "typekind.h"
+#include "defs_GOOS_GOARCH.h"
+#include "os_GOOS.h"
+#include "zasm_GOOS_GOARCH.h"
+
+typedef	struct	Callbacks	Callbacks;
+struct	Callbacks {
+	Lock;
+	WinCallbackContext*	ctxt[cb_max];
+	int32			n;
+};
+
+static	Callbacks	cbs;
+
+WinCallbackContext** runtime·cbctxts; // to simplify access to cbs.ctxt in sys_windows_*.s
+
+// Call back from windows dll into go.
+byte *
+runtime·compilecallback(Eface fn, bool cleanstack)
+{
+	FuncType *ft;
+	Type *t;
+	int32 argsize, i, n;
+	WinCallbackContext *c;
+
+	if(fn.type == nil || fn.type->kind != KindFunc)
+		runtime·panicstring("compilecallback: not a function");
+	ft = (FuncType*)fn.type;
+	if(ft->out.len != 1)
+		runtime·panicstring("compilecallback: function must have one output parameter");
+	if(((Type**)ft->out.array)[0]->size != sizeof(uintptr))
+		runtime·panicstring("compilecallback: output parameter size is wrong");
+	argsize = 0;
+	for(i=0; i<ft->in.len; i++) {
+		t = ((Type**)ft->in.array)[i];
+		if(t->size > sizeof(uintptr))
+			runtime·panicstring("compilecallback: input parameter size is wrong");
+		argsize += sizeof(uintptr);
+	}
+
+	runtime·lock(&cbs);
+	if(runtime·cbctxts == nil)
+		runtime·cbctxts = &(cbs.ctxt[0]);
+	n = cbs.n;
+	for(i=0; i<n; i++) {
+		if(cbs.ctxt[i]->gobody == fn.data) {
+			runtime·unlock(&cbs);
+			// runtime·callbackasm is just a series of CALL instructions
+			// (each is 5 bytes long), and we want callback to arrive at
+			// correspondent call instruction instead of start of
+			// runtime·callbackasm.
+			return (byte*)runtime·callbackasm + i * 5;
+		}
+	}
+	if(n >= cb_max)
+		runtime·throw("too many callback functions");
+	c = runtime·mal(sizeof *c);
+	c->gobody = fn.data;
+	c->argsize = argsize;
+	if(cleanstack && argsize!=0)
+		c->restorestack = argsize;
+	else
+		c->restorestack = 0;
+	cbs.ctxt[n] = c;
+	cbs.n++;
+	runtime·unlock(&cbs);
+
+	// as before
+	return (byte*)runtime·callbackasm + n * 5;
+}