diff --git a/src/emu/emucore.c b/src/emu/emucore.c
index feea859693e..d4c970223fe 100644
--- a/src/emu/emucore.c
+++ b/src/emu/emucore.c
@@ -9,3 +9,19 @@
     Visit http://mamedev.org for licensing and usage restrictions.
 
 ****************************************************************************/
+
+#include "emu.h"
+
+void bitch_bad_cast(const std::type_info &src_type, const std::type_info &dst_type)
+{
+	fprintf(stderr, "Error: bad downcast<> or device<>.  Tried to convert a %s to a %s, which are incompatible.\n",
+			src_type.name(), dst_type.name());
+	abort();
+}
+
+void bitch_bad_device_cast(const device_t *dev, const std::type_info &dst_type)
+{
+	fprintf(stderr, "Error: bad downcast<> or device<>.  Tried to convert the device %s of type %s to a %s, which are incompatible.\n",
+			dev->tag(), dev->name(), dst_type.name());
+	abort();
+}
diff --git a/src/emu/emucore.h b/src/emu/emucore.h
index b3104c6167b..831b360a94d 100644
--- a/src/emu/emucore.h
+++ b/src/emu/emucore.h
@@ -332,19 +332,40 @@ private:
 //  CASTING TEMPLATES
 //**************************************************************************
 
+class device_t;
+
+void bitch_bad_cast(const std::type_info &src_type, const std::type_info &dst_type);
+void bitch_bad_device_cast(const device_t *dev, const std::type_info &dst_type);
+
 // template function for casting from a base class to a derived class that is checked
 // in debug builds and fast in release builds
 template<class _Dest, class _Source>
 inline _Dest downcast(_Source *src)
 {
-	assert(dynamic_cast<_Dest>(src) == src);
+#ifndef NDEBUG
+	if(dynamic_cast<_Dest>(src) != src) {
+		fprintf(stderr, "buh\n");
+		if(dynamic_cast<const device_t *>(src))
+			bitch_bad_device_cast(dynamic_cast<const device_t *>(src), typeid(_Dest));
+		else
+			bitch_bad_cast(typeid(src), typeid(_Dest));
+	}
+#endif
 	return static_cast<_Dest>(src);
 }
 
 template<class _Dest, class _Source>
 inline _Dest downcast(_Source &src)
 {
-	assert(&dynamic_cast<_Dest>(src) == &src);
+#ifndef NDEBUG
+	if(&dynamic_cast<_Dest>(src) != &src) {
+		fprintf(stderr, "gah\n");
+		if(dynamic_cast<const device_t *>(&src))
+			bitch_bad_device_cast(dynamic_cast<const device_t *>(&src), typeid(_Dest));
+		else
+			bitch_bad_cast(typeid(src), typeid(_Dest));
+	}
+#endif
 	return static_cast<_Dest>(src);
 }