diff --git a/common.h b/common.h
new file mode 100644
index 0000000..6b751ba
--- /dev/null
+++ b/common.h
@@ -0,0 +1,34 @@
+#pragma once
+
+#include <stdint.h>
+#include <string.h>
+
+#define __FILENAME__ \
+	(strrchr(__FILE__, '/') ? strrchr(__FILE__, '/') + 1 \
+		: strrchr(__FILE__, '\\') ? strrchr(__FILE__, '\\') + 1 : __FILE__)
+
+
+#define ASSERT(message, body) \
+	{ \
+		if (!body) \
+			THROW("Assert failed: " message " [" #body "]"); \
+	}
+
+#define MAX_CATCH_LEN 32
+
+typedef void (* handle_t)(intptr_t);
+
+typedef struct
+{
+	handle_t fn;
+	intptr_t arg;
+} catch_t;
+
+extern catch_t g_catch[MAX_CATCH_LEN];
+extern unsigned g_catch_len;
+
+void throw_(const char *msg, const char *file, unsigned int line);
+void catch_(handle_t hdl, intptr_t arg);
+
+#define THROW(msg) throw_(msg, __FILENAME__, __LINE__)
+#define CATCH(fn, arg) catch_((handle_t) fn, (intptr_t) arg)