diff --git a/src/debug.cpp b/src/debug.cpp
new file mode 100644
--- /dev/null
+++ b/src/debug.cpp
@@ -0,0 +1,153 @@
+/* $Id$ */
+
+#include "stdafx.h"
+#include <stdio.h>
+#include <stdarg.h>
+#include "openttd.h"
+#include "console.h"
+#include "debug.h"
+#include "functions.h"
+#include "string.h"
+
+int _debug_ai_level;
+int _debug_driver_level;
+int _debug_grf_level;
+int _debug_map_level;
+int _debug_misc_level;
+int _debug_ms_level;
+int _debug_net_level;
+int _debug_sprite_level;
+int _debug_oldloader_level;
+int _debug_ntp_level;
+int _debug_npf_level;
+int _debug_yapf_level;
+int _debug_freetype_level;
+int _debug_sl_level;
+
+
+typedef struct DebugLevel {
+	const char *name;
+	int *level;
+} DebugLevel;
+
+#define DEBUG_LEVEL(x) { #x, &_debug_##x##_level }
+	static const DebugLevel debug_level[] = {
+	DEBUG_LEVEL(ai),
+	DEBUG_LEVEL(driver),
+	DEBUG_LEVEL(grf),
+	DEBUG_LEVEL(map),
+	DEBUG_LEVEL(misc),
+	DEBUG_LEVEL(ms),
+	DEBUG_LEVEL(net),
+	DEBUG_LEVEL(sprite),
+	DEBUG_LEVEL(oldloader),
+	DEBUG_LEVEL(ntp),
+	DEBUG_LEVEL(npf),
+	DEBUG_LEVEL(yapf),
+	DEBUG_LEVEL(freetype),
+	DEBUG_LEVEL(sl),
+	};
+#undef DEBUG_LEVEL
+
+#if !defined(NO_DEBUG_MESSAGES)
+
+/** Functionized DEBUG macro for compilers that don't support
+ * variadic macros (__VA_ARGS__) such as...yes MSVC2003 and lower */
+#if defined(NO_VARARG_MACRO)
+void CDECL DEBUG(int name, int level, ...)
+{
+	va_list va;
+	const char *dbg;
+	const DebugLevel *dl = &debug_level[name];
+
+	if (level != 0 && *dl->level < level) return;
+	dbg = dl->name;
+	va_start(va, level);
+#else
+void CDECL debug(const char *dbg, ...)
+{
+	va_list va;
+	va_start(va, dbg);
+#endif /* NO_VARARG_MACRO */
+	{
+		const char *s;
+		char buf[1024];
+
+		s = va_arg(va, const char*);
+		vsnprintf(buf, lengthof(buf), s, va);
+		va_end(va);
+		fprintf(stderr, "dbg: [%s] %s\n", dbg, buf);
+		IConsoleDebug(dbg, buf);
+	}
+}
+#endif /* NO_DEBUG_MESSAGES */
+
+void SetDebugString(const char *s)
+{
+	int v;
+	char *end;
+	const char *t;
+
+	// global debugging level?
+	if (*s >= '0' && *s <= '9') {
+		const DebugLevel *i;
+
+		v = strtoul(s, &end, 0);
+		s = end;
+
+		for (i = debug_level; i != endof(debug_level); ++i) *i->level = v;
+	}
+
+	// individual levels
+	for (;;) {
+		const DebugLevel *i;
+		int *p;
+
+		// skip delimiters
+		while (*s == ' ' || *s == ',' || *s == '\t') s++;
+		if (*s == '\0') break;
+
+		t = s;
+		while (*s >= 'a' && *s <= 'z') s++;
+
+		// check debugging levels
+		p = NULL;
+		for (i = debug_level; i != endof(debug_level); ++i)
+			if (s == t + strlen(i->name) && strncmp(t, i->name, s - t) == 0) {
+				p = i->level;
+				break;
+			}
+
+		if (*s == '=') s++;
+		v = strtoul(s, &end, 0);
+		s = end;
+		if (p != NULL) {
+			*p = v;
+		} else {
+			ShowInfoF("Unknown debug level '%.*s'", s - t, t);
+			return;
+		}
+	}
+}
+
+/** Print out the current debug-level
+ * Just return a string with the values of all the debug categorites
+ * @return string with debug-levels
+ */
+const char *GetDebugString(void)
+{
+	const DebugLevel *i;
+	static char dbgstr[100];
+	char dbgval[20];
+
+	memset(dbgstr, 0, sizeof(dbgstr));
+	i = debug_level;
+	snprintf(dbgstr, sizeof(dbgstr), "%s=%d", i->name, *i->level);
+
+	for (i++; i != endof(debug_level); i++) {
+		snprintf(dbgval, sizeof(dbgval), ", %s=%d", i->name, *i->level);
+		ttd_strlcat(dbgstr, dbgval, sizeof(dbgstr));
+	}
+
+	return dbgstr;
+}