1 files changed, 56 insertions, 0 deletions
diff --git a/engines/mortevielle/sound.cpp b/engines/mortevielle/sound.cpp
new file mode 100644
index 0000000000..f2b70cf8ee
--- /dev/null
+++ b/engines/mortevielle/sound.cpp
@@ -0,0 +1,56 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+/*
+ * This code is based on original Mortville Manor DOS source code
+ * Copyright (c) 1988-1989 Lankhor
+ */
+
+#include "common/scummsys.h"
+#include "mortevielle/sound.h"
+
+namespace Mortevielle {
+
+const int tab[16] = { -96, -72, -48, -32, -20, -12, -8, -4, 0, 4, 8, 12, 20, 32, 48, 72 };
+
+/**
+ * Decode music data
+ */
+void demus(const byte *PSrc, byte *PDest, int NbreSeg) {
+	int seed = 128;
+	int v;
+
+	for (int idx1 = 0; idx1 < (NbreSeg * 2); ++idx1) {
+		for (int idx2 = 0; idx2 < 64; ++idx2) {
+			byte srcByte = *PSrc++;
+			v = tab[srcByte >> 4];
+			seed += v;
+			*PDest++ = seed & 0xff;
+
+			v = tab[srcByte & 0xf];
+			seed += v;
+			*PDest++ = seed & 0xff;
+		}
+	}
+}
+
+} // End of namespace Mortevielle