Merge commit '0132cbcf33a3ae568c361751a42ff53c41e08f68' as 'external/pure_doom/PureDOOM'

external/pure_doom/PureDOOM/src/DOOM/m_swap.c

@@ -0,0 +1,53 @@
+// Emacs style mode select   -*- C++ -*- 
+//-----------------------------------------------------------------------------
+//
+// $Id:$
+//
+// Copyright (C) 1993-1996 by id Software, Inc.
+//
+// This source is available for distribution and/or modification
+// only under the terms of the DOOM Source Code License as
+// published by id Software. All rights reserved.
+//
+// The source is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
+// for more details.
+//
+// $Log:$
+//
+// DESCRIPTION:
+//        Endianess handling, swapping 16bit and 32bit.
+//
+//-----------------------------------------------------------------------------
+
+
+#include "doom_config.h"
+
+#include "m_swap.h"
+
+
+// Not needed with big endian.
+#ifdef __BIG_ENDIAN__
+
+
+// Swap 16bit, that is, MSB and LSB byte.
+unsigned short SwapSHORT(unsigned short x)
+{
+    // No masking with 0xFF should be necessary. 
+    return (x >> 8) | (x << 8);
+}
+
+
+// Swapping 32bit.
+unsigned long SwapLONG(unsigned long x)
+{
+    return
+        (x >> 24)
+        | ((x >> 8) & 0xff00)
+        | ((x << 8) & 0xff0000)
+        | (x << 24);
+}
+
+
+#endif