Add endian conversion routines

xtoskrnl/rtl/byteswap.c

@@ -0,0 +1,72 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/rtl/byteswap.c
+ * DESCRIPTION:     Endian conversion routines
+ * DEVELOPERS:      Rafal Kupiec <belliash@codingworkshop.eu.org>
+ */
+
+#include <xtos.h>
+
+
+/**
+ * This routine converts endianness on 32bit value.
+ *
+ * @param Source
+ *        Supplies a value to swap bytes.
+ *
+ * @return Swapped 32bit value.
+ *
+ * @since NT 4.0
+ */
+XTFASTCALL
+ULONG
+RtlUlongByteSwap(IN ULONG Source)
+{
+    return (ULONG)(((Source >> 24) & 0x000000FF) |
+                   ((Source >> 8)  & 0x0000FF00) |
+                   ((Source << 8)  & 0x00FF0000) |
+                   ((Source << 24) & 0xFF000000));
+}
+
+/**
+ * This routine converts endianness on 64bit value.
+ *
+ * @param Source
+ *        Supplies a value to swap bytes.
+ *
+ * @return Swapped 64bit value.
+ *
+ * @since NT 4.0
+ */
+XTFASTCALL
+ULONGLONG
+RtlUlonglongByteSwap(IN ULONGLONG Source)
+{
+    return (ULONGLONG)(((Source >> 56) & 0x00000000000000FF) |
+                       ((Source >> 40) & 0x000000000000FF00) |
+                       ((Source >> 24) & 0x0000000000FF0000) |
+                       ((Source >> 8)  & 0x00000000FF000000) |
+                       ((Source << 8)  & 0x000000FF00000000) |
+                       ((Source << 24) & 0x0000FF0000000000) |
+                       ((Source << 40) & 0x00FF000000000000) |
+                       ((Source << 56) & 0xFF00000000000000));
+}
+
+/**
+ * This routine converts endianness on 16bit value.
+ *
+ * @param Source
+ *        Supplies a value to swap bytes.
+ *
+ * @return Swapped 16bit value.
+ *
+ * @since NT 4.0
+ */
+XTFASTCALL
+USHORT
+RtlUshortByteSwap(IN USHORT Source)
+{
+    return (USHORT)(((Source >> 8) & 0x00FF) |
+                    ((Source << 8) & 0xFF00));
+}