MdePkg/BaseLib: Add one wrapper on RdRand access for parameter check.

Add one wrapper implementation over assembly RdRand access to check
possible NULL parameter, for better alignment with comment description.

Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Qin Long <qin.long@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

MdePkg/Library/BaseLib/X86RdRand.c

@@ -0,0 +1,79 @@
+/** @file
+  IA-32/x64 AsmRdRandxx()
+  Generates random number through CPU RdRand instruction.
+
+  Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php.
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include "BaseLibInternals.h"
+
+/**
+  Generates a 16-bit random number through RDRAND instruction.
+
+  if Rand is NULL, then ASSERT().
+
+  @param[out]  Rand     Buffer pointer to store the random result.
+
+  @retval TRUE          RDRAND call was successful.
+  @retval FALSE         Failed attempts to call RDRAND.
+
+ **/
+BOOLEAN
+EFIAPI
+AsmRdRand16 (
+  OUT     UINT16                    *Rand
+  )
+{
+  ASSERT (Rand != NULL);
+  return InternalX86RdRand16 (Rand);
+}
+
+/**
+  Generates a 32-bit random number through RDRAND instruction.
+
+  if Rand is NULL, then ASSERT().
+
+  @param[out]  Rand     Buffer pointer to store the random result.
+
+  @retval TRUE          RDRAND call was successful.
+  @retval FALSE         Failed attempts to call RDRAND.
+
+**/
+BOOLEAN
+EFIAPI
+AsmRdRand32 (
+  OUT     UINT32                    *Rand
+  )
+{
+  ASSERT (Rand != NULL);
+  return InternalX86RdRand32 (Rand);
+}
+
+/**
+  Generates a 64-bit random number through RDRAND instruction.
+
+  if Rand is NULL, then ASSERT().
+
+  @param[out]  Rand     Buffer pointer to store the random result.
+
+  @retval TRUE          RDRAND call was successful.
+  @retval FALSE         Failed attempts to call RDRAND.
+
+**/
+BOOLEAN
+EFIAPI
+AsmRdRand64  (
+  OUT     UINT64                    *Rand
+  )
+{
+  ASSERT (Rand != NULL);
+  return InternalX86RdRand64 (Rand);
+}