1 files changed, 67 insertions, 0 deletions
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/IA32/AsmRdRand.asm b/SecurityPkg/RandomNumberGenerator/RngDxe/IA32/AsmRdRand.asm
new file mode 100644
index 0000000000..37b38307e2
--- /dev/null
+++ b/SecurityPkg/RandomNumberGenerator/RngDxe/IA32/AsmRdRand.asm
@@ -0,0 +1,67 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2013, 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.
+;
+; Module Name:
+;
+;   AsmRdRand.Asm
+;
+; Abstract:
+;
+;   Implementation for 16-, and 32- invocations of RDRAND instruction under 32bit platform.
+;
+; Notes:
+;
+;   Visual Studio coding practices do not use inline asm since multiple compilers and 
+;   architectures are supported assembler not recognizing rdrand instruction so using DB's.
+;
+;------------------------------------------------------------------------------
+
+    .586P
+    .model flat, C
+    .code
+ 
+;------------------------------------------------------------------------------
+;  Generate a 16 bit random number
+;  Return TRUE if Rand generated successfully, or FALSE if not
+;
+;  BOOLEAN EFIAPI RdRand16Step (UINT16 *Rand);   ECX
+;------------------------------------------------------------------------------
+RdRand16Step  PROC
+    ; rdrand   ax                  ; generate a 16 bit RN into ax, CF=1 if RN generated ok, otherwise CF=0
+    db     0fh, 0c7h, 0f0h         ; rdrand r16:  "0f c7 /6  ModRM:r/m(w)"
+    jb     rn16_ok                 ; jmp if CF=1
+    xor    eax, eax                ; reg=0 if CF=0
+    ret                            ; return with failure status
+rn16_ok:
+    mov    [ecx], ax
+    mov    eax, 1
+    ret
+RdRand16Step ENDP
+
+;------------------------------------------------------------------------------
+;  Generate a 32 bit random number
+;    Return TRUE if Rand generated successfully, or FALSE if not
+;
+;  BOOLEAN EFIAPI RdRand32Step (UINT32 *Rand);   ECX
+;------------------------------------------------------------------------------
+RdRand32Step  PROC
+    ; rdrand   eax                 ; generate a 32 bit RN into eax, CF=1 if RN generated ok, otherwise CF=0
+    db     0fh, 0c7h, 0f0h         ; rdrand r32:  "0f c7 /6  ModRM:r/m(w)"
+    jb     rn32_ok                 ; jmp if CF=1
+    xor    eax, eax                ; reg=0 if CF=0
+    ret                            ; return with failure status
+rn32_ok:
+    mov    [ecx], eax
+    mov    eax,  1
+    ret
+RdRand32Step  ENDP
+
+    END