diff options
Diffstat (limited to 'Core/MdePkg/Library/BaseLib/Ia32/RdRand.asm')
-rw-r--r-- | Core/MdePkg/Library/BaseLib/Ia32/RdRand.asm | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/Core/MdePkg/Library/BaseLib/Ia32/RdRand.asm b/Core/MdePkg/Library/BaseLib/Ia32/RdRand.asm new file mode 100644 index 0000000000..cb4e811098 --- /dev/null +++ b/Core/MdePkg/Library/BaseLib/Ia32/RdRand.asm @@ -0,0 +1,94 @@ +;------------------------------------------------------------------------------
+;
+; Copyright (c) 2015 - 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.
+;
+; Module Name:
+;
+; RdRand.asm
+;
+; Abstract:
+;
+; Generates random number through CPU RdRand instruction under 32-bit platform.
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+.686P
+.model flat, C
+
+.code
+
+;------------------------------------------------------------------------------
+; Generates a 16 bit random number through RDRAND instruction.
+; Return TRUE if Rand generated successfully, or FALSE if not.
+;
+; BOOLEAN EFIAPI InternalX86RdRand16 (UINT16 *Rand);
+;------------------------------------------------------------------------------
+InternalX86RdRand16 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)"
+ jc rn16_ok ; jmp if CF=1
+ xor eax, eax ; reg=0 if CF=0
+ ret ; return with failure status
+rn16_ok:
+ mov edx, dword ptr [esp + 4]
+ mov [edx], ax
+ mov eax, 1
+ ret
+InternalX86RdRand16 ENDP
+
+;------------------------------------------------------------------------------
+; Generates a 32 bit random number through RDRAND instruction.
+; Return TRUE if Rand generated successfully, or FALSE if not.
+;
+; BOOLEAN EFIAPI InternalX86RdRand32 (UINT32 *Rand);
+;------------------------------------------------------------------------------
+InternalX86RdRand32 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)"
+ jc rn32_ok ; jmp if CF=1
+ xor eax, eax ; reg=0 if CF=0
+ ret ; return with failure status
+rn32_ok:
+ mov edx, dword ptr [esp + 4]
+ mov [edx], eax
+ mov eax, 1
+ ret
+InternalX86RdRand32 ENDP
+
+;------------------------------------------------------------------------------
+; Generates a 64 bit random number through RDRAND instruction.
+; Return TRUE if Rand generated successfully, or FALSE if not.
+;
+; BOOLEAN EFIAPI InternalX86RdRand64 (UINT64 *Rand);
+;------------------------------------------------------------------------------
+InternalX86RdRand64 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)"
+ jnc rn64_ret ; jmp if CF=0
+ mov edx, dword ptr [esp + 4]
+ mov [edx], eax
+
+ db 0fh, 0c7h, 0f0h ; generate another 32 bit RN
+ jnc rn64_ret ; jmp if CF=0
+ mov [edx + 4], eax
+
+ mov eax, 1
+ ret
+rn64_ret:
+ xor eax, eax
+ ret ; return with failure status
+InternalX86RdRand64 ENDP
+
+ END
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