mirror of https://github.com/acidanthera/audk.git
68 lines
2.6 KiB
NASM
68 lines
2.6 KiB
NASM
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;------------------------------------------------------------------------------
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;
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; Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>
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; This program and the accompanying materials
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; are licensed and made available under the terms and conditions of the BSD License
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; which accompanies this distribution. The full text of the license may be found at
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; http://opensource.org/licenses/bsd-license.php.
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;
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; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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;
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; Module Name:
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;
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; AsmRdRand.Asm
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;
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; Abstract:
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;
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; Implementation for 16-, and 32- invocations of RDRAND instruction under 32bit platform.
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;
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; Notes:
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;
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; Visual Studio coding practices do not use inline asm since multiple compilers and
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; architectures are supported assembler not recognizing rdrand instruction so using DB's.
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;
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;------------------------------------------------------------------------------
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.586P
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.model flat, C
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.code
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;------------------------------------------------------------------------------
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; Generate a 16 bit random number
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; Return TRUE if Rand generated successfully, or FALSE if not
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;
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; BOOLEAN EFIAPI RdRand16Step (UINT16 *Rand); ECX
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;------------------------------------------------------------------------------
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RdRand16Step PROC
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; rdrand ax ; generate a 16 bit RN into ax, CF=1 if RN generated ok, otherwise CF=0
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db 0fh, 0c7h, 0f0h ; rdrand r16: "0f c7 /6 ModRM:r/m(w)"
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jb rn16_ok ; jmp if CF=1
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xor eax, eax ; reg=0 if CF=0
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ret ; return with failure status
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rn16_ok:
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mov [ecx], ax
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mov eax, 1
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ret
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RdRand16Step ENDP
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;------------------------------------------------------------------------------
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; Generate a 32 bit random number
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; Return TRUE if Rand generated successfully, or FALSE if not
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;
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; BOOLEAN EFIAPI RdRand32Step (UINT32 *Rand); ECX
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;------------------------------------------------------------------------------
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RdRand32Step PROC
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; rdrand eax ; generate a 32 bit RN into eax, CF=1 if RN generated ok, otherwise CF=0
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db 0fh, 0c7h, 0f0h ; rdrand r32: "0f c7 /6 ModRM:r/m(w)"
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jb rn32_ok ; jmp if CF=1
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xor eax, eax ; reg=0 if CF=0
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ret ; return with failure status
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rn32_ok:
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mov [ecx], eax
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mov eax, 1
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ret
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RdRand32Step ENDP
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END
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