mirror of https://github.com/acidanthera/audk.git
95 lines
3.5 KiB
NASM
95 lines
3.5 KiB
NASM
;------------------------------------------------------------------------------
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;
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; Copyright (c) 2015, 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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; RdRand.asm
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;
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; Abstract:
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;
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; Generates random number through CPU RdRand instruction under 32-bit platform.
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;
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; Notes:
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;
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;------------------------------------------------------------------------------
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.686P
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.model flat, C
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.code
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;------------------------------------------------------------------------------
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; Generates a 16 bit random number through RDRAND instruction.
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; Return TRUE if Rand generated successfully, or FALSE if not.
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;
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; BOOLEAN EFIAPI AsmRdRand16 (UINT16 *Rand);
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;------------------------------------------------------------------------------
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AsmRdRand16 PROC
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; rdrand ax ; generate a 16 bit RN into ax
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; 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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jc 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 edx, dword ptr [esp + 4]
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mov [edx], ax
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mov eax, 1
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ret
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AsmRdRand16 ENDP
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;------------------------------------------------------------------------------
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; Generates a 32 bit random number through RDRAND instruction.
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; Return TRUE if Rand generated successfully, or FALSE if not.
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;
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; BOOLEAN EFIAPI AsmRdRand32 (UINT32 *Rand);
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;------------------------------------------------------------------------------
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AsmRdRand32 PROC
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; rdrand eax ; generate a 32 bit RN into eax
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; 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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jc 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 edx, dword ptr [esp + 4]
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mov [edx], eax
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mov eax, 1
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ret
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AsmRdRand32 ENDP
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;------------------------------------------------------------------------------
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; Generates a 64 bit random number through RDRAND instruction.
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; Return TRUE if Rand generated successfully, or FALSE if not.
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;
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; BOOLEAN EFIAPI AsmRdRand64 (UINT64 *Rand);
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;------------------------------------------------------------------------------
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AsmRdRand64 PROC
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; rdrand eax ; generate a 32 bit RN into eax
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; 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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jnc rn64_ret ; jmp if CF=0
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mov edx, dword ptr [esp + 4]
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mov [edx], eax
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db 0fh, 0c7h, 0f0h ; generate another 32 bit RN
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jnc rn64_ret ; jmp if CF=0
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mov [edx + 4], eax
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mov eax, 1
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ret
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rn64_ret:
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xor eax, eax
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ret ; return with failure status
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AsmRdRand64 ENDP
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END
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