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;------------------------------------------------------------------------------
;
; Copyright (c) 2015 - 2022, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
; Module Name:
;
; RdRand.nasm
;
; Abstract:
;
; Generates random number through CPU RdRand instruction under 32-bit platform.
;
; Notes:
;
;------------------------------------------------------------------------------
SECTION .text
;------------------------------------------------------------------------------
; Generates a 16 bit random number through RDRAND instruction.
; Return TRUE if Rand generated successfully, or FALSE if not.
;
; BOOLEAN EFIAPI InternalX86RdRand16 (UINT16 *Rand);
;------------------------------------------------------------------------------
global ASM_PFX(InternalX86RdRand16)
ASM_PFX(InternalX86RdRand16):
rdrand eax ; generate a 16 bit RN into ax
; CF=1 if RN generated ok, otherwise CF=0
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 [esp + 4]
mov [edx], ax
mov eax, 1
ret
;------------------------------------------------------------------------------
; Generates a 32 bit random number through RDRAND instruction.
; Return TRUE if Rand generated successfully, or FALSE if not.
;
; BOOLEAN EFIAPI InternalX86RdRand32 (UINT32 *Rand);
;------------------------------------------------------------------------------
global ASM_PFX(InternalX86RdRand32)
ASM_PFX(InternalX86RdRand32):
rdrand eax ; generate a 32 bit RN into eax
; CF=1 if RN generated ok, otherwise CF=0
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 [esp + 4]
mov [edx], eax
mov eax, 1
ret
;------------------------------------------------------------------------------
; Generates a 64 bit random number through RDRAND instruction.
; Return TRUE if Rand generated successfully, or FALSE if not.
;
; BOOLEAN EFIAPI InternalX86RdRand64 (UINT64 *Rand);
;------------------------------------------------------------------------------
global ASM_PFX(InternalX86RdRand64)
ASM_PFX(InternalX86RdRand64):
rdrand eax ; generate a 32 bit RN into eax
; CF=1 if RN generated ok, otherwise CF=0
jnc rn64_ret ; jmp if CF=0
mov edx, dword [esp + 4]
mov [edx], eax
rdrand eax ; 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
|
