MdePkg/Library/BaseLib/X64/RdRand.nasm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2015 - 2022, Intel Corporation. All rights reserved.<BR>
   4 ; SPDX-License-Identifier: BSD-2-Clause-Patent
   5 ;
   6 ; Module Name:
   7 ;
   8 ;   RdRand.nasm
   9 ;
  10 ; Abstract:
  11 ;
  12 ;   Generates random number through CPU RdRand instruction under 64-bit platform.
  13 ;
  14 ; Notes:
  15 ;
  16 ;------------------------------------------------------------------------------
  17
  18     DEFAULT REL
  19     SECTION .text
  20
  21 ;------------------------------------------------------------------------------
  22 ;  Generates a 16 bit random number through RDRAND instruction.
  23 ;  Return TRUE if Rand generated successfully, or FALSE if not.
  24 ;
  25 ;  BOOLEAN EFIAPI InternalX86RdRand16 (UINT16 *Rand);
  26 ;------------------------------------------------------------------------------
  27 global ASM_PFX(InternalX86RdRand16)
  28 ASM_PFX(InternalX86RdRand16):
  29     rdrand eax                     ; generate a 16 bit RN into eax,
  30                                    ; CF=1 if RN generated ok, otherwise CF=0
  31     jc     rn16_ok                 ; jmp if CF=1
  32     xor    rax, rax                ; reg=0 if CF=0
  33     ret                            ; return with failure status
  34 rn16_ok:
  35     mov    [rcx], ax
  36     mov    rax,  1
  37     ret
  38
  39 ;------------------------------------------------------------------------------
  40 ;  Generates a 32 bit random number through RDRAND instruction.
  41 ;  Return TRUE if Rand generated successfully, or FALSE if not.
  42 ;
  43 ;  BOOLEAN EFIAPI InternalX86RdRand32 (UINT32 *Rand);
  44 ;------------------------------------------------------------------------------
  45 global ASM_PFX(InternalX86RdRand32)
  46 ASM_PFX(InternalX86RdRand32):
  47     rdrand eax                     ; generate a 32 bit RN into eax,
  48                                    ; CF=1 if RN generated ok, otherwise CF=0
  49     jc     rn32_ok                 ; jmp if CF=1
  50     xor    rax, rax                ; reg=0 if CF=0
  51     ret                            ; return with failure status
  52 rn32_ok:
  53     mov    [rcx], eax
  54     mov    rax,  1
  55     ret
  56
  57 ;------------------------------------------------------------------------------
  58 ;  Generates a 64 bit random number through one RDRAND instruction.
  59 ;  Return TRUE if Rand generated successfully, or FALSE if not.
  60 ;
  61 ;  BOOLEAN EFIAPI InternalX86RdRand64 (UINT64 *Random);
  62 ;------------------------------------------------------------------------------
  63 global ASM_PFX(InternalX86RdRand64)
  64 ASM_PFX(InternalX86RdRand64):
  65     rdrand rax                     ; generate a 64 bit RN into rax,
  66                                    ; CF=1 if RN generated ok, otherwise CF=0
  67     jc     rn64_ok                 ; jmp if CF=1
  68     xor    rax, rax                ; reg=0 if CF=0
  69     ret                            ; return with failure status
  70 rn64_ok:
  71     mov    [rcx], rax
  72     mov    rax, 1
  73     ret
  74