MdePkg/Library/BaseRngLib/AArch64/ArmRng.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # ArmRndr() for AArch64
   4 #
   5 # Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
   6 #
   7 # SPDX-License-Identifier: BSD-2-Clause-Patent
   8 #
   9 #------------------------------------------------------------------------------
  10
  11 #include "BaseRngLibInternals.h"
  12
  13 .text
  14 .p2align 2
  15 GCC_ASM_EXPORT(ArmRndr)
  16
  17 #/**
  18 #  Generates a random number using RNDR.
  19 #  Returns TRUE on success; FALSE on failure.
  20 #
  21 #  @param[out] Rand     Buffer pointer to store the 64-bit random value.
  22 #
  23 #  @retval TRUE         Random number generated successfully.
  24 #  @retval FALSE        Failed to generate the random number.
  25 #
  26 #**/
  27 #BOOLEAN
  28 #EFIAPI
  29 #ArmRndr (
  30 #  OUT UINT64 *Rand
  31 #  );
  32 #
  33 ASM_PFX(ArmRndr):
  34   mrs  x1, RNDR
  35   str  x1, [x0]
  36   cset x0, ne    // RNDR sets NZCV to 0b0100 on failure
  37   ret