diff --git a/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.S b/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.S
deleted file mode 100644
index d30b63fe5c..0000000000
--- a/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.S
+++ /dev/null
@@ -1,30 +0,0 @@
-#------------------------------------------------------------------------------
-#
-# ArmReadIdIsar0() for AArch64
-#
-# Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
-#
-# SPDX-License-Identifier: BSD-2-Clause-Patent
-#
-#------------------------------------------------------------------------------
-
-.text
-.p2align 2
-GCC_ASM_EXPORT(ArmReadIdIsar0)
-
-#/**
-#  Reads the ID_AA64ISAR0 Register.
-#
-#  @return The contents of the ID_AA64ISAR0 register.
-#
-#**/
-#UINT64
-#EFIAPI
-#ArmReadIdIsar0 (
-#  VOID
-#  );
-#
-ASM_PFX(ArmReadIdIsar0):
-  AARCH64_BTI(c)
-  mrs  x0, id_aa64isar0_el1 // Read ID_AA64ISAR0 Register
-  ret
diff --git a/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.asm b/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.asm
deleted file mode 100644
index 1d9f9a808c..0000000000
--- a/MdePkg/Library/BaseRngLib/AArch64/ArmReadIdIsar0.asm
+++ /dev/null
@@ -1,30 +0,0 @@
-;------------------------------------------------------------------------------
-;
-; ArmReadIdIsar0() for AArch64
-;
-; Copyright (c) 2021, NUVIA Inc. All rights reserved.<BR>
-;
-; SPDX-License-Identifier: BSD-2-Clause-Patent
-;
-;------------------------------------------------------------------------------
-
-  EXPORT ArmReadIdIsar0
-  AREA BaseLib_LowLevel, CODE, READONLY
-
-;/**
-;  Reads the ID_AA64ISAR0 Register.
-;
-; @return The contents of the ID_AA64ISAR0 register.
-;
-;**/
-;UINT64
-;EFIAPI
-;ArmReadIdIsar0 (
-;  VOID
-;  );
-;
-ArmReadIdIsar0
-  mrs  x0, id_aa64isar0_el1 // Read ID_AA64ISAR0 Register
-  ret
-
-  END
diff --git a/MdePkg/Library/BaseRngLib/AArch64/ArmRng.h b/MdePkg/Library/BaseRngLib/AArch64/ArmRng.h
index 2d6ef48ab9..b4b3c97071 100644
--- a/MdePkg/Library/BaseRngLib/AArch64/ArmRng.h
+++ b/MdePkg/Library/BaseRngLib/AArch64/ArmRng.h
@@ -27,16 +27,4 @@ ArmRndr (
   OUT UINT64  *Rand
   );
 
-/**
-  Reads the ID_AA64ISAR0 Register.
-
-  @return The contents of the ID_AA64ISAR0 register.
-
-**/
-UINT64
-EFIAPI
-ArmReadIdIsar0 (
-  VOID
-  );
-
 #endif /* ARM_RNG_H_ */
diff --git a/MdePkg/Library/BaseRngLib/AArch64/Rndr.c b/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
index 3a556a2e3f..2c53443840 100644
--- a/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
+++ b/MdePkg/Library/BaseRngLib/AArch64/Rndr.c
@@ -21,11 +21,6 @@
 
 STATIC BOOLEAN  mRndrSupported;
 
-//
-// Bit mask used to determine if RNDR instruction is supported.
-//
-#define RNDR_MASK  ((UINT64)MAX_UINT16 << 60U)
-
 /**
   The constructor function checks whether or not RNDR instruction is supported
   by the host hardware.
@@ -49,9 +44,8 @@ BaseRngLibConstructor (
   // Determine RNDR support by examining bits 63:60 of the ISAR0 register returned by
   // MSR. A non-zero value indicates that the processor supports the RNDR instruction.
   //
-  Isar0 = ArmReadIdIsar0 ();
-
-  mRndrSupported = ((Isar0 & RNDR_MASK) != 0);
+  Isar0          = ArmReadIdAA64Isar0Reg ();
+  mRndrSupported = !!((Isar0 >> ARM_ID_AA64ISAR0_EL1_RNDR_SHIFT) & ARM_ID_AA64ISAR0_EL1_RNDR_MASK);
 
   return EFI_SUCCESS;
 }
diff --git a/MdePkg/Library/BaseRngLib/BaseRngLib.inf b/MdePkg/Library/BaseRngLib/BaseRngLib.inf
index a1614a900f..53833a76b2 100644
--- a/MdePkg/Library/BaseRngLib/BaseRngLib.inf
+++ b/MdePkg/Library/BaseRngLib/BaseRngLib.inf
@@ -38,10 +38,8 @@
   AArch64/Rndr.c
   AArch64/ArmRng.h
 
-  AArch64/ArmReadIdIsar0.S   | GCC
   AArch64/ArmRng.S           | GCC
 
-  AArch64/ArmReadIdIsar0.asm | MSFT
   AArch64/ArmRng.asm         | MSFT
 
 [Guids.AARCH64]