diff --git a/IntelUndiPkg/GigUndiDxe/Dma.c b/IntelUndiPkg/GigUndiDxe/Dma.c
index bf94c1e2fd54..eee2aa8a1ce3 100644
--- a/IntelUndiPkg/GigUndiDxe/Dma.c
+++ b/IntelUndiPkg/GigUndiDxe/Dma.c
@@ -127,7 +127,7 @@ FREE_BUF_ON_ERROR:
   PciIo->FreeBuffer (
            PciIo,
            BytesToPages (DmaMapping->Size),
-           (VOID *) DmaMapping->UnmappedAddress
+           (VOID *)(UINTN)DmaMapping->UnmappedAddress
            );
   DmaMapping->Size = 0;
   DmaMapping->UnmappedAddress = 0;
@@ -173,7 +173,7 @@ UndiDmaFreeCommonBuffer (
   PciIo->FreeBuffer (
            PciIo,
            BytesToPages (DmaMapping->Size),
-           (VOID *) DmaMapping->UnmappedAddress
+           (VOID *)(UINTN)DmaMapping->UnmappedAddress
            );
 
   DmaMapping->UnmappedAddress = 0;
@@ -209,7 +209,7 @@ UndiDmaMapCommonBuffer (
   return PciIo->Map (
                   PciIo,
                   EfiPciIoOperationBusMasterCommonBuffer,
-                  (VOID *) DmaMapping->UnmappedAddress,
+                  (VOID *)(UINTN)DmaMapping->UnmappedAddress,
                   &DmaMapping->Size,
                   &DmaMapping->PhysicalAddress,
                   &DmaMapping->Mapping
@@ -243,7 +243,7 @@ UndiDmaMapMemoryRead (
   return PciIo->Map (
                   PciIo,
                   EfiPciIoOperationBusMasterRead,
-                  (VOID *) DmaMapping->UnmappedAddress,
+                  (VOID *)(UINTN)DmaMapping->UnmappedAddress,
                   &DmaMapping->Size,
                   &DmaMapping->PhysicalAddress,
                   &DmaMapping->Mapping
diff --git a/IntelUndiPkg/GigUndiDxe/DriverDiagnostics.c b/IntelUndiPkg/GigUndiDxe/DriverDiagnostics.c
index 559f2133281e..aceb015e480f 100644
--- a/IntelUndiPkg/GigUndiDxe/DriverDiagnostics.c
+++ b/IntelUndiPkg/GigUndiDxe/DriverDiagnostics.c
@@ -1132,7 +1132,7 @@ GigUndiRunPhyLoopback (
   while (j < PHY_LOOPBACK_ITERATIONS) {
     Status = E1000Transmit (
                GigAdapterInfo,
-               (UINT64) &PxeCpbTransmit,
+               (UINT64)(UINTN)&PxeCpbTransmit,
                PXE_OPFLAGS_TRANSMIT_WHOLE
              );
     _DisplayBuffersAndDescriptors (GigAdapterInfo);
@@ -1161,8 +1161,8 @@ GigUndiRunPhyLoopback (
     for (i = 0; i <= 100000; i++) {
       Status = E1000Receive (
                  GigAdapterInfo,
-                 (UINT64) &CpbReceive,
-                 (UINT64) &DbReceive
+                 (UINT64)(UINTN)&CpbReceive,
+                 (UINT64)(UINTN)&DbReceive
                );
       gBS->Stall (10);
 
diff --git a/IntelUndiPkg/GigUndiDxe/Init.c b/IntelUndiPkg/GigUndiDxe/Init.c
index 74b933674589..f99734d72823 100644
--- a/IntelUndiPkg/GigUndiDxe/Init.c
+++ b/IntelUndiPkg/GigUndiDxe/Init.c
@@ -301,7 +301,7 @@ GigUndiPxeStructInit (
                            PXE_ROMID_IMP_TX_COMPLETE_INT_SUPPORTED |
                            PXE_ROMID_IMP_PACKET_RX_INT_SUPPORTED;
 
-  PxePtr->EntryPoint    = (UINT64) E1000UndiApiEntry;
+  PxePtr->EntryPoint    = (UINT64)(UINTN)E1000UndiApiEntry;
   PxePtr->reserved2[0]  = 0;
   PxePtr->reserved2[1]  = 0;
   PxePtr->reserved2[2]  = 0;
@@ -842,7 +842,7 @@ InitNiiProtocol (
     return EFI_INVALID_PARAMETER;
   }
 
-  NiiProtocol31->Id             = (UINT64) (mE1000Pxe31);
+  NiiProtocol31->Id             = (UINT64)(UINTN)mE1000Pxe31;
   NiiProtocol31->IfNum          = mE1000Pxe31->IFcnt;
 
   NiiProtocol31->Revision       = EFI_NETWORK_INTERFACE_IDENTIFIER_PROTOCOL_REVISION_31;
@@ -938,7 +938,7 @@ InitUndiCallbackFunctions (
   NicInfo->MapMem      = (VOID *) 0;
   NicInfo->UnMapMem    = (VOID *) 0;
   NicInfo->SyncMem     = (VOID *) 0;
-  NicInfo->UniqueId    = (UINT64) NicInfo;
+  NicInfo->UniqueId    = (UINT64)(UINTN)NicInfo;
   NicInfo->VersionFlag = 0x31;
 }
 
diff --git a/IntelUndiPkg/GigUndiDxe/e1000.c b/IntelUndiPkg/GigUndiDxe/e1000.c
index 6f8529abf046..1f08a5d67b2d 100644
--- a/IntelUndiPkg/GigUndiDxe/e1000.c
+++ b/IntelUndiPkg/GigUndiDxe/e1000.c
@@ -128,7 +128,7 @@ E1000MapMem (
                     VirtualAddress,
                     Size,
                     TO_DEVICE,
-                    (UINT64) MappedAddress
+                    (UINT64)(UINTN)MappedAddress
                   );
 
     if (*MappedAddress == 0) {
@@ -1079,7 +1079,7 @@ E1000TxRxConfigure (
 
   ZeroMem (GigAdapter->TxBufferMappings, sizeof (GigAdapter->TxBufferMappings));
 
-  RxBuffer = (LOCAL_RX_BUFFER *) GigAdapter->RxBufferMapping.PhysicalAddress;
+  RxBuffer = (LOCAL_RX_BUFFER *)(UINTN)GigAdapter->RxBufferMapping.PhysicalAddress;
 
   DEBUGPRINT (
     E1000, ("Tx Ring %x Added %x\n",
@@ -1578,17 +1578,17 @@ E1000Inititialize (
   TempBar = NULL;
 
   ZeroMem (
-    (VOID *) GigAdapter->RxRing.UnmappedAddress,
+    (VOID *)(UINTN)GigAdapter->RxRing.UnmappedAddress,
     RX_RING_SIZE
     );
 
   ZeroMem (
-    (VOID *) GigAdapter->TxRing.UnmappedAddress,
+    (VOID *)(UINTN)GigAdapter->TxRing.UnmappedAddress,
     TX_RING_SIZE
     );
 
   ZeroMem (
-    (VOID *) GigAdapter->RxBufferMapping.UnmappedAddress,
+    (VOID *)(UINTN)GigAdapter->RxBufferMapping.UnmappedAddress,
     RX_BUFFERS_SIZE
     );
 
diff --git a/IntelUndiPkg/GigUndiDxe/e1000.h b/IntelUndiPkg/GigUndiDxe/e1000.h
index 71fe4591af05..a44fe3fa2ec8 100644
--- a/IntelUndiPkg/GigUndiDxe/e1000.h
+++ b/IntelUndiPkg/GigUndiDxe/e1000.h
@@ -233,7 +233,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    @return   Descriptor retrieved
 **/
 #define E1000_RX_DESC(R, i)          \
-          (&(((struct e1000_rx_desc *) ((R)->UnmappedAddress))[i]))
+          (&(((struct e1000_rx_desc *)(UINTN)((R)->UnmappedAddress))[i]))
 
 /** Retrieves TX descriptor from TX ring structure
 
@@ -243,7 +243,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    @return   Descriptor retrieved
 **/
 #define E1000_TX_DESC(R, i)          \
-          (&(((struct e1000_tx_desc *) ((R)->UnmappedAddress))[i]))
+          (&(((struct e1000_tx_desc *)(UINTN)((R)->UnmappedAddress))[i]))
 
 /** Retrieves UNDI_PRIVATE_DATA structure using NII Protocol 3.1 instance
 
