diff --git a/desktop/prefix.h b/desktop/prefix.h
index 1b14398..bafa2aa 100644
--- a/desktop/prefix.h
+++ b/desktop/prefix.h
@@ -176,6 +176,14 @@ ES_EXTERN_C uintptr_t _APISyscall(uintptr_t argument0, uintptr_t argument1, uint
 #define ES_FUNCTION_OPTIMISE_O2 __attribute__((optimize("-O2")))
 #define ES_FUNCTION_OPTIMISE_O3 __attribute__((optimize("-O3")))
 
+#ifdef ES_BITS_64
+#define ES_PTR64_MS32(x) ((uint32_t) ((uintptr_t) (x) >> 32))
+#define ES_PTR64_LS32(x) ((uint32_t) ((uintptr_t) (x) & 0xFFFFFFFF))
+#else
+#define ES_PTR64_MS32(x) ((uint32_t) (0))
+#define ES_PTR64_LS32(x) ((uint32_t) (x))
+#endif
+
 // --------- Algorithms:
 
 #define ES_MACRO_SORT(_name, _type, _compar, _contextType) void _name(_type *base, size_t nmemb, _contextType context) { \
diff --git a/drivers/ahci.cpp b/drivers/ahci.cpp
index ebf9167..b6f910b 100644
--- a/drivers/ahci.cpp
+++ b/drivers/ahci.cpp
@@ -280,12 +280,8 @@ bool AHCIController::Access(uintptr_t portIndex, uint64_t offsetBytes, size_t co
 
 		KDMASegment segment = KDMABufferNextSegment(buffer);
 
-		prdt[0 + 4 * prdtEntryCount] = segment.physicalAddress;
-#ifdef ES_BITS_64
-		prdt[1 + 4 * prdtEntryCount] = segment.physicalAddress >> 32;
-#else
-		prdt[1 + 4 * prdtEntryCount] = 0;
-#endif
+		prdt[0 + 4 * prdtEntryCount] = ES_PTR64_LS32(segment.physicalAddress);
+		prdt[1 + 4 * prdtEntryCount] = ES_PTR64_MS32(segment.physicalAddress);
 		prdt[2 + 4 * prdtEntryCount] = 0;
 		prdt[3 + 4 * prdtEntryCount] = (segment.byteCount - 1) | (segment.isLast ? (1 << 31) /* IRQ when done */ : 0);
 
@@ -575,15 +571,10 @@ void AHCIController::Initialise() {
 
 		// Set the registers to the physical addresses.
 
-		WR_REGISTER_PCLB(i, physicalAddress); 
-		WR_REGISTER_PFB(i, (physicalAddress + 0x400));
-#ifdef ES_BITS_64
-		if (dma64Supported) WR_REGISTER_PCLBU(i, physicalAddress >> 32);
-		if (dma64Supported) WR_REGISTER_PFBU(i, (physicalAddress + 0x400) >> 32);
-#else
-		if (dma64Supported) WR_REGISTER_PCLBU(i, 0);
-		if (dma64Supported) WR_REGISTER_PFBU(i, 0);
-#endif
+		WR_REGISTER_PCLB(i, ES_PTR64_LS32(physicalAddress)); 
+		WR_REGISTER_PFB(i, ES_PTR64_LS32(physicalAddress + 0x400));
+		if (dma64Supported) WR_REGISTER_PCLBU(i, ES_PTR64_MS32(physicalAddress));
+		if (dma64Supported) WR_REGISTER_PFBU(i, ES_PTR64_MS32(physicalAddress + 0x400));
 
 		// Point each command list entry to the corresponding command table.
 
@@ -591,12 +582,8 @@ void AHCIController::Initialise() {
 
 		for (uintptr_t j = 0; j < commandSlotCount; j++) {
 			uintptr_t address = physicalAddress + COMMAND_LIST_SIZE + RECEIVED_FIS_SIZE + COMMAND_TABLE_SIZE * j;
-			commandList[j * 8 + 2] = address;
-#ifdef ES_BITS_64
-			commandList[j * 8 + 3] = address >> 32;
-#else
-			commandList[j * 8 + 3] = 0;
-#endif
+			commandList[j * 8 + 2] = ES_PTR64_LS32(address);
+			commandList[j * 8 + 3] = ES_PTR64_MS32(address);
 		}
 
 		// Reset the port.
@@ -737,12 +724,8 @@ void AHCIController::Initialise() {
 		// Setup the PRDT.
 
 		uint32_t *prdt = (uint32_t *) (ports[i].commandTables + 0x80);
-		prdt[0] = identifyDataPhysical;
-#ifdef ES_BITS_64
-		prdt[1] = identifyDataPhysical >> 32;
-#else
-		prdt[1] = 0;
-#endif
+		prdt[0] = ES_PTR64_LS32(identifyDataPhysical);
+		prdt[1] = ES_PTR64_MS32(identifyDataPhysical);
 		prdt[2] = 0;
 		prdt[3] = 0x200 - 1;
 
diff --git a/drivers/pci.cpp b/drivers/pci.cpp
index 6483258..9bb8d80 100644
--- a/drivers/pci.cpp
+++ b/drivers/pci.cpp
@@ -287,11 +287,7 @@ bool KPCIDevice::EnableMSI(KIRQHandler irqHandler, void *context, const char *cO
 		WriteConfig32(pointer + 4, msi.address & 0xFFFFFFFF);
 
 		if (control & (1 << 7)) {
-#ifdef ES_BITS_64
-			WriteConfig32(pointer + 8, msi.address >> 32);
-#else
-			WriteConfig32(pointer + 8, 0);
-#endif
+			WriteConfig32(pointer + 8, ES_PTR64_MS32(msi.address));
 			WriteConfig16(pointer + 12, (ReadConfig16(pointer + 12) & 0x3800) | msi.data);
 			if (control & (1 << 8)) WriteConfig32(pointer + 16, 0);
 		} else {