diff --git a/Machines/ZX8081/ZX8081.cpp b/Machines/ZX8081/ZX8081.cpp
index 8c6dc32d8..43994044a 100644
--- a/Machines/ZX8081/ZX8081.cpp
+++ b/Machines/ZX8081/ZX8081.cpp
@@ -29,7 +29,7 @@ Machine::Machine() :
 	clear_all_keys();
 }
 
-int Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
+Cycles Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
 	HalfCycles previous_counter = horizontal_counter_;
 	horizontal_counter_ += cycle.length;
 
@@ -65,7 +65,7 @@ int Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
 	}
 
 	if(!cycle.is_terminal()) {
-		return 0;
+		return Cycles(0);
 	}
 
 	uint16_t address = cycle.address ? *cycle.address : 0;
@@ -182,7 +182,7 @@ int Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
 
 	if(typer_) typer_->update(cycle.length.as_int());
 
-	return 0;
+	return Cycles(0);
 }
 
 void Machine::flush() {
diff --git a/Machines/ZX8081/ZX8081.hpp b/Machines/ZX8081/ZX8081.hpp
index 031ce8b7e..a27d3d380 100644
--- a/Machines/ZX8081/ZX8081.hpp
+++ b/Machines/ZX8081/ZX8081.hpp
@@ -47,7 +47,7 @@ class Machine:
 	public:
 		Machine();
 
-		int perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle);
+		Cycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle);
 		void flush();
 
 		void setup_output(float aspect_ratio);
diff --git a/Processors/Z80/Z80.hpp b/Processors/Z80/Z80.hpp
index 035b255cd..2fe5df078 100644
--- a/Processors/Z80/Z80.hpp
+++ b/Processors/Z80/Z80.hpp
@@ -888,7 +888,7 @@ template <class T> class Processor: public ClockReceiver<Processor<T>> {
 
 				while(bus_request_line_) {
 					static PartialMachineCycle bus_acknowledge_cycle = {PartialMachineCycle::BusAcknowledge, 1, nullptr, nullptr, false};
-					number_of_cycles_ -= Cycles(static_cast<T *>(this)->perform_machine_cycle(bus_acknowledge_cycle) + 1);
+					number_of_cycles_ -= static_cast<T *>(this)->perform_machine_cycle(bus_acknowledge_cycle) + Cycles(1);
 					if(!number_of_cycles_) {
 						static_cast<T *>(this)->flush();
 						return;
@@ -1703,8 +1703,8 @@ template <class T> class Processor: public ClockReceiver<Processor<T>> {
 		*/
 		void flush() {}
 
-		int perform_machine_cycle(const PartialMachineCycle &cycle) {
-			return 0;
+		Cycles perform_machine_cycle(const PartialMachineCycle &cycle) {
+			return Cycles(0);
 		}
 
 		/*!
diff --git a/Processors/Z80/Z80AllRAM.cpp b/Processors/Z80/Z80AllRAM.cpp
index bd6e4caa5..982231fc3 100644
--- a/Processors/Z80/Z80AllRAM.cpp
+++ b/Processors/Z80/Z80AllRAM.cpp
@@ -16,10 +16,10 @@ class ConcreteAllRAMProcessor: public AllRAMProcessor, public Processor<Concrete
 	public:
 		ConcreteAllRAMProcessor() : AllRAMProcessor() {}
 
-		inline int perform_machine_cycle(const PartialMachineCycle &cycle) {
+		inline Cycles perform_machine_cycle(const PartialMachineCycle &cycle) {
 			timestamp_ += cycle.length.as_int();
 			if(!cycle.is_terminal()) {
-				return 0;
+				return Cycles(0);
 			}
 
 			uint16_t address = cycle.address ? *cycle.address : 0x0000;
@@ -60,7 +60,7 @@ class ConcreteAllRAMProcessor: public AllRAMProcessor, public Processor<Concrete
 				delegate_->z80_all_ram_processor_did_perform_bus_operation(*this, cycle.operation, address, cycle.value ? *cycle.value : 0x00, timestamp_);
 			}
 
-			return 0;
+			return Cycles(0);
 		}
 
 		void run_for(const Cycles &cycles) {