diff --git a/OSBindings/Mac/Clock SignalTests/ZexallTests.swift b/OSBindings/Mac/Clock SignalTests/ZexallTests.swift
index 19580acc8..0246cd4cb 100644
--- a/OSBindings/Mac/Clock SignalTests/ZexallTests.swift	
+++ b/OSBindings/Mac/Clock SignalTests/ZexallTests.swift	
@@ -18,6 +18,9 @@ class ZexallTests: XCTestCase {
 				let machine = CSTestMachineZ80()
 				machine.setData(testData, atAddress: 0x0100)
 
+				machine.setValue(0x0100, for: .programCounter)
+				machine.setValue(0xffff, for: .stackPointer)
+
 				machine.runForNumber(ofCycles: 20)
 			}
 		}
diff --git a/Processors/Z80/Z80.hpp b/Processors/Z80/Z80.hpp
index 5b1e42a01..d7de7a154 100644
--- a/Processors/Z80/Z80.hpp
+++ b/Processors/Z80/Z80.hpp
@@ -146,7 +146,7 @@ template <class T> class Processor: public MicroOpScheduler<MicroOp> {
 						if(number_of_cycles_ < operation->machine_cycle.cycle_length()) {
 							return;
 						}
-						perform_machine_cycle(&operation->machine_cycle);
+						static_cast<T *>(this)->perform_machine_cycle(&operation->machine_cycle);
 					break;
 					case MicroOp::MoveToNextProgram:
 						move_to_next_program();