diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index 2925ec984..2b7baf4c3 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		4B01A6881F22F0DB001FD6E3 /* Z80MemptrTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B01A6871F22F0DB001FD6E3 /* Z80MemptrTests.swift */; };
 		4B049CDD1DA3C82F00322067 /* BCDTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B049CDC1DA3C82F00322067 /* BCDTest.swift */; };
 		4B08A2751EE35D56008B7065 /* Z80InterruptTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B08A2741EE35D56008B7065 /* Z80InterruptTests.swift */; };
 		4B08A2781EE39306008B7065 /* TestMachine.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B08A2771EE39306008B7065 /* TestMachine.mm */; };
@@ -456,6 +457,7 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		4B01A6871F22F0DB001FD6E3 /* Z80MemptrTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Z80MemptrTests.swift; sourceTree = "<group>"; };
 		4B046DC31CFE651500E9E45E /* CRTMachine.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CRTMachine.hpp; sourceTree = "<group>"; };
 		4B049CDC1DA3C82F00322067 /* BCDTest.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = BCDTest.swift; sourceTree = "<group>"; };
 		4B08A2741EE35D56008B7065 /* Z80InterruptTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Z80InterruptTests.swift; sourceTree = "<group>"; };
@@ -1880,6 +1882,7 @@
 				4B14145F1B58885000E04248 /* WolfgangLorenzTests.swift */,
 				4B08A2741EE35D56008B7065 /* Z80InterruptTests.swift */,
 				4BDDBA981EF3451200347E61 /* Z80MachineCycleTests.swift */,
+				4B01A6871F22F0DB001FD6E3 /* Z80MemptrTests.swift */,
 				4BFCA12A1ECBE7C400AC40C1 /* ZexallTests.swift */,
 				4B3BA0C41D318B44005DD7A7 /* Bridges */,
 				4B1414631B588A1100E04248 /* Test Binaries */,
@@ -2709,6 +2712,7 @@
 				4B92EACA1B7C112B00246143 /* 6502TimingTests.swift in Sources */,
 				4BFCA1201ECBDC1500AC40C1 /* Z80AllRAM.cpp in Sources */,
 				4BB73EB71B587A5100552FC2 /* AllSuiteATests.swift in Sources */,
+				4B01A6881F22F0DB001FD6E3 /* Z80MemptrTests.swift in Sources */,
 				4B121F9B1E06293F00BFDA12 /* PCMSegmentEventSourceTests.mm in Sources */,
 				4BEF6AAC1D35D1C400E73575 /* DPLLTests.swift in Sources */,
 				4B3BA0CF1D318B44005DD7A7 /* MOS6522Bridge.mm in Sources */,
diff --git a/OSBindings/Mac/Clock SignalTests/Bridges/TestMachineZ80.h b/OSBindings/Mac/Clock SignalTests/Bridges/TestMachineZ80.h
index 592b1bca3..1abdf63d8 100644
--- a/OSBindings/Mac/Clock SignalTests/Bridges/TestMachineZ80.h	
+++ b/OSBindings/Mac/Clock SignalTests/Bridges/TestMachineZ80.h	
@@ -42,7 +42,8 @@ typedef NS_ENUM(NSInteger, CSTestMachineZ80Register) {
 	CSTestMachineZ80RegisterHLDash,
 	CSTestMachineZ80RegisterIX,		CSTestMachineZ80RegisterIY,
 	CSTestMachineZ80RegisterI,		CSTestMachineZ80RegisterR,
-	CSTestMachineZ80RegisterIFF1,	CSTestMachineZ80RegisterIFF2,	CSTestMachineZ80RegisterIM
+	CSTestMachineZ80RegisterIFF1,	CSTestMachineZ80RegisterIFF2,	CSTestMachineZ80RegisterIM,
+	CSTestMachineZ80RegisterMemPtr
 };
 
 @interface CSTestMachineZ80 : CSTestMachine
diff --git a/OSBindings/Mac/Clock SignalTests/Bridges/TestMachineZ80.mm b/OSBindings/Mac/Clock SignalTests/Bridges/TestMachineZ80.mm
index 37f64f599..83cc41033 100644
--- a/OSBindings/Mac/Clock SignalTests/Bridges/TestMachineZ80.mm	
+++ b/OSBindings/Mac/Clock SignalTests/Bridges/TestMachineZ80.mm	
@@ -65,6 +65,8 @@ static CPU::Z80::Register registerForRegister(CSTestMachineZ80Register reg) {
 
 		case CSTestMachineZ80RegisterProgramCounter:	return CPU::Z80::Register::ProgramCounter;
 		case CSTestMachineZ80RegisterStackPointer:		return CPU::Z80::Register::StackPointer;
+
+		case CSTestMachineZ80RegisterMemPtr:			return CPU::Z80::Register::MemPtr;
 	}
 }
 
diff --git a/OSBindings/Mac/Clock SignalTests/Z80MemptrTests.swift b/OSBindings/Mac/Clock SignalTests/Z80MemptrTests.swift
new file mode 100644
index 000000000..5b7dd6aef
--- /dev/null
+++ b/OSBindings/Mac/Clock SignalTests/Z80MemptrTests.swift	
@@ -0,0 +1,34 @@
+//
+//  Z80MemptrTests.swift
+//  Clock Signal
+//
+//  Created by Thomas Harte on 21/07/2017.
+//  Copyright © 2017 Thomas Harte. All rights reserved.
+//
+
+import XCTest
+
+class Z80MemptrTests: XCTestCase {
+	private func test(program : [UInt8], length : Int32, initialValue : UInt16) -> UInt16 {
+		// Create a machine and install the supplied program at address 0, setting the PC to run from there
+		let machine = CSTestMachineZ80()
+		machine.setValue(0x0000, for: .programCounter)
+		machine.setData(Data(bytes: program), atAddress: 0x0000)
+
+		// Set the initial value of memptr, run for the requested number of cycles,
+		// return the new value
+		machine.setValue(initialValue, for: .memPtr)
+		machine.runForNumber(ofCycles: length)
+		return machine.value(for: .memPtr)
+	}
+
+	// LD A,(addr)
+	func testLDAnn() {
+		let program: [UInt8] = [
+			0x3a, 0x00, 0x00
+		]
+		let result = test(program: program, length: 13, initialValue: 0xffff)
+		XCTAssertEqual(result, 0x0001)
+	}
+
+}