diff --git a/Machines/Apple/ADB/Mouse.cpp b/Machines/Apple/ADB/Mouse.cpp
index af3bec90d..2bd2e7ae6 100644
--- a/Machines/Apple/ADB/Mouse.cpp
+++ b/Machines/Apple/ADB/Mouse.cpp
@@ -12,5 +12,51 @@ using namespace Apple::ADB;
 
 Mouse::Mouse(Bus &bus) : ReactiveDevice(bus, 3) {}
 
-void Mouse::perform_command(const Command &) {
+void Mouse::perform_command(const Command &command) {
+	if(command.type == Command::Type::Talk && command.reg == 0) {
+		// Read current deltas and buttons, thread safely.
+		auto delta_x = delta_x_.exchange(0);
+		auto delta_y = delta_y_.exchange(0);
+		const int buttons = button_flags_;
+
+		// Clamp deltas.
+		delta_x = std::max(std::min(delta_x, int16_t(127)), int16_t(-128));
+		delta_y = std::max(std::min(delta_y, int16_t(127)), int16_t(-128));
+
+		// Figure out what that would look like, and don't respond if there's
+		// no change to report.
+		const uint16_t reg0 =
+			((buttons & 1) ? 0x0000 : 0x8000) |
+			((buttons & 2) ? 0x0000 : 0x0080) |
+			uint16_t(delta_x & 0x7f) |
+			uint16_t((delta_y & 0x7f) << 8);
+		if(reg0 == last_posted_reg0_) return;
+
+		// Post change.
+		last_posted_reg0_ = reg0;
+		post_response({uint8_t(reg0 >> 8), uint8_t(reg0)});
+	}
+}
+
+void Mouse::move(int x, int y) {
+	delta_x_ += int16_t(x);
+	delta_y_ += int16_t(y);
+	post_service_request();
+}
+
+int Mouse::get_number_of_buttons() {
+	return 2;
+}
+
+void Mouse::set_button_pressed(int index, bool is_pressed) {
+	if(is_pressed)
+		button_flags_ |= (1 << index);
+	else
+		button_flags_ &= ~(1 << index);
+	post_service_request();
+}
+
+void Mouse::reset_all_buttons() {
+	button_flags_ = 0;
+	post_service_request();
 }
diff --git a/Machines/Apple/ADB/Mouse.hpp b/Machines/Apple/ADB/Mouse.hpp
index 0ab032922..3e8a4dc1f 100644
--- a/Machines/Apple/ADB/Mouse.hpp
+++ b/Machines/Apple/ADB/Mouse.hpp
@@ -10,16 +10,26 @@
 #define Mouse_hpp
 
 #include "ReactiveDevice.hpp"
+#include "../../../Inputs/Mouse.hpp"
 
 namespace Apple {
 namespace ADB {
 
-class Mouse: public ReactiveDevice {
+class Mouse: public ReactiveDevice, public Inputs::Mouse {
 	public:
 		Mouse(Bus &);
 
 	private:
 		void perform_command(const Command &command) override;
+
+		void move(int x, int y) override;
+		int get_number_of_buttons() override;
+		void set_button_pressed(int index, bool is_pressed) override;
+		void reset_all_buttons() override;
+
+		std::atomic<int16_t> delta_x_, delta_y_;
+		std::atomic<int> button_flags_ = 0;
+		uint16_t last_posted_reg0_ = 0;
 };
 
 }
diff --git a/Machines/Apple/ADB/ReactiveDevice.cpp b/Machines/Apple/ADB/ReactiveDevice.cpp
index a55645d70..d8bbc4436 100644
--- a/Machines/Apple/ADB/ReactiveDevice.cpp
+++ b/Machines/Apple/ADB/ReactiveDevice.cpp
@@ -125,7 +125,7 @@ void ReactiveDevice::adb_bus_did_observe_event(Bus::Event event, uint8_t value)
 		phase_ = Phase::AwaitingAttention;
 
 		command_ = decode_command(value);
-		LOG(command_);
+//		LOG(command_);
 
 		// If this command doesn't apply here, but a service request is requested,
 		// post a service request.
diff --git a/Machines/Apple/AppleIIgs/ADB.hpp b/Machines/Apple/AppleIIgs/ADB.hpp
index ec10c0ba2..6ce473572 100644
--- a/Machines/Apple/AppleIIgs/ADB.hpp
+++ b/Machines/Apple/AppleIIgs/ADB.hpp
@@ -45,10 +45,16 @@ class GLU: public InstructionSet::M50740::PortHandler {
 		bool get_option_button() const;
 
 		void set_vertical_blank(bool);
+		bool get_vertical_blank() {
+			return vertical_blank_;
+		}
 
 		Apple::ADB::Keyboard &keyboard() {
 			return keyboard_;
 		}
+		Inputs::Mouse &get_mouse() {
+			return mouse_;
+		}
 
 	private:
 		InstructionSet::M50740::Executor executor_;
@@ -70,6 +76,8 @@ class GLU: public InstructionSet::M50740::PortHandler {
 
 		uint8_t modifier_state_ = 0;
 
+		bool vertical_blank_ = false;
+
 		// For now, attach only a keyboard and mouse.
 		Apple::ADB::Mouse mouse_;
 		Apple::ADB::Keyboard keyboard_;
diff --git a/Machines/Apple/AppleIIgs/AppleIIgs.cpp b/Machines/Apple/AppleIIgs/AppleIIgs.cpp
index 3a92c5b12..50234875d 100644
--- a/Machines/Apple/AppleIIgs/AppleIIgs.cpp
+++ b/Machines/Apple/AppleIIgs/AppleIIgs.cpp
@@ -52,6 +52,7 @@ class ConcreteMachine:
 	public MachineTypes::ScanProducer,
 	public MachineTypes::TimedMachine,
 	public MachineTypes::MappedKeyboardMachine,
+	public MachineTypes::MouseMachine,
 	public CPU::MOS6502Esque::BusHandler<uint32_t> {
 
 	public:
@@ -898,7 +899,9 @@ class ConcreteMachine:
 				update_interrupts();
 
 				const bool is_vertical_blank = video_.last_valid()->get_is_vertical_blank(video_.time_since_flush());
-				adb_glu_->set_vertical_blank(is_vertical_blank);
+				if(is_vertical_blank != adb_glu_.last_valid()->get_vertical_blank()) {
+					adb_glu_->set_vertical_blank(is_vertical_blank);
+				}
 			}
 
 			return duration;
@@ -910,7 +913,7 @@ class ConcreteMachine:
 			m65816_.set_irq_line(video_.last_valid()->get_interrupt_line() || sound_glu_.get_interrupt_line());
 		}
 
-		// MARK: - Keyboard input.
+		// MARK: - Input.
 		KeyboardMapper *get_keyboard_mapper() final {
 			return &keyboard_mapper_;
 		}
@@ -923,6 +926,10 @@ class ConcreteMachine:
 			adb_glu_.last_valid()->keyboard().clear_all_keys();
 		}
 
+		Inputs::Mouse &get_mouse() final {
+			return adb_glu_.last_valid()->get_mouse();
+		}
+
 	private:
 		CPU::WDC65816::Processor<ConcreteMachine, false> m65816_;
 		MemoryMap memory_;