diff --git a/services/inputflinger/reader/Android.bp b/services/inputflinger/reader/Android.bp
index a53fcd7..24168a1 100644
--- a/services/inputflinger/reader/Android.bp
+++ b/services/inputflinger/reader/Android.bp
@@ -55,6 +55,7 @@
         "mapper/accumulator/CursorButtonAccumulator.cpp",
         "mapper/accumulator/CursorScrollAccumulator.cpp",
         "mapper/accumulator/HidUsageAccumulator.cpp",
+        "mapper/accumulator/MultiTouchMotionAccumulator.cpp",
         "mapper/accumulator/SingleTouchMotionAccumulator.cpp",
         "mapper/accumulator/TouchButtonAccumulator.cpp",
     ],
diff --git a/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp b/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp
index acba4f6..8e757a5 100644
--- a/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp
@@ -28,163 +28,6 @@
 // Maximum number of slots supported when using the slot-based Multitouch Protocol B.
 static constexpr size_t MAX_SLOTS = 32;
 
-// --- MultiTouchMotionAccumulator ---
-
-MultiTouchMotionAccumulator::MultiTouchMotionAccumulator()
-      : mCurrentSlot(-1),
-        mUsingSlotsProtocol(false),
-        mHaveStylus(false) {}
-
-void MultiTouchMotionAccumulator::configure(InputDeviceContext& deviceContext, size_t slotCount,
-                                            bool usingSlotsProtocol) {
-    mUsingSlotsProtocol = usingSlotsProtocol;
-    mHaveStylus = deviceContext.hasAbsoluteAxis(ABS_MT_TOOL_TYPE);
-    mSlots = std::vector<Slot>(slotCount);
-
-    mCurrentSlot = -1;
-    if (mUsingSlotsProtocol) {
-        // Query the driver for the current slot index and use it as the initial slot
-        // before we start reading events from the device.  It is possible that the
-        // current slot index will not be the same as it was when the first event was
-        // written into the evdev buffer, which means the input mapper could start
-        // out of sync with the initial state of the events in the evdev buffer.
-        // In the extremely unlikely case that this happens, the data from
-        // two slots will be confused until the next ABS_MT_SLOT event is received.
-        // This can cause the touch point to "jump", but at least there will be
-        // no stuck touches.
-        int32_t initialSlot;
-        if (const auto status = deviceContext.getAbsoluteAxisValue(ABS_MT_SLOT, &initialSlot);
-            status == OK) {
-            mCurrentSlot = initialSlot;
-        } else {
-            ALOGD("Could not retrieve current multi-touch slot index. status=%d", status);
-        }
-    }
-}
-
-void MultiTouchMotionAccumulator::resetSlots() {
-    for (Slot& slot : mSlots) {
-        slot.clear();
-    }
-    mCurrentSlot = -1;
-}
-
-void MultiTouchMotionAccumulator::process(const RawEvent* rawEvent) {
-    if (rawEvent->type == EV_ABS) {
-        bool newSlot = false;
-        if (mUsingSlotsProtocol) {
-            if (rawEvent->code == ABS_MT_SLOT) {
-                mCurrentSlot = rawEvent->value;
-                newSlot = true;
-            }
-        } else if (mCurrentSlot < 0) {
-            mCurrentSlot = 0;
-        }
-
-        if (mCurrentSlot < 0 || size_t(mCurrentSlot) >= mSlots.size()) {
-            if (DEBUG_POINTERS) {
-                if (newSlot) {
-                    ALOGW("MultiTouch device emitted invalid slot index %d but it "
-                          "should be between 0 and %zd; ignoring this slot.",
-                          mCurrentSlot, mSlots.size() - 1);
-                }
-            }
-        } else {
-            Slot& slot = mSlots[mCurrentSlot];
-            // If mUsingSlotsProtocol is true, it means the raw pointer has axis info of
-            // ABS_MT_TRACKING_ID and ABS_MT_SLOT, so driver should send a valid trackingId while
-            // updating the slot.
-            if (!mUsingSlotsProtocol) {
-                slot.mInUse = true;
-            }
-
-            switch (rawEvent->code) {
-                case ABS_MT_POSITION_X:
-                    slot.mAbsMTPositionX = rawEvent->value;
-                    warnIfNotInUse(*rawEvent, slot);
-                    break;
-                case ABS_MT_POSITION_Y:
-                    slot.mAbsMTPositionY = rawEvent->value;
-                    warnIfNotInUse(*rawEvent, slot);
-                    break;
-                case ABS_MT_TOUCH_MAJOR:
-                    slot.mAbsMTTouchMajor = rawEvent->value;
-                    break;
-                case ABS_MT_TOUCH_MINOR:
-                    slot.mAbsMTTouchMinor = rawEvent->value;
-                    slot.mHaveAbsMTTouchMinor = true;
-                    break;
-                case ABS_MT_WIDTH_MAJOR:
-                    slot.mAbsMTWidthMajor = rawEvent->value;
-                    break;
-                case ABS_MT_WIDTH_MINOR:
-                    slot.mAbsMTWidthMinor = rawEvent->value;
-                    slot.mHaveAbsMTWidthMinor = true;
-                    break;
-                case ABS_MT_ORIENTATION:
-                    slot.mAbsMTOrientation = rawEvent->value;
-                    break;
-                case ABS_MT_TRACKING_ID:
-                    if (mUsingSlotsProtocol && rawEvent->value < 0) {
-                        // The slot is no longer in use but it retains its previous contents,
-                        // which may be reused for subsequent touches.
-                        slot.mInUse = false;
-                    } else {
-                        slot.mInUse = true;
-                        slot.mAbsMTTrackingId = rawEvent->value;
-                    }
-                    break;
-                case ABS_MT_PRESSURE:
-                    slot.mAbsMTPressure = rawEvent->value;
-                    break;
-                case ABS_MT_DISTANCE:
-                    slot.mAbsMTDistance = rawEvent->value;
-                    break;
-                case ABS_MT_TOOL_TYPE:
-                    slot.mAbsMTToolType = rawEvent->value;
-                    slot.mHaveAbsMTToolType = true;
-                    break;
-            }
-        }
-    } else if (rawEvent->type == EV_SYN && rawEvent->code == SYN_MT_REPORT) {
-        // MultiTouch Sync: The driver has returned all data for *one* of the pointers.
-        mCurrentSlot += 1;
-    }
-}
-
-void MultiTouchMotionAccumulator::finishSync() {
-    if (!mUsingSlotsProtocol) {
-        resetSlots();
-    }
-}
-
-bool MultiTouchMotionAccumulator::hasStylus() const {
-    return mHaveStylus;
-}
-
-void MultiTouchMotionAccumulator::warnIfNotInUse(const RawEvent& event, const Slot& slot) {
-    if (!slot.mInUse) {
-        ALOGW("Received unexpected event (0x%0x, 0x%0x) for slot %i with tracking id %i",
-              event.code, event.value, mCurrentSlot, slot.mAbsMTTrackingId);
-    }
-}
-
-// --- MultiTouchMotionAccumulator::Slot ---
-
-int32_t MultiTouchMotionAccumulator::Slot::getToolType() const {
-    if (mHaveAbsMTToolType) {
-        switch (mAbsMTToolType) {
-            case MT_TOOL_FINGER:
-                return AMOTION_EVENT_TOOL_TYPE_FINGER;
-            case MT_TOOL_PEN:
-                return AMOTION_EVENT_TOOL_TYPE_STYLUS;
-            case MT_TOOL_PALM:
-                return AMOTION_EVENT_TOOL_TYPE_PALM;
-        }
-    }
-    return AMOTION_EVENT_TOOL_TYPE_UNKNOWN;
-}
-
 // --- MultiTouchInputMapper ---
 
 MultiTouchInputMapper::MultiTouchInputMapper(InputDeviceContext& deviceContext)
diff --git a/services/inputflinger/reader/mapper/MultiTouchInputMapper.h b/services/inputflinger/reader/mapper/MultiTouchInputMapper.h
index 047e62d..ddf9e80 100644
--- a/services/inputflinger/reader/mapper/MultiTouchInputMapper.h
+++ b/services/inputflinger/reader/mapper/MultiTouchInputMapper.h
@@ -17,77 +17,10 @@
 #pragma once
 
 #include "TouchInputMapper.h"
+#include "accumulator/MultiTouchMotionAccumulator.h"
 
 namespace android {
 
-/* Keeps track of the state of multi-touch protocol. */
-class MultiTouchMotionAccumulator {
-public:
-    class Slot {
-    public:
-        inline bool isInUse() const { return mInUse; }
-        inline int32_t getX() const { return mAbsMTPositionX; }
-        inline int32_t getY() const { return mAbsMTPositionY; }
-        inline int32_t getTouchMajor() const { return mAbsMTTouchMajor; }
-        inline int32_t getTouchMinor() const {
-            return mHaveAbsMTTouchMinor ? mAbsMTTouchMinor : mAbsMTTouchMajor;
-        }
-        inline int32_t getToolMajor() const { return mAbsMTWidthMajor; }
-        inline int32_t getToolMinor() const {
-            return mHaveAbsMTWidthMinor ? mAbsMTWidthMinor : mAbsMTWidthMajor;
-        }
-        inline int32_t getOrientation() const { return mAbsMTOrientation; }
-        inline int32_t getTrackingId() const { return mAbsMTTrackingId; }
-        inline int32_t getPressure() const { return mAbsMTPressure; }
-        inline int32_t getDistance() const { return mAbsMTDistance; }
-        inline int32_t getToolType() const;
-
-    private:
-        friend class MultiTouchMotionAccumulator;
-
-        bool mInUse = false;
-        bool mHaveAbsMTTouchMinor = false;
-        bool mHaveAbsMTWidthMinor = false;
-        bool mHaveAbsMTToolType = false;
-
-        int32_t mAbsMTPositionX = 0;
-        int32_t mAbsMTPositionY = 0;
-        int32_t mAbsMTTouchMajor = 0;
-        int32_t mAbsMTTouchMinor = 0;
-        int32_t mAbsMTWidthMajor = 0;
-        int32_t mAbsMTWidthMinor = 0;
-        int32_t mAbsMTOrientation = 0;
-        int32_t mAbsMTTrackingId = -1;
-        int32_t mAbsMTPressure = 0;
-        int32_t mAbsMTDistance = 0;
-        int32_t mAbsMTToolType = 0;
-
-        void clear() { *this = Slot(); }
-    };
-
-    MultiTouchMotionAccumulator();
-
-    void configure(InputDeviceContext& deviceContext, size_t slotCount, bool usingSlotsProtocol);
-    void process(const RawEvent* rawEvent);
-    void finishSync();
-    bool hasStylus() const;
-
-    inline size_t getSlotCount() const { return mSlots.size(); }
-    inline const Slot& getSlot(size_t index) const {
-        LOG_ALWAYS_FATAL_IF(index < 0 || index >= mSlots.size(), "Invalid index: %zu", index);
-        return mSlots[index];
-    }
-
-private:
-    int32_t mCurrentSlot;
-    std::vector<Slot> mSlots;
-    bool mUsingSlotsProtocol;
-    bool mHaveStylus;
-
-    void resetSlots();
-    void warnIfNotInUse(const RawEvent& event, const Slot& slot);
-};
-
 class MultiTouchInputMapper : public TouchInputMapper {
 public:
     explicit MultiTouchInputMapper(InputDeviceContext& deviceContext);
diff --git a/services/inputflinger/reader/mapper/accumulator/MultiTouchMotionAccumulator.cpp b/services/inputflinger/reader/mapper/accumulator/MultiTouchMotionAccumulator.cpp
new file mode 100644
index 0000000..b0cef67
--- /dev/null
+++ b/services/inputflinger/reader/mapper/accumulator/MultiTouchMotionAccumulator.cpp
@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// clang-format off
+#include "../Macros.h"
+// clang-format on
+#include "MultiTouchMotionAccumulator.h"
+
+namespace android {
+
+// --- MultiTouchMotionAccumulator ---
+
+MultiTouchMotionAccumulator::MultiTouchMotionAccumulator()
+      : mCurrentSlot(-1), mUsingSlotsProtocol(false), mHaveStylus(false) {}
+
+void MultiTouchMotionAccumulator::configure(InputDeviceContext& deviceContext, size_t slotCount,
+                                            bool usingSlotsProtocol) {
+    mUsingSlotsProtocol = usingSlotsProtocol;
+    mHaveStylus = deviceContext.hasAbsoluteAxis(ABS_MT_TOOL_TYPE);
+    mSlots = std::vector<Slot>(slotCount);
+
+    mCurrentSlot = -1;
+    if (mUsingSlotsProtocol) {
+        // Query the driver for the current slot index and use it as the initial slot before we
+        // start reading events from the device.  It is possible that the current slot index will
+        // not be the same as it was when the first event was written into the evdev buffer, which
+        // means the input mapper could start out of sync with the initial state of the events in
+        // the evdev buffer. In the extremely unlikely case that this happens, the data from two
+        // slots will be confused until the next ABS_MT_SLOT event is received. This can cause the
+        // touch point to "jump", but at least there will be no stuck touches.
+        int32_t initialSlot;
+        if (const auto status = deviceContext.getAbsoluteAxisValue(ABS_MT_SLOT, &initialSlot);
+            status == OK) {
+            mCurrentSlot = initialSlot;
+        } else {
+            ALOGD("Could not retrieve current multi-touch slot index. status=%d", status);
+        }
+    }
+}
+
+void MultiTouchMotionAccumulator::resetSlots() {
+    for (Slot& slot : mSlots) {
+        slot.clear();
+    }
+    mCurrentSlot = -1;
+}
+
+void MultiTouchMotionAccumulator::process(const RawEvent* rawEvent) {
+    if (rawEvent->type == EV_ABS) {
+        bool newSlot = false;
+        if (mUsingSlotsProtocol) {
+            if (rawEvent->code == ABS_MT_SLOT) {
+                mCurrentSlot = rawEvent->value;
+                newSlot = true;
+            }
+        } else if (mCurrentSlot < 0) {
+            mCurrentSlot = 0;
+        }
+
+        if (mCurrentSlot < 0 || size_t(mCurrentSlot) >= mSlots.size()) {
+            if (newSlot) {
+                ALOGW_IF(DEBUG_POINTERS,
+                         "MultiTouch device emitted invalid slot index %d but it "
+                         "should be between 0 and %zd; ignoring this slot.",
+                         mCurrentSlot, mSlots.size() - 1);
+            }
+        } else {
+            Slot& slot = mSlots[mCurrentSlot];
+            // If mUsingSlotsProtocol is true, it means the raw pointer has axis info of
+            // ABS_MT_TRACKING_ID and ABS_MT_SLOT, so driver should send a valid trackingId while
+            // updating the slot.
+            if (!mUsingSlotsProtocol) {
+                slot.mInUse = true;
+            }
+
+            switch (rawEvent->code) {
+                case ABS_MT_POSITION_X:
+                    slot.mAbsMtPositionX = rawEvent->value;
+                    warnIfNotInUse(*rawEvent, slot);
+                    break;
+                case ABS_MT_POSITION_Y:
+                    slot.mAbsMtPositionY = rawEvent->value;
+                    warnIfNotInUse(*rawEvent, slot);
+                    break;
+                case ABS_MT_TOUCH_MAJOR:
+                    slot.mAbsMtTouchMajor = rawEvent->value;
+                    break;
+                case ABS_MT_TOUCH_MINOR:
+                    slot.mAbsMtTouchMinor = rawEvent->value;
+                    slot.mHaveAbsMtTouchMinor = true;
+                    break;
+                case ABS_MT_WIDTH_MAJOR:
+                    slot.mAbsMtWidthMajor = rawEvent->value;
+                    break;
+                case ABS_MT_WIDTH_MINOR:
+                    slot.mAbsMtWidthMinor = rawEvent->value;
+                    slot.mHaveAbsMtWidthMinor = true;
+                    break;
+                case ABS_MT_ORIENTATION:
+                    slot.mAbsMtOrientation = rawEvent->value;
+                    break;
+                case ABS_MT_TRACKING_ID:
+                    if (mUsingSlotsProtocol && rawEvent->value < 0) {
+                        // The slot is no longer in use but it retains its previous contents,
+                        // which may be reused for subsequent touches.
+                        slot.mInUse = false;
+                    } else {
+                        slot.mInUse = true;
+                        slot.mAbsMtTrackingId = rawEvent->value;
+                    }
+                    break;
+                case ABS_MT_PRESSURE:
+                    slot.mAbsMtPressure = rawEvent->value;
+                    break;
+                case ABS_MT_DISTANCE:
+                    slot.mAbsMtDistance = rawEvent->value;
+                    break;
+                case ABS_MT_TOOL_TYPE:
+                    slot.mAbsMtToolType = rawEvent->value;
+                    slot.mHaveAbsMtToolType = true;
+                    break;
+            }
+        }
+    } else if (rawEvent->type == EV_SYN && rawEvent->code == SYN_MT_REPORT) {
+        // MultiTouch Sync: The driver has returned all data for *one* of the pointers.
+        mCurrentSlot += 1;
+    }
+}
+
+void MultiTouchMotionAccumulator::finishSync() {
+    if (!mUsingSlotsProtocol) {
+        resetSlots();
+    }
+}
+
+bool MultiTouchMotionAccumulator::hasStylus() const {
+    return mHaveStylus;
+}
+
+void MultiTouchMotionAccumulator::warnIfNotInUse(const RawEvent& event, const Slot& slot) {
+    if (!slot.mInUse) {
+        ALOGW("Received unexpected event (0x%0x, 0x%0x) for slot %i with tracking id %i",
+              event.code, event.value, mCurrentSlot, slot.mAbsMtTrackingId);
+    }
+}
+
+// --- MultiTouchMotionAccumulator::Slot ---
+
+int32_t MultiTouchMotionAccumulator::Slot::getToolType() const {
+    if (mHaveAbsMtToolType) {
+        switch (mAbsMtToolType) {
+            case MT_TOOL_FINGER:
+                return AMOTION_EVENT_TOOL_TYPE_FINGER;
+            case MT_TOOL_PEN:
+                return AMOTION_EVENT_TOOL_TYPE_STYLUS;
+            case MT_TOOL_PALM:
+                return AMOTION_EVENT_TOOL_TYPE_PALM;
+        }
+    }
+    return AMOTION_EVENT_TOOL_TYPE_UNKNOWN;
+}
+
+} // namespace android
diff --git a/services/inputflinger/reader/mapper/accumulator/MultiTouchMotionAccumulator.h b/services/inputflinger/reader/mapper/accumulator/MultiTouchMotionAccumulator.h
new file mode 100644
index 0000000..625a00f
--- /dev/null
+++ b/services/inputflinger/reader/mapper/accumulator/MultiTouchMotionAccumulator.h
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <linux/input-event-codes.h>
+#include <stdint.h>
+#include <vector>
+
+#include "EventHub.h"
+#include "InputDevice.h"
+
+namespace android {
+
+/* Keeps track of the state of multi-touch protocol. */
+class MultiTouchMotionAccumulator {
+public:
+    class Slot {
+    public:
+        inline bool isInUse() const { return mInUse; }
+        inline int32_t getX() const { return mAbsMtPositionX; }
+        inline int32_t getY() const { return mAbsMtPositionY; }
+        inline int32_t getTouchMajor() const { return mAbsMtTouchMajor; }
+        inline int32_t getTouchMinor() const {
+            return mHaveAbsMtTouchMinor ? mAbsMtTouchMinor : mAbsMtTouchMajor;
+        }
+        inline int32_t getToolMajor() const { return mAbsMtWidthMajor; }
+        inline int32_t getToolMinor() const {
+            return mHaveAbsMtWidthMinor ? mAbsMtWidthMinor : mAbsMtWidthMajor;
+        }
+        inline int32_t getOrientation() const { return mAbsMtOrientation; }
+        inline int32_t getTrackingId() const { return mAbsMtTrackingId; }
+        inline int32_t getPressure() const { return mAbsMtPressure; }
+        inline int32_t getDistance() const { return mAbsMtDistance; }
+        int32_t getToolType() const;
+
+    private:
+        friend class MultiTouchMotionAccumulator;
+
+        bool mInUse = false;
+        bool mHaveAbsMtTouchMinor = false;
+        bool mHaveAbsMtWidthMinor = false;
+        bool mHaveAbsMtToolType = false;
+
+        int32_t mAbsMtPositionX = 0;
+        int32_t mAbsMtPositionY = 0;
+        int32_t mAbsMtTouchMajor = 0;
+        int32_t mAbsMtTouchMinor = 0;
+        int32_t mAbsMtWidthMajor = 0;
+        int32_t mAbsMtWidthMinor = 0;
+        int32_t mAbsMtOrientation = 0;
+        int32_t mAbsMtTrackingId = -1;
+        int32_t mAbsMtPressure = 0;
+        int32_t mAbsMtDistance = 0;
+        int32_t mAbsMtToolType = 0;
+
+        void clear() { *this = Slot(); }
+    };
+
+    MultiTouchMotionAccumulator();
+
+    void configure(InputDeviceContext& deviceContext, size_t slotCount, bool usingSlotsProtocol);
+    void process(const RawEvent* rawEvent);
+    void finishSync();
+    bool hasStylus() const;
+
+    inline size_t getSlotCount() const { return mSlots.size(); }
+    inline const Slot& getSlot(size_t index) const {
+        LOG_ALWAYS_FATAL_IF(index < 0 || index >= mSlots.size(), "Invalid index: %zu", index);
+        return mSlots[index];
+    }
+
+private:
+    int32_t mCurrentSlot;
+    std::vector<Slot> mSlots;
+    bool mUsingSlotsProtocol;
+    bool mHaveStylus;
+
+    void resetSlots();
+    void warnIfNotInUse(const RawEvent& event, const Slot& slot);
+};
+
+} // namespace android