diff --git a/share/qtcreator/debugger/lldbbridge.py b/share/qtcreator/debugger/lldbbridge.py
index 6987065c2aede290d474bc88d83e114deee0bdd4..c08acacf05dcfc8de699d2cc15e9d79508860c21 100644
--- a/share/qtcreator/debugger/lldbbridge.py
+++ b/share/qtcreator/debugger/lldbbridge.py
@@ -1278,6 +1278,19 @@ class Dumper(DumperBase):
                 result += ']'
                 self.report(result)
 
+    def setRegister(self, args):
+        self.reportToken(args)
+        name = args["name"]
+        value = args["value"]
+        result = lldb.SBCommandReturnObject()
+        self.debugger.GetCommandInterpreter().HandleCommand(
+            "register write %s %s" % (name, value), result)
+        success = result.Succeeded()
+        if success:
+            self.report('output="%s"' % result.GetOutput())
+        else:
+            self.report('error="%s"' % result.GetError())
+
     def report(self, stuff):
         with self.outputLock:
             sys.stdout.write("@\n" + stuff + "@\n")
diff --git a/src/plugins/debugger/cdb/cdbengine.cpp b/src/plugins/debugger/cdb/cdbengine.cpp
index a18de4de12b3aacf0d391421e8d8762dc656cd26..4c7dc4e9c55ca482b12d76d33534af3b92634697 100644
--- a/src/plugins/debugger/cdb/cdbengine.cpp
+++ b/src/plugins/debugger/cdb/cdbengine.cpp
@@ -1672,7 +1672,7 @@ void CdbEngine::handleRegistersExt(const DebuggerResponse &response)
                 reg.name = item["name"].data();
                 reg.description = item["description"].data();
                 reg.reportedType = item["type"].data();
-                reg.value = item["value"].data();
+                reg.value.fromByteArray(item["value"].data(), HexadecimalFormat);
                 reg.size = item["size"].data().toInt();
                 handler->updateRegister(reg);
             }
diff --git a/src/plugins/debugger/debuggerengine.cpp b/src/plugins/debugger/debuggerengine.cpp
index e19c526c7a036002681654683551e950d36cf2ab..2279e8c996d610670898d13ceb21768d778d6032 100644
--- a/src/plugins/debugger/debuggerengine.cpp
+++ b/src/plugins/debugger/debuggerengine.cpp
@@ -195,7 +195,7 @@ public:
         m_remoteSetupState(RemoteSetupNone),
         m_inferiorPid(0),
         m_modulesHandler(engine),
-        m_registerHandler(),
+        m_registerHandler(engine),
         m_sourceFilesHandler(),
         m_stackHandler(),
         m_threadsHandler(),
diff --git a/src/plugins/debugger/gdb/gdbengine.cpp b/src/plugins/debugger/gdb/gdbengine.cpp
index 435cb85098a9164e34cc70fbcf7cbb2ec6001519..855fd85f287dda753914f21b428cd638caf4abfc 100644
--- a/src/plugins/debugger/gdb/gdbengine.cpp
+++ b/src/plugins/debugger/gdb/gdbengine.cpp
@@ -3632,14 +3632,18 @@ void GdbEngine::handleMaintPrintRegisters(const DebuggerResponse &response)
         readWord(ba, &pos); // Offset
         reg.size = readWord(ba, &pos).toInt();
         reg.reportedType = readWord(ba, &pos);
-        reg.value = readWord(ba, &pos);
+        reg.value.fromByteArray(readWord(ba, &pos), HexadecimalFormat);
         handler->updateRegister(reg);
     }
     handler->commitUpdates();
 }
+
 void GdbEngine::setRegisterValue(const QByteArray &name, const QString &value)
 {
-    postCommand("set $" + name  + "=" + value.toLatin1());
+    QByteArray fullName = name;
+    if (name.startsWith("xmm"))
+        fullName += ".uint128";
+    postCommand("set $" + fullName  + "=" + value.toLatin1());
     reloadRegisters();
 }
 
@@ -3705,7 +3709,7 @@ void GdbEngine::handleRegisterListValues(const DebuggerResponse &response)
         Register reg = m_registers[number];
         QByteArray data = item["value"].data();
         if (data.startsWith("0x")) {
-            reg.value = data;
+            reg.value.fromByteArray(data, HexadecimalFormat);
         } else if (data == "<error reading variable>") {
             // Nothing. See QTCREATORBUG-14029.
         } else {
@@ -3718,7 +3722,7 @@ void GdbEngine::handleRegisterListValues(const DebuggerResponse &response)
             // v2_int64 = {0x0000000000000000, 0x0000000000000000},
             // uint128 = <error reading variable>}"}
             // Try to make sense of it using the int32 chunks:
-            QByteArray result = "0x";
+            QByteArray result;
             const int pos1 = data.indexOf("_int32");
             const int pos2 = data.indexOf('{', pos1) + 1;
             const int pos3 = data.indexOf('}', pos2);
@@ -3733,7 +3737,7 @@ void GdbEngine::handleRegisterListValues(const DebuggerResponse &response)
                 QTC_ASSERT(chunk.size() == 8, continue);
                 result.append(chunk);
             }
-            reg.value = result;
+            reg.value.fromByteArray(result, HexadecimalFormat);
         }
         handler->updateRegister(reg);
     }
diff --git a/src/plugins/debugger/lldb/lldbengine.cpp b/src/plugins/debugger/lldb/lldbengine.cpp
index 6d135df89ca69783fddc294d8993ae619cd409c0..9173a77cc1c0aac787cb750ab17dfaa1c296ce65 100644
--- a/src/plugins/debugger/lldb/lldbengine.cpp
+++ b/src/plugins/debugger/lldb/lldbengine.cpp
@@ -1033,9 +1033,11 @@ void LldbEngine::refreshRegisters(const GdbMi &registers)
     foreach (const GdbMi &item, registers.children()) {
         Register reg;
         reg.name = item["name"].data();
-        reg.value = item["value"].data();
+        reg.value.fromByteArray(item["value"].data(), HexadecimalFormat);
         reg.size = item["size"].data().toInt();
         reg.reportedType = item["type"].data();
+        if (reg.reportedType.startsWith("unsigned"))
+            reg.kind = IntegerRegister;
         handler->updateRegister(reg);
     }
     handler->commitUpdates();
diff --git a/src/plugins/debugger/registerhandler.cpp b/src/plugins/debugger/registerhandler.cpp
index ca2dd95706c65824f89ec6a76a3c6858a2b9bce3..16279988f7096be5e95de9d613bfd7337c0b87c0 100644
--- a/src/plugins/debugger/registerhandler.cpp
+++ b/src/plugins/debugger/registerhandler.cpp
@@ -29,6 +29,8 @@
 ****************************************************************************/
 
 #include "registerhandler.h"
+
+#include "debuggerengine.h"
 #include "watchdelegatewidgets.h"
 
 #include <utils/qtcassert.h>
@@ -100,27 +102,37 @@ static uint decodeHexChar(unsigned char c)
     return uint(-1);
 }
 
-void RegisterValue::operator=(const QByteArray &ba)
+void RegisterValue::fromByteArray(const QByteArray &ba, RegisterFormat format)
 {
     known = !ba.isEmpty();
-    uint shift = 0;
-    int j = 0;
     v.u64[1] = v.u64[0] = 0;
-    for (int i = ba.size(); --i >= 0 && j < 16; ++j) {
-        quint64 d = decodeHexChar(ba.at(i));
-        if (d == uint(-1))
-            return;
-        v.u64[0] |= (d << shift);
-        shift += 4;
+
+    const int n = ba.size();
+    int pos = 0;
+    if (ba.startsWith("0x"))
+        pos += 2;
+
+    bool negative = pos < n && ba.at(pos) == '-';
+    if (negative)
+        ++pos;
+
+    while (pos < n) {
+        uint c = ba.at(pos);
+        if (format != CharacterFormat) {
+            c = decodeHexChar(c);
+            if (c == uint(-1))
+                break;
+        }
+        shiftOneDigit(c, format);
+        ++pos;
     }
-    j = 0;
-    shift = 0;
-    for (int i = ba.size() - 16; --i >= 0 && j < 16; ++j) {
-        quint64 d = decodeHexChar(ba.at(i));
-        if (d == uint(-1))
-            return;
-        v.u64[1] |= (d << shift);
-        shift += 4;
+
+    if (negative) {
+        v.u64[1] = ~v.u64[1];
+        v.u64[0] = ~v.u64[0];
+        ++v.u64[0];
+        if (v.u64[0] == 0)
+            ++v.u64[1];
     }
 }
 
@@ -205,18 +217,102 @@ RegisterValue RegisterValue::subValue(int size, int index) const
     return value;
 }
 
+void RegisterValue::setSubValue(int size, int index, RegisterValue subValue)
+{
+    switch (size) {
+        case 1:
+            v.u8[index] = subValue.v.u8[0];
+            break;
+        case 2:
+            v.u16[index] = subValue.v.u16[0];
+            break;
+        case 4:
+            v.u32[index] = subValue.v.u32[0];
+            break;
+        case 8:
+            v.u64[index] = subValue.v.u64[0];
+            break;
+    }
+}
+
+static inline void shiftBitsLeft(RegisterValue *val, int amount)
+{
+    val->v.u64[1] <<= amount;
+    val->v.u64[1] |= val->v.u64[0] >> (64 - amount);
+    val->v.u64[0] <<= amount;
+}
+
+void RegisterValue::shiftOneDigit(uint digit, RegisterFormat format)
+{
+    switch (format) {
+    case HexadecimalFormat:
+        shiftBitsLeft(this, 4);
+        v.u64[0] |= digit;
+        break;
+    case OctalFormat:
+        shiftBitsLeft(this, 3);
+        v.u64[0] |= digit;
+        break;
+    case BinaryFormat:
+        shiftBitsLeft(this, 1);
+        v.u64[0] |= digit;
+        break;
+    case DecimalFormat:
+    case SignedDecimalFormat: {
+        shiftBitsLeft(this, 1);
+        quint64 tmp0 = v.u64[0];
+        quint64 tmp1 = v.u64[1];
+        shiftBitsLeft(this, 2);
+        v.u64[1] += tmp1;
+        v.u64[0] += tmp0;
+        if (v.u64[0] < tmp0)
+            ++v.u64[1];
+        v.u64[0] += digit;
+        if (v.u64[0] < digit)
+            ++v.u64[1];
+        break;
+    }
+    case CharacterFormat:
+        shiftBitsLeft(this, 8);
+        v.u64[0] |= digit;
+    }
+}
+
 //////////////////////////////////////////////////////////////////
 //
 // RegisterSubItem and RegisterItem
 //
 //////////////////////////////////////////////////////////////////
 
+class RegisterSubItem;
+
+class RegisterEditItem : public Utils::TreeItem
+{
+public:
+    RegisterEditItem(int pos, RegisterKind subKind, int subSize, RegisterFormat format)
+        : m_index(pos), m_subKind(subKind), m_subSize(subSize), m_subFormat(format)
+    {}
+
+    QVariant data(int column, int role) const override;
+    bool setData(int column, const QVariant &value, int role) override;
+    Qt::ItemFlags flags(int column) const override;
+
+    int m_index;
+    RegisterKind m_subKind;
+    int m_subSize;
+    RegisterFormat m_subFormat;
+};
+
+
 class RegisterSubItem : public Utils::TreeItem
 {
 public:
     RegisterSubItem(RegisterKind subKind, int subSize, int count, RegisterFormat format)
         : m_subKind(subKind), m_subFormat(format), m_subSize(subSize), m_count(count), m_changed(false)
-    {}
+    {
+        for (int i = 0; i != count; ++i)
+            appendChild(new RegisterEditItem(i, subKind, subSize, format));
+    }
 
     QVariant data(int column, int role) const;
 
@@ -240,10 +336,12 @@ class RegisterItem : public Utils::TreeItem
 public:
     explicit RegisterItem(const Register &reg);
 
-    QVariant data(int column, int role) const;
-    Qt::ItemFlags flags(int column) const;
+    QVariant data(int column, int role) const override;
+    bool setData(int column, const QVariant &value, int role) override;
+    Qt::ItemFlags flags(int column) const override;
 
     quint64 addressValue() const;
+    void triggerChange();
 
     Register m_reg;
     RegisterFormat m_format;
@@ -289,6 +387,13 @@ quint64 RegisterItem::addressValue() const
     return m_reg.value.v.u64[0];
 }
 
+void RegisterItem::triggerChange()
+{
+    QByteArray ba = "0x" + m_reg.value.toByteArray(m_reg.kind, m_reg.size, HexadecimalFormat);
+    DebuggerEngine *engine = static_cast<RegisterHandler *>(model())->engine();
+    engine->setRegisterValue(m_reg.name, QString::fromLatin1(ba));
+}
+
 QVariant RegisterItem::data(int column, int role) const
 {
     switch (role) {
@@ -326,7 +431,7 @@ QVariant RegisterItem::data(int column, int role) const
                     .arg(QString::fromLatin1(m_reg.previousValue.toByteArray(m_reg.kind, m_reg.size, m_format)));
 
         case Qt::EditRole: // Edit: Unpadded for editing
-            return m_reg.value.toByteArray(m_reg.kind, m_reg.size, m_format);
+            return QString::fromLatin1(m_reg.value.toByteArray(m_reg.kind, m_reg.size, m_format));
 
         case Qt::TextAlignmentRole:
             return column == RegisterValueColumn ? QVariant(Qt::AlignRight) : QVariant();
@@ -337,6 +442,16 @@ QVariant RegisterItem::data(int column, int role) const
     return QVariant();
 }
 
+bool RegisterItem::setData(int column, const QVariant &value, int role)
+{
+    if (column == RegisterValueColumn && role == Qt::EditRole) {
+        m_reg.value.fromByteArray(value.toString().toLatin1(), m_format);
+        triggerChange();
+        return true;
+    }
+    return false;
+}
+
 QVariant RegisterSubItem::data(int column, int role) const
 {
     switch (role) {
@@ -401,10 +516,11 @@ QVariant RegisterSubItem::data(int column, int role) const
 //
 //////////////////////////////////////////////////////////////////
 
-RegisterHandler::RegisterHandler()
+RegisterHandler::RegisterHandler(DebuggerEngine *engine)
+    : m_engine(engine)
 {
     setObjectName(QLatin1String("RegisterModel"));
-    setHeader(QStringList() << tr("Name") << tr("Value"));
+    setHeader({tr("Name"), tr("Value")});
 }
 
 void RegisterHandler::updateRegister(const Register &r)
@@ -454,5 +570,58 @@ RegisterMap RegisterHandler::registerMap() const
     return result;
 }
 
+QVariant RegisterEditItem::data(int column, int role) const
+{
+    switch (role) {
+        case Qt::DisplayRole:
+        case Qt::EditRole:
+            switch (column) {
+                case RegisterNameColumn: {
+                    return QString::fromLatin1("[%1]").arg(m_index);
+                }
+                case RegisterValueColumn: {
+                    RegisterItem *registerItem = static_cast<RegisterItem *>(parent()->parent());
+                    RegisterValue value = registerItem->m_reg.value;
+                    return value.subValue(m_subSize, m_index).toByteArray(m_subKind, m_subSize, m_subFormat);
+                }
+            }
+        case Qt::ToolTipRole: {
+                RegisterItem *registerItem = static_cast<RegisterItem *>(parent()->parent());
+                return RegisterHandler::tr("Edit bits %1...%2 of register %3")
+                        .arg(m_index * 8).arg(m_index * 8 + 8)
+                        .arg(QString::fromLatin1(registerItem->m_reg.name));
+            }
+        default:
+            break;
+    }
+    return QVariant();
+}
+
+bool RegisterEditItem::setData(int column, const QVariant &value, int role)
+{
+    if (column == RegisterValueColumn && role == Qt::EditRole) {
+        QTC_ASSERT(parent(), return false);
+        QTC_ASSERT(parent()->parent(), return false);
+        RegisterItem *registerItem = static_cast<RegisterItem *>(parent()->parent());
+        Register &reg = registerItem->m_reg;
+        RegisterValue vv;
+        vv.fromByteArray(value.toString().toLatin1(), m_subFormat);
+        reg.value.setSubValue(m_subSize, m_index, vv);
+        registerItem->triggerChange();
+        return true;
+    }
+    return false;
+}
+
+Qt::ItemFlags RegisterEditItem::flags(int column) const
+{
+    QTC_ASSERT(parent(), return Qt::ItemFlags());
+    RegisterSubItem *registerSubItem = static_cast<RegisterSubItem *>(parent());
+    Qt::ItemFlags f = registerSubItem->flags(column);
+    if (column == RegisterValueColumn)
+        f |= Qt::ItemIsEditable;
+    return f;
+}
+
 } // namespace Internal
 } // namespace Debugger
diff --git a/src/plugins/debugger/registerhandler.h b/src/plugins/debugger/registerhandler.h
index 3afe40bd4cafb95a571f4b02a0b6c51a5c86e026..fae27ae2a02d6d58da5436b988008e4e2f8e48d4 100644
--- a/src/plugins/debugger/registerhandler.h
+++ b/src/plugins/debugger/registerhandler.h
@@ -40,6 +40,8 @@
 namespace Debugger {
 namespace Internal {
 
+class DebuggerEngine;
+
 enum RegisterColumns
 {
     RegisterNameColumn,
@@ -80,11 +82,16 @@ class RegisterValue
 {
 public:
     RegisterValue() { known = false; v.u64[1] = v.u64[0] = 0; }
-    void operator=(const QByteArray &ba);
     bool operator==(const RegisterValue &other);
     bool operator!=(const RegisterValue &other) { return !operator==(other); }
+
+    void fromByteArray(const QByteArray &ba, RegisterFormat format);
     QByteArray toByteArray(RegisterKind kind, int size, RegisterFormat format) const;
+
     RegisterValue subValue(int size, int index) const;
+    void setSubValue(int size, int index, RegisterValue subValue);
+
+    void shiftOneDigit(uint digit, RegisterFormat format);
 
     union {
         quint8  u8[16];
@@ -120,9 +127,10 @@ class RegisterHandler : public Utils::TreeModel
     Q_OBJECT
 
 public:
-    RegisterHandler();
+    explicit RegisterHandler(DebuggerEngine *engine);
 
     QAbstractItemModel *model() { return this; }
+    DebuggerEngine *engine() const { return m_engine; }
 
     void updateRegister(const Register &reg);
 
@@ -135,6 +143,7 @@ signals:
 
 private:
     QHash<QByteArray, RegisterItem *> m_registerByName;
+    DebuggerEngine * const m_engine;
 };
 
 } // namespace Internal
diff --git a/src/plugins/debugger/registerwindow.cpp b/src/plugins/debugger/registerwindow.cpp
index 1cdc690f5e42d9b5870e0c4aa167c9de5729ef12..254007ca59b62eddc0660c05d5c712ff0e2a4c4e 100644
--- a/src/plugins/debugger/registerwindow.cpp
+++ b/src/plugins/debugger/registerwindow.cpp
@@ -63,58 +63,42 @@ public:
     {}
 
     QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &,
-        const QModelIndex &index) const
+        const QModelIndex &index) const override
     {
-        IntegerWatchLineEdit *lineEdit = new IntegerWatchLineEdit(parent);
-        const RegisterFormat format = RegisterFormat(index.data(RegisterFormatRole).toInt());
-        const bool big = index.data(RegisterIsBigRole).toBool();
-        // Big integers are assumed to be hexadecimal.
-        int base = 16;
-        if (!big) {
-            if (format == DecimalFormat || format == SignedDecimalFormat)
-                base = 10;
-            else if (format == OctalFormat)
-                base = 8;
-            else if (format == BinaryFormat)
-                base = 2;
+        if (index.column() == RegisterValueColumn) {
+            auto lineEdit = new QLineEdit(parent);
+            lineEdit->setAlignment(Qt::AlignLeft);
+            lineEdit->setFrame(false);
+            return lineEdit;
         }
-        lineEdit->setBigInt(big);
-        lineEdit->setBase(base);
-        lineEdit->setSigned(false);
-        lineEdit->setAlignment(Qt::AlignRight);
-        lineEdit->setFrame(false);
-        return lineEdit;
+        return 0;
     }
 
-    void setEditorData(QWidget *editor, const QModelIndex &index) const
+    void setEditorData(QWidget *editor, const QModelIndex &index) const override
     {
-        IntegerWatchLineEdit *lineEdit = qobject_cast<IntegerWatchLineEdit *>(editor);
+        auto lineEdit = qobject_cast<QLineEdit *>(editor);
         QTC_ASSERT(lineEdit, return);
-        lineEdit->setModelData(index.data(Qt::EditRole));
+        lineEdit->setText(index.data(Qt::EditRole).toString());
     }
 
-    void setModelData(QWidget *editor, QAbstractItemModel *,
-        const QModelIndex &index) const
+    void setModelData(QWidget *editor, QAbstractItemModel *model,
+        const QModelIndex &index) const override
     {
-        if (index.column() != 1)
-            return;
-        IntegerWatchLineEdit *lineEdit = qobject_cast<IntegerWatchLineEdit*>(editor);
-        QTC_ASSERT(lineEdit, return);
-        const RegisterFormat format = RegisterFormat(index.data(RegisterFormatRole).toInt());
-        QString value = lineEdit->text();
-        if (format == HexadecimalFormat && !value.startsWith(QLatin1String("0x")))
-            value.insert(0, QLatin1String("0x"));
-        currentEngine()->setRegisterValue(index.data(RegisterNameRole).toByteArray(), value);
+        if (index.column() == RegisterValueColumn) {
+            auto lineEdit = qobject_cast<QLineEdit *>(editor);
+            QTC_ASSERT(lineEdit, return);
+            model->setData(index, lineEdit->text(), Qt::EditRole);
+        }
     }
 
     void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option,
-        const QModelIndex &) const
+        const QModelIndex &) const override
     {
         editor->setGeometry(option.rect);
     }
 
     void paint(QPainter *painter, const QStyleOptionViewItem &option,
-        const QModelIndex &index) const
+        const QModelIndex &index) const override
     {
         if (index.column() == RegisterValueColumn) {
             const bool paintRed = index.data(RegisterChangedRole).toBool();