diff --git a/WindCore/emu.cpp b/WindCore/emu.cpp
index b8fa8de..d3418db 100644
--- a/WindCore/emu.cpp
+++ b/WindCore/emu.cpp
@@ -6,7 +6,6 @@
 
 
 Emu::Emu() {
-	configure();
 }
 
 
@@ -464,7 +463,10 @@ void Emu::loadROM(const char *path) {
 }
 
 void Emu::executeUntil(int64_t cycles) {
-    while (!asleep && cpu.cycles <= cycles) {
+    if (!configured)
+        configure();
+
+    while (!asleep && cpu.cycles < cycles) {
         if (cpu.cycles >= nextTickAt) {
             // increment RTCDIV
             if ((pwrsr & 0x3F) == 0x3F) {
diff --git a/WindCore/emu.h b/WindCore/emu.h
index e743987..35ac805 100644
--- a/WindCore/emu.h
+++ b/WindCore/emu.h
@@ -82,4 +82,5 @@ public:
     void dumpRAM(const char *path);
     void executeUntil(int64_t cycles);
     int64_t currentCycles() const { return cpu.cycles; }
+    uint32_t getGPR(int index) const { return cpu.gprs[index]; }
 };
diff --git a/WindQt/mainwindow.cpp b/WindQt/mainwindow.cpp
index 0dd9d20..2c9da90 100644
--- a/WindQt/mainwindow.cpp
+++ b/WindQt/mainwindow.cpp
@@ -3,6 +3,7 @@
 #include "../WindCore/wind.h"
 #include <QTimer>
 #include <QKeyEvent>
+#include "../WindCore/decoder.h"
 
 MainWindow::MainWindow(QWidget *parent) :
     QMainWindow(parent),
@@ -14,8 +15,10 @@ MainWindow::MainWindow(QWidget *parent) :
     emu->loadROM("/Users/ash/src/psion/Sys$rom.bin");
 
     timer = new QTimer(this);
-    timer->start(1000/64);
+    timer->setInterval(1000/64);
     connect(timer, SIGNAL(timeout()), SLOT(execTimer()));
+
+    updateScreen();
 }
 
 MainWindow::~MainWindow()
@@ -23,22 +26,54 @@ MainWindow::~MainWindow()
     delete ui;
 }
 
-void MainWindow::execTimer()
-{
-    emu->executeUntil(emu->currentCycles() + (CLOCK_SPEED / 64));
-    ui->cycleCounter->setText(QString("Cycles: %1").arg(emu->currentCycles()));
-    updateScreen();
-}
-
-void MainWindow::on_stepButton_clicked()
-{
-    emu->executeUntil(emu->currentCycles() + (CLOCK_SPEED * 2));
-    ui->cycleCounter->setText(QString("Cycles: %1").arg(emu->currentCycles()));
-    updateScreen();
-}
-
 void MainWindow::updateScreen()
 {
+    ui->cycleCounter->setText(QString("Cycles: %1").arg(emu->currentCycles()));
+
+    ui->regsLabel->setText(
+                QString("R0: %1 / R1: %2 / R2: %3 / R3: %4 / R4: %5 / R5: %6 / R6: %7 / R7: %8 / R8: %9\nR9: %10 / R10:%11 / R11:%12 / R12:%13 / SP: %14 / LR: %15 / PC: %16")
+                .arg(emu->getGPR(0), 8, 16)
+                .arg(emu->getGPR(1), 8, 16)
+                .arg(emu->getGPR(2), 8, 16)
+                .arg(emu->getGPR(3), 8, 16)
+                .arg(emu->getGPR(4), 8, 16)
+                .arg(emu->getGPR(5), 8, 16)
+                .arg(emu->getGPR(6), 8, 16)
+                .arg(emu->getGPR(7), 8, 16)
+                .arg(emu->getGPR(8), 8, 16)
+                .arg(emu->getGPR(9), 8, 16)
+                .arg(emu->getGPR(10), 8, 16)
+                .arg(emu->getGPR(11), 8, 16)
+                .arg(emu->getGPR(12), 8, 16)
+                .arg(emu->getGPR(13), 8, 16)
+                .arg(emu->getGPR(14), 8, 16)
+                .arg(emu->getGPR(15), 8, 16)
+                );
+
+    // show a crude disassembly
+    const int context = 8 * 4;
+    uint32_t pc = emu->getGPR(15) - 4;
+    uint32_t minCode = pc - context;
+    if (minCode >= (UINT32_MAX - context))
+        minCode = 0;
+    uint32_t maxCode = pc + context;
+    if (maxCode < context)
+        maxCode = UINT32_MAX;
+
+    QStringList codeLines;
+    for (uint32_t addr = minCode; addr >= minCode && addr <= maxCode; addr += 4) {
+        const char *prefix = (addr == pc) ? "==>" : "   ";
+        struct ARMInstructionInfo info;
+        char buffer[512];
+
+        uint32_t opcode = emu->readVirt32(addr);
+        ARMDecodeARM(opcode, &info);
+        ARMDisassemble(&info, addr, buffer, sizeof(buffer));
+        codeLines.append(QString("%1 %2 | %3 | %4").arg(prefix).arg(addr, 8, 16).arg(opcode, 8, 16).arg(buffer));
+    }
+    ui->codeLabel->setText(codeLines.join('\n'));
+
+    // now, the actual screen
     const uint8_t *lcdBuf = emu->getLCDBuffer();
     if (lcdBuf) {
         QImage img(640, 240, QImage::Format_Grayscale8);
@@ -169,3 +204,42 @@ void MainWindow::keyReleaseEvent(QKeyEvent *event)
     if (k >= 0)
         emu->keyboardKeys[k] = false;
 }
+
+
+
+
+void MainWindow::on_startButton_clicked()
+{
+    timer->start();
+    ui->startButton->setEnabled(false);
+    ui->stopButton->setEnabled(true);
+    ui->stepInsnButton->setEnabled(false);
+    ui->stepTickButton->setEnabled(false);
+}
+
+void MainWindow::on_stopButton_clicked()
+{
+    timer->stop();
+    ui->startButton->setEnabled(true);
+    ui->stopButton->setEnabled(false);
+    ui->stepInsnButton->setEnabled(true);
+    ui->stepTickButton->setEnabled(true);
+}
+
+void MainWindow::on_stepTickButton_clicked()
+{
+    emu->executeUntil(emu->currentCycles() + (CLOCK_SPEED * 2));
+    updateScreen();
+}
+
+void MainWindow::on_stepInsnButton_clicked()
+{
+    emu->executeUntil(emu->currentCycles() + 1);
+    updateScreen();
+}
+
+void MainWindow::execTimer()
+{
+    emu->executeUntil(emu->currentCycles() + (CLOCK_SPEED / 64));
+    updateScreen();
+}
diff --git a/WindQt/mainwindow.h b/WindQt/mainwindow.h
index 6059f6d..b2cb200 100644
--- a/WindQt/mainwindow.h
+++ b/WindQt/mainwindow.h
@@ -17,9 +17,13 @@ public:
     ~MainWindow() override;
 
 private slots:
-    void on_stepButton_clicked();
     void execTimer();
 
+    void on_startButton_clicked();
+    void on_stopButton_clicked();
+    void on_stepInsnButton_clicked();
+    void on_stepTickButton_clicked();
+
 private:
     Ui::MainWindow *ui;
     Emu *emu;
diff --git a/WindQt/mainwindow.ui b/WindQt/mainwindow.ui
index 43a46e0..6d4db52 100644
--- a/WindQt/mainwindow.ui
+++ b/WindQt/mainwindow.ui
@@ -15,6 +15,75 @@
   </property>
   <widget class="QWidget" name="centralWidget">
    <layout class="QGridLayout" name="gridLayout">
+    <item row="1" column="4">
+     <widget class="QPushButton" name="stopButton">
+      <property name="enabled">
+       <bool>false</bool>
+      </property>
+      <property name="text">
+       <string>Stop</string>
+      </property>
+     </widget>
+    </item>
+    <item row="2" column="3">
+     <widget class="QPushButton" name="stepInsnButton">
+      <property name="text">
+       <string>Step (Insn)</string>
+      </property>
+     </widget>
+    </item>
+    <item row="4" column="0" colspan="5">
+     <widget class="QTabWidget" name="tabWidget">
+      <property name="currentIndex">
+       <number>1</number>
+      </property>
+      <widget class="QWidget" name="tab">
+       <attribute name="title">
+        <string>Memory</string>
+       </attribute>
+      </widget>
+      <widget class="QWidget" name="tab_2">
+       <attribute name="title">
+        <string>Code</string>
+       </attribute>
+       <layout class="QVBoxLayout" name="verticalLayout">
+        <item>
+         <widget class="QLabel" name="codeLabel">
+          <property name="font">
+           <font>
+            <family>Courier New</family>
+           </font>
+          </property>
+          <property name="text">
+           <string>TextLabel</string>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </widget>
+     </widget>
+    </item>
+    <item row="0" column="0" colspan="6">
+     <widget class="QLabel" name="screen">
+      <property name="text">
+       <string/>
+      </property>
+     </widget>
+    </item>
+    <item row="1" column="3">
+     <widget class="QPushButton" name="startButton">
+      <property name="text">
+       <string>Start</string>
+      </property>
+     </widget>
+    </item>
+    <item row="1" column="0">
+     <widget class="QLabel" name="cycleCounter">
+      <property name="text">
+       <string>Cycles</string>
+      </property>
+     </widget>
+    </item>
     <item row="1" column="2">
      <spacer name="horizontalSpacer">
       <property name="orientation">
@@ -28,22 +97,20 @@
       </property>
      </spacer>
     </item>
-    <item row="1" column="3">
-     <widget class="QPushButton" name="stepButton">
+    <item row="2" column="4">
+     <widget class="QPushButton" name="stepTickButton">
       <property name="text">
-       <string>Step</string>
+       <string>Step (Tick)</string>
       </property>
      </widget>
     </item>
-    <item row="1" column="0">
-     <widget class="QLabel" name="cycleCounter">
-      <property name="text">
-       <string>Cycles</string>
+    <item row="3" column="0" colspan="5">
+     <widget class="QLabel" name="regsLabel">
+      <property name="font">
+       <font>
+        <family>Courier New</family>
+       </font>
       </property>
-     </widget>
-    </item>
-    <item row="0" column="0" colspan="4">
-     <widget class="QLabel" name="screen">
       <property name="text">
        <string/>
       </property>