Allow to create simulator without loaded executable.

This allows to test simple instruction sequences without
need to install compiler.

Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>

7 files changed, 53 insertions, 16 deletions

diff --git a/qtmips_gui/NewDialog.ui b/qtmips_gui/NewDialog.ui
index b494ffa..03f364f 100644
--- a/qtmips_gui/NewDialog.ui
+++ b/qtmips_gui/NewDialog.ui
@@ -420,10 +420,20 @@
       </spacer>
      </item>
      <item>
+      <widget class="QPushButton" name="pushButton_start_empty">
+       <property name="text">
+        <string>Start empty</string>
+       </property>
+      </widget>
+     </item>
+     <item>
       <widget class="QPushButton" name="pushButton_load">
        <property name="text">
         <string>Load machine</string>
        </property>
+       <property name="default">
+        <bool>true</bool>
+       </property>
       </widget>
      </item>
      <item>
diff --git a/qtmips_gui/mainwindow.cpp b/qtmips_gui/mainwindow.cpp
index 32bdd5b..0dc6bd5 100644
--- a/qtmips_gui/mainwindow.cpp
+++ b/qtmips_gui/mainwindow.cpp
@@ -139,9 +139,13 @@ void MainWindow::start() {
     ndialog->show();
 }
 
-void MainWindow::create_core(const machine::MachineConfig &config) {
+void MainWindow::create_core(const machine::MachineConfig &config, bool load_executable) {
     // Create machine
-    machine::QtMipsMachine *new_machine = new machine::QtMipsMachine(&config, true);
+    machine::QtMipsMachine *new_machine = new machine::QtMipsMachine(&config, true, load_executable);
+
+    if (!load_executable && (machine != nullptr)) {
+        new_machine->memory_rw()->reset(*machine->memory());
+    }
 
     // Remove old machine
     if (machine != nullptr)
@@ -233,9 +237,10 @@ void MainWindow::new_machine() {
 }
 
 void MainWindow::machine_reload() {
+    bool load_executable = machine->executable_loaded();
     machine::MachineConfig cnf(&machine->config()); // We have to make local copy as create_core will delete current machine
     try {
-        create_core(cnf);
+        create_core(cnf, load_executable);
     } catch (const machine::QtMipsExceptionInput &e) {
         QMessageBox msg(this);
         msg.setText(e.msg(false));
diff --git a/qtmips_gui/mainwindow.h b/qtmips_gui/mainwindow.h
index cbbc9ec..8a63bd8 100644
--- a/qtmips_gui/mainwindow.h
+++ b/qtmips_gui/mainwindow.h
@@ -60,7 +60,7 @@ public:
     ~MainWindow();
 
     void start();
-    void create_core(const machine::MachineConfig &config);
+    void create_core(const machine::MachineConfig &config, bool load_executable = true);
 
     bool configured();
 
diff --git a/qtmips_gui/newdialog.cpp b/qtmips_gui/newdialog.cpp
index 67d3f1d..0e1c5dc 100644
--- a/qtmips_gui/newdialog.cpp
+++ b/qtmips_gui/newdialog.cpp
@@ -52,6 +52,7 @@ NewDialog::NewDialog(QWidget *parent, QSettings *settings) : QDialog(parent) {
     ui_cache_d = new Ui::NewDialogCache();
     ui_cache_d->setupUi(ui->tab_cache_data);
 
+    connect(ui->pushButton_start_empty, SIGNAL(clicked(bool)), this, SLOT(create_empty()));
     connect(ui->pushButton_load, SIGNAL(clicked(bool)), this, SLOT(create()));
     connect(ui->pushButton_cancel, SIGNAL(clicked(bool)), this, SLOT(cancel()));
     connect(ui->pushButton_browse, SIGNAL(clicked(bool)), this, SLOT(browse_elf()));
@@ -136,6 +137,14 @@ void NewDialog::create() {
     this->close();
 }
 
+void NewDialog::create_empty() {
+    MainWindow *prnt = (MainWindow*)parent();
+    prnt->create_core(*config, false);
+    store_settings(); // Save to settings
+    this->close();
+}
+
+
 void NewDialog::browse_elf() {
     QFileDialog elf_dialog(this);
     elf_dialog.setFileMode(QFileDialog::ExistingFile);
diff --git a/qtmips_gui/newdialog.h b/qtmips_gui/newdialog.h
index 6e6ed8a..077b1ab 100644
--- a/qtmips_gui/newdialog.h
+++ b/qtmips_gui/newdialog.h
@@ -60,6 +60,7 @@ protected:
 private slots:
     void cancel();
     void create();
+    void create_empty();
     void browse_elf();
     void elf_change(QString val);
     void set_preset();
diff --git a/qtmips_machine/qtmipsmachine.cpp b/qtmips_machine/qtmipsmachine.cpp
index 35843f4..362b243 100644
--- a/qtmips_machine/qtmipsmachine.cpp
+++ b/qtmips_machine/qtmipsmachine.cpp
@@ -39,22 +39,28 @@
 
 using namespace machine;
 
-QtMipsMachine::QtMipsMachine(const MachineConfig &cc, bool load_symtab) :
+QtMipsMachine::QtMipsMachine(const MachineConfig &cc, bool load_symtab, bool load_executable) :
                              QObject(), mcnf(&cc) {
     MemoryAccess *cpu_mem;
     stat = ST_READY;
     symtab = nullptr;
 
-    ProgramLoader program(cc.elf());
-    mem_program_only = new Memory();
-    program.to_memory(mem_program_only);
-    if (load_symtab)
-        symtab = program.get_symbol_table();
-    program_end = program.end();
     regs = new Registers();
-    if (program.get_executable_entry())
-        regs->pc_abs_jmp(program.get_executable_entry());
-    mem = new Memory(*mem_program_only);
+    if (load_executable) {
+        ProgramLoader program(cc.elf());
+        mem_program_only = new Memory();
+        program.to_memory(mem_program_only);
+        if (load_symtab)
+            symtab = program.get_symbol_table();
+        program_end = program.end();
+        if (program.get_executable_entry())
+            regs->pc_abs_jmp(program.get_executable_entry());
+        mem = new Memory(*mem_program_only);
+    } else {
+        program_end = 0xf0000000;
+        mem_program_only = nullptr;
+        mem = new Memory();
+    }
 
     physaddrspace = new PhysAddrSpace();
     physaddrspace->insert_range(mem, 0x00000000, 0xefffffff, false);
@@ -201,6 +207,10 @@ const CorePipelined *QtMipsMachine::core_pipelined() {
     return mcnf.pipelined() ? (const CorePipelined*)cr : nullptr;
 }
 
+bool QtMipsMachine::executable_loaded() const {
+    return (mem_program_only != nullptr);
+}
+
 enum QtMipsMachine::Status QtMipsMachine::status() {
     return stat;
 }
@@ -266,7 +276,8 @@ void QtMipsMachine::step_timer() {
 void QtMipsMachine::restart() {
     pause();
     regs->reset();
-    mem->reset(*mem_program_only);
+    if (mem_program_only != nullptr)
+        mem->reset(*mem_program_only);
     cch_program->reset();
     cch_data->reset();
     cr->reset();
diff --git a/qtmips_machine/qtmipsmachine.h b/qtmips_machine/qtmipsmachine.h
index 5cb4100..6c0c007 100644
--- a/qtmips_machine/qtmipsmachine.h
+++ b/qtmips_machine/qtmipsmachine.h
@@ -56,7 +56,7 @@ namespace machine {
 class QtMipsMachine : public QObject {
     Q_OBJECT
 public:
-    QtMipsMachine(const MachineConfig &cc, bool load_symtab = false);
+    QtMipsMachine(const MachineConfig &cc, bool load_symtab = false, bool load_executable = true);
     ~QtMipsMachine();
 
     const MachineConfig &config();
@@ -75,6 +75,7 @@ public:
     const Core *core();
     const CoreSingle *core_singe();
     const CorePipelined *core_pipelined();
+    bool executable_loaded() const;
 
     enum Status {
         ST_READY, // Machine is ready to be started or step to be called