11 files changed, 567 insertions, 58 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 4fcda4874..9b004440c 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -25,6 +25,8 @@ set(SRCS
             file_sys/ivfc_archive.cpp
             hle/config_mem.cpp
             hle/hle.cpp
+            hle/applets/applet.cpp
+            hle/applets/swkbd.cpp
             hle/kernel/address_arbiter.cpp
             hle/kernel/event.cpp
             hle/kernel/kernel.cpp
@@ -150,6 +152,8 @@ set(HEADERS
             hle/config_mem.h
             hle/function_wrappers.h
             hle/hle.h
+            hle/applets/applet.h
+            hle/applets/swkbd.h
             hle/kernel/address_arbiter.h
             hle/kernel/event.h
             hle/kernel/kernel.h
diff --git a/src/core/hle/applets/applet.cpp b/src/core/hle/applets/applet.cpp
new file mode 100644
index 000000000..4dcce729a
--- /dev/null
+++ b/src/core/hle/applets/applet.cpp
@@ -0,0 +1,94 @@
+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/assert.h"
+#include "common/logging/log.h"
+
+#include "core/core_timing.h"
+#include "core/hle/applets/applet.h"
+#include "core/hle/applets/swkbd.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+// Specializes std::hash for AppletId, so that we can use it in std::unordered_map.
+// Workaround for libstdc++ bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60970
+namespace std {
+    template <>
+    struct hash<Service::APT::AppletId> {
+        typedef Service::APT::AppletId argument_type;
+        typedef std::size_t result_type;
+
+        result_type operator()(const argument_type& id_code) const {
+            typedef std::underlying_type<argument_type>::type Type;
+            return std::hash<Type>()(static_cast<Type>(id_code));
+        }
+    };
+}
+
+namespace HLE {
+namespace Applets {
+
+static std::unordered_map<Service::APT::AppletId, std::shared_ptr<Applet>> applets;
+static u32 applet_update_event = -1; ///< The CoreTiming event identifier for the Applet update callback.
+/// The interval at which the Applet update callback will be called, 16.6ms
+static const u64 applet_update_interval_us = 16666;
+
+ResultCode Applet::Create(Service::APT::AppletId id) {
+    switch (id) {
+    case Service::APT::AppletId::SoftwareKeyboard1:
+    case Service::APT::AppletId::SoftwareKeyboard2:
+        applets[id] = std::make_shared<SoftwareKeyboard>(id);
+        break;
+    default:
+        // TODO(Subv): Find the right error code
+        return ResultCode(ErrorDescription::NotFound, ErrorModule::Applet, ErrorSummary::NotSupported, ErrorLevel::Permanent);
+    }
+
+    return RESULT_SUCCESS;
+}
+
+std::shared_ptr<Applet> Applet::Get(Service::APT::AppletId id) {
+    auto itr = applets.find(id);
+    if (itr != applets.end())
+        return itr->second;
+    return nullptr;
+}
+
+/// Handles updating the current Applet every time it's called.
+static void AppletUpdateEvent(u64 applet_id, int cycles_late) {
+    Service::APT::AppletId id = static_cast<Service::APT::AppletId>(applet_id);
+    std::shared_ptr<Applet> applet = Applet::Get(id);
+    ASSERT_MSG(applet != nullptr, "Applet doesn't exist! applet_id=%08X", id);
+
+    applet->Update();
+
+    // If the applet is still running after the last update, reschedule the event
+    if (applet->IsRunning()) {
+        CoreTiming::ScheduleEvent(usToCycles(applet_update_interval_us) - cycles_late,
+            applet_update_event, applet_id);
+    } else {
+        // Otherwise the applet has terminated, in which case we should clean it up
+        applets[id] = nullptr;
+    }
+}
+
+ResultCode Applet::Start(const Service::APT::AppletStartupParameter& parameter) {
+    ResultCode result = StartImpl(parameter);
+    if (result.IsError())
+        return result;
+    // Schedule the update event
+    CoreTiming::ScheduleEvent(usToCycles(applet_update_interval_us), applet_update_event, static_cast<u64>(id));
+    return result;
+}
+
+void Init() {
+    // Register the applet update callback
+    applet_update_event = CoreTiming::RegisterEvent("HLE Applet Update Event", AppletUpdateEvent);
+}
+
+void Shutdown() {
+}
+
+}
+} // namespace
diff --git a/src/core/hle/applets/applet.h b/src/core/hle/applets/applet.h
new file mode 100644
index 000000000..fe537e70d
--- /dev/null
+++ b/src/core/hle/applets/applet.h
@@ -0,0 +1,77 @@
+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_types.h"
+#include "core/hle/kernel/kernel.h"
+#include "core/hle/kernel/shared_memory.h"
+#include "core/hle/service/apt/apt.h"
+
+namespace HLE {
+namespace Applets {
+
+class Applet {
+public:
+    virtual ~Applet() { }
+    Applet(Service::APT::AppletId id) : id(id) { }
+
+    /**
+     * Creates an instance of the Applet subclass identified by the parameter.
+     * and stores it in a global map.
+     * @param id Id of the applet to create.
+     * @returns ResultCode Whether the operation was successful or not.
+     */
+    static ResultCode Create(Service::APT::AppletId id);
+
+    /**
+     * Retrieves the Applet instance identified by the specified id.
+     * @param id Id of the Applet to retrieve.
+     * @returns Requested Applet or nullptr if not found.
+     */
+    static std::shared_ptr<Applet> Get(Service::APT::AppletId id);
+
+    /**
+     * Handles a parameter from the application.
+     * @param parameter Parameter data to handle.
+     * @returns ResultCode Whether the operation was successful or not.
+     */
+    virtual ResultCode ReceiveParameter(const Service::APT::MessageParameter& parameter) = 0;
+
+    /**
+     * Handles the Applet start event, triggered from the application.
+     * @param parameter Parameter data to handle.
+     * @returns ResultCode Whether the operation was successful or not.
+     */
+    ResultCode Start(const Service::APT::AppletStartupParameter& parameter);
+
+    /**
+     * Whether the applet is currently executing instead of the host application or not.
+     */
+    virtual bool IsRunning() const = 0;
+
+    /**
+     * Handles an update tick for the Applet, lets it update the screen, send commands, etc.
+     */
+    virtual void Update() = 0;
+
+protected:
+    /**
+     * Handles the Applet start event, triggered from the application.
+     * @param parameter Parameter data to handle.
+     * @returns ResultCode Whether the operation was successful or not.
+     */
+    virtual ResultCode StartImpl(const Service::APT::AppletStartupParameter& parameter) = 0;
+
+    Service::APT::AppletId id; ///< Id of this Applet
+};
+
+/// Initializes the HLE applets
+void Init();
+
+/// Shuts down the HLE applets
+void Shutdown();
+
+}
+} // namespace
diff --git a/src/core/hle/applets/swkbd.cpp b/src/core/hle/applets/swkbd.cpp
new file mode 100644
index 000000000..7431ebcf8
--- /dev/null
+++ b/src/core/hle/applets/swkbd.cpp
@@ -0,0 +1,105 @@
+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/assert.h"
+#include "common/logging/log.h"
+#include "common/string_util.h"
+
+#include "core/hle/applets/swkbd.h"
+#include "core/hle/service/hid/hid.h"
+#include "core/hle/service/gsp_gpu.h"
+#include "video_core/video_core.h"
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+namespace HLE {
+namespace Applets {
+
+SoftwareKeyboard::SoftwareKeyboard(Service::APT::AppletId id) : Applet(id), started(false) {
+    // Create the SharedMemory that will hold the framebuffer data
+    // TODO(Subv): What size should we use here?
+    using Kernel::MemoryPermission;
+    framebuffer_memory = Kernel::SharedMemory::Create(0x1000, MemoryPermission::ReadWrite, MemoryPermission::ReadWrite, "SoftwareKeyboard Memory");
+}
+
+ResultCode SoftwareKeyboard::ReceiveParameter(Service::APT::MessageParameter const& parameter) {
+    if (parameter.signal != static_cast<u32>(Service::APT::SignalType::LibAppJustStarted)) {
+        LOG_ERROR(Service_APT, "unsupported signal %u", parameter.signal);
+        UNIMPLEMENTED();
+        // TODO(Subv): Find the right error code
+        return ResultCode(-1);
+    }
+
+    Service::APT::MessageParameter result;
+    // The buffer passed in parameter contains the data returned by GSPGPU::ImportDisplayCaptureInfo
+    result.signal = static_cast<u32>(Service::APT::SignalType::LibAppFinished);
+    result.data = nullptr;
+    result.buffer_size = 0;
+    result.destination_id = static_cast<u32>(Service::APT::AppletId::Application);
+    result.sender_id = static_cast<u32>(id);
+    result.object = framebuffer_memory;
+
+    Service::APT::SendParameter(result);
+    return RESULT_SUCCESS;
+}
+
+ResultCode SoftwareKeyboard::StartImpl(Service::APT::AppletStartupParameter const& parameter) {
+    ASSERT_MSG(parameter.buffer_size == sizeof(config), "The size of the parameter (SoftwareKeyboardConfig) is wrong");
+
+    memcpy(&config, parameter.data, parameter.buffer_size);
+    text_memory = boost::static_pointer_cast<Kernel::SharedMemory, Kernel::Object>(parameter.object);
+
+    // TODO(Subv): Verify if this is the correct behavior
+    memset(text_memory->GetPointer(), 0, text_memory->size);
+
+    DrawScreenKeyboard();
+
+    started = true;
+    return RESULT_SUCCESS;
+}
+
+void SoftwareKeyboard::Update() {
+    // TODO(Subv): Handle input using the touch events from the HID module
+
+    // TODO(Subv): Remove this hardcoded text
+    std::u16string text = Common::UTF8ToUTF16("Citra");
+    memcpy(text_memory->GetPointer(), text.c_str(), text.length() * sizeof(char16_t));
+
+    // TODO(Subv): Ask for input and write it to the shared memory
+    // TODO(Subv): Find out what are the possible values for the return code,
+    // some games seem to check for a hardcoded 2
+    config.return_code = 2;
+    config.text_length = 6;
+    config.text_offset = 0;
+
+    // TODO(Subv): We're finalizing the applet immediately after it's started,
+    // but we should defer this call until after all the input has been collected.
+    Finalize();
+}
+
+void SoftwareKeyboard::DrawScreenKeyboard() {
+    auto bottom_screen = GSP_GPU::GetFrameBufferInfo(0, 1);
+    auto info = bottom_screen->framebuffer_info[bottom_screen->index];
+
+    // TODO(Subv): Draw the HLE keyboard, for now just zero-fill the framebuffer
+    memset(Memory::GetPointer(info.address_left), 0, info.stride * 320);
+
+    GSP_GPU::SetBufferSwap(1, info);
+}
+
+void SoftwareKeyboard::Finalize() {
+    // Let the application know that we're closing
+    Service::APT::MessageParameter message;
+    message.buffer_size = sizeof(SoftwareKeyboardConfig);
+    message.data = reinterpret_cast<u8*>(&config);
+    message.signal = static_cast<u32>(Service::APT::SignalType::LibAppClosed);
+    message.destination_id = static_cast<u32>(Service::APT::AppletId::Application);
+    message.sender_id = static_cast<u32>(id);
+    Service::APT::SendParameter(message);
+
+    started = false;
+}
+
+}
+} // namespace
diff --git a/src/core/hle/applets/swkbd.h b/src/core/hle/applets/swkbd.h
new file mode 100644
index 000000000..98e81c48a
--- /dev/null
+++ b/src/core/hle/applets/swkbd.h
@@ -0,0 +1,87 @@
+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_types.h"
+#include "core/hle/applets/applet.h"
+#include "core/hle/kernel/kernel.h"
+#include "core/hle/kernel/shared_memory.h"
+#include "core/hle/service/apt/apt.h"
+
+namespace HLE {
+namespace Applets {
+
+struct SoftwareKeyboardConfig {
+    INSERT_PADDING_WORDS(0x8);
+
+    u16 max_text_length; ///< Maximum length of the input text
+
+    INSERT_PADDING_BYTES(0x6E);
+
+    char16_t display_text[65]; ///< Text to display when asking the user for input
+
+    INSERT_PADDING_BYTES(0xE);
+
+    u32 default_text_offset; ///< Offset of the default text in the output SharedMemory
+
+    INSERT_PADDING_WORDS(0x3);
+
+    u32 shared_memory_size; ///< Size of the SharedMemory
+
+    INSERT_PADDING_WORDS(0x1);
+
+    u32 return_code; ///< Return code of the SoftwareKeyboard, usually 2, other values are unknown
+
+    INSERT_PADDING_WORDS(0x2);
+
+    u32 text_offset; ///< Offset in the SharedMemory where the output text starts
+    u16 text_length; ///< Length in characters of the output text
+
+    INSERT_PADDING_BYTES(0x2B6);
+};
+
+/**
+ * The size of this structure (0x400) has been verified via reverse engineering of multiple games
+ * that use the software keyboard.
+ */
+static_assert(sizeof(SoftwareKeyboardConfig) == 0x400, "Software Keyboard Config size is wrong");
+
+class SoftwareKeyboard final : public Applet {
+public:
+    SoftwareKeyboard(Service::APT::AppletId id);
+    ~SoftwareKeyboard() {}
+
+    ResultCode ReceiveParameter(const Service::APT::MessageParameter& parameter) override;
+    ResultCode StartImpl(const Service::APT::AppletStartupParameter& parameter) override;
+    void Update() override;
+    bool IsRunning() const override { return started; }
+
+    /**
+     * Draws a keyboard to the current bottom screen framebuffer.
+     */
+    void DrawScreenKeyboard();
+
+    /**
+     * Sends the LibAppletClosing signal to the application,
+     * along with the relevant data buffers.
+     */
+    void Finalize();
+
+    /// TODO(Subv): Find out what this is actually used for.
+    /// It is believed that the application stores the current screen image here.
+    Kernel::SharedPtr<Kernel::SharedMemory> framebuffer_memory;
+
+    /// SharedMemory where the output text will be stored
+    Kernel::SharedPtr<Kernel::SharedMemory> text_memory;
+
+    /// Configuration of this instance of the SoftwareKeyboard, as received from the application
+    SoftwareKeyboardConfig config;
+
+    /// Whether this applet is currently running instead of the host application or not.
+    bool started;
+};
+
+}
+} // namespace
diff --git a/src/core/hle/service/apt/apt.cpp b/src/core/hle/service/apt/apt.cpp
index b454a2709..b364beed9 100644
--- a/src/core/hle/service/apt/apt.cpp
+++ b/src/core/hle/service/apt/apt.cpp
@@ -6,6 +6,7 @@
 #include "common/file_util.h"
 #include "common/logging/log.h"
 
+#include "core/hle/applets/applet.h"
 #include "core/hle/service/service.h"
 #include "core/hle/service/apt/apt.h"
 #include "core/hle/service/apt/apt_a.h"
@@ -34,12 +35,21 @@ static Kernel::SharedPtr<Kernel::SharedMemory> shared_font_mem;
 
 static Kernel::SharedPtr<Kernel::Mutex> lock;
 static Kernel::SharedPtr<Kernel::Event> notification_event; ///< APT notification event
-static Kernel::SharedPtr<Kernel::Event> start_event; ///< APT start event
+static Kernel::SharedPtr<Kernel::Event> parameter_event; ///< APT parameter event
 
 static std::vector<u8> shared_font;
 
 static u32 cpu_percent; ///< CPU time available to the running application
 
+/// Parameter data to be returned in the next call to Glance/ReceiveParameter
+static MessageParameter next_parameter;
+
+void SendParameter(const MessageParameter& parameter) {
+    next_parameter = parameter;
+    // Signal the event to let the application know that a new parameter is ready to be read
+    parameter_event->Signal();
+}
+
 void Initialize(Service::Interface* self) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 app_id = cmd_buff[1];
@@ -47,18 +57,18 @@ void Initialize(Service::Interface* self) {
 
     cmd_buff[2] = IPC::MoveHandleDesc(2);
     cmd_buff[3] = Kernel::g_handle_table.Create(notification_event).MoveFrom();
-    cmd_buff[4] = Kernel::g_handle_table.Create(start_event).MoveFrom();
+    cmd_buff[4] = Kernel::g_handle_table.Create(parameter_event).MoveFrom();
 
     // TODO(bunnei): Check if these events are cleared every time Initialize is called.
     notification_event->Clear();
-    start_event->Clear();
+    parameter_event->Clear();
 
     ASSERT_MSG((nullptr != lock), "Cannot initialize without lock");
     lock->Release();
 
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
 
-    LOG_TRACE(Service_APT, "called app_id=0x%08X, flags=0x%08X", app_id, flags);
+    LOG_DEBUG(Service_APT, "called app_id=0x%08X, flags=0x%08X", app_id, flags);
 }
 
 void GetSharedFont(Service::Interface* self) {
@@ -85,9 +95,6 @@ void GetSharedFont(Service::Interface* self) {
 void NotifyToWait(Service::Interface* self) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 app_id = cmd_buff[1];
-    // TODO(Subv): Verify this, it seems to get SWKBD and Home Menu further.
-    start_event->Signal();
-
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
     LOG_WARNING(Service_APT, "(STUBBED) app_id=%u", app_id);
 }
@@ -100,7 +107,7 @@ void GetLockHandle(Service::Interface* self) {
 
     // Not sure what these parameters are used for, but retail apps check that they are 0 after
     // GetLockHandle has been called.
-    cmd_buff[2] = 0;
+    cmd_buff[2] = 0; // Applet Attributes, this value is passed to Enable.
     cmd_buff[3] = 0;
     cmd_buff[4] = 0;
 
@@ -110,9 +117,10 @@ void GetLockHandle(Service::Interface* self) {
 
 void Enable(Service::Interface* self) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
-    u32 unk = cmd_buff[1]; // TODO(bunnei): What is this field used for?
+    u32 attributes = cmd_buff[1];
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
-    LOG_WARNING(Service_APT, "(STUBBED) called unk=0x%08X", unk);
+    parameter_event->Signal(); // Let the application know that it has been started
+    LOG_WARNING(Service_APT, "(STUBBED) called attributes=0x%08X", attributes);
 }
 
 void GetAppletManInfo(Service::Interface* self) {
@@ -121,8 +129,8 @@ void GetAppletManInfo(Service::Interface* self) {
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
     cmd_buff[2] = 0;
     cmd_buff[3] = 0;
-    cmd_buff[4] = static_cast<u32>(AppID::HomeMenu); // Home menu AppID
-    cmd_buff[5] = static_cast<u32>(AppID::Application); // TODO(purpasmart96): Do this correctly
+    cmd_buff[4] = static_cast<u32>(AppletId::HomeMenu); // Home menu AppID
+    cmd_buff[5] = static_cast<u32>(AppletId::Application); // TODO(purpasmart96): Do this correctly
 
     LOG_WARNING(Service_APT, "(STUBBED) called unk=0x%08X", unk);
 }
@@ -131,7 +139,13 @@ void IsRegistered(Service::Interface* self) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 app_id = cmd_buff[1];
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
-    cmd_buff[2] = 1; // Set to registered
+    /// TODO(Subv): It is currently unknown what this value (0x400) means,
+    /// but i believe it is used as a global "LibraryApplet" id, to verify if there's
+    /// any LibApplet currently running. This is not verified.
+    if (app_id != 0x400)
+        cmd_buff[2] = 1; // Set to registered
+    else
+        cmd_buff[2] = 0; // Set to not registered
     LOG_WARNING(Service_APT, "(STUBBED) called app_id=0x%08X", app_id);
 }
 
@@ -145,50 +159,82 @@ void InquireNotification(Service::Interface* self) {
 
 void SendParameter(Service::Interface* self) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
-    u32 src_app_id          = cmd_buff[1];
-    u32 dst_app_id          = cmd_buff[2];
-    u32 signal_type         = cmd_buff[3];
-    u32 buffer_size         = cmd_buff[4];
-    u32 value               = cmd_buff[5];
-    u32 handle              = cmd_buff[6];
-    u32 size                = cmd_buff[7];
-    u32 in_param_buffer_ptr = cmd_buff[8];
+    u32 src_app_id     = cmd_buff[1];
+    u32 dst_app_id     = cmd_buff[2];
+    u32 signal_type    = cmd_buff[3];
+    u32 buffer_size    = cmd_buff[4];
+    u32 value          = cmd_buff[5];
+    u32 handle         = cmd_buff[6];
+    u32 size           = cmd_buff[7];
+    u32 buffer         = cmd_buff[8];
+
+    std::shared_ptr<HLE::Applets::Applet> dest_applet = HLE::Applets::Applet::Get(static_cast<AppletId>(dst_app_id));
+
+    if (dest_applet == nullptr) {
+        LOG_ERROR(Service_APT, "Unknown applet id=0x%08X", dst_app_id);
+        cmd_buff[1] = -1; // TODO(Subv): Find the right error code
+        return;
+    }
 
-    cmd_buff[1] = RESULT_SUCCESS.raw; // No error
+    MessageParameter param;
+    param.buffer_size = buffer_size;
+    param.destination_id = dst_app_id;
+    param.sender_id = src_app_id;
+    param.object = Kernel::g_handle_table.GetGeneric(handle);
+    param.signal = signal_type;
+    param.data = Memory::GetPointer(buffer);
+
+    cmd_buff[1] = dest_applet->ReceiveParameter(param).raw;
 
     LOG_WARNING(Service_APT, "(STUBBED) called src_app_id=0x%08X, dst_app_id=0x%08X, signal_type=0x%08X,"
                "buffer_size=0x%08X, value=0x%08X, handle=0x%08X, size=0x%08X, in_param_buffer_ptr=0x%08X",
-               src_app_id, dst_app_id, signal_type, buffer_size, value, handle, size, in_param_buffer_ptr);
+               src_app_id, dst_app_id, signal_type, buffer_size, value, handle, size, buffer);
 }
 
 void ReceiveParameter(Service::Interface* self) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 app_id = cmd_buff[1];
     u32 buffer_size = cmd_buff[2];
+    VAddr buffer = cmd_buff[0x104 >> 2];
+
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
-    cmd_buff[2] = 0;
-    cmd_buff[3] = static_cast<u32>(SignalType::AppJustStarted); // Signal type
-    cmd_buff[4] = 0x10; // Parameter buffer size (16)
-    cmd_buff[5] = 0;
+    cmd_buff[2] = next_parameter.sender_id;
+    cmd_buff[3] = next_parameter.signal; // Signal type
+    cmd_buff[4] = next_parameter.buffer_size; // Parameter buffer size
+    cmd_buff[5] = 0x10;
     cmd_buff[6] = 0;
-    cmd_buff[7] = 0;
-    LOG_WARNING(Service_APT, "(STUBBED) called app_id=0x%08X, buffer_size=0x%08X", app_id, buffer_size);
+    if (next_parameter.object != nullptr)
+        cmd_buff[6] = Kernel::g_handle_table.Create(next_parameter.object).MoveFrom();
+    cmd_buff[7] = (next_parameter.buffer_size << 14) | 2;
+    cmd_buff[8] = buffer;
+
+    if (next_parameter.data)
+        memcpy(Memory::GetPointer(buffer), next_parameter.data, std::min(buffer_size, next_parameter.buffer_size));
+
+    LOG_WARNING(Service_APT, "called app_id=0x%08X, buffer_size=0x%08X", app_id, buffer_size);
 }
 
 void GlanceParameter(Service::Interface* self) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 app_id = cmd_buff[1];
     u32 buffer_size = cmd_buff[2];
+    VAddr buffer = cmd_buff[0x104 >> 2];
 
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
-    cmd_buff[2] = 0;
-    cmd_buff[3] = static_cast<u32>(SignalType::AppJustStarted); // Signal type
-    cmd_buff[4] = 0x10; // Parameter buffer size (16)
-    cmd_buff[5] = 0;
+    cmd_buff[2] = next_parameter.sender_id;
+    cmd_buff[3] = next_parameter.signal; // Signal type
+    cmd_buff[4] = next_parameter.buffer_size; // Parameter buffer size
+    cmd_buff[5] = 0x10;
     cmd_buff[6] = 0;
-    cmd_buff[7] = 0;
+    if (next_parameter.object != nullptr)
+        cmd_buff[6] = Kernel::g_handle_table.Create(next_parameter.object).MoveFrom();
+    cmd_buff[7] = (next_parameter.buffer_size << 14) | 2;
+    cmd_buff[8] = buffer;
+
+    if (next_parameter.data)
+        memcpy(Memory::GetPointer(buffer), next_parameter.data, std::min(buffer_size, next_parameter.buffer_size));
 
-    LOG_WARNING(Service_APT, "(STUBBED) called app_id=0x%08X, buffer_size=0x%08X", app_id, buffer_size);
+    LOG_WARNING(Service_APT, "called app_id=0x%08X, buffer_size=0x%08X", app_id, buffer_size);
 }
 
 void CancelParameter(Service::Interface* self) {
@@ -240,7 +286,7 @@ void AppletUtility(Service::Interface* self) {
     u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // These are from 3dbrew - I'm not really sure what they're used for.
-    u32 unk = cmd_buff[1];
+    u32 command = cmd_buff[1];
     u32 buffer1_size = cmd_buff[2];
     u32 buffer2_size = cmd_buff[3];
     u32 buffer1_addr = cmd_buff[5];
@@ -248,8 +294,8 @@ void AppletUtility(Service::Interface* self) {
 
     cmd_buff[1] = RESULT_SUCCESS.raw; // No error
 
-    LOG_WARNING(Service_APT, "(STUBBED) called unk=0x%08X, buffer1_size=0x%08X, buffer2_size=0x%08X, "
-             "buffer1_addr=0x%08X, buffer2_addr=0x%08X", unk, buffer1_size, buffer2_size,
+    LOG_WARNING(Service_APT, "(STUBBED) called command=0x%08X, buffer1_size=0x%08X, buffer2_size=0x%08X, "
+             "buffer1_addr=0x%08X, buffer2_addr=0x%08X", command, buffer1_size, buffer2_size,
              buffer1_addr, buffer2_addr);
 }
 
@@ -281,11 +327,41 @@ void GetAppCpuTimeLimit(Service::Interface* self) {
     LOG_WARNING(Service_APT, "(STUBBED) called value=%u", value);
 }
 
+void PrepareToStartLibraryApplet(Service::Interface* self) {
+    u32* cmd_buff = Kernel::GetCommandBuffer();
+    AppletId applet_id = static_cast<AppletId>(cmd_buff[1]);
+    cmd_buff[1] = HLE::Applets::Applet::Create(applet_id).raw;
+    LOG_DEBUG(Service_APT, "called applet_id=%08X", applet_id);
+}
+
+void StartLibraryApplet(Service::Interface* self) {
+    u32* cmd_buff = Kernel::GetCommandBuffer();
+    AppletId applet_id = static_cast<AppletId>(cmd_buff[1]);
+    std::shared_ptr<HLE::Applets::Applet> applet = HLE::Applets::Applet::Get(applet_id);
+
+    LOG_DEBUG(Service_APT, "called applet_id=%08X", applet_id);
+
+    if (applet == nullptr) {
+        LOG_ERROR(Service_APT, "unknown applet id=%08X", applet_id);
+        cmd_buff[1] = -1; // TODO(Subv): Find the right error code
+        return;
+    }
+
+    AppletStartupParameter parameter;
+    parameter.buffer_size = cmd_buff[2];
+    parameter.object = Kernel::g_handle_table.GetGeneric(cmd_buff[4]);
+    parameter.data = Memory::GetPointer(cmd_buff[6]);
+
+    cmd_buff[1] = applet->Start(parameter).raw;
+}
+
 void Init() {
     AddService(new APT_A_Interface);
     AddService(new APT_S_Interface);
     AddService(new APT_U_Interface);
 
+    HLE::Applets::Init();
+
     // Load the shared system font (if available).
     // The expected format is a decrypted, uncompressed BCFNT file with the 0x80 byte header
     // generated by the APT:U service. The best way to get is by dumping it from RAM. We've provided
@@ -318,7 +394,10 @@ void Init() {
 
     // TODO(bunnei): Check if these are created in Initialize or on APT process startup.
     notification_event = Kernel::Event::Create(RESETTYPE_ONESHOT, "APT_U:Notification");
-    start_event = Kernel::Event::Create(RESETTYPE_ONESHOT, "APT_U:Start");
+    parameter_event = Kernel::Event::Create(RESETTYPE_ONESHOT, "APT_U:Start");
+
+    next_parameter.signal = static_cast<u32>(SignalType::AppJustStarted);
+    next_parameter.destination_id = 0x300;
 }
 
 void Shutdown() {
@@ -326,7 +405,8 @@ void Shutdown() {
     shared_font_mem = nullptr;
     lock = nullptr;
     notification_event = nullptr;
-    start_event = nullptr;
+    parameter_event = nullptr;
+    HLE::Applets::Shutdown();
 }
 
 } // namespace APT
diff --git a/src/core/hle/service/apt/apt.h b/src/core/hle/service/apt/apt.h
index a03e1712a..9f0802508 100644
--- a/src/core/hle/service/apt/apt.h
+++ b/src/core/hle/service/apt/apt.h
@@ -11,6 +11,23 @@
 namespace Service {
 namespace APT {
 
+/// Holds information about the parameters used in Send/Glance/ReceiveParameter
+struct MessageParameter {
+    u32 sender_id = 0;
+    u32 destination_id = 0;
+    u32 signal = 0;
+    u32 buffer_size = 0;
+    Kernel::SharedPtr<Kernel::Object> object = nullptr;
+    u8* data = nullptr;
+};
+
+/// Holds information about the parameters used in StartLibraryApplet
+struct AppletStartupParameter {
+    u32 buffer_size = 0;
+    Kernel::SharedPtr<Kernel::Object> object = nullptr;
+    u8* data = nullptr;
+};
+
 /// Signals used by APT functions
 enum class SignalType : u32 {
     None              = 0x0,
@@ -23,7 +40,7 @@ enum class SignalType : u32 {
 };
 
 /// App Id's used by APT functions
-enum class AppID : u32 {
+enum class AppletId : u32 {
     HomeMenu           = 0x101,
     AlternateMenu      = 0x103,
     Camera             = 0x110,
@@ -45,6 +62,9 @@ enum class AppID : u32 {
     SoftwareKeyboard2  = 0x401,
 };
 
+/// Send a parameter to the currently-running application, which will read it via ReceiveParameter
+void SendParameter(const MessageParameter& parameter);
+
 /**
  * APT::Initialize service function
  * Service function that initializes the APT process for the running application
@@ -249,6 +269,33 @@ void SetAppCpuTimeLimit(Service::Interface* self);
  */
 void GetAppCpuTimeLimit(Service::Interface* self);
 
+/**
+ * APT::PrepareToStartLibraryApplet service function
+ *  Inputs:
+ *      0 : Command header [0x00180040]
+ *      1 : Id of the applet to start
+ *  Outputs:
+ *      0 : Return header
+ *      1 : Result of function, 0 on success, otherwise error code
+ */
+void PrepareToStartLibraryApplet(Service::Interface* self);
+
+/**
+ * APT::StartLibraryApplet service function
+ *  Inputs:
+ *      0 : Command header [0x001E0084]
+ *      1 : Id of the applet to start
+ *      2 : Buffer size
+ *      3 : Always 0?
+ *      4 : Handle passed to the applet
+ *      5 : (Size << 14) | 2
+ *      6 : Input buffer virtual address
+ *  Outputs:
+ *      0 : Return header
+ *      1 : Result of function, 0 on success, otherwise error code
+ */
+void StartLibraryApplet(Service::Interface* self);
+
 /// Initialize the APT service
 void Init();
 
diff --git a/src/core/hle/service/apt/apt_a.cpp b/src/core/hle/service/apt/apt_a.cpp
index 864934245..88de339f9 100644
--- a/src/core/hle/service/apt/apt_a.cpp
+++ b/src/core/hle/service/apt/apt_a.cpp
@@ -10,19 +10,24 @@ namespace Service {
 namespace APT {
 
 const Interface::FunctionInfo FunctionTable[] = {
-    {0x00010040, GetLockHandle,      "GetLockHandle?"},
-    {0x00020080, Initialize,         "Initialize?"},
-    {0x00030040, Enable,             "Enable?"},
-    {0x00040040, nullptr,            "Finalize?"},
-    {0x00050040, nullptr,            "GetAppletManInfo?"},
-    {0x00060040, nullptr,            "GetAppletInfo?"},
-    {0x000D0080, ReceiveParameter,   "ReceiveParameter?"},
-    {0x000E0080, GlanceParameter,    "GlanceParameter?"},
-    {0x003B0040, nullptr,            "CancelLibraryApplet?"},
-    {0x00430040, NotifyToWait,       "NotifyToWait?"},
-    {0x00440000, GetSharedFont,      "GetSharedFont?"},
-    {0x004B00C2, AppletUtility,      "AppletUtility?"},
-    {0x00550040, nullptr,            "WriteInputToNsState?"},
+    {0x00010040, GetLockHandle,                "GetLockHandle?"},
+    {0x00020080, Initialize,                   "Initialize?"},
+    {0x00030040, Enable,                       "Enable?"},
+    {0x00040040, nullptr,                      "Finalize?"},
+    {0x00050040, nullptr,                      "GetAppletManInfo?"},
+    {0x00060040, nullptr,                      "GetAppletInfo?"},
+    {0x00090040, IsRegistered,                 "IsRegistered"},
+    {0x000C0104, SendParameter,                "SendParameter"},
+    {0x000D0080, ReceiveParameter,             "ReceiveParameter"},
+    {0x000E0080, GlanceParameter,              "GlanceParameter"},
+    {0x000F0100, CancelParameter,              "CancelParameter"},
+    {0x00180040, PrepareToStartLibraryApplet,  "PrepareToStartLibraryApplet"},
+    {0x001E0084, StartLibraryApplet,           "StartLibraryApplet"},
+    {0x003B0040, nullptr,                      "CancelLibraryApplet?"},
+    {0x00430040, NotifyToWait,                 "NotifyToWait?"},
+    {0x00440000, GetSharedFont,                "GetSharedFont?"},
+    {0x004B00C2, AppletUtility,                "AppletUtility?"},
+    {0x00550040, nullptr,                      "WriteInputToNsState?"},
 };
 
 APT_A_Interface::APT_A_Interface() {
diff --git a/src/core/hle/service/apt/apt_u.cpp b/src/core/hle/service/apt/apt_u.cpp
index d006b5930..b724cd72b 100644
--- a/src/core/hle/service/apt/apt_u.cpp
+++ b/src/core/hle/service/apt/apt_u.cpp
@@ -35,13 +35,13 @@ const Interface::FunctionInfo FunctionTable[] = {
     {0x00150140, nullptr,                         "PrepareToStartApplication"},
     {0x00160040, nullptr,                         "PreloadLibraryApplet"},
     {0x00170040, nullptr,                         "FinishPreloadingLibraryApplet"},
-    {0x00180040, nullptr,                         "PrepareToStartLibraryApplet"},
+    {0x00180040, PrepareToStartLibraryApplet,     "PrepareToStartLibraryApplet"},
     {0x00190040, nullptr,                         "PrepareToStartSystemApplet"},
     {0x001A0000, nullptr,                         "PrepareToStartNewestHomeMenu"},
     {0x001B00C4, nullptr,                         "StartApplication"},
     {0x001C0000, nullptr,                         "WakeupApplication"},
     {0x001D0000, nullptr,                         "CancelApplication"},
-    {0x001E0084, nullptr,                         "StartLibraryApplet"},
+    {0x001E0084, StartLibraryApplet,              "StartLibraryApplet"},
     {0x001F0084, nullptr,                         "StartSystemApplet"},
     {0x00200044, nullptr,                         "StartNewestHomeMenu"},
     {0x00210000, nullptr,                         "OrderToCloseApplication"},
diff --git a/src/core/hle/service/gsp_gpu.cpp b/src/core/hle/service/gsp_gpu.cpp
index f56bbe50f..f175085e8 100644
--- a/src/core/hle/service/gsp_gpu.cpp
+++ b/src/core/hle/service/gsp_gpu.cpp
@@ -42,7 +42,7 @@ static inline u8* GetCommandBuffer(u32 thread_id) {
     return g_shared_memory->GetPointer(0x800 + (thread_id * sizeof(CommandBuffer)));
 }
 
-static inline FrameBufferUpdate* GetFrameBufferInfo(u32 thread_id, u32 screen_index) {
+FrameBufferUpdate* GetFrameBufferInfo(u32 thread_id, u32 screen_index) {
     DEBUG_ASSERT_MSG(screen_index < 2, "Invalid screen index");
 
     // For each thread there are two FrameBufferUpdate fields
@@ -205,7 +205,7 @@ static void ReadHWRegs(Service::Interface* self) {
     }
 }
 
-static void SetBufferSwap(u32 screen_id, const FrameBufferInfo& info) {
+void SetBufferSwap(u32 screen_id, const FrameBufferInfo& info) {
     u32 base_address = 0x400000;
     PAddr phys_address_left = Memory::VirtualToPhysicalAddress(info.address_left);
     PAddr phys_address_right = Memory::VirtualToPhysicalAddress(info.address_right);
diff --git a/src/core/hle/service/gsp_gpu.h b/src/core/hle/service/gsp_gpu.h
index d9e9a1a60..268089fdd 100644
--- a/src/core/hle/service/gsp_gpu.h
+++ b/src/core/hle/service/gsp_gpu.h
@@ -173,4 +173,14 @@ public:
  */
 void SignalInterrupt(InterruptId interrupt_id);
 
+void SetBufferSwap(u32 screen_id, const FrameBufferInfo& info);
+
+/**
+ * Retrieves the framebuffer info stored in the GSP shared memory for the
+ * specified screen index and thread id.
+ * @param thread_id GSP thread id of the process that accesses the structure that we are requesting.
+ * @param screen_index Index of the screen we are requesting (Top = 0, Bottom = 1).
+ * @returns FramebufferUpdate Information about the specified framebuffer.
+ */
+FrameBufferUpdate* GetFrameBufferInfo(u32 thread_id, u32 screen_index);
 } // namespace