Merge remote-tracking branch 'upstream/nx2' into nx2

6 files changed, 451 insertions, 24 deletions

diff --git a/src/core/loader/deconstructed_rom_directory.cpp b/src/core/loader/deconstructed_rom_directory.cpp
index cda1645548..4b1168a59b 100644
--- a/src/core/loader/deconstructed_rom_directory.cpp
+++ b/src/core/loader/deconstructed_rom_directory.cpp
@@ -6,7 +6,11 @@
 
 #include <algorithm>
 #include <cctype>
+#include <chrono>
 #include <cstring>
+#include <map>
+#include <memory>
+#include <mutex>
 #include <string_view>
 #include "common/logging.h"
 #include "common/random.h"
@@ -90,34 +94,42 @@ FileSys::VirtualFile FindLooseRomFS(const FileSys::VirtualDir& exefs_dir) {
     }
     if (const auto parent = exefs_dir->GetParentDirectory()) {
         if (const auto romfs_dir = parent->GetSubdirectory("romfs")) {
+            // Building it walks every file and keeps an object for each (title 1: 206k files, ~150
+            // MiB), so loaders of the same directory share one build while any of them holds it.
+            static std::mutex cache_mutex;
+            static std::map<std::string, std::weak_ptr<FileSys::VfsFile>> cache;
+            std::scoped_lock lk{cache_mutex};
+            auto& cached = cache[romfs_dir->GetFullPath()];
+            if (auto built = cached.lock()) {
+                return built;
+            }
             LOG_INFO(Loader, "Using RomFS directory next to the ExeFS");
-            return FileSys::CreateRomFS(romfs_dir);
+            const auto started = std::chrono::steady_clock::now();
+            auto built = FileSys::CreateRomFS(romfs_dir);
+            LOG_INFO(Loader, "Loose RomFS image ready: elapsed_ms={}",
+                     std::chrono::duration_cast<std::chrono::milliseconds>(
+                         std::chrono::steady_clock::now() - started)
+                         .count());
+            cached = built;
+            return built;
         }
     }
     return nullptr;
 }
 
-// The display version of a dump without control data, from its RomFS: Nintendo EPD titles name
-// their resource size tables after it (System/Resource/ResourceSizeTable.Product.180.* in Mario
-// Kart World 1.8.0). A hotfix can keep its minor version's tables (Product.110 in a 1.1.1).
-std::string RomFSProductVersion(const FileSys::VirtualDir& romfs_dir) {
-    if (romfs_dir == nullptr) {
-        return {};
-    }
-    const auto system_dir = romfs_dir->GetSubdirectory("System");
-    const auto resource_dir = system_dir != nullptr ? system_dir->GetSubdirectory("Resource") : nullptr;
-    if (resource_dir == nullptr) {
-        return {};
-    }
-    constexpr std::string_view Prefix = "ResourceSizeTable.Product.";
+// The newest three-digit tag in a directory's file names of the form <prefix>NNN.<anything>.
+std::string NewestProductTag(const FileSys::VirtualDir& dir, std::string_view prefix) {
     std::string best;
-    for (const auto& file : resource_dir->GetFiles()) {
+    if (dir == nullptr) {
+        return best;
+    }
+    for (const auto& file : dir->GetFiles()) {
         const std::string file_name = file->GetName();
-        if (!file_name.starts_with(Prefix) || file_name.size() < Prefix.size() + 4) {
+        if (!file_name.starts_with(prefix) || file_name.size() < prefix.size() + 4) {
             continue;
         }
-        const std::string_view digits = std::string_view{file_name}.substr(Prefix.size(), 3);
-        if (file_name[Prefix.size() + 3] != '.' ||
+        const std::string_view digits = std::string_view{file_name}.substr(prefix.size(), 3);
+        if (file_name[prefix.size() + 3] != '.' ||
             !std::all_of(digits.begin(), digits.end(), [](char c) { return c >= '0' && c <= '9'; })) {
             continue;
         }
@@ -125,6 +137,27 @@ std::string RomFSProductVersion(const FileSys::VirtualDir& romfs_dir) {
             best = version;
         }
     }
+    return best;
+}
+
+// The display version of a dump without control data, from its RomFS: Nintendo EPD titles name
+// their resource size tables after it (System/Resource/ResourceSizeTable.Product.180.* in Mario
+// Kart World 1.8.0), and some name their game data list instead (GameData/GameDataList.Product.320.*
+// in Donkey Kong Bananza 3.2.0). A hotfix can keep its minor version's tables (Product.110 in a
+// 1.1.1).
+std::string RomFSProductVersion(const FileSys::VirtualDir& romfs_dir) {
+    if (romfs_dir == nullptr) {
+        return {};
+    }
+    const auto system_dir = romfs_dir->GetSubdirectory("System");
+    std::string best = NewestProductTag(
+        system_dir != nullptr ? system_dir->GetSubdirectory("Resource") : nullptr,
+        "ResourceSizeTable.Product.");
+    if (const auto game_data = NewestProductTag(romfs_dir->GetSubdirectory("GameData"),
+                                                "GameDataList.Product.");
+        game_data > best) {
+        best = game_data;
+    }
     if (best.empty()) {
         return {};
     }
@@ -233,7 +266,7 @@ AppLoader_DeconstructedRomDirectory::AppLoader_DeconstructedRomDirectory(FileSys
         name = control->GetApplicationName();
     }
 
-    romfs = FindLooseRomFS(file_dir);
+    romfs_exefs_dir = file_dir;
     if (const auto title_dir = file_dir->GetParentDirectory()) {
         romfs_version = RomFSProductVersion(title_dir->GetSubdirectory("romfs"));
     }
@@ -245,7 +278,17 @@ AppLoader_DeconstructedRomDirectory::AppLoader_DeconstructedRomDirectory(
     , dir(std::move(directory))
     , override_update(override_update_)
 {
-    romfs = FindLooseRomFS(dir);
+    romfs_exefs_dir = dir;
+}
+
+// Loaders made only for metadata (the game list, title lookups) never need the RomFS, and several
+// of them were alive with a whole copy each.
+const FileSys::VirtualFile& AppLoader_DeconstructedRomDirectory::LooseRomFS() {
+    if (!romfs_resolved) {
+        romfs_resolved = true;
+        romfs = FindLooseRomFS(romfs_exefs_dir);
+    }
+    return romfs;
 }
 
 FileType AppLoader_DeconstructedRomDirectory::IdentifyType(const FileSys::VirtualFile& dir_file) {
@@ -304,7 +347,7 @@ AppLoader_DeconstructedRomDirectory::LoadResult AppLoader_DeconstructedRomDirect
 
     // Loose-ExeFS loads bypass the NCA/NSP loaders, which are the ones that normally apply
     // LayeredFS to the RomFS; apply it here so mods in user/load/<titleid>/ work too.
-    if (romfs != nullptr) {
+    if (LooseRomFS() != nullptr) {
         const FileSys::PatchManager patch_manager(metadata.GetTitleID(),
                                                   system.GetFileSystemController(),
                                                   system.GetContentProvider());
@@ -414,7 +457,7 @@ AppLoader_DeconstructedRomDirectory::LoadResult AppLoader_DeconstructedRomDirect
 }
 
 ResultStatus AppLoader_DeconstructedRomDirectory::ReadRomFS(FileSys::VirtualFile& out_dir) {
-    if (romfs == nullptr) {
+    if (LooseRomFS() == nullptr) {
         return ResultStatus::ErrorNoRomFS;
     }
 
diff --git a/src/core/loader/deconstructed_rom_directory.h b/src/core/loader/deconstructed_rom_directory.h
index b976b71ecb..db0120f4ad 100644
--- a/src/core/loader/deconstructed_rom_directory.h
+++ b/src/core/loader/deconstructed_rom_directory.h
@@ -58,8 +58,13 @@ public:
     ResultStatus ReadNSOModules(Modules& out_modules) override;
 
 private:
+    /// The loose RomFS next to the ExeFS, found (and built) on first use.
+    const FileSys::VirtualFile& LooseRomFS();
+
     FileSys::ProgramMetadata metadata;
     FileSys::VirtualFile romfs;
+    FileSys::VirtualDir romfs_exefs_dir; ///< Where LooseRomFS looks
+    bool romfs_resolved{};
     FileSys::VirtualDir dir;
 
     std::vector<u8> icon_data;
diff --git a/src/core/loader/loader.cpp b/src/core/loader/loader.cpp
index 33a93573cf..839bb4d80b 100644
--- a/src/core/loader/loader.cpp
+++ b/src/core/loader/loader.cpp
@@ -29,6 +29,7 @@
 #include "core/loader/nro.h"
 #include "core/loader/nso.h"
 #include "core/loader/nsp.h"
+#include "core/loader/nup.h"
 #include "core/loader/xci.h"
 
 namespace Loader {
@@ -130,6 +131,8 @@ FileType IdentifyFile(FileSys::VirtualFile file) {
         return *nsp_type;
     } else if (const auto xci_type = IdentifyFileLoader<AppLoader_XCI>(file)) {
         return *xci_type;
+    } else if (const auto nup_type = IdentifyFileLoader<AppLoader_NUP>(file)) {
+        return *nup_type;
     } else if (const auto nro_type = IdentifyFileLoader<AppLoader_NRO>(file)) {
         return *nro_type;
     } else if (const auto nca_type = IdentifyFileLoader<AppLoader_NCA>(file)) {
@@ -150,7 +153,7 @@ FileType IdentifyFile(FileSys::VirtualFile file) {
 
 bool IsContainerType(FileType type) {
     return type == FileType::NSP || type == FileType::NSZ || type == FileType::XCI ||
-           type == FileType::XCZ;
+           type == FileType::XCZ || type == FileType::NUP;
 }
 
 bool IsBootableGameContainer(FileSys::VirtualFile file, FileType type, u64 program_id,
@@ -163,6 +166,24 @@ bool IsBootableGameContainer(FileSys::VirtualFile file, FileType type, u64 progr
         type = IdentifyFile(file);
     }
 
+    if (type == FileType::NUP) {
+        FileSys::NupContainer nup{file};
+        if (nup.GetStatus() != ResultStatus::Success) {
+            return false;
+        }
+        // A base package boots normally; a standalone update (no base) carries
+        // a complete patched tree and boots on its own (SPEC section 4.1.2).
+        if (const auto base = nup.FindBasePackage();
+            base.has_value() && nup.GetExeFSDir(*base) != nullptr) {
+            return true;
+        }
+        if (const auto update = nup.FindBestUpdatePackage();
+            update.has_value() && nup.GetExeFSDir(*update) != nullptr) {
+            return true;
+        }
+        return false;
+    }
+
     if (!IsContainerType(type)) {
         return false;
     }
@@ -190,6 +211,8 @@ FileType GuessFromFilename(const std::string& name) {
         return FileType::XCZ;
     else if (extension == "nsp")
         return FileType::NSP;
+    else if (extension == "nup")
+        return FileType::NUP;
     else if (extension == "nsz")
         return FileType::NSZ;
     else if (extension == "kip")
@@ -215,6 +238,8 @@ std::string GetFileTypeString(FileType type) {
         return "NSP";
     case FileType::NSZ:
         return "NSZ";
+    case FileType::NUP:
+        return "NUP";
     case FileType::KIP:
         return "KIP";
     case FileType::DeconstructedRomDirectory:
@@ -227,7 +252,7 @@ std::string GetFileTypeString(FileType type) {
     return "unknown";
 }
 
-constexpr std::array<const char*, 68> RESULT_MESSAGES{
+constexpr std::array<const char*, 70> RESULT_MESSAGES{
     "The operation completed successfully.",
     "The loader requested to load is already loaded.",
     "The operation is not implemented.",
@@ -296,6 +321,8 @@ constexpr std::array<const char*, 68> RESULT_MESSAGES{
     "The INI file contains more than the maximum allowable number of KIP files.",
     "Integrity verification could not be performed for this file.",
     "Integrity verification failed.",
+    "The NUP container is malformed or its TOC hash does not match.",
+    "The NUP container does not contain a loadable base package.",
 };
 
 std::string GetResultStatusString(ResultStatus status) {
@@ -380,6 +407,10 @@ static std::unique_ptr<AppLoader> GetFileLoader(Core::System& system, FileSys::V
     case FileType::KIP:
         return std::make_unique<AppLoader_KIP>(std::move(file));
 
+    // NUP (NX Package) container format.
+    case FileType::NUP:
+        return std::make_unique<AppLoader_NUP>(std::move(file));
+
     // NX deconstructed ROM directory.
     case FileType::DeconstructedRomDirectory:
         return std::make_unique<AppLoader_DeconstructedRomDirectory>(std::move(file));
diff --git a/src/core/loader/loader.h b/src/core/loader/loader.h
index 431aeace73..23be3597f5 100644
--- a/src/core/loader/loader.h
+++ b/src/core/loader/loader.h
@@ -47,6 +47,7 @@ enum class FileType {
     XCZ,
     NAX,
     KIP,
+    NUP,
     DeconstructedRomDirectory,
 };
 
@@ -157,6 +158,8 @@ enum class ResultStatus : u16 {
     ErrorINITooManyKIPs,
     ErrorIntegrityVerificationNotImplemented,
     ErrorIntegrityVerificationFailed,
+    ErrorNUPBadFormat,
+    ErrorNUPNoBasePackage,
 };
 
 std::string GetResultStatusString(ResultStatus status);
diff --git a/src/core/loader/nup.cpp b/src/core/loader/nup.cpp
new file mode 100644
index 0000000000..7ddfb8947e
--- /dev/null
+++ b/src/core/loader/nup.cpp
@@ -0,0 +1,280 @@
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "core/loader/nup.h"
+
+#include <algorithm>
+#include <cstring>
+
+#include "common/logging.h"
+#include "common/string_util.h"
+#include "core/core.h"
+#include "core/file_sys/nup_container.h"
+#include "core/file_sys/control_metadata.h"
+#include "core/file_sys/patch_manager.h"
+#include "core/file_sys/romfs.h"
+#include "core/file_sys/romfs_factory.h"
+#include "core/file_sys/vfs/vfs_vector.h"
+#include "core/hle/kernel/k_process.h"
+#include "core/hle/service/filesystem/filesystem.h"
+#include "core/loader/deconstructed_rom_directory.h"
+
+namespace Loader {
+
+namespace {
+
+using FileSys::NupContainer;
+
+// NACP stores 16 uncompressed language entries; map BCP-47 tags onto them.
+struct LanguageSlot {
+    std::string_view tag;
+    std::size_t index;
+};
+
+constexpr std::array<LanguageSlot, 18> LanguageSlots{{
+    {"en-us", 0},   {"en-gb", 1},  {"ja", 2},     {"fr", 3},     {"de", 4},
+    {"es-419", 5},  {"es", 6},     {"it", 7},     {"nl", 8},     {"fr-ca", 9},
+    {"pt", 10},     {"ru", 11},    {"ko", 12},    {"zh-hant", 13}, {"zh-hans", 14},
+    {"pt-br", 15},  {"pl", 16},    {"th", 17},
+}};
+
+void CopyNameToEntry(FileSys::LanguageEntry& entry, std::string_view name) {
+    const std::size_t length = std::min(name.size(), entry.application_name.size() - 1);
+    std::memcpy(entry.application_name.data(), name.data(), length);
+    entry.application_name[length] = '\0';
+}
+
+std::unique_ptr<FileSys::NACP> BuildNacp(const NupContainer::PackageInfo& base,
+                                         const std::string& version) {
+    if (base.title_name.empty() && base.localized_titles.empty() && version.empty()) {
+        return nullptr;
+    }
+    auto nacp = std::make_unique<FileSys::NACP>();
+    nacp->raw.supported_languages = static_cast<FileSys::SupportedLanguage>(0x3FFFF);
+
+    for (const auto& [lang, name] : base.localized_titles) {
+        for (const auto& slot : LanguageSlots) {
+            // The uncompressed RawNACP only stores 16 entries; Polish/Thai exist
+            // only in the compressed format, so they fall back to the default.
+            if (slot.index < 16 && slot.tag == lang) {
+                CopyNameToEntry(nacp->raw.language_entries.language_entries[slot.index], name);
+            }
+        }
+    }
+    if (!base.title_name.empty()) {
+        CopyNameToEntry(nacp->raw.language_entries.language_entries[0], base.title_name);
+    }
+    if (!version.empty()) {
+        const std::size_t length = std::min(version.size(), nacp->raw.version_string.size() - 1);
+        std::memcpy(nacp->raw.version_string.data(), version.data(), length);
+        nacp->raw.version_string[length] = '\0';
+    }
+    nacp->raw.save_data_owner_id = base.title_id;
+
+    nacp->language_entries.resize(16);
+    std::memcpy(nacp->language_entries.data(), nacp->raw.language_entries.language_entries.data(),
+                sizeof(nacp->raw.language_entries.language_entries));
+    return nacp;
+}
+
+std::string DecodeVersion(u32 version) {
+    if (version == 0) {
+        return {};
+    }
+    return fmt::format("{}.{}.{}", version >> 16, (version >> 8) & 0xFF, version & 0xFF);
+}
+
+} // namespace
+
+AppLoader_NUP::AppLoader_NUP(FileSys::VirtualFile file_)
+    : AppLoader(std::move(file_)), nup(std::make_unique<NupContainer>(file)) {
+    if (nup->GetStatus() != ResultStatus::Success) {
+        return;
+    }
+
+    const auto base_index = nup->FindBasePackage();
+    const auto update_index = nup->FindBestUpdatePackage();
+
+    // The program comes from the base package; a standalone update container
+    // (SPEC §4.1.2) carries a complete patched tree and boots on its own.
+    std::optional<std::size_t> program_index;
+    std::optional<std::size_t> exefs_index;
+    if (base_index && nup->GetExeFSDir(*base_index) != nullptr) {
+        program_index = base_index;
+        exefs_index = update_index && nup->GetExeFSDir(*update_index) != nullptr
+                          ? update_index
+                          : base_index;
+    } else if (update_index && nup->GetExeFSDir(*update_index) != nullptr) {
+        LOG_INFO(Loader,
+                 "NUP container is a standalone update; booting the update program directly");
+        program_index = update_index;
+        exefs_index = update_index;
+    }
+    if (!program_index || !exefs_index) {
+        LOG_ERROR(Loader, "NUP container has no package with a usable ExeFS");
+        return;
+    }
+
+    const auto& program = nup->GetPackages()[*program_index];
+    base_title_id = program.title_id;
+    has_program = true;
+
+    const auto exefs = nup->GetExeFSDir(*exefs_index);
+    if (exefs == nullptr || exefs->GetFile("main") == nullptr ||
+        exefs->GetFile("main.npdm") == nullptr) {
+        LOG_ERROR(Loader, "NUP package has no usable ExeFS");
+        return;
+    }
+    secondary_loader = std::make_unique<AppLoader_DeconstructedRomDirectory>(exefs, true);
+
+    if (update_index) {
+        const auto& update = nup->GetPackages()[*update_index];
+        display_version = update.display_version.empty() ? DecodeVersion(update.version)
+                                                         : update.display_version;
+    } else {
+        display_version = program.display_version.empty() ? DecodeVersion(program.version)
+                                                          : program.display_version;
+    }
+    nacp_file = BuildNacp(program, display_version);
+    if (nacp_file != nullptr && !program.icon.empty()) {
+        icon_file = std::make_shared<FileSys::VectorVfsFile>(program.icon, "icon.dat");
+    } else if (nacp_file != nullptr) {
+        for (const auto& [lang, icon] : program.localized_icons) {
+            if (lang == "en-us") {
+                icon_file = std::make_shared<FileSys::VectorVfsFile>(icon, "icon_" + lang + ".dat");
+                break;
+            }
+        }
+        if (icon_file == nullptr && !program.localized_icons.empty()) {
+            icon_file = std::make_shared<FileSys::VectorVfsFile>(
+                program.localized_icons.front().second, "icon.dat");
+        }
+    }
+
+    const auto addon_count = std::count_if(nup->GetPackages().begin(), nup->GetPackages().end(),
+                                           [](const auto& package) {
+                                               return package.kind ==
+                                                      NupContainer::PackageKind::Addon;
+                                           });
+    if (addon_count > 0) {
+        LOG_WARNING(Loader,
+                    "NUP container has {} add-on content package(s); AoC mounting is not "
+                    "supported yet",
+                    addon_count);
+    }
+}
+
+AppLoader_NUP::~AppLoader_NUP() = default;
+
+FileType AppLoader_NUP::IdentifyType(const FileSys::VirtualFile& nup_file) {
+    return FileSys::NupContainer::IsNupFile(nup_file) ? FileType::NUP : FileType::Error;
+}
+
+AppLoader::LoadResult AppLoader_NUP::Load(Kernel::KProcess& process, Core::System& system) {
+    if (is_loaded) {
+        return {ResultStatus::ErrorAlreadyLoaded, {}};
+    }
+    if (nup->GetStatus() != ResultStatus::Success) {
+        return {nup->GetStatus(), {}};
+    }
+    if (!has_program || secondary_loader == nullptr) {
+        return {ResultStatus::ErrorNUPNoBasePackage, {}};
+    }
+
+    const auto result = secondary_loader->Load(process, system);
+    if (result.first != ResultStatus::Success) {
+        return result;
+    }
+
+    system.GetFileSystemController().RegisterProcess(
+        process.GetProcessId(), base_title_id,
+        std::make_shared<FileSys::RomFSFactory>(*this, system.GetContentProvider(),
+                                                system.GetFileSystemController()));
+
+    is_loaded = true;
+    return result;
+}
+
+ResultStatus AppLoader_NUP::VerifyIntegrity(
+    std::function<bool(size_t, size_t)> progress_callback) {
+    if (nup->GetStatus() != ResultStatus::Success) {
+        return nup->GetStatus();
+    }
+    return nup->VerifyIntegrity(std::move(progress_callback));
+}
+
+ResultStatus AppLoader_NUP::ReadRomFS(FileSys::VirtualFile& out_file) {
+    const auto base_index = nup->FindBasePackage();
+    const auto base_romfs = base_index ? nup->GetRomFSDir(*base_index) : FileSys::VirtualDir{};
+    const auto update_index = nup->FindBestUpdatePackage();
+    const auto update_romfs =
+        update_index ? nup->GetRomFSDir(*update_index) : FileSys::VirtualDir{};
+    // A standalone update carries the complete merged tree; a base+update pair
+    // overlays the update onto the base (SPEC §4.1.4).
+    const auto merged = FileSys::NupContainer::MergeShadowDirs(base_romfs, update_romfs);
+    if (merged == nullptr) {
+        return ResultStatus::ErrorNoRomFS;
+    }
+    out_file = FileSys::CreateRomFS(merged);
+    if (out_file == nullptr) {
+        return ResultStatus::ErrorNoRomFS;
+    }
+    return ResultStatus::Success;
+}
+
+bool AppLoader_NUP::IsRomFSUpdatable() const {
+    // The update is already merged into the exposed RomFS.
+    return false;
+}
+
+ResultStatus AppLoader_NUP::ReadProgramId(u64& out_program_id) {
+    if (!has_program) {
+        return ResultStatus::ErrorNotInitialized;
+    }
+    out_program_id = base_title_id;
+    return ResultStatus::Success;
+}
+
+ResultStatus AppLoader_NUP::ReadProgramIds(std::vector<u64>& out_program_ids) {
+    if (!has_program) {
+        return ResultStatus::ErrorNotInitialized;
+    }
+    out_program_ids.push_back(base_title_id);
+    return ResultStatus::Success;
+}
+
+ResultStatus AppLoader_NUP::ReadIcon(std::vector<u8>& buffer) {
+    if (icon_file == nullptr) {
+        return ResultStatus::ErrorNoIcon;
+    }
+    buffer = icon_file->ReadAllBytes();
+    return ResultStatus::Success;
+}
+
+ResultStatus AppLoader_NUP::ReadTitle(std::string& title) {
+    if (nacp_file == nullptr) {
+        return ResultStatus::ErrorNoControl;
+    }
+    title = nacp_file->GetApplicationName();
+    if (title.empty()) {
+        return ResultStatus::ErrorNoControl;
+    }
+    return ResultStatus::Success;
+}
+
+ResultStatus AppLoader_NUP::ReadControlData(FileSys::NACP& control) {
+    if (nacp_file == nullptr) {
+        return ResultStatus::ErrorNoControl;
+    }
+    control = *nacp_file;
+    return ResultStatus::Success;
+}
+
+ResultStatus AppLoader_NUP::ReadNSOModules(Modules& modules) {
+    if (secondary_loader == nullptr) {
+        return ResultStatus::ErrorNotInitialized;
+    }
+    return secondary_loader->ReadNSOModules(modules);
+}
+
+} // namespace Loader
diff --git a/src/core/loader/nup.h b/src/core/loader/nup.h
new file mode 100644
index 0000000000..1f9dd5922b
--- /dev/null
+++ b/src/core/loader/nup.h
@@ -0,0 +1,65 @@
+// SPDX-FileCopyrightText: Copyright 2026 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#include <memory>
+#include <optional>
+#include <string>
+
+#include "core/file_sys/nup_container.h"
+#include "core/loader/loader.h"
+
+namespace FileSys {
+class NACP;
+class NupContainer;
+} // namespace FileSys
+
+namespace Loader {
+
+/// Loads a NUP (NX Package) container: loose ExeFS/RomFS trees for a base
+/// program plus its updates in one file. The newest update package is layered
+/// over the base; add-on content packages are recognized but not yet mounted.
+class AppLoader_NUP final : public AppLoader {
+public:
+    explicit AppLoader_NUP(FileSys::VirtualFile file_);
+    ~AppLoader_NUP() override;
+
+    /**
+     * Identifies whether or not the given file is a NUP container.
+     *
+     * @param nup_file The file to identify.
+     *
+     * @return FileType::NUP, or FileType::Error if the file is not a NUP.
+     */
+    static FileType IdentifyType(const FileSys::VirtualFile& nup_file);
+
+    FileType GetFileType() const override {
+        return FileType::NUP;
+    }
+
+    LoadResult Load(Kernel::KProcess& process, Core::System& system) override;
+
+    ResultStatus VerifyIntegrity(std::function<bool(size_t, size_t)> progress_callback) override;
+
+    ResultStatus ReadRomFS(FileSys::VirtualFile& out_file) override;
+    bool IsRomFSUpdatable() const override;
+    ResultStatus ReadProgramId(u64& out_program_id) override;
+    ResultStatus ReadProgramIds(std::vector<u64>& out_program_ids) override;
+    ResultStatus ReadIcon(std::vector<u8>& buffer) override;
+    ResultStatus ReadTitle(std::string& title) override;
+    ResultStatus ReadControlData(FileSys::NACP& control) override;
+    ResultStatus ReadNSOModules(Modules& modules) override;
+
+private:
+    std::unique_ptr<FileSys::NupContainer> nup;
+    std::unique_ptr<AppLoader> secondary_loader;
+
+    std::unique_ptr<FileSys::NACP> nacp_file;
+    FileSys::VirtualFile icon_file;
+    u64 base_title_id{};
+    std::string display_version;
+    bool has_program{};
+};
+
+} // namespace Loader