2 files changed, 58 insertions, 2 deletions

diff --git a/src/core/file_sys/common_funcs.h b/src/core/file_sys/common_funcs.h
new file mode 100644
index 000000000..7ed97aa50
--- /dev/null
+++ b/src/core/file_sys/common_funcs.h
@@ -0,0 +1,56 @@
+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_types.h"
+
+namespace FileSys {
+
+constexpr u64 AOC_TITLE_ID_MASK = 0x7FF;
+constexpr u64 AOC_TITLE_ID_OFFSET = 0x1000;
+constexpr u64 BASE_TITLE_ID_MASK = 0xFFFFFFFFFFFFE000;
+
+/**
+ * Gets the base title ID from a given title ID.
+ *
+ * @param title_id The title ID.
+ * @returns The base title ID.
+ */
+[[nodiscard]] constexpr u64 GetBaseTitleID(u64 title_id) {
+    return title_id & BASE_TITLE_ID_MASK;
+}
+
+/**
+ * Gets the base title ID with a program index offset from a given title ID.
+ *
+ * @param title_id The title ID.
+ * @param program_index The program index.
+ * @returns The base title ID with a program index offset.
+ */
+[[nodiscard]] constexpr u64 GetBaseTitleIDWithProgramIndex(u64 title_id, u64 program_index) {
+    return GetBaseTitleID(title_id) + program_index;
+}
+
+/**
+ * Gets the AOC (Add-On Content) base title ID from a given title ID.
+ *
+ * @param title_id The title ID.
+ * @returns The AOC base title ID.
+ */
+[[nodiscard]] constexpr u64 GetAOCBaseTitleID(u64 title_id) {
+    return GetBaseTitleID(title_id) + AOC_TITLE_ID_OFFSET;
+}
+
+/**
+ * Gets the AOC (Add-On Content) ID from a given AOC title ID.
+ *
+ * @param aoc_title_id The AOC title ID.
+ * @returns The AOC ID.
+ */
+[[nodiscard]] constexpr u64 GetAOCID(u64 aoc_title_id) {
+    return aoc_title_id & AOC_TITLE_ID_MASK;
+}
+
+} // namespace FileSys
diff --git a/src/core/file_sys/patch_manager.cpp b/src/core/file_sys/patch_manager.cpp
index e9d1607d0..7c3284df8 100644
--- a/src/core/file_sys/patch_manager.cpp
+++ b/src/core/file_sys/patch_manager.cpp
@@ -12,6 +12,7 @@
 #include "common/logging/log.h"
 #include "common/string_util.h"
 #include "core/core.h"
+#include "core/file_sys/common_funcs.h"
 #include "core/file_sys/content_archive.h"
 #include "core/file_sys/control_metadata.h"
 #include "core/file_sys/ips_layer.h"
@@ -30,7 +31,6 @@ namespace FileSys {
 namespace {
 
 constexpr u32 SINGLE_BYTE_MODULUS = 0x100;
-constexpr u64 DLC_BASE_TITLE_ID_MASK = 0xFFFFFFFFFFFFE000;
 
 constexpr std::array<const char*, 14> EXEFS_FILE_NAMES{
     "main",    "main.npdm", "rtld",    "sdk",     "subsdk0", "subsdk1", "subsdk2",
@@ -532,7 +532,7 @@ PatchManager::PatchVersionNames PatchManager::GetPatchVersionNames(VirtualFile u
     dlc_match.reserve(dlc_entries.size());
     std::copy_if(dlc_entries.begin(), dlc_entries.end(), std::back_inserter(dlc_match),
                  [this](const ContentProviderEntry& entry) {
-                     return (entry.title_id & DLC_BASE_TITLE_ID_MASK) == title_id &&
+                     return GetBaseTitleID(entry.title_id) == title_id &&
                             content_provider.GetEntry(entry)->GetStatus() ==
                                 Loader::ResultStatus::Success;
                  });