35 files changed, 182 insertions, 170 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 4f6a87b0a..f2e774a6b 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -522,6 +522,23 @@ add_library(core STATIC
     tools/freezer.h
 )
 
+if (MSVC)
+    target_compile_options(core PRIVATE
+        # 'expression' : signed/unsigned mismatch
+        /we4018
+        # 'argument' : conversion from 'type1' to 'type2', possible loss of data (floating-point)
+        /we4244
+        # 'conversion' : conversion from 'type1' to 'type2', signed/unsigned mismatch
+        /we4245
+        # 'operator': conversion from 'type1:field_bits' to 'type2:field_bits', possible loss of data
+        /we4254
+        # 'var' : conversion from 'size_t' to 'type', possible loss of data
+        /we4267
+        # 'context' : truncation from 'type1' to 'type2'
+        /we4305
+    )
+endif()
+
 create_target_directory_groups(core)
 
 target_link_libraries(core PUBLIC common PRIVATE audio_core video_core)
diff --git a/src/core/arm/dynarmic/arm_dynarmic.cpp b/src/core/arm/dynarmic/arm_dynarmic.cpp
index 700c4afff..a0705b2b8 100644
--- a/src/core/arm/dynarmic/arm_dynarmic.cpp
+++ b/src/core/arm/dynarmic/arm_dynarmic.cpp
@@ -67,7 +67,7 @@ public:
         ARM_Interface::ThreadContext ctx;
         parent.SaveContext(ctx);
         parent.inner_unicorn.LoadContext(ctx);
-        parent.inner_unicorn.ExecuteInstructions(static_cast<int>(num_instructions));
+        parent.inner_unicorn.ExecuteInstructions(num_instructions);
         parent.inner_unicorn.SaveContext(ctx);
         parent.LoadContext(ctx);
         num_interpreted_instructions += num_instructions;
diff --git a/src/core/arm/unicorn/arm_unicorn.cpp b/src/core/arm/unicorn/arm_unicorn.cpp
index d4f41bfc1..9698172db 100644
--- a/src/core/arm/unicorn/arm_unicorn.cpp
+++ b/src/core/arm/unicorn/arm_unicorn.cpp
@@ -67,10 +67,11 @@ ARM_Unicorn::ARM_Unicorn(System& system) : system{system} {
     CHECKED(uc_reg_write(uc, UC_ARM64_REG_CPACR_EL1, &fpv));
 
     uc_hook hook{};
-    CHECKED(uc_hook_add(uc, &hook, UC_HOOK_INTR, (void*)InterruptHook, this, 0, -1));
-    CHECKED(uc_hook_add(uc, &hook, UC_HOOK_MEM_INVALID, (void*)UnmappedMemoryHook, &system, 0, -1));
+    CHECKED(uc_hook_add(uc, &hook, UC_HOOK_INTR, (void*)InterruptHook, this, 0, UINT64_MAX));
+    CHECKED(uc_hook_add(uc, &hook, UC_HOOK_MEM_INVALID, (void*)UnmappedMemoryHook, &system, 0,
+                        UINT64_MAX));
     if (GDBStub::IsServerEnabled()) {
-        CHECKED(uc_hook_add(uc, &hook, UC_HOOK_CODE, (void*)CodeHook, this, 0, -1));
+        CHECKED(uc_hook_add(uc, &hook, UC_HOOK_CODE, (void*)CodeHook, this, 0, UINT64_MAX));
         last_bkpt_hit = false;
     }
 }
@@ -154,9 +155,10 @@ void ARM_Unicorn::SetTPIDR_EL0(u64 value) {
 
 void ARM_Unicorn::Run() {
     if (GDBStub::IsServerEnabled()) {
-        ExecuteInstructions(std::max(4000000, 0));
+        ExecuteInstructions(std::max(4000000U, 0U));
     } else {
-        ExecuteInstructions(std::max(system.CoreTiming().GetDowncount(), s64{0}));
+        ExecuteInstructions(
+            std::max(std::size_t(system.CoreTiming().GetDowncount()), std::size_t{0}));
     }
 }
 
@@ -166,7 +168,7 @@ void ARM_Unicorn::Step() {
 
 MICROPROFILE_DEFINE(ARM_Jit_Unicorn, "ARM JIT", "Unicorn", MP_RGB(255, 64, 64));
 
-void ARM_Unicorn::ExecuteInstructions(int num_instructions) {
+void ARM_Unicorn::ExecuteInstructions(std::size_t num_instructions) {
     MICROPROFILE_SCOPE(ARM_Jit_Unicorn);
     CHECKED(uc_emu_start(uc, GetPC(), 1ULL << 63, 0, num_instructions));
     system.CoreTiming().AddTicks(num_instructions);
diff --git a/src/core/arm/unicorn/arm_unicorn.h b/src/core/arm/unicorn/arm_unicorn.h
index fe2ffd70c..b39426ea0 100644
--- a/src/core/arm/unicorn/arm_unicorn.h
+++ b/src/core/arm/unicorn/arm_unicorn.h
@@ -34,7 +34,7 @@ public:
     void LoadContext(const ThreadContext& ctx) override;
     void PrepareReschedule() override;
     void ClearExclusiveState() override;
-    void ExecuteInstructions(int num_instructions);
+    void ExecuteInstructions(std::size_t num_instructions);
     void Run() override;
     void Step() override;
     void ClearInstructionCache() override;
diff --git a/src/core/crypto/key_manager.cpp b/src/core/crypto/key_manager.cpp
index 487b57053..87e6a1fd3 100644
--- a/src/core/crypto/key_manager.cpp
+++ b/src/core/crypto/key_manager.cpp
@@ -22,6 +22,7 @@
 #include "common/file_util.h"
 #include "common/hex_util.h"
 #include "common/logging/log.h"
+#include "common/string_util.h"
 #include "core/core.h"
 #include "core/crypto/aes_util.h"
 #include "core/crypto/key_manager.h"
@@ -378,8 +379,9 @@ std::vector<Ticket> GetTicketblob(const FileUtil::IOFile& ticket_save) {
 template <size_t size>
 static std::array<u8, size> operator^(const std::array<u8, size>& lhs,
                                       const std::array<u8, size>& rhs) {
-    std::array<u8, size> out{};
-    std::transform(lhs.begin(), lhs.end(), rhs.begin(), out.begin(), std::bit_xor<>());
+    std::array<u8, size> out;
+    std::transform(lhs.begin(), lhs.end(), rhs.begin(), out.begin(),
+                   [](u8 lhs, u8 rhs) { return u8(lhs ^ rhs); });
     return out;
 }
 
@@ -538,7 +540,7 @@ void KeyManager::LoadFromFile(const std::string& filename, bool is_title_keys) {
             Key128 key = Common::HexStringToArray<16>(out[1]);
             s128_keys[{S128KeyType::Titlekey, rights_id[1], rights_id[0]}] = key;
         } else {
-            std::transform(out[0].begin(), out[0].end(), out[0].begin(), ::tolower);
+            out[0] = Common::ToLower(out[0]);
             if (s128_file_id.find(out[0]) != s128_file_id.end()) {
                 const auto index = s128_file_id.at(out[0]);
                 Key128 key = Common::HexStringToArray<16>(out[1]);
@@ -948,12 +950,10 @@ void KeyManager::DeriveETicket(PartitionDataManager& data) {
         return;
     }
 
-    Key128 rsa_oaep_kek{};
-    std::transform(seed3.begin(), seed3.end(), mask0.begin(), rsa_oaep_kek.begin(),
-                   std::bit_xor<>());
-
-    if (rsa_oaep_kek == Key128{})
+    const Key128 rsa_oaep_kek = seed3 ^ mask0;
+    if (rsa_oaep_kek == Key128{}) {
         return;
+    }
 
     SetKey(S128KeyType::Source, rsa_oaep_kek,
            static_cast<u64>(SourceKeyType::RSAOaepKekGeneration));
diff --git a/src/core/crypto/partition_data_manager.cpp b/src/core/crypto/partition_data_manager.cpp
index a4b09fd12..d64302f2e 100644
--- a/src/core/crypto/partition_data_manager.cpp
+++ b/src/core/crypto/partition_data_manager.cpp
@@ -204,11 +204,12 @@ static std::array<Key128, 0x20> FindEncryptedMasterKeyFromHex(const std::vector<
 
 FileSys::VirtualFile FindFileInDirWithNames(const FileSys::VirtualDir& dir,
                                             const std::string& name) {
-    auto upper = name;
-    std::transform(upper.begin(), upper.end(), upper.begin(), [](u8 c) { return std::toupper(c); });
+    const auto upper = Common::ToUpper(name);
+
     for (const auto& fname : {name, name + ".bin", upper, upper + ".BIN"}) {
-        if (dir->GetFile(fname) != nullptr)
+        if (dir->GetFile(fname) != nullptr) {
             return dir->GetFile(fname);
+        }
     }
 
     return nullptr;
diff --git a/src/core/file_sys/kernel_executable.cpp b/src/core/file_sys/kernel_executable.cpp
index 371300684..76313679d 100644
--- a/src/core/file_sys/kernel_executable.cpp
+++ b/src/core/file_sys/kernel_executable.cpp
@@ -147,7 +147,7 @@ std::vector<u32> KIP::GetKernelCapabilities() const {
 }
 
 s32 KIP::GetMainThreadPriority() const {
-    return header.main_thread_priority;
+    return static_cast<s32>(header.main_thread_priority);
 }
 
 u32 KIP::GetMainThreadStackSize() const {
diff --git a/src/core/file_sys/program_metadata.cpp b/src/core/file_sys/program_metadata.cpp
index 7310b3602..1d6c30962 100644
--- a/src/core/file_sys/program_metadata.cpp
+++ b/src/core/file_sys/program_metadata.cpp
@@ -52,14 +52,14 @@ Loader::ResultStatus ProgramMetadata::Load(VirtualFile file) {
 }
 
 void ProgramMetadata::LoadManual(bool is_64_bit, ProgramAddressSpaceType address_space,
-                                 u8 main_thread_prio, u8 main_thread_core,
+                                 s32 main_thread_prio, u32 main_thread_core,
                                  u32 main_thread_stack_size, u64 title_id,
                                  u64 filesystem_permissions,
                                  KernelCapabilityDescriptors capabilities) {
     npdm_header.has_64_bit_instructions.Assign(is_64_bit);
     npdm_header.address_space_type.Assign(address_space);
-    npdm_header.main_thread_priority = main_thread_prio;
-    npdm_header.main_thread_cpu = main_thread_core;
+    npdm_header.main_thread_priority = static_cast<u8>(main_thread_prio);
+    npdm_header.main_thread_cpu = static_cast<u8>(main_thread_core);
     npdm_header.main_stack_size = main_thread_stack_size;
     aci_header.title_id = title_id;
     aci_file_access.permissions = filesystem_permissions;
diff --git a/src/core/file_sys/program_metadata.h b/src/core/file_sys/program_metadata.h
index 88ec97d85..f8759a396 100644
--- a/src/core/file_sys/program_metadata.h
+++ b/src/core/file_sys/program_metadata.h
@@ -47,8 +47,8 @@ public:
     Loader::ResultStatus Load(VirtualFile file);
 
     // Load from parameters instead of NPDM file, used for KIP
-    void LoadManual(bool is_64_bit, ProgramAddressSpaceType address_space, u8 main_thread_prio,
-                    u8 main_thread_core, u32 main_thread_stack_size, u64 title_id,
+    void LoadManual(bool is_64_bit, ProgramAddressSpaceType address_space, s32 main_thread_prio,
+                    u32 main_thread_core, u32 main_thread_stack_size, u64 title_id,
                     u64 filesystem_permissions, KernelCapabilityDescriptors capabilities);
 
     bool Is64BitProgram() const;
diff --git a/src/core/file_sys/romfs_factory.cpp b/src/core/file_sys/romfs_factory.cpp
index 4bd2e6183..418a39a7e 100644
--- a/src/core/file_sys/romfs_factory.cpp
+++ b/src/core/file_sys/romfs_factory.cpp
@@ -71,12 +71,12 @@ ResultVal<VirtualFile> RomFSFactory::Open(u64 title_id, StorageId storage,
 
     if (res == nullptr) {
         // TODO(DarkLordZach): Find the right error code to use here
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
     const auto romfs = res->GetRomFS();
     if (romfs == nullptr) {
         // TODO(DarkLordZach): Find the right error code to use here
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
     return MakeResult<VirtualFile>(romfs);
 }
diff --git a/src/core/file_sys/savedata_factory.cpp b/src/core/file_sys/savedata_factory.cpp
index e2a7eaf7b..f3def93ab 100644
--- a/src/core/file_sys/savedata_factory.cpp
+++ b/src/core/file_sys/savedata_factory.cpp
@@ -90,7 +90,7 @@ ResultVal<VirtualDir> SaveDataFactory::Create(SaveDataSpaceId space,
     // Return an error if the save data doesn't actually exist.
     if (out == nullptr) {
         // TODO(DarkLordZach): Find out correct error code.
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
 
     return MakeResult<VirtualDir>(std::move(out));
@@ -111,7 +111,7 @@ ResultVal<VirtualDir> SaveDataFactory::Open(SaveDataSpaceId space,
     // Return an error if the save data doesn't actually exist.
     if (out == nullptr) {
         // TODO(Subv): Find out correct error code.
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
 
     return MakeResult<VirtualDir>(std::move(out));
diff --git a/src/core/file_sys/vfs_libzip.cpp b/src/core/file_sys/vfs_libzip.cpp
index 8bdaa7e4a..11d1978ea 100644
--- a/src/core/file_sys/vfs_libzip.cpp
+++ b/src/core/file_sys/vfs_libzip.cpp
@@ -27,7 +27,7 @@ VirtualDir ExtractZIP(VirtualFile file) {
 
     std::shared_ptr<VectorVfsDirectory> out = std::make_shared<VectorVfsDirectory>();
 
-    const auto num_entries = zip_get_num_entries(zip.get(), 0);
+    const auto num_entries = static_cast<std::size_t>(zip_get_num_entries(zip.get(), 0));
 
     zip_stat_t stat{};
     zip_stat_init(&stat);
diff --git a/src/core/file_sys/xts_archive.cpp b/src/core/file_sys/xts_archive.cpp
index 7ca375791..86e06ccb9 100644
--- a/src/core/file_sys/xts_archive.cpp
+++ b/src/core/file_sys/xts_archive.cpp
@@ -7,12 +7,13 @@
 #include <cstring>
 #include <regex>
 #include <string>
+
 #include <mbedtls/md.h>
 #include <mbedtls/sha256.h>
-#include "common/assert.h"
+
 #include "common/file_util.h"
 #include "common/hex_util.h"
-#include "common/logging/log.h"
+#include "common/string_util.h"
 #include "core/crypto/aes_util.h"
 #include "core/crypto/xts_encryption_layer.h"
 #include "core/file_sys/partition_filesystem.h"
@@ -53,11 +54,8 @@ NAX::NAX(VirtualFile file_) : header(std::make_unique<NAXHeader>()), file(std::m
         return;
     }
 
-    std::string two_dir = match[1];
-    std::string nca_id = match[2];
-    std::transform(two_dir.begin(), two_dir.end(), two_dir.begin(), ::toupper);
-    std::transform(nca_id.begin(), nca_id.end(), nca_id.begin(), ::tolower);
-
+    const std::string two_dir = Common::ToUpper(match[1]);
+    const std::string nca_id = Common::ToLower(match[2]);
     status = Parse(fmt::format("/registered/{}/{}.nca", two_dir, nca_id));
 }
 
diff --git a/src/core/gdbstub/gdbstub.cpp b/src/core/gdbstub/gdbstub.cpp
index 20bb50868..54ed680db 100644
--- a/src/core/gdbstub/gdbstub.cpp
+++ b/src/core/gdbstub/gdbstub.cpp
@@ -468,7 +468,8 @@ static u8 ReadByte() {
 
 /// Calculate the checksum of the current command buffer.
 static u8 CalculateChecksum(const u8* buffer, std::size_t length) {
-    return static_cast<u8>(std::accumulate(buffer, buffer + length, 0, std::plus<u8>()));
+    return static_cast<u8>(std::accumulate(buffer, buffer + length, u8{0},
+                                           [](u8 lhs, u8 rhs) { return u8(lhs + rhs); }));
 }
 
 /**
diff --git a/src/core/hle/kernel/scheduler.cpp b/src/core/hle/kernel/scheduler.cpp
index 0e2dbf13e..16e95381b 100644
--- a/src/core/hle/kernel/scheduler.cpp
+++ b/src/core/hle/kernel/scheduler.cpp
@@ -35,12 +35,12 @@ void GlobalScheduler::RemoveThread(const Thread* thread) {
                       thread_list.end());
 }
 
-void GlobalScheduler::UnloadThread(s32 core) {
+void GlobalScheduler::UnloadThread(std::size_t core) {
     Scheduler& sched = system.Scheduler(core);
     sched.UnloadThread();
 }
 
-void GlobalScheduler::SelectThread(u32 core) {
+void GlobalScheduler::SelectThread(std::size_t core) {
     const auto update_thread = [](Thread* thread, Scheduler& sched) {
         if (thread != sched.selected_thread) {
             if (thread == nullptr) {
@@ -77,9 +77,9 @@ void GlobalScheduler::SelectThread(u32 core) {
     // if we got a suggested thread, select it, else do a second pass.
     if (winner && winner->GetPriority() > 2) {
         if (winner->IsRunning()) {
-            UnloadThread(winner->GetProcessorID());
+            UnloadThread(static_cast<u32>(winner->GetProcessorID()));
         }
-        TransferToCore(winner->GetPriority(), core, winner);
+        TransferToCore(winner->GetPriority(), static_cast<s32>(core), winner);
         update_thread(winner, sched);
         return;
     }
@@ -91,9 +91,9 @@ void GlobalScheduler::SelectThread(u32 core) {
             Thread* thread_on_core = scheduled_queue[src_core].front();
             Thread* to_change = *it;
             if (thread_on_core->IsRunning() || to_change->IsRunning()) {
-                UnloadThread(src_core);
+                UnloadThread(static_cast<u32>(src_core));
             }
-            TransferToCore(thread_on_core->GetPriority(), core, thread_on_core);
+            TransferToCore(thread_on_core->GetPriority(), static_cast<s32>(core), thread_on_core);
             current_thread = thread_on_core;
             break;
         }
@@ -154,9 +154,9 @@ bool GlobalScheduler::YieldThreadAndBalanceLoad(Thread* yielding_thread) {
     if (winner != nullptr) {
         if (winner != yielding_thread) {
             if (winner->IsRunning()) {
-                UnloadThread(winner->GetProcessorID());
+                UnloadThread(static_cast<u32>(winner->GetProcessorID()));
             }
-            TransferToCore(winner->GetPriority(), core_id, winner);
+            TransferToCore(winner->GetPriority(), s32(core_id), winner);
         }
     } else {
         winner = next_thread;
@@ -196,9 +196,9 @@ bool GlobalScheduler::YieldThreadAndWaitForLoadBalancing(Thread* yielding_thread
         if (winner != nullptr) {
             if (winner != yielding_thread) {
                 if (winner->IsRunning()) {
-                    UnloadThread(winner->GetProcessorID());
+                    UnloadThread(static_cast<u32>(winner->GetProcessorID()));
                 }
-                TransferToCore(winner->GetPriority(), core_id, winner);
+                TransferToCore(winner->GetPriority(), static_cast<s32>(core_id), winner);
             }
         } else {
             winner = yielding_thread;
@@ -248,7 +248,7 @@ void GlobalScheduler::PreemptThreads() {
 
         if (winner != nullptr) {
             if (winner->IsRunning()) {
-                UnloadThread(winner->GetProcessorID());
+                UnloadThread(static_cast<u32>(winner->GetProcessorID()));
             }
             TransferToCore(winner->GetPriority(), s32(core_id), winner);
             current_thread =
@@ -281,7 +281,7 @@ void GlobalScheduler::PreemptThreads() {
 
             if (winner != nullptr) {
                 if (winner->IsRunning()) {
-                    UnloadThread(winner->GetProcessorID());
+                    UnloadThread(static_cast<u32>(winner->GetProcessorID()));
                 }
                 TransferToCore(winner->GetPriority(), s32(core_id), winner);
                 current_thread = winner;
@@ -292,30 +292,30 @@ void GlobalScheduler::PreemptThreads() {
     }
 }
 
-void GlobalScheduler::Suggest(u32 priority, u32 core, Thread* thread) {
+void GlobalScheduler::Suggest(u32 priority, std::size_t core, Thread* thread) {
     suggested_queue[core].add(thread, priority);
 }
 
-void GlobalScheduler::Unsuggest(u32 priority, u32 core, Thread* thread) {
+void GlobalScheduler::Unsuggest(u32 priority, std::size_t core, Thread* thread) {
     suggested_queue[core].remove(thread, priority);
 }
 
-void GlobalScheduler::Schedule(u32 priority, u32 core, Thread* thread) {
+void GlobalScheduler::Schedule(u32 priority, std::size_t core, Thread* thread) {
     ASSERT_MSG(thread->GetProcessorID() == s32(core), "Thread must be assigned to this core.");
     scheduled_queue[core].add(thread, priority);
 }
 
-void GlobalScheduler::SchedulePrepend(u32 priority, u32 core, Thread* thread) {
+void GlobalScheduler::SchedulePrepend(u32 priority, std::size_t core, Thread* thread) {
     ASSERT_MSG(thread->GetProcessorID() == s32(core), "Thread must be assigned to this core.");
     scheduled_queue[core].add(thread, priority, false);
 }
 
-void GlobalScheduler::Reschedule(u32 priority, u32 core, Thread* thread) {
+void GlobalScheduler::Reschedule(u32 priority, std::size_t core, Thread* thread) {
     scheduled_queue[core].remove(thread, priority);
     scheduled_queue[core].add(thread, priority);
 }
 
-void GlobalScheduler::Unschedule(u32 priority, u32 core, Thread* thread) {
+void GlobalScheduler::Unschedule(u32 priority, std::size_t core, Thread* thread) {
     scheduled_queue[core].remove(thread, priority);
 }
 
@@ -327,14 +327,14 @@ void GlobalScheduler::TransferToCore(u32 priority, s32 destination_core, Thread*
     }
     thread->SetProcessorID(destination_core);
     if (source_core >= 0) {
-        Unschedule(priority, source_core, thread);
+        Unschedule(priority, static_cast<u32>(source_core), thread);
     }
     if (destination_core >= 0) {
-        Unsuggest(priority, destination_core, thread);
-        Schedule(priority, destination_core, thread);
+        Unsuggest(priority, static_cast<u32>(destination_core), thread);
+        Schedule(priority, static_cast<u32>(destination_core), thread);
     }
     if (source_core >= 0) {
-        Suggest(priority, source_core, thread);
+        Suggest(priority, static_cast<u32>(source_core), thread);
     }
 }
 
@@ -357,7 +357,7 @@ void GlobalScheduler::Shutdown() {
     thread_list.clear();
 }
 
-Scheduler::Scheduler(Core::System& system, Core::ARM_Interface& cpu_core, u32 core_id)
+Scheduler::Scheduler(Core::System& system, Core::ARM_Interface& cpu_core, std::size_t core_id)
     : system(system), cpu_core(cpu_core), core_id(core_id) {}
 
 Scheduler::~Scheduler() = default;
diff --git a/src/core/hle/kernel/scheduler.h b/src/core/hle/kernel/scheduler.h
index f2d6311b8..311849dfb 100644
--- a/src/core/hle/kernel/scheduler.h
+++ b/src/core/hle/kernel/scheduler.h
@@ -42,41 +42,34 @@ public:
      * Add a thread to the suggested queue of a cpu core. Suggested threads may be
      * picked if no thread is scheduled to run on the core.
      */
-    void Suggest(u32 priority, u32 core, Thread* thread);
+    void Suggest(u32 priority, std::size_t core, Thread* thread);
 
     /**
      * Remove a thread to the suggested queue of a cpu core. Suggested threads may be
      * picked if no thread is scheduled to run on the core.
      */
-    void Unsuggest(u32 priority, u32 core, Thread* thread);
+    void Unsuggest(u32 priority, std::size_t core, Thread* thread);
 
     /**
      * Add a thread to the scheduling queue of a cpu core. The thread is added at the
      * back the queue in its priority level.
      */
-    void Schedule(u32 priority, u32 core, Thread* thread);
+    void Schedule(u32 priority, std::size_t core, Thread* thread);
 
     /**
      * Add a thread to the scheduling queue of a cpu core. The thread is added at the
      * front the queue in its priority level.
      */
-    void SchedulePrepend(u32 priority, u32 core, Thread* thread);
+    void SchedulePrepend(u32 priority, std::size_t core, Thread* thread);
 
     /// Reschedule an already scheduled thread based on a new priority
-    void Reschedule(u32 priority, u32 core, Thread* thread);
+    void Reschedule(u32 priority, std::size_t core, Thread* thread);
 
     /// Unschedules a thread.
-    void Unschedule(u32 priority, u32 core, Thread* thread);
-
-    /**
-     * Transfers a thread into an specific core. If the destination_core is -1
-     * it will be unscheduled from its source code and added into its suggested
-     * queue.
-     */
-    void TransferToCore(u32 priority, s32 destination_core, Thread* thread);
+    void Unschedule(u32 priority, std::size_t core, Thread* thread);
 
     /// Selects a core and forces it to unload its current thread's context
-    void UnloadThread(s32 core);
+    void UnloadThread(std::size_t core);
 
     /**
      * Takes care of selecting the new scheduled thread in three steps:
@@ -90,9 +83,9 @@ public:
      * 3. Third is no suggested thread is found, we do a second pass and pick a running
      *    thread in another core and swap it with its current thread.
      */
-    void SelectThread(u32 core);
+    void SelectThread(std::size_t core);
 
-    bool HaveReadyThreads(u32 core_id) const {
+    bool HaveReadyThreads(std::size_t core_id) const {
         return !scheduled_queue[core_id].empty();
     }
 
@@ -145,6 +138,13 @@ public:
     void Shutdown();
 
 private:
+    /**
+     * Transfers a thread into an specific core. If the destination_core is -1
+     * it will be unscheduled from its source code and added into its suggested
+     * queue.
+     */
+    void TransferToCore(u32 priority, s32 destination_core, Thread* thread);
+
     bool AskForReselectionOrMarkRedundant(Thread* current_thread, const Thread* winner);
 
     static constexpr u32 min_regular_priority = 2;
@@ -163,7 +163,7 @@ private:
 
 class Scheduler final {
 public:
-    explicit Scheduler(Core::System& system, Core::ARM_Interface& cpu_core, u32 core_id);
+    explicit Scheduler(Core::System& system, Core::ARM_Interface& cpu_core, std::size_t core_id);
     ~Scheduler();
 
     /// Returns whether there are any threads that are ready to run.
@@ -220,7 +220,7 @@ private:
     Core::ARM_Interface& cpu_core;
     u64 last_context_switch_time = 0;
     u64 idle_selection_count = 0;
-    const u32 core_id;
+    const std::size_t core_id;
 
     bool is_context_switch_pending = false;
 };
diff --git a/src/core/hle/kernel/thread.cpp b/src/core/hle/kernel/thread.cpp
index 962530d2d..ee7531f2d 100644
--- a/src/core/hle/kernel/thread.cpp
+++ b/src/core/hle/kernel/thread.cpp
@@ -77,18 +77,6 @@ void Thread::CancelWakeupTimer() {
                                                              callback_handle);
 }
 
-static std::optional<s32> GetNextProcessorId(u64 mask) {
-    for (s32 index = 0; index < Core::NUM_CPU_CORES; ++index) {
-        if (mask & (1ULL << index)) {
-            if (!Core::System::GetInstance().Scheduler(index).GetCurrentThread()) {
-                // Core is enabled and not running any threads, use this one
-                return index;
-            }
-        }
-    }
-    return {};
-}
-
 void Thread::ResumeFromWait() {
     ASSERT_MSG(wait_objects.empty(), "Thread is waking up while waiting for objects");
 
@@ -173,7 +161,7 @@ ResultVal<SharedPtr<Thread>> Thread::Create(KernelCore& kernel, std::string name
     if (!Memory::IsValidVirtualAddress(owner_process, entry_point)) {
         LOG_ERROR(Kernel_SVC, "(name={}): invalid entry {:016X}", name, entry_point);
         // TODO (bunnei): Find the correct error code to use here
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
 
     auto& system = Core::System::GetInstance();
@@ -401,7 +389,7 @@ void Thread::SetCurrentPriority(u32 new_priority) {
 
 ResultCode Thread::SetCoreAndAffinityMask(s32 new_core, u64 new_affinity_mask) {
     const auto HighestSetCore = [](u64 mask, u32 max_cores) {
-        for (s32 core = max_cores - 1; core >= 0; core--) {
+        for (s32 core = static_cast<s32>(max_cores - 1); core >= 0; core--) {
             if (((mask >> core) & 1) != 0) {
                 return core;
             }
@@ -425,7 +413,7 @@ ResultCode Thread::SetCoreAndAffinityMask(s32 new_core, u64 new_affinity_mask) {
         if (old_affinity_mask != new_affinity_mask) {
             const s32 old_core = processor_id;
             if (processor_id >= 0 && ((affinity_mask >> processor_id) & 1) == 0) {
-                if (ideal_core < 0) {
+                if (static_cast<s32>(ideal_core) < 0) {
                     processor_id = HighestSetCore(affinity_mask, GlobalScheduler::NUM_CPU_CORES);
                 } else {
                     processor_id = ideal_core;
@@ -447,23 +435,23 @@ void Thread::AdjustSchedulingOnStatus(u32 old_flags) {
         ThreadSchedStatus::Runnable) {
         // In this case the thread was running, now it's pausing/exitting
         if (processor_id >= 0) {
-            scheduler.Unschedule(current_priority, processor_id, this);
+            scheduler.Unschedule(current_priority, static_cast<u32>(processor_id), this);
         }
 
-        for (s32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
-            if (core != processor_id && ((affinity_mask >> core) & 1) != 0) {
-                scheduler.Unsuggest(current_priority, static_cast<u32>(core), this);
+        for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
+            if (core != static_cast<u32>(processor_id) && ((affinity_mask >> core) & 1) != 0) {
+                scheduler.Unsuggest(current_priority, core, this);
             }
         }
     } else if (GetSchedulingStatus() == ThreadSchedStatus::Runnable) {
         // The thread is now set to running from being stopped
         if (processor_id >= 0) {
-            scheduler.Schedule(current_priority, processor_id, this);
+            scheduler.Schedule(current_priority, static_cast<u32>(processor_id), this);
         }
 
-        for (s32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
-            if (core != processor_id && ((affinity_mask >> core) & 1) != 0) {
-                scheduler.Suggest(current_priority, static_cast<u32>(core), this);
+        for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
+            if (core != static_cast<u32>(processor_id) && ((affinity_mask >> core) & 1) != 0) {
+                scheduler.Suggest(current_priority, core, this);
             }
         }
     }
@@ -477,11 +465,11 @@ void Thread::AdjustSchedulingOnPriority(u32 old_priority) {
     }
     auto& scheduler = Core::System::GetInstance().GlobalScheduler();
     if (processor_id >= 0) {
-        scheduler.Unschedule(old_priority, processor_id, this);
+        scheduler.Unschedule(old_priority, static_cast<u32>(processor_id), this);
     }
 
     for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
-        if (core != processor_id && ((affinity_mask >> core) & 1) != 0) {
+        if (core != static_cast<u32>(processor_id) && ((affinity_mask >> core) & 1) != 0) {
             scheduler.Unsuggest(old_priority, core, this);
         }
     }
@@ -491,14 +479,14 @@ void Thread::AdjustSchedulingOnPriority(u32 old_priority) {
 
     if (processor_id >= 0) {
         if (current_thread == this) {
-            scheduler.SchedulePrepend(current_priority, processor_id, this);
+            scheduler.SchedulePrepend(current_priority, static_cast<u32>(processor_id), this);
         } else {
-            scheduler.Schedule(current_priority, processor_id, this);
+            scheduler.Schedule(current_priority, static_cast<u32>(processor_id), this);
         }
     }
 
     for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
-        if (core != processor_id && ((affinity_mask >> core) & 1) != 0) {
+        if (core != static_cast<u32>(processor_id) && ((affinity_mask >> core) & 1) != 0) {
             scheduler.Suggest(current_priority, core, this);
         }
     }
@@ -515,7 +503,7 @@ void Thread::AdjustSchedulingOnAffinity(u64 old_affinity_mask, s32 old_core) {
 
     for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
         if (((old_affinity_mask >> core) & 1) != 0) {
-            if (core == old_core) {
+            if (core == static_cast<u32>(old_core)) {
                 scheduler.Unschedule(current_priority, core, this);
             } else {
                 scheduler.Unsuggest(current_priority, core, this);
@@ -525,7 +513,7 @@ void Thread::AdjustSchedulingOnAffinity(u64 old_affinity_mask, s32 old_core) {
 
     for (u32 core = 0; core < GlobalScheduler::NUM_CPU_CORES; core++) {
         if (((affinity_mask >> core) & 1) != 0) {
-            if (core == processor_id) {
+            if (core == static_cast<u32>(processor_id)) {
                 scheduler.Schedule(current_priority, core, this);
             } else {
                 scheduler.Suggest(current_priority, core, this);
diff --git a/src/core/hle/kernel/vm_manager.cpp b/src/core/hle/kernel/vm_manager.cpp
index c7af87073..e6eee09d7 100644
--- a/src/core/hle/kernel/vm_manager.cpp
+++ b/src/core/hle/kernel/vm_manager.cpp
@@ -167,7 +167,7 @@ ResultVal<VAddr> VMManager::FindFreeRegion(VAddr begin, VAddr end, u64 size) con
 
     if (vma_handle == vma_map.cend()) {
         // TODO(Subv): Find the correct error code here.
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
 
     const VAddr target = std::max(begin, vma_handle->second.base);
diff --git a/src/core/hle/result.h b/src/core/hle/result.h
index 8a3701151..450f61fea 100644
--- a/src/core/hle/result.h
+++ b/src/core/hle/result.h
@@ -147,6 +147,14 @@ constexpr bool operator!=(const ResultCode& a, const ResultCode& b) {
 constexpr ResultCode RESULT_SUCCESS(0);
 
 /**
+ * Placeholder result code used for unknown error codes.
+ *
+ * @note This should only be used when a particular error code
+ *       is not known yet.
+ */
+constexpr ResultCode RESULT_UNKNOWN(UINT32_MAX);
+
+/**
  * This is an optional value type. It holds a `ResultCode` and, if that code is a success code,
  * also holds a result of type `T`. If the code is an error code then trying to access the inner
  * value fails, thus ensuring that the ResultCode of functions is always checked properly before
@@ -183,7 +191,7 @@ class ResultVal {
 public:
     /// Constructs an empty `ResultVal` with the given error code. The code must not be a success
     /// code.
-    ResultVal(ResultCode error_code = ResultCode(-1)) : result_code(error_code) {
+    ResultVal(ResultCode error_code = RESULT_UNKNOWN) : result_code(error_code) {
         ASSERT(error_code.IsError());
     }
 
diff --git a/src/core/hle/service/acc/acc.cpp b/src/core/hle/service/acc/acc.cpp
index 0c0f7ed6e..7e3e311fb 100644
--- a/src/core/hle/service/acc/acc.cpp
+++ b/src/core/hle/service/acc/acc.cpp
@@ -84,7 +84,7 @@ protected:
             LOG_ERROR(Service_ACC, "Failed to get profile base and data for user={}",
                       user_id.Format());
             IPC::ResponseBuilder rb{ctx, 2};
-            rb.Push(ResultCode(-1)); // TODO(ogniK): Get actual error code
+            rb.Push(RESULT_UNKNOWN); // TODO(ogniK): Get actual error code
         }
     }
 
@@ -98,7 +98,7 @@ protected:
         } else {
             LOG_ERROR(Service_ACC, "Failed to get profile base for user={}", user_id.Format());
             IPC::ResponseBuilder rb{ctx, 2};
-            rb.Push(ResultCode(-1)); // TODO(ogniK): Get actual error code
+            rb.Push(RESULT_UNKNOWN); // TODO(ogniK): Get actual error code
         }
     }
 
@@ -442,7 +442,7 @@ void Module::Interface::TrySelectUserWithoutInteraction(Kernel::HLERequestContex
     const auto user_list = profile_manager->GetAllUsers();
     if (std::all_of(user_list.begin(), user_list.end(),
                     [](const auto& user) { return user.uuid == Common::INVALID_UUID; })) {
-        rb.Push(ResultCode(-1)); // TODO(ogniK): Find the correct error code
+        rb.Push(RESULT_UNKNOWN); // TODO(ogniK): Find the correct error code
         rb.PushRaw<u128>(Common::INVALID_UUID);
         return;
     }
diff --git a/src/core/hle/service/acc/profile_manager.cpp b/src/core/hle/service/acc/profile_manager.cpp
index 8f9986326..3e756e59e 100644
--- a/src/core/hle/service/acc/profile_manager.cpp
+++ b/src/core/hle/service/acc/profile_manager.cpp
@@ -31,8 +31,8 @@ struct ProfileDataRaw {
 static_assert(sizeof(ProfileDataRaw) == 0x650, "ProfileDataRaw has incorrect size.");
 
 // TODO(ogniK): Get actual error codes
-constexpr ResultCode ERROR_TOO_MANY_USERS(ErrorModule::Account, -1);
-constexpr ResultCode ERROR_USER_ALREADY_EXISTS(ErrorModule::Account, -2);
+constexpr ResultCode ERROR_TOO_MANY_USERS(ErrorModule::Account, u32(-1));
+constexpr ResultCode ERROR_USER_ALREADY_EXISTS(ErrorModule::Account, u32(-2));
 constexpr ResultCode ERROR_ARGUMENT_IS_NULL(ErrorModule::Account, 20);
 
 constexpr char ACC_SAVE_AVATORS_BASE_PATH[] = "/system/save/8000000000000010/su/avators/";
diff --git a/src/core/hle/service/am/am.cpp b/src/core/hle/service/am/am.cpp
index d52ec4387..a5702e1ab 100644
--- a/src/core/hle/service/am/am.cpp
+++ b/src/core/hle/service/am/am.cpp
@@ -991,7 +991,7 @@ void ILibraryAppletCreator::CreateLibraryApplet(Kernel::HLERequestContext& ctx)
         LOG_ERROR(Service_AM, "Applet doesn't exist! applet_id={}", static_cast<u32>(applet_id));
 
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultCode(-1));
+        rb.Push(RESULT_UNKNOWN);
         return;
     }
 
@@ -1027,7 +1027,7 @@ void ILibraryAppletCreator::CreateTransferMemoryStorage(Kernel::HLERequestContex
     if (transfer_mem == nullptr) {
         LOG_ERROR(Service_AM, "shared_mem is a nullpr for handle={:08X}", handle);
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultCode(-1));
+        rb.Push(RESULT_UNKNOWN);
         return;
     }
 
diff --git a/src/core/hle/service/am/applets/web_browser.cpp b/src/core/hle/service/am/applets/web_browser.cpp
index 32283e819..5546ef6e8 100644
--- a/src/core/hle/service/am/applets/web_browser.cpp
+++ b/src/core/hle/service/am/applets/web_browser.cpp
@@ -337,7 +337,7 @@ void WebBrowser::ExecuteInternal() {
 void WebBrowser::InitializeShop() {
     if (frontend_e_commerce == nullptr) {
         LOG_ERROR(Service_AM, "Missing ECommerce Applet frontend!");
-        status = ResultCode(-1);
+        status = RESULT_UNKNOWN;
         return;
     }
 
@@ -353,7 +353,7 @@ void WebBrowser::InitializeShop() {
 
     if (url == args.end()) {
         LOG_ERROR(Service_AM, "Missing EShop Arguments URL for initialization!");
-        status = ResultCode(-1);
+        status = RESULT_UNKNOWN;
         return;
     }
 
@@ -366,7 +366,7 @@ void WebBrowser::InitializeShop() {
     // Less is missing info, More is malformed
     if (split_query.size() != 2) {
         LOG_ERROR(Service_AM, "EShop Arguments has more than one question mark, malformed");
-        status = ResultCode(-1);
+        status = RESULT_UNKNOWN;
         return;
     }
 
@@ -390,7 +390,7 @@ void WebBrowser::InitializeShop() {
 
     if (scene == shop_query.end()) {
         LOG_ERROR(Service_AM, "No scene parameter was passed via shop query!");
-        status = ResultCode(-1);
+        status = RESULT_UNKNOWN;
         return;
     }
 
@@ -406,7 +406,7 @@ void WebBrowser::InitializeShop() {
     const auto target = target_map.find(scene->second);
     if (target == target_map.end()) {
         LOG_ERROR(Service_AM, "Scene for shop query is invalid! (scene={})", scene->second);
-        status = ResultCode(-1);
+        status = RESULT_UNKNOWN;
         return;
     }
 
@@ -427,7 +427,7 @@ void WebBrowser::InitializeOffline() {
     if (args.find(WebArgTLVType::DocumentPath) == args.end() ||
         args.find(WebArgTLVType::DocumentKind) == args.end() ||
         args.find(WebArgTLVType::ApplicationID) == args.end()) {
-        status = ResultCode(-1);
+        status = RESULT_UNKNOWN;
         LOG_ERROR(Service_AM, "Missing necessary parameters for initialization!");
     }
 
@@ -476,7 +476,7 @@ void WebBrowser::InitializeOffline() {
 
     offline_romfs = GetApplicationRomFS(system, title_id, type);
     if (offline_romfs == nullptr) {
-        status = ResultCode(-1);
+        status = RESULT_UNKNOWN;
         LOG_ERROR(Service_AM, "Failed to find offline data for request!");
     }
 
@@ -496,7 +496,7 @@ void WebBrowser::ExecuteShop() {
     const auto check_optional_parameter = [this](const auto& p) {
         if (!p.has_value()) {
             LOG_ERROR(Service_AM, "Missing one or more necessary parameters for execution!");
-            status = ResultCode(-1);
+            status = RESULT_UNKNOWN;
             return false;
         }
 
diff --git a/src/core/hle/service/aoc/aoc_u.cpp b/src/core/hle/service/aoc/aoc_u.cpp
index f36ccbc49..30076a53e 100644
--- a/src/core/hle/service/aoc/aoc_u.cpp
+++ b/src/core/hle/service/aoc/aoc_u.cpp
@@ -131,7 +131,7 @@ void AOC_U::ListAddOnContent(Kernel::HLERequestContext& ctx) {
     if (out.size() < offset) {
         IPC::ResponseBuilder rb{ctx, 2};
         // TODO(DarkLordZach): Find the correct error code.
-        rb.Push(ResultCode(-1));
+        rb.Push(RESULT_UNKNOWN);
         return;
     }
 
diff --git a/src/core/hle/service/audio/hwopus.cpp b/src/core/hle/service/audio/hwopus.cpp
index cb4a1160d..cb839e4a2 100644
--- a/src/core/hle/service/audio/hwopus.cpp
+++ b/src/core/hle/service/audio/hwopus.cpp
@@ -80,7 +80,7 @@ private:
             LOG_ERROR(Audio, "Failed to decode opus data");
             IPC::ResponseBuilder rb{ctx, 2};
             // TODO(ogniK): Use correct error code
-            rb.Push(ResultCode(-1));
+            rb.Push(RESULT_UNKNOWN);
             return;
         }
 
@@ -278,7 +278,7 @@ void HwOpus::OpenOpusDecoder(Kernel::HLERequestContext& ctx) {
         LOG_ERROR(Audio, "Failed to create Opus decoder (error={}).", error);
         IPC::ResponseBuilder rb{ctx, 2};
         // TODO(ogniK): Use correct error code
-        rb.Push(ResultCode(-1));
+        rb.Push(RESULT_UNKNOWN);
         return;
     }
 
diff --git a/src/core/hle/service/bcat/backend/boxcat.cpp b/src/core/hle/service/bcat/backend/boxcat.cpp
index 1411a646f..67e39a5c4 100644
--- a/src/core/hle/service/bcat/backend/boxcat.cpp
+++ b/src/core/hle/service/bcat/backend/boxcat.cpp
@@ -114,7 +114,7 @@ void HandleDownloadDisplayResult(const AM::Applets::AppletManager& applet_manage
 
     const auto& frontend{applet_manager.GetAppletFrontendSet()};
     frontend.error->ShowCustomErrorText(
-        ResultCode(-1), "There was an error while attempting to use Boxcat.",
+        RESULT_UNKNOWN, "There was an error while attempting to use Boxcat.",
         DOWNLOAD_RESULT_LOG_MESSAGES[static_cast<std::size_t>(res)], [] {});
 }
 
diff --git a/src/core/hle/service/filesystem/filesystem.cpp b/src/core/hle/service/filesystem/filesystem.cpp
index 11e5c56b7..102017d73 100644
--- a/src/core/hle/service/filesystem/filesystem.cpp
+++ b/src/core/hle/service/filesystem/filesystem.cpp
@@ -58,11 +58,11 @@ ResultCode VfsDirectoryServiceWrapper::CreateFile(const std::string& path_, u64
     auto file = dir->CreateFile(FileUtil::GetFilename(path));
     if (file == nullptr) {
         // TODO(DarkLordZach): Find a better error code for this
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
     if (!file->Resize(size)) {
         // TODO(DarkLordZach): Find a better error code for this
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
     return RESULT_SUCCESS;
 }
@@ -80,7 +80,7 @@ ResultCode VfsDirectoryServiceWrapper::DeleteFile(const std::string& path_) cons
     }
     if (!dir->DeleteFile(FileUtil::GetFilename(path))) {
         // TODO(DarkLordZach): Find a better error code for this
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
 
     return RESULT_SUCCESS;
@@ -94,7 +94,7 @@ ResultCode VfsDirectoryServiceWrapper::CreateDirectory(const std::string& path_)
     auto new_dir = dir->CreateSubdirectory(FileUtil::GetFilename(path));
     if (new_dir == nullptr) {
         // TODO(DarkLordZach): Find a better error code for this
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
     return RESULT_SUCCESS;
 }
@@ -104,7 +104,7 @@ ResultCode VfsDirectoryServiceWrapper::DeleteDirectory(const std::string& path_)
     auto dir = GetDirectoryRelativeWrapped(backing, FileUtil::GetParentPath(path));
     if (!dir->DeleteSubdirectory(FileUtil::GetFilename(path))) {
         // TODO(DarkLordZach): Find a better error code for this
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
     return RESULT_SUCCESS;
 }
@@ -114,7 +114,7 @@ ResultCode VfsDirectoryServiceWrapper::DeleteDirectoryRecursively(const std::str
     auto dir = GetDirectoryRelativeWrapped(backing, FileUtil::GetParentPath(path));
     if (!dir->DeleteSubdirectoryRecursive(FileUtil::GetFilename(path))) {
         // TODO(DarkLordZach): Find a better error code for this
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
     return RESULT_SUCCESS;
 }
@@ -125,7 +125,7 @@ ResultCode VfsDirectoryServiceWrapper::CleanDirectoryRecursively(const std::stri
 
     if (!dir->CleanSubdirectoryRecursive(FileUtil::GetFilename(sanitized_path))) {
         // TODO(DarkLordZach): Find a better error code for this
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
 
     return RESULT_SUCCESS;
@@ -142,7 +142,7 @@ ResultCode VfsDirectoryServiceWrapper::RenameFile(const std::string& src_path_,
             return FileSys::ERROR_PATH_NOT_FOUND;
         if (!src->Rename(FileUtil::GetFilename(dest_path))) {
             // TODO(DarkLordZach): Find a better error code for this
-            return ResultCode(-1);
+            return RESULT_UNKNOWN;
         }
         return RESULT_SUCCESS;
     }
@@ -160,7 +160,7 @@ ResultCode VfsDirectoryServiceWrapper::RenameFile(const std::string& src_path_,
 
     if (!src->GetContainingDirectory()->DeleteFile(FileUtil::GetFilename(src_path))) {
         // TODO(DarkLordZach): Find a better error code for this
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
 
     return RESULT_SUCCESS;
@@ -177,7 +177,7 @@ ResultCode VfsDirectoryServiceWrapper::RenameDirectory(const std::string& src_pa
             return FileSys::ERROR_PATH_NOT_FOUND;
         if (!src->Rename(FileUtil::GetFilename(dest_path))) {
             // TODO(DarkLordZach): Find a better error code for this
-            return ResultCode(-1);
+            return RESULT_UNKNOWN;
         }
         return RESULT_SUCCESS;
     }
@@ -189,7 +189,7 @@ ResultCode VfsDirectoryServiceWrapper::RenameDirectory(const std::string& src_pa
                src_path, dest_path);
 
     // TODO(DarkLordZach): Find a better error code for this
-    return ResultCode(-1);
+    return RESULT_UNKNOWN;
 }
 
 ResultVal<FileSys::VirtualFile> VfsDirectoryServiceWrapper::OpenFile(const std::string& path_,
@@ -287,7 +287,7 @@ ResultVal<FileSys::VirtualFile> FileSystemController::OpenRomFSCurrentProcess()
 
     if (romfs_factory == nullptr) {
         // TODO(bunnei): Find a better error code for this
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
 
     return romfs_factory->OpenCurrentProcess(system.CurrentProcess()->GetTitleID());
@@ -300,7 +300,7 @@ ResultVal<FileSys::VirtualFile> FileSystemController::OpenRomFS(
 
     if (romfs_factory == nullptr) {
         // TODO(bunnei): Find a better error code for this
-        return ResultCode(-1);
+        return RESULT_UNKNOWN;
     }
 
     return romfs_factory->Open(title_id, storage_id, type);
diff --git a/src/core/hle/service/filesystem/fsp_srv.cpp b/src/core/hle/service/filesystem/fsp_srv.cpp
index cbd5466c1..92162d3e1 100644
--- a/src/core/hle/service/filesystem/fsp_srv.cpp
+++ b/src/core/hle/service/filesystem/fsp_srv.cpp
@@ -785,7 +785,7 @@ void FSP_SRV::OpenFileSystemWithPatch(Kernel::HLERequestContext& ctx) {
                 static_cast<u8>(type), title_id);
 
     IPC::ResponseBuilder rb{ctx, 2, 0, 0};
-    rb.Push(ResultCode(-1));
+    rb.Push(RESULT_UNKNOWN);
 }
 
 void FSP_SRV::OpenSdCardFileSystem(Kernel::HLERequestContext& ctx) {
@@ -891,7 +891,7 @@ void FSP_SRV::OpenDataStorageByCurrentProcess(Kernel::HLERequestContext& ctx) {
         // TODO (bunnei): Find the right error code to use here
         LOG_CRITICAL(Service_FS, "no file system interface available!");
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultCode(-1));
+        rb.Push(RESULT_UNKNOWN);
         return;
     }
 
@@ -928,7 +928,7 @@ void FSP_SRV::OpenDataStorageByDataId(Kernel::HLERequestContext& ctx) {
                   "could not open data storage with title_id={:016X}, storage_id={:02X}", title_id,
                   static_cast<u8>(storage_id));
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultCode(-1));
+        rb.Push(RESULT_UNKNOWN);
         return;
     }
 
diff --git a/src/core/hle/service/mii/mii.cpp b/src/core/hle/service/mii/mii.cpp
index 0b3923ad9..0ffc5009e 100644
--- a/src/core/hle/service/mii/mii.cpp
+++ b/src/core/hle/service/mii/mii.cpp
@@ -242,7 +242,7 @@ private:
         const auto index = db.IndexOf(uuid);
         if (index > MAX_MIIS) {
             // TODO(DarkLordZach): Find a better error code
-            rb.Push(ResultCode(-1));
+            rb.Push(RESULT_UNKNOWN);
             rb.Push(index);
         } else {
             rb.Push(RESULT_SUCCESS);
@@ -268,7 +268,7 @@ private:
 
         IPC::ResponseBuilder rb{ctx, 2};
         // TODO(DarkLordZach): Find a better error code
-        rb.Push(success ? RESULT_SUCCESS : ResultCode(-1));
+        rb.Push(success ? RESULT_SUCCESS : RESULT_UNKNOWN);
     }
 
     void AddOrReplace(Kernel::HLERequestContext& ctx) {
@@ -282,7 +282,7 @@ private:
 
         IPC::ResponseBuilder rb{ctx, 2};
         // TODO(DarkLordZach): Find a better error code
-        rb.Push(success ? RESULT_SUCCESS : ResultCode(-1));
+        rb.Push(success ? RESULT_SUCCESS : RESULT_UNKNOWN);
     }
 
     void Delete(Kernel::HLERequestContext& ctx) {
diff --git a/src/core/hle/service/nfp/nfp.cpp b/src/core/hle/service/nfp/nfp.cpp
index 795d7b716..3bf753dee 100644
--- a/src/core/hle/service/nfp/nfp.cpp
+++ b/src/core/hle/service/nfp/nfp.cpp
@@ -16,10 +16,7 @@
 #include "core/hle/service/nfp/nfp_user.h"
 
 namespace Service::NFP {
-
 namespace ErrCodes {
-[[maybe_unused]] constexpr ResultCode ERR_TAG_FAILED(ErrorModule::NFP,
-                                                     -1); // TODO(ogniK): Find the actual error code
 constexpr ResultCode ERR_NO_APPLICATION_AREA(ErrorModule::NFP, 152);
 } // namespace ErrCodes
 
diff --git a/src/core/hle/service/ns/ns.cpp b/src/core/hle/service/ns/ns.cpp
index 15c156ce1..eeba0aa19 100644
--- a/src/core/hle/service/ns/ns.cpp
+++ b/src/core/hle/service/ns/ns.cpp
@@ -271,7 +271,7 @@ void IApplicationManagerInterface::GetApplicationControlData(Kernel::HLERequestC
                       "output buffer is too small! (actual={:016X}, expected_min=0x4000)", size);
             IPC::ResponseBuilder rb{ctx, 2};
             // TODO(DarkLordZach): Find a better error code for this.
-            rb.Push(ResultCode(-1));
+            rb.Push(RESULT_UNKNOWN);
             return;
         }
 
@@ -291,7 +291,7 @@ void IApplicationManagerInterface::GetApplicationControlData(Kernel::HLERequestC
                       0x4000 + control.second->GetSize());
             IPC::ResponseBuilder rb{ctx, 2};
             // TODO(DarkLordZach): Find a better error code for this.
-            rb.Push(ResultCode(-1));
+            rb.Push(RESULT_UNKNOWN);
             return;
         }
 
diff --git a/src/core/hle/service/ns/pl_u.cpp b/src/core/hle/service/ns/pl_u.cpp
index 23477315f..db433305f 100644
--- a/src/core/hle/service/ns/pl_u.cpp
+++ b/src/core/hle/service/ns/pl_u.cpp
@@ -97,7 +97,7 @@ void EncryptSharedFont(const std::vector<u32>& input, std::vector<u8>& output,
     const auto key = Common::swap32(EXPECTED_RESULT ^ EXPECTED_MAGIC);
     std::vector<u32> transformed_font(input.size() + 2);
     transformed_font[0] = Common::swap32(EXPECTED_MAGIC);
-    transformed_font[1] = Common::swap32(input.size() * sizeof(u32)) ^ key;
+    transformed_font[1] = Common::swap32(static_cast<u32>(input.size() * sizeof(u32))) ^ key;
     std::transform(input.begin(), input.end(), transformed_font.begin() + 2,
                    [key](u32 in) { return in ^ key; });
     std::memcpy(output.data() + offset, transformed_font.data(),
diff --git a/src/core/hle/service/time/time.cpp b/src/core/hle/service/time/time.cpp
index 1b9ab8401..62efe021e 100644
--- a/src/core/hle/service/time/time.cpp
+++ b/src/core/hle/service/time/time.cpp
@@ -34,12 +34,12 @@ static void PosixToCalendar(u64 posix_time, CalendarTime& calendar_time,
         additional_info = {};
         return;
     }
-    calendar_time.year = tm->tm_year + 1900;
-    calendar_time.month = tm->tm_mon + 1;
-    calendar_time.day = tm->tm_mday;
-    calendar_time.hour = tm->tm_hour;
-    calendar_time.minute = tm->tm_min;
-    calendar_time.second = tm->tm_sec;
+    calendar_time.year = static_cast<u16_le>(tm->tm_year + 1900);
+    calendar_time.month = static_cast<u8>(tm->tm_mon + 1);
+    calendar_time.day = static_cast<u8>(tm->tm_mday);
+    calendar_time.hour = static_cast<u8>(tm->tm_hour);
+    calendar_time.minute = static_cast<u8>(tm->tm_min);
+    calendar_time.second = static_cast<u8>(tm->tm_sec);
 
     additional_info.day_of_week = tm->tm_wday;
     additional_info.day_of_year = tm->tm_yday;
@@ -322,7 +322,7 @@ void Module::Interface::GetClockSnapshot(Kernel::HLERequestContext& ctx) {
     if (tm == nullptr) {
         LOG_ERROR(Service_Time, "tm is a nullptr");
         IPC::ResponseBuilder rb{ctx, 2};
-        rb.Push(ResultCode(-1)); // TODO(ogniK): Find appropriate error code
+        rb.Push(RESULT_UNKNOWN); // TODO(ogniK): Find appropriate error code
         return;
     }
 
@@ -331,12 +331,12 @@ void Module::Interface::GetClockSnapshot(Kernel::HLERequestContext& ctx) {
     const SteadyClockTimePoint steady_clock_time_point{static_cast<u64_le>(ms.count() / 1000), {}};
 
     CalendarTime calendar_time{};
-    calendar_time.year = tm->tm_year + 1900;
-    calendar_time.month = tm->tm_mon + 1;
-    calendar_time.day = tm->tm_mday;
-    calendar_time.hour = tm->tm_hour;
-    calendar_time.minute = tm->tm_min;
-    calendar_time.second = tm->tm_sec;
+    calendar_time.year = static_cast<u16_le>(tm->tm_year + 1900);
+    calendar_time.month = static_cast<u8>(tm->tm_mon + 1);
+    calendar_time.day = static_cast<u8>(tm->tm_mday);
+    calendar_time.hour = static_cast<u8>(tm->tm_hour);
+    calendar_time.minute = static_cast<u8>(tm->tm_min);
+    calendar_time.second = static_cast<u8>(tm->tm_sec);
 
     ClockSnapshot clock_snapshot{};
     clock_snapshot.system_posix_time = time_since_epoch;
diff --git a/src/core/hle/service/vi/vi.cpp b/src/core/hle/service/vi/vi.cpp
index 611cecc20..abfc3a801 100644
--- a/src/core/hle/service/vi/vi.cpp
+++ b/src/core/hle/service/vi/vi.cpp
@@ -541,7 +541,7 @@ private:
             } else {
                 // Wait the current thread until a buffer becomes available
                 ctx.SleepClientThread(
-                    "IHOSBinderDriver::DequeueBuffer", -1,
+                    "IHOSBinderDriver::DequeueBuffer", UINT64_MAX,
                     [=](Kernel::SharedPtr<Kernel::Thread> thread, Kernel::HLERequestContext& ctx,
                         Kernel::ThreadWakeupReason reason) {
                         // Repeat TransactParcel DequeueBuffer when a buffer is available
diff --git a/src/core/perf_stats.cpp b/src/core/perf_stats.cpp
index d2c69d1a0..f1ae9d4df 100644
--- a/src/core/perf_stats.cpp
+++ b/src/core/perf_stats.cpp
@@ -81,7 +81,7 @@ double PerfStats::GetMeanFrametime() {
         return 0;
     }
     const double sum = std::accumulate(perf_history.begin() + IgnoreFrames,
-                                       perf_history.begin() + current_index, 0);
+                                       perf_history.begin() + current_index, 0.0);
     return sum / (current_index - IgnoreFrames);
 }