(feat) Apple Silicon macOS CI building and Setup.pkg documentation (#118)

* docs(macos): document Setup.pkg installation

Add Apple Silicon macOS CI coverage for runtime configuration, substrate tests, and Setup.pkg packaging alongside the macOS installation instructions.

* macos: pin Apple Silicon deployment target

* fix(macos): restore Retro Rewind local builds

.github/workflows/build.yml

@@ -34,3 +34,34 @@ jobs:
 
       - name: Test
         run: dotnet test translator/Translator.sln -c Release --no-build --verbosity normal
+
+  macos_substrate:
+    name: macOS arm64 (configure + substrate tests)
+    runs-on: macos-14
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          persist-credentials: false
+
+      - name: Configure native runtime
+        shell: bash
+        run: |
+          test "$(uname -m)" = arm64
+          cmake -S runtime -B build-macos -G Ninja \
+            -DCMAKE_BUILD_TYPE=Release -DMKW_BUILD_PRODUCTS=OFF
+          grep -qx 'CMAKE_OSX_DEPLOYMENT_TARGET:STRING=14.0' \
+            build-macos/CMakeCache.txt
+
+      - name: Build macOS portability targets
+        shell: bash
+        run: |
+          cmake --build build-macos --target \
+            mkw_platform_paths_tests \
+            mkw_macos_native_compile \
+            mkw_macos_context_abi_tests \
+            mkw_macos_host_context_tests \
+            mkw_macos_guest_flat_memory_tests
+
+      - name: Test execution substrate
+        shell: bash
+        run: ctest --test-dir build-macos --output-on-failure

.github/workflows/package.yml

@@ -1,8 +1,8 @@
 name: Package installers
 
 # Builds the per-platform installer/setup tool (WiiCompiled-Setup.exe /
-# WiiCompiled-Setup-x86_64.AppImage) via Launcher/Build-Installer.ps1 and
-# Launcher/build-appimage.sh respectively - the same scripts a maintainer runs by hand today to
+# WiiCompiled-Setup-x86_64.AppImage / WiiCompiled-Setup.pkg) via the platform packaging scripts -
+# the same scripts a maintainer runs by hand today to
 # produce a GitHub Release asset. This does NOT build the actual translated game executable:
 # that step requires the end user's own Mario Kart Wii dump (Assets/main.dol, Assets/StaticR.rel),
 # which is proprietary and not present in this repository or in CI.
@@ -11,6 +11,11 @@ on:
     tags:
       - '*'
   workflow_dispatch:
+    inputs:
+      version:
+        description: Package version
+        required: true
+        type: string
 
 permissions:
   contents: read
@@ -86,14 +91,99 @@ jobs:
           if-no-files-found: error
           archive: false
 
+  macos-setup-package:
+    name: macOS (Setup.pkg, Apple Silicon)
+    runs-on: macos-14
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          persist-credentials: false
+
+      - uses: actions/setup-dotnet@v6
+        with:
+          dotnet-version: '8.0.x'
+
+      - name: Verify Apple Silicon runner tools
+        shell: bash
+        run: |
+          test "$(uname -m)" = arm64
+          xcode-select -p
+          command -v ninja
+          file "$(command -v ninja)" | grep -q arm64
+
+      - name: Download pinned nodtool release
+        shell: bash
+        run: |
+          mkdir -p Launcher/artifacts/macos
+          nodtool_version=v2.0.0-alpha.10
+          nodtool_asset=nodtool-macos-arm64
+          nodtool_sha256=e23ca466999b720c55e6d29c9683fce8cc74451ba64ead2e543d50129f24528a
+          curl -fsSL --retry 3 \
+            "https://github.com/encounter/nod/releases/download/${nodtool_version}/${nodtool_asset}" \
+            -o Launcher/artifacts/macos/nodtool
+          printf '%s  %s\n' "$nodtool_sha256" Launcher/artifacts/macos/nodtool | shasum -a 256 -c -
+          chmod +x Launcher/artifacts/macos/nodtool
+          Launcher/artifacts/macos/nodtool --version
+
+      - name: Publish self-contained translator
+        shell: bash
+        run: |
+          dotnet publish translator/src/Translator.Cli/Translator.Cli.csproj \
+            -c Release -r osx-arm64 --self-contained true \
+            -p:PublishSingleFile=true \
+            -o Launcher/artifacts/macos/translator
+
+      - name: Download pinned portable CMake
+        shell: bash
+        run: |
+          cmake_version=4.4.3
+          archive="cmake-${cmake_version}-macos-universal.tar.gz"
+          base_url="https://github.com/Kitware/CMake/releases/download/v${cmake_version}"
+          expected_sha256=0c5d65251c14cc884bfa16bdbed3c263ce5bffe2e21c0d0d00962cb0610464fa
+          curl -fsSL --retry 3 "$base_url/$archive" -o "$archive"
+          printf '%s  %s\n' "$expected_sha256" "$archive" | shasum -a 256 -c -
+          tar -xzf "$archive"
+          mv "cmake-${cmake_version}-macos-universal/CMake.app/Contents" Launcher/artifacts/macos/cmake
+
+      - name: Build Setup.pkg
+        env:
+          PACKAGE_VERSION: ${{ inputs.version }}
+          TAG_VERSION: ${{ github.ref_name }}
+        shell: bash
+        run: |
+          package_version="$PACKAGE_VERSION"
+          if [[ -z "$package_version" ]]; then package_version="${TAG_VERSION#v}"; fi
+          mkdir -p Launcher/dist
+          Launcher/macos/build-setup-pkg.command \
+            --nodtool Launcher/artifacts/macos/nodtool \
+            --translator Launcher/artifacts/macos/translator/Translator.Cli \
+            --cmake-root Launcher/artifacts/macos/cmake \
+            --ninja "$(command -v ninja)" \
+            --output Launcher/dist/WiiCompiled-Setup.pkg \
+            --version "$package_version"
+
+      - name: Verify package boundary
+        shell: bash
+        run: |
+          pkgutil --check-signature Launcher/dist/WiiCompiled-Setup.pkg
+          ! pkgutil --payload-files Launcher/dist/WiiCompiled-Setup.pkg | \
+            grep -E '/(Assets|generated|PulsarPacks|WiiCompiled.app|RetroRewind.app)(/|$)'
+
+      - uses: actions/upload-artifact@v7
+        with:
+          name: WiiCompiled-Setup-macos-arm64
+          path: Launcher/dist/WiiCompiled-Setup.pkg
+          if-no-files-found: error
+          archive: false
+
   # Publishes the packaged installers as a GitHub Release whenever a v* tag is pushed. Wheel Wizard
   # discovers updates from these releases, so the contract it relies on is enforced here: a full
-  # (non-prerelease) release whose tag is v<semver>, carrying an asset named exactly
-  # WiiCompiled-Setup.exe, produced by a setup host that reports that same version.
+  # (non-prerelease) release whose tag is v<semver>, carrying the expected platform assets,
+  # produced by setup hosts that report that same version.
   release:
     name: Publish GitHub Release
     if: startsWith(github.ref, 'refs/tags/v')
-    needs: [linux-appimage, windows-installer]
+    needs: [linux-appimage, windows-installer, macos-setup-package]
     runs-on: ubuntu-latest
     permissions:
       contents: write
@@ -139,7 +229,7 @@ jobs:
           set -euo pipefail
           ls -lR artifacts
           assets=()
-          for name in WiiCompiled-Setup.exe WiiCompiled-Setup-x86_64.AppImage WiiCompiled-Setup-aarch64.AppImage; do
+          for name in WiiCompiled-Setup.exe WiiCompiled-Setup-x86_64.AppImage WiiCompiled-Setup-aarch64.AppImage WiiCompiled-Setup.pkg; do
             found="$(find artifacts -type f -name "$name" | head -n 1)"
             [ -n "$found" ] && [ -s "$found" ] || { echo "::error::missing release asset $name"; exit 1; }
             assets+=("$found")

Launcher/WiiCompiled.Setup.Linux/Models.cs

@@ -3,7 +3,7 @@ namespace WiiCompiled.Setup.Linux;
 internal static class ProductInfo
 {
     public const string Name = "WiiCompiled";
-    public const string Version = "0.2.22";
+    public const string Version = "0.2.27";
 }
 
 /// <summary>One installed product's record inside install-state.json.</summary>

Launcher/WiiCompiled.Setup.Windows/InstallerEngine.cs

@@ -22,6 +22,9 @@ internal sealed class InstallerEngine
         var existing = new Installation(installDirectory);
 
         PortableInstallHealing.HealMovedInstall(existing, _reporter);
+        // Capture this before publishing anything. An existing installation may be repaired or
+        // updated by this invocation, but those operations must not recreate the user's shortcuts.
+        var firstInstall = !existing.IsPresent;
         var previousState = existing.ReadInstallState();
         using var scratch = Directory.Exists(installDirectory)
             ? InstallScratchSpace.CreateInsideInstall(installDirectory, _reporter)
@@ -139,7 +142,7 @@ internal sealed class InstallerEngine
                     updatedState.RetroRewindInstalled, candidateRuntimeAssetsFingerprint,
                     remainingCancellation);
             Publish(staging, installDirectory, canonicalRetroRoot, updatedState,
-                releaseEntries, remainingCancellation);
+                releaseEntries, remainingCancellation, createShortcuts: firstInstall);
             return;
         }
 
@@ -161,7 +164,8 @@ internal sealed class InstallerEngine
 
         await PublishToolkitAndReconcileProductsAsync(existing, staging, workspace, manifest,
             previousState, options, canonicalRetroRoot, retroCompileInputs,
-            publishGameAssets: reusableGameAssets is null, cancellationToken);
+            publishGameAssets: reusableGameAssets is null, createShortcuts: firstInstall,
+            cancellationToken: cancellationToken);
     }
 
 
@@ -186,7 +190,7 @@ internal sealed class InstallerEngine
         string stagedWorkspace, PayloadManifest manifest, InstallState? previousState,
         InstallOptions options, string? canonicalRetroRoot,
         RetroRewindCompileInputs? retroCompileInputs,
-        bool publishGameAssets, CancellationToken cancellationToken)
+        bool publishGameAssets, bool createShortcuts, CancellationToken cancellationToken)
     {
         var installDirectory = existing.Root;
 
@@ -214,7 +218,8 @@ internal sealed class InstallerEngine
         if (publishGameAssets) AddComponent(entries, staging, installDirectory, "GameAssets");
 
         Publish(staging, installDirectory, canonicalRetroRoot, state,
-            entries, cancellationToken, progressPercent: 8, completionPercent: 10);
+            entries, cancellationToken, progressPercent: 8, completionPercent: 10,
+            createShortcuts: createShortcuts);
 
         _reporter.Progress(InstallStages.BuildBase,
             "Producing the installed products with the published toolkit...", 11);
@@ -277,7 +282,7 @@ internal sealed class InstallerEngine
     private void Publish(string staging, string installDirectory,
         string? canonicalRetroRoot, InstallState state,
         List<InstallTransactionEntry> entries, CancellationToken cancellationToken,
-        int progressPercent = 95, int completionPercent = 99)
+        int progressPercent = 95, int completionPercent = 99, bool createShortcuts = false)
     {
         entries.Add(InstallTransactionEntry.Directory(Path.Combine(staging, "licenses"),
             Path.Combine(installDirectory, "licenses")));
@@ -322,7 +327,8 @@ internal sealed class InstallerEngine
             {
                 ShellIntegration.RegisterUninstaller(installDirectory, state.RetroRewindInstalled);
             }
-            ShellIntegration.CreateShortcuts(installDirectory);
+            if (createShortcuts)
+                ShellIntegration.CreateShortcuts(installDirectory);
         }
         catch (Exception ex)
         {

Launcher/local-build-macos.command

@@ -131,7 +131,9 @@ if (( builds_retro )); then args+=(--resolved-profile "$mod_out/resolved_dispatc
 step emit-build-shards 'Preparing native build shards'; translator "${args[@]}"
 
 step configure-native 'Configuring the native toolchain'
-"$cmake_bin" -S "$workspace/runtime" -B "$native_build" -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_MAKE_PROGRAM="$ninja_bin" -DMKW_TRANSLATED_COMPILE_JOBS="$translated_jobs"
+# Use Aurora's pinned SDL3 source on macOS.  A system SDL3 can be older than
+# Aurora's required API even when find_package() succeeds.
+"$cmake_bin" -S "$workspace/runtime" -B "$native_build" -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_MAKE_PROGRAM="$ninja_bin" -DMKW_TRANSLATED_COMPILE_JOBS="$translated_jobs" -DAURORA_SDL3_PROVIDER=vendor
 targets=(); [[ "$profile" != retro-rewind ]] && targets+=(WiiCompiled); [[ "$profile" != base ]] && targets+=(RetroRewind)
 step compile "Compiling ${targets[*]} locally"; "$cmake_bin" --build "$native_build" --target "${targets[@]}" --parallel "$global_jobs"
 if [[ "$profile" != retro-rewind ]]; then "$script_dir/macos/publish-app.command" --build-dir "$native_build" --product WiiCompiled --output-dir "${base_output_dir:-$output_dir}"; fi

Launcher/macos/build-setup-pkg.command

@@ -103,6 +103,9 @@ copy_clean "$workspace/Launcher/local-build-macos.command" "$resources/workspace
 copy_clean "$workspace/Launcher/macos/extract-disc.command" "$resources/workspace/Launcher/macos/extract-disc.command"
 copy_clean "$workspace/Launcher/macos/publish-app.command" "$resources/workspace/Launcher/macos/publish-app.command"
 chmod +x "$resources/workspace/Launcher/local-build-macos.command" "$resources/workspace/Launcher/macos/"*.command
+# setup.command uses this marker to update source inputs in an existing user
+# workspace without replacing extracted game assets or Retro Rewind files.
+printf '%s\n' "$version" > "$resources/workspace/.bundle-version"
 mkdir -p "$resources/tools/cmake"
 copy_clean "$nodtool" "$resources/tools/nodtool"; chmod +x "$resources/tools/nodtool"
 copy_clean "$translator" "$resources/tools/Translator.Cli"; chmod +x "$resources/tools/Translator.Cli"

Launcher/macos/setup.command

@@ -62,10 +62,30 @@ if ! /usr/bin/xcode-select -p >/dev/null 2>&1; then
 fi
 
 mkdir -p "$support_root" "$products"
-if [[ ! -d "$workspace/.git" && ! -f "$workspace/projects/mkwii/recomp.yml" ]]; then
+source_bundle_version="$workspace_source/.bundle-version"
+workspace_bundle_version="$workspace/.bundle-version"
+needs_workspace_refresh=0
+if [[ ! -f "$workspace/projects/mkwii/recomp.yml" ]]; then
+    needs_workspace_refresh=1
+elif [[ -f "$source_bundle_version" ]] && [[ ! -f "$workspace_bundle_version" || "$(<"$source_bundle_version")" != "$(<"$workspace_bundle_version")" ]]; then
+    needs_workspace_refresh=1
+fi
+
+if (( needs_workspace_refresh )); then
     printf 'Preparing the local build workspace...\n'
-    rm -rf "$workspace"
-    /usr/bin/ditto "$workspace_source" "$workspace"
+    if [[ ! -d "$workspace" ]]; then
+        /usr/bin/ditto "$workspace_source" "$workspace"
+    else
+        # Refresh only packaged source inputs. Assets and the staged Retro
+        # Rewind package belong to the user and stay in place.
+        for source in aurora-main projects runtime translator Launcher; do
+            /usr/bin/ditto "$workspace_source/$source" "$workspace/$source"
+        done
+        /usr/bin/ditto "$source_bundle_version" "$workspace_bundle_version"
+        # A dependency provider can be cached in this directory, so make the
+        # refreshed sources configure from a clean native build tree.
+        rm -rf "$workspace/native-build-macos"
+    fi
 fi
 
 profile=base

README.md

@@ -46,7 +46,9 @@ Press **F10** while the game window has focus:
 - Internal resolution
 - FPS counter
 - Controller assignment for all four ports
-- Full per-controller button mapping
+- Full per-controller button mapping, including the bumpers
+- Dolphin-syntax input expressions and GCPadNew.ini import
+- Controller vibration on/off
 - Volume, instant mute, and the music ducking toggle
 
 Everything you change is saved to `Config.toml` on the spot and restored next launch.
@@ -56,25 +58,20 @@ Controllers are fed to the game as a GameCube controller.
 Mappings are positional (`south`, `east`, `west`, `north`) rather than Xbox-labelled, so the
 same config makes sense on Xbox, PlayStation, Nintendo and generic SDL pads alike, and extra
 inputs like paddles, touchpads and share buttons show up when the hardware reports them.
+
+**Dolphin-compatible input expressions.** 
+Each GameCube control can carry an expression in Dolphin's input syntax, with the same operators
+and the same functions.
+A Dolphin `GCPadNew.ini` can be imported directly from the F10 bar.
+
+**Vibration toggle.** 
+Force feedback can be turned off for every port at once.
 The official Wii U / Switch GameCube adapter (WUP-028) works too; as with Dolphin, on Windows the
 adapter must be switched to the WinUSB driver once (Zadig).
 
 **Real Wii Remotes over Bluetooth.**
 Pair a Wii Remote with Windows (Settings > Bluetooth > Add device, press 1+2 or SYNC, leave the
-PIN empty) and the game reads it as an actual Wii Remote through KPAD: Wii Remote icons and
-prompts, Wii Wheel tilt steering, wheelies and tricks all come from the game's own motion code.
-Nunchuk and Classic Controller are real Wii extensions too: the game gets the Nunchuk's stick,
-C/Z and accelerometer, and the Classic Controller through `KPADGetUnifiedWpadStatus` with its own
-layout and icons, so its buttons do what the game says they do and no mapping is involved. Plug an
-extension in or pull it out mid-game and the game switches control scheme like on the console
-(the runtime patches SDL's Wii driver, which otherwise loses the remote for good on an extension
-change). Only the Wii U Pro Controller, which has no Wii-era equivalent, is fed to the game as a
-GameCube pad with Nintendo's layout. If a remote drops out or was switched on after launch, the
-runtime keeps rescanning Bluetooth until it comes back (F10 > Controller settings > Wii Remotes). SDL's read of
-the remote's factory accelerometer calibration often times out over Bluetooth (`console.log`
-then says "Using fallback accelerometer calibration") and it falls back to a nominal zero point,
-so the same menu has a one-button calibration (remote flat, buttons up) that removes the small
-tilt offset some remotes show.
+PIN empty)
 
 Known limitations of the Wii Remote path:
 - No IR pointer yet: menus are navigated with the D-pad and A (the game treats the remote as
@@ -114,6 +111,21 @@ image under Settings, turn on **WiiCompiled (beta)**, and hit install from the H
 Wheel Wizard downloads the setup tool from this repo and walks you through install, updates and
 launching. The backend itself is deliberately command-line only, Wheel Wizard is a wrapper around it.
 
+### macOS
+
+Download `WiiCompiled-Setup.pkg` from this repository's Releases page and open it. It requires an
+Apple Silicon Mac because its bundled nodtool and Translator.Cli executables are arm64. It installs
+**WiiCompiled Setup** in Applications; open that app, choose your clean PAL `RMCP01` disc image,
+and select either the base game or Retro Rewind. For Retro Rewind, choose the `RetroRewind6` folder
+or its parent folder.
+
+Setup verifies and extracts the image locally, then translates and compiles the native app on your
+Mac. On a first run it may ask macOS to install Xcode Command Line Tools; complete Apple's installer,
+then open Setup again. When the build completes, Setup asks for administrator approval once to install
+`WiiCompiled.app` (and, if selected, `RetroRewind.app`) in `/Applications`.
+
+Setup opens Terminal while it works, so the extraction and build progress—and any error that needs
+reporting—remain visible.
 
 > [!CAUTION]
 > Only take builds from this repository's

aurora-main/cmake/AuroraSDL3Provider.cmake

@@ -41,7 +41,10 @@ if (_aurora_sdl3_provider STREQUAL "auto")
     set(_aurora_sdl3_provider "package")
   else ()
     set(CMAKE_FIND_PACKAGE_TARGETS_GLOBAL ON)
-    find_package(SDL3 QUIET)
+    # Aurora uses APIs from the SDL version pinned by AURORA_SDL3_VERSION.
+    # Do not silently select an older system package and fail later while
+    # compiling its headers.
+    find_package(SDL3 ${AURORA_SDL3_VERSION} QUIET)
     set(CMAKE_FIND_PACKAGE_TARGETS_GLOBAL OFF)
     if (SDL3_FOUND)
       set(_aurora_sdl3_provider "system")
@@ -58,7 +61,7 @@ if (_aurora_sdl3_provider STREQUAL "system")
   message(STATUS "aurora: Using system SDL3 (provider=system)")
   if (NOT SDL3_FOUND)
     set(CMAKE_FIND_PACKAGE_TARGETS_GLOBAL ON)
-    find_package(SDL3 REQUIRED)
+    find_package(SDL3 ${AURORA_SDL3_VERSION} REQUIRED)
     set(CMAKE_FIND_PACKAGE_TARGETS_GLOBAL OFF)
   endif ()
   _aurora_sdl3_select_target()

aurora-main/lib/dolphin/pad/pad.cpp

@@ -1438,7 +1438,10 @@ void __PADWriteDeadZones(SDL_IOStream* file, // NOLINT(*-reserved-identifier)
 void PADSerializeMappings() {
   const std::filesystem::path basePath = fs_path_from_string(aurora::g_config.userPath);
 
-  for (auto& controller : aurora::input::g_GameControllers | std::views::values) {
+  // Avoid std::views::values here: older Apple libc++ releases implement the
+  // C++20 ranges algorithms we use but not this adaptor.
+  for (auto& entry : aurora::input::g_GameControllers) {
+    auto& controller = entry.second;
     EnsureMappingLoaded(&controller);
     const auto filePath =
         basePath / fmt::format("{}_{:04X}_{:04X}.controller", aurora::input::controller_name(controller.m_index),

aurora-main/lib/system_info.cpp

@@ -235,7 +235,7 @@ std::string GetOSVersion() {
   constexpr auto name = "iOS";
 #elif TARGET_OS_TV
   constexpr auto name = "tvOS";
-#elif
+#else
   constexpr auto name = Unknown;
 #endif
 

runtime/CMakeLists.txt

@@ -17,6 +17,16 @@ else()
     message(FATAL_ERROR
         "WiiCompiled supports 64-bit LLVM-MinGW Clang on Windows, native Linux x86_64/aarch64, or Apple Clang on macOS arm64")
 endif()
+
+# Do not inherit the host SDK's deployment target (macOS 26 on current
+# toolchains). The supported Apple Silicon release is macOS 14 and the app
+# bundle advertises that same minimum. This remains arm64-only until the Intel
+# support work is merged.
+if(MKW_PLATFORM_MACOS)
+    set(CMAKE_OSX_DEPLOYMENT_TARGET "14.0" CACHE STRING
+        "Minimum macOS version for the Apple Silicon build" FORCE)
+endif()
+
 if(NOT CMAKE_BUILD_TYPE STREQUAL "Release")
     message(FATAL_ERROR "WiiCompiled only supports Release builds")
 endif()
@@ -277,6 +287,15 @@ target_link_libraries(mkw_platform_paths_tests PRIVATE mkw_platform)
 target_compile_features(mkw_platform_paths_tests PRIVATE cxx_std_17)
 add_test(NAME mkw_platform_paths_tests COMMAND mkw_platform_paths_tests)
 
+# The input expression engine is self-contained, so it can be exercised without
+# linking the runtime or SDL.
+add_executable(mkw_input_expr_tests
+    "${CMAKE_CURRENT_LIST_DIR}/tests/test_expr.cpp"
+    "${CMAKE_CURRENT_LIST_DIR}/src/input_expr.cpp")
+target_include_directories(mkw_input_expr_tests PRIVATE "${CMAKE_CURRENT_LIST_DIR}/include")
+target_compile_features(mkw_input_expr_tests PRIVATE cxx_std_17)
+add_test(NAME mkw_input_expr_tests COMMAND mkw_input_expr_tests)
+
 # HostContext deliberately keeps the platform-specific context primitive out
 # of fiber_manager.cpp. Exercise the Linux libco handoff directly so future
 # refactors cannot silently remove its headers, implementation, or link edge.

runtime/include/controller_button_names.h

@@ -0,0 +1,159 @@
+#pragma once
+
+// The single vocabulary shared by everything that has to turn a Config.toml
+// controller name into a real button: the F10 settings bar, the macro engine,
+// and the startup mapping pass. Keeping one table here means a name that the
+// settings bar offers is always a name the config parser accepts, and vice
+// versa; the two used to drift because each side carried its own copy.
+
+#include <algorithm>
+#include <array>
+#include <cstdint>
+#include <string>
+#include <string_view>
+
+#include <SDL3/SDL_gamepad.h>
+#include <dolphin/pad.h>
+
+namespace ControllerNames {
+
+// A GameCube button as the game sees it, with the Config.toml key that selects
+// it. Order matches RuntimeConfigFile::kControllerButtonKeys.
+struct GameCubeButtonItem {
+    const char* configKey;
+    const char* label;
+    PADButton padButton;
+};
+
+inline constexpr std::array<GameCubeButtonItem, PAD_BUTTON_COUNT> kGameCubeButtons = {{
+    {"a", "A", PAD_BUTTON_A},
+    {"b", "B", PAD_BUTTON_B},
+    {"x", "X", PAD_BUTTON_X},
+    {"y", "Y", PAD_BUTTON_Y},
+    {"start", "Start", PAD_BUTTON_START},
+    {"z", "Z", PAD_TRIGGER_Z},
+    {"l", "L", PAD_TRIGGER_L},
+    {"r", "R", PAD_TRIGGER_R},
+    {"up", "D-pad Up", PAD_BUTTON_UP},
+    {"down", "D-pad Down", PAD_BUTTON_DOWN},
+    {"left", "D-pad Left", PAD_BUTTON_LEFT},
+    {"right", "D-pad Right", PAD_BUTTON_RIGHT},
+}};
+
+// A physical button on the host pad. Names are positional (south/east/...)
+// rather than Xbox-labelled so one config reads the same on any hardware.
+struct NativeButtonItem {
+    const char* configName;
+    const char* label;
+    uint32_t nativeButton;
+};
+
+inline constexpr std::array<NativeButtonItem, SDL_GAMEPAD_BUTTON_COUNT + 1> kNativeButtons = {{
+    {"unmapped", "Unmapped / analog trigger", PAD_NATIVE_BUTTON_INVALID},
+    {"south", "South (A / Cross)", SDL_GAMEPAD_BUTTON_SOUTH},
+    {"east", "East (B / Circle)", SDL_GAMEPAD_BUTTON_EAST},
+    {"west", "West (X / Square)", SDL_GAMEPAD_BUTTON_WEST},
+    {"north", "North (Y / Triangle)", SDL_GAMEPAD_BUTTON_NORTH},
+    {"back", "Back / Select / Create", SDL_GAMEPAD_BUTTON_BACK},
+    {"guide", "Guide / Home / PS", SDL_GAMEPAD_BUTTON_GUIDE},
+    {"start", "Start / Options", SDL_GAMEPAD_BUTTON_START},
+    {"left_stick", "Left stick click (L3)", SDL_GAMEPAD_BUTTON_LEFT_STICK},
+    {"right_stick", "Right stick click (R3)", SDL_GAMEPAD_BUTTON_RIGHT_STICK},
+    {"left_shoulder", "Left bumper (LB / L1)", SDL_GAMEPAD_BUTTON_LEFT_SHOULDER},
+    {"right_shoulder", "Right bumper (RB / R1)", SDL_GAMEPAD_BUTTON_RIGHT_SHOULDER},
+    {"dpad_up", "D-pad Up", SDL_GAMEPAD_BUTTON_DPAD_UP},
+    {"dpad_down", "D-pad Down", SDL_GAMEPAD_BUTTON_DPAD_DOWN},
+    {"dpad_left", "D-pad Left", SDL_GAMEPAD_BUTTON_DPAD_LEFT},
+    {"dpad_right", "D-pad Right", SDL_GAMEPAD_BUTTON_DPAD_RIGHT},
+    {"misc1", "Misc 1 / Share / Mic", SDL_GAMEPAD_BUTTON_MISC1},
+    {"right_paddle1", "Right paddle 1", SDL_GAMEPAD_BUTTON_RIGHT_PADDLE1},
+    {"left_paddle1", "Left paddle 1", SDL_GAMEPAD_BUTTON_LEFT_PADDLE1},
+    {"right_paddle2", "Right paddle 2", SDL_GAMEPAD_BUTTON_RIGHT_PADDLE2},
+    {"left_paddle2", "Left paddle 2", SDL_GAMEPAD_BUTTON_LEFT_PADDLE2},
+    {"touchpad", "Touchpad click", SDL_GAMEPAD_BUTTON_TOUCHPAD},
+    {"misc2", "Misc 2", SDL_GAMEPAD_BUTTON_MISC2},
+    {"misc3", "Misc 3 / GC L click", SDL_GAMEPAD_BUTTON_MISC3},
+    {"misc4", "Misc 4 / GC R click", SDL_GAMEPAD_BUTTON_MISC4},
+    {"misc5", "Misc 5", SDL_GAMEPAD_BUTTON_MISC5},
+    {"misc6", "Misc 6", SDL_GAMEPAD_BUTTON_MISC6},
+}};
+
+inline std::string TrimToken(std::string_view token) {
+    const size_t begin = token.find_first_not_of(" \t");
+    if (begin == std::string_view::npos) {
+        return {};
+    }
+    const size_t end = token.find_last_not_of(" \t");
+    return std::string(token.substr(begin, end - begin + 1));
+}
+
+inline const NativeButtonItem* FindNativeButton(std::string_view configName) {
+    const std::string name = TrimToken(configName);
+    const auto it = std::find_if(kNativeButtons.begin(), kNativeButtons.end(),
+                                 [&](const NativeButtonItem& item) { return name == item.configName; });
+    return it == kNativeButtons.end() ? nullptr : &*it;
+}
+
+// Falls back to the "unmapped" entry so callers always have a label to draw.
+inline const NativeButtonItem& NativeButtonForValue(uint32_t nativeButton) {
+    const auto it = std::find_if(kNativeButtons.begin(), kNativeButtons.end(),
+                                 [&](const NativeButtonItem& item) { return nativeButton == item.nativeButton; });
+    return it == kNativeButtons.end() ? kNativeButtons.front() : *it;
+}
+
+inline const GameCubeButtonItem* FindGameCubeButton(std::string_view configKey) {
+    const std::string key = TrimToken(configKey);
+    const auto it = std::find_if(kGameCubeButtons.begin(), kGameCubeButtons.end(),
+                                 [&](const GameCubeButtonItem& item) { return key == item.configKey; });
+    return it == kGameCubeButtons.end() ? nullptr : &*it;
+}
+
+// "up" or "up,a" -> the OR of those GC button bits. Unknown names are skipped so
+// a typo costs one button instead of the whole macro.
+inline uint16_t GameCubeMaskFromKeys(std::string_view keys) {
+    uint16_t mask = 0;
+    size_t begin = 0;
+    while (begin <= keys.size()) {
+        const size_t comma = keys.find(',', begin);
+        const std::string_view token =
+            keys.substr(begin, comma == std::string_view::npos ? std::string_view::npos : comma - begin);
+        if (const GameCubeButtonItem* item = FindGameCubeButton(token)) {
+            mask |= static_cast<uint16_t>(item->padButton);
+        }
+        if (comma == std::string_view::npos) {
+            break;
+        }
+        begin = comma + 1;
+    }
+    return mask;
+}
+
+inline std::string GameCubeKeysFromMask(uint16_t mask) {
+    std::string keys;
+    for (const auto& item : kGameCubeButtons) {
+        if ((mask & static_cast<uint16_t>(item.padButton)) == 0) {
+            continue;
+        }
+        if (!keys.empty()) {
+            keys += ',';
+        }
+        keys += item.configKey;
+    }
+    return keys;
+}
+
+inline std::string GameCubeLabelsFromMask(uint16_t mask) {
+    std::string labels;
+    for (const auto& item : kGameCubeButtons) {
+        if ((mask & static_cast<uint16_t>(item.padButton)) == 0) {
+            continue;
+        }
+        if (!labels.empty()) {
+            labels += " + ";
+        }
+        labels += item.label;
+    }
+    return labels.empty() ? std::string("None") : labels;
+}
+
+} // namespace ControllerNames

runtime/include/input_bindings.h

@@ -0,0 +1,67 @@
+#pragma once
+
+// Per-port expression bindings for the GameCube controls, plus import of a
+// Dolphin GCPadNew.ini.
+
+#include <array>
+#include <cstdint>
+#include <string>
+
+#include <dolphin/pad.h>
+
+namespace InputBindings {
+
+// The controls an expression can drive, in Dolphin's own naming so an
+// imported config maps across without translation.
+struct ControlInfo {
+    const char* dolphinName;
+    const char* label;
+    uint16_t padButton;   // 0 for the analog-only controls below
+    int analog;           // 0 none, 1 trigger L, 2 trigger R
+};
+
+inline constexpr std::array<ControlInfo, 14> kControls = {{
+    {"Buttons/A", "A", PAD_BUTTON_A, 0},
+    {"Buttons/B", "B", PAD_BUTTON_B, 0},
+    {"Buttons/X", "X", PAD_BUTTON_X, 0},
+    {"Buttons/Y", "Y", PAD_BUTTON_Y, 0},
+    {"Buttons/Z", "Z", PAD_TRIGGER_Z, 0},
+    {"Buttons/Start", "Start", PAD_BUTTON_START, 0},
+    {"D-Pad/Up", "D-pad Up", PAD_BUTTON_UP, 0},
+    {"D-Pad/Down", "D-pad Down", PAD_BUTTON_DOWN, 0},
+    {"D-Pad/Left", "D-pad Left", PAD_BUTTON_LEFT, 0},
+    {"D-Pad/Right", "D-pad Right", PAD_BUTTON_RIGHT, 0},
+    {"Triggers/L", "L", PAD_TRIGGER_L, 1},
+    {"Triggers/R", "R", PAD_TRIGGER_R, 2},
+    {"Triggers/L-Analog", "L analog", 0, 1},
+    {"Triggers/R-Analog", "R analog", 0, 2},
+}};
+
+void Reload() noexcept;
+
+// The pad library has PADBlockInput but no matching query, so the settings
+// overlay reports its own state here.
+void SetInputBlocked(bool blocked) noexcept;
+bool InputBlocked() noexcept;
+
+// Mix expression output into a freshly read status set. Call once per guest
+// PADRead, after every other input source has been merged.
+void Apply(PADStatus* statuses) noexcept;
+
+std::string GetExpression(uint32_t port, size_t control) noexcept;
+// Returns false and fills error if the text does not parse; the binding is
+// left unchanged in that case.
+bool SetExpression(uint32_t port, size_t control, const std::string& text, std::string& error) noexcept;
+
+// True while the control's expression is above the press threshold.
+bool IsActive(uint32_t port, size_t control) noexcept;
+
+// The default Dolphin config location on Windows, then next to the executable.
+std::string DefaultDolphinConfigPath() noexcept;
+
+// Imports [GCPad<padIndex>] into the given port. Returns the number of controls
+// imported, or -1 on failure with error filled.
+int ImportDolphinConfig(const std::string& path, int padIndex, uint32_t port,
+                        std::string& summary, std::string& error) noexcept;
+
+} // namespace InputBindings

runtime/include/input_expr.h

@@ -0,0 +1,53 @@
+#pragma once
+
+// Dolphin-compatible input expressions.
+//
+// Values are doubles in Dolphin's ControlState style; a control counts as
+// pressed above kConditionThreshold. Timing matches Dolphin: wall-clock
+// seconds on a steady clock, so an expression copied from GCPadNew.ini
+// behaves the same here as it does there.
+
+#include <filesystem>
+#include <functional>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace InputExpr {
+
+inline constexpr double kConditionThreshold = 0.5;
+
+// Resolves a backtick-quoted input name to its current value.
+using InputSource = std::function<double(const std::string&)>;
+
+struct Node;
+
+class Expression {
+public:
+    Expression();
+    ~Expression();
+    Expression(Expression&&) noexcept;
+    Expression& operator=(Expression&&) noexcept;
+
+    // Returns false and fills error on a syntax problem.
+    static bool Parse(const std::string& text, Expression& out, std::string& error);
+
+    bool Empty() const { return m_root == nullptr; }
+    double Evaluate(const InputSource& source) const;
+
+    // Input names the expression references, for diagnostics.
+    std::vector<std::string> ReferencedInputs() const;
+
+private:
+    std::unique_ptr<Node> m_root;
+};
+
+// Parses a Dolphin GCPadNew.ini and returns the expression text for each
+// control of the requested pad, keyed by Dolphin's own control names
+// ("Buttons/A", "D-Pad/Up", "Triggers/L", ...). Returns false if the file
+// cannot be read or the section is missing.
+bool ReadDolphinConfig(const std::filesystem::path& path, int padIndex,
+                       std::vector<std::pair<std::string, std::string>>& controls,
+                       std::string& deviceName, std::string& error);
+
+} // namespace InputExpr

runtime/include/runtime_config.h

@@ -11,6 +11,7 @@
 #include <iomanip>
 #include <iostream>
 #include <limits>
+#include <map>
 #include <optional>
 #include <sstream>
 #include <string>
@@ -89,6 +90,8 @@ struct RuntimeUserConfig {
     // comma-separated SDL-style physical button names ("south", or
     // "dpad_up,left_shoulder") as values; pressing either bound button counts.
     std::array<std::optional<std::string>, 12> controllerButtons;
+    std::optional<bool> rumbleEnabled;
+    std::map<std::string, std::string> controllerExpressions;
 };
 
 namespace RuntimeConfigFile {
@@ -407,6 +410,17 @@ inline RuntimeUserConfig ParseConfigDocument(const toml::value& document) {
             FindConfigValue<std::string>(document, "controller", buttonKeys[index]);
     }
 
+    config.rumbleEnabled = FindConfigValue<bool>(document, "controller", "rumble");
+
+    if (const auto* section = document.contains("controller") ? &document.at("controller") : nullptr;
+        section != nullptr && section->is_table()) {
+        for (const auto& [key, value] : section->as_table()) {
+            if (key.rfind("expr_", 0) == 0 && value.is_string()) {
+                config.controllerExpressions[key] = value.as_string();
+            }
+        }
+    }
+
     config.widescreen = FindConfigValue<bool>(document, "video", "widescreen");
     config.windowPosX = FindConfigInt(document, "video", "window_x");
     config.windowPosY = FindConfigInt(document, "video", "window_y");
@@ -677,6 +691,25 @@ inline bool SetControllerButton(size_t index, std::string value) {
     return WriteSetting("controller", kControllerButtonKeys[index], FormatString(value));
 }
 
+inline std::string ControllerExpression(const std::string& key) {
+    const auto it = Get().controllerExpressions.find(key);
+    return it == Get().controllerExpressions.end() ? std::string() : it->second;
+}
+
+inline bool SetControllerExpression(const std::string& key, const std::string& value) {
+    Mutable().controllerExpressions[key] = value;
+    return WriteSetting("controller", key, FormatString(value));
+}
+
+inline bool RumbleEnabled(bool fallback = true) {
+    return Get().rumbleEnabled.value_or(fallback);
+}
+
+inline bool SetRumbleEnabled(bool value) {
+    Mutable().rumbleEnabled = value;
+    return WriteSetting("controller", "rumble", value ? "true" : "false");
+}
+
 inline bool SetAudioVolume(float value) {
     value = std::clamp(value, 0.0f, 1.0f);
     Mutable().audioVolume = value;

runtime/src/hle/input/pad.cpp

@@ -1,18 +1,75 @@
 #include "hle_stubs.h"
 #include "memory.h"
 #include "hle/controller_status_contract.h"
+#include "input_bindings.h"
 #include "wii_remote_input.h"
 
 #include <algorithm>
+#include <atomic>
 #include <cstdio>
 #include <cstdint>
 #include <cstdlib>
 #include <cstring>
 
+#include <SDL3/SDL_gamepad.h>
 #include <dolphin/pad.h>
 
 namespace {
 
+std::atomic<bool> g_rumbleEnabled{true};
+
+bool NativeButtonHeld(SDL_Gamepad* gamepad, uint32_t nativeButton) {
+    if (gamepad == nullptr || nativeButton == PAD_NATIVE_BUTTON_INVALID ||
+        nativeButton >= SDL_GAMEPAD_BUTTON_COUNT) {
+        return false;
+    }
+    return SDL_GetGamepadButton(gamepad, static_cast<SDL_GamepadButton>(nativeButton));
+}
+
+// A digital button bound to L or R has no analog travel of its own. On real
+// hardware the click only engages at full depression, so report a full pull.
+void FillTriggersHeldByButtons(PADStatus* statuses) {
+    if (InputBindings::InputBlocked()) {
+        return;
+    }
+    for (uint32_t port = 0; port < PAD_CHANMAX; ++port) {
+        if (statuses[port].err != PAD_ERR_NONE) {
+            continue;
+        }
+        const s32 index = PADGetIndexForPort(port);
+        if (index < 0) {
+            continue;
+        }
+        SDL_Gamepad* gamepad = PADGetSDLGamepadForIndex(static_cast<u32>(index));
+        if (gamepad == nullptr) {
+            continue;
+        }
+        const auto scan = [&](PADButtonMapping* mappings, u32 count) {
+            if (mappings == nullptr) {
+                return;
+            }
+            for (u32 i = 0; i < count; ++i) {
+                const PADButtonMapping& mapping = mappings[i];
+                if (mapping.padButton != PAD_TRIGGER_L && mapping.padButton != PAD_TRIGGER_R) {
+                    continue;
+                }
+                if (!NativeButtonHeld(gamepad, mapping.nativeButton)) {
+                    continue;
+                }
+                if (mapping.padButton == PAD_TRIGGER_L) {
+                    statuses[port].triggerLeft = 255;
+                } else {
+                    statuses[port].triggerRight = 255;
+                }
+            }
+        };
+        u32 count = 0;
+        scan(PADGetButtonMappings(port, &count), count);
+        count = 0;
+        scan(PADGetAltButtonMappings(port, &count), count);
+    }
+}
+
 void WritePadStatus(uint32_t base, const PADStatus& status) {
     const auto guestStatus = PadStatusContract::Encode({
         status.button,
@@ -32,6 +89,11 @@ void WritePadStatus(uint32_t base, const PADStatus& status) {
 
 } // namespace
 
+extern "C" void PAD_HLE_SetRumbleEnabled(bool enabled)
+{
+    g_rumbleEnabled.store(enabled, std::memory_order_relaxed);
+}
+
 extern "C" uint32_t PAD__Init_HLE()
 {
     return PADInit() ? 1u : 0u;
@@ -54,6 +116,9 @@ extern "C" uint32_t PAD__Read_HLE(uint32_t statusPtr)
     // between "connected" and "no controller" every time the overlay toggles.
     WiiRemoteInput::HideRemotesFromPad(statuses, PAD_CHANMAX);
 
+    FillTriggersHeldByButtons(statuses);
+    InputBindings::Apply(statuses);
+
     try {
         for (uint32_t i = 0; i < PAD_CHANMAX; ++i) {
             WritePadStatus(statusPtr + static_cast<uint32_t>(i * PadStatusContract::kGuestStatusSize),
@@ -81,6 +146,9 @@ PPC_NATIVE_OVERRIDE(801AF1E4, PAD__Recalibrate_HLE, uint32_t, (uint32_t mask), (
 
 extern "C" void PAD__ControlMotor_HLE(int32_t chan, uint32_t command)
 {
+    if (command == PAD_MOTOR_RUMBLE && !g_rumbleEnabled.load(std::memory_order_relaxed)) {
+        command = PAD_MOTOR_STOP;
+    }
     PADControlMotor(chan, command);
 }
 PPC_NATIVE_OVERRIDE_VOID(801AF908, PAD__ControlMotor_HLE, (int32_t chan, uint32_t command), (chan, command));

runtime/src/input_bindings.cpp

@@ -0,0 +1,302 @@
+#include "input_bindings.h"
+
+#include "controller_button_names.h"
+#include "input_expr.h"
+#include "runtime_config.h"
+#include "runtime_log.h"
+
+#include <algorithm>
+#include <cmath>
+#include <cstdlib>
+#include <filesystem>
+#include <mutex>
+#include <unordered_map>
+
+#include <SDL3/SDL_gamepad.h>
+
+namespace InputBindings {
+namespace {
+
+struct Binding {
+    std::string text;
+    InputExpr::Expression expr;
+    bool active = false;
+};
+
+std::mutex g_mutex;
+std::array<std::array<Binding, kControls.size()>, PAD_CHANMAX> g_bindings;
+bool g_anyBound = false;
+bool g_inputBlocked = false;
+
+// Dolphin input names, mapped onto SDL. XInput-style names are exact; DInput
+// "Button <n>" indices follow the common PlayStation layout, which is what
+// DInput reports for a DualShock/DualSense. Other pads may number differently.
+const std::unordered_map<std::string, SDL_GamepadButton>& ButtonNames() {
+    static const std::unordered_map<std::string, SDL_GamepadButton> table = {
+        {"Button A", SDL_GAMEPAD_BUTTON_SOUTH},      {"Button B", SDL_GAMEPAD_BUTTON_EAST},
+        {"Button X", SDL_GAMEPAD_BUTTON_WEST},       {"Button Y", SDL_GAMEPAD_BUTTON_NORTH},
+        {"Shoulder L", SDL_GAMEPAD_BUTTON_LEFT_SHOULDER},
+        {"Shoulder R", SDL_GAMEPAD_BUTTON_RIGHT_SHOULDER},
+        {"Thumb L", SDL_GAMEPAD_BUTTON_LEFT_STICK},  {"Thumb R", SDL_GAMEPAD_BUTTON_RIGHT_STICK},
+        {"Start", SDL_GAMEPAD_BUTTON_START},         {"Back", SDL_GAMEPAD_BUTTON_BACK},
+        {"Guide", SDL_GAMEPAD_BUTTON_GUIDE},
+        {"Pad N", SDL_GAMEPAD_BUTTON_DPAD_UP},       {"Pad S", SDL_GAMEPAD_BUTTON_DPAD_DOWN},
+        {"Pad W", SDL_GAMEPAD_BUTTON_DPAD_LEFT},     {"Pad E", SDL_GAMEPAD_BUTTON_DPAD_RIGHT},
+        {"Hat 0 N", SDL_GAMEPAD_BUTTON_DPAD_UP},     {"Hat 0 S", SDL_GAMEPAD_BUTTON_DPAD_DOWN},
+        {"Hat 0 W", SDL_GAMEPAD_BUTTON_DPAD_LEFT},   {"Hat 0 E", SDL_GAMEPAD_BUTTON_DPAD_RIGHT},
+        {"Button 0", SDL_GAMEPAD_BUTTON_WEST},       {"Button 1", SDL_GAMEPAD_BUTTON_SOUTH},
+        {"Button 2", SDL_GAMEPAD_BUTTON_EAST},       {"Button 3", SDL_GAMEPAD_BUTTON_NORTH},
+        {"Button 4", SDL_GAMEPAD_BUTTON_LEFT_SHOULDER},
+        {"Button 5", SDL_GAMEPAD_BUTTON_RIGHT_SHOULDER},
+        {"Button 8", SDL_GAMEPAD_BUTTON_BACK},       {"Button 9", SDL_GAMEPAD_BUTTON_START},
+        {"Button 10", SDL_GAMEPAD_BUTTON_LEFT_STICK},
+        {"Button 11", SDL_GAMEPAD_BUTTON_RIGHT_STICK},
+        {"Button 12", SDL_GAMEPAD_BUTTON_GUIDE},     {"Button 13", SDL_GAMEPAD_BUTTON_TOUCHPAD},
+    };
+    return table;
+}
+
+// Signed axis names: SDL axis plus the direction that counts as positive.
+struct AxisRef {
+    SDL_GamepadAxis axis;
+    int sign;
+};
+
+const std::unordered_map<std::string, AxisRef>& AxisNames() {
+    static const std::unordered_map<std::string, AxisRef> table = {
+        {"Axis X-", {SDL_GAMEPAD_AXIS_LEFTX, -1}},  {"Axis X+", {SDL_GAMEPAD_AXIS_LEFTX, 1}},
+        {"Axis Y-", {SDL_GAMEPAD_AXIS_LEFTY, -1}},  {"Axis Y+", {SDL_GAMEPAD_AXIS_LEFTY, 1}},
+        {"Axis Z-", {SDL_GAMEPAD_AXIS_RIGHTX, -1}}, {"Axis Z+", {SDL_GAMEPAD_AXIS_RIGHTX, 1}},
+        {"Axis Zr-", {SDL_GAMEPAD_AXIS_RIGHTY, -1}},{"Axis Zr+", {SDL_GAMEPAD_AXIS_RIGHTY, 1}},
+        {"Left X-", {SDL_GAMEPAD_AXIS_LEFTX, -1}},  {"Left X+", {SDL_GAMEPAD_AXIS_LEFTX, 1}},
+        {"Left Y-", {SDL_GAMEPAD_AXIS_LEFTY, 1}},   {"Left Y+", {SDL_GAMEPAD_AXIS_LEFTY, -1}},
+        {"Right X-", {SDL_GAMEPAD_AXIS_RIGHTX, -1}},{"Right X+", {SDL_GAMEPAD_AXIS_RIGHTX, 1}},
+        {"Right Y-", {SDL_GAMEPAD_AXIS_RIGHTY, 1}}, {"Right Y+", {SDL_GAMEPAD_AXIS_RIGHTY, -1}},
+        {"Full Axis Xr+", {SDL_GAMEPAD_AXIS_LEFT_TRIGGER, 1}},
+        {"Full Axis Yr+", {SDL_GAMEPAD_AXIS_RIGHT_TRIGGER, 1}},
+        {"Trigger L", {SDL_GAMEPAD_AXIS_LEFT_TRIGGER, 1}},
+        {"Trigger R", {SDL_GAMEPAD_AXIS_RIGHT_TRIGGER, 1}},
+    };
+    return table;
+}
+
+double ReadInput(SDL_Gamepad* gamepad, const std::string& name) {
+    if (gamepad == nullptr) {
+        return 0.0;
+    }
+    if (const auto it = ButtonNames().find(name); it != ButtonNames().end()) {
+        return SDL_GetGamepadButton(gamepad, it->second) ? 1.0 : 0.0;
+    }
+    if (const auto it = AxisNames().find(name); it != AxisNames().end()) {
+        const double raw = SDL_GetGamepadAxis(gamepad, it->second.axis) / 32767.0;
+        return std::clamp(raw * it->second.sign, 0.0, 1.0);
+    }
+    // Fall back to this project's own positional names, so a binding written
+    // here does not have to use Dolphin vocabulary.
+    if (const auto* native = ControllerNames::FindNativeButton(name)) {
+        if (native->nativeButton != PAD_NATIVE_BUTTON_INVALID) {
+            return SDL_GetGamepadButton(gamepad, static_cast<SDL_GamepadButton>(native->nativeButton)) ? 1.0
+                                                                                                      : 0.0;
+        }
+    }
+    return 0.0;
+}
+
+SDL_Gamepad* GamepadForPort(uint32_t port) {
+    const s32 index = PADGetIndexForPort(port);
+    return index < 0 ? nullptr : PADGetSDLGamepadForIndex(static_cast<u32>(index));
+}
+
+size_t ControlIndexForDolphinName(const std::string& name) {
+    for (size_t i = 0; i < kControls.size(); ++i) {
+        if (name == kControls[i].dolphinName) {
+            return i;
+        }
+    }
+    return kControls.size();
+}
+
+void RecomputeAnyBoundLocked() {
+    g_anyBound = false;
+    for (const auto& port : g_bindings) {
+        for (const auto& binding : port) {
+            if (!binding.expr.Empty()) {
+                g_anyBound = true;
+                return;
+            }
+        }
+    }
+}
+
+std::string ConfigKey(uint32_t port, size_t control) {
+    std::string key = "expr_" + std::to_string(port + 1) + "_";
+    for (const char* c = kControls[control].dolphinName; *c != '\0'; ++c) {
+        key += (*c == '/' || *c == '-') ? '_' : static_cast<char>(std::tolower(*c));
+    }
+    return key;
+}
+
+} // namespace
+
+void SetInputBlocked(bool blocked) noexcept {
+    std::lock_guard<std::mutex> lock(g_mutex);
+    g_inputBlocked = blocked;
+}
+
+bool InputBlocked() noexcept {
+    std::lock_guard<std::mutex> lock(g_mutex);
+    return g_inputBlocked;
+}
+
+void Reload() noexcept {
+    std::lock_guard<std::mutex> lock(g_mutex);
+    for (uint32_t port = 0; port < PAD_CHANMAX; ++port) {
+        for (size_t control = 0; control < kControls.size(); ++control) {
+            Binding& binding = g_bindings[port][control];
+            binding = Binding{};
+            binding.text = RuntimeConfigFile::ControllerExpression(ConfigKey(port, control));
+            std::string error;
+            if (!binding.text.empty() &&
+                !InputExpr::Expression::Parse(binding.text, binding.expr, error)) {
+                RT_LOG(RT_TAG_CONFIG) << "expression for port " << (port + 1) << " "
+                                      << kControls[control].dolphinName << ": " << error << std::endl;
+            }
+        }
+    }
+    RecomputeAnyBoundLocked();
+}
+
+void Apply(PADStatus* statuses) noexcept {
+    if (statuses == nullptr) {
+        return;
+    }
+    std::lock_guard<std::mutex> lock(g_mutex);
+    if (!g_anyBound) {
+        return;
+    }
+    const bool blocked = g_inputBlocked;
+    for (uint32_t port = 0; port < PAD_CHANMAX; ++port) {
+        if (statuses[port].err != PAD_ERR_NONE) {
+            continue;
+        }
+        SDL_Gamepad* gamepad = GamepadForPort(port);
+        const InputExpr::InputSource source = [gamepad](const std::string& name) {
+            return ReadInput(gamepad, name);
+        };
+        for (size_t control = 0; control < kControls.size(); ++control) {
+            Binding& binding = g_bindings[port][control];
+            if (binding.expr.Empty()) {
+                continue;
+            }
+            if (blocked) {
+                binding.active = false;
+                continue;
+            }
+            const double value = binding.expr.Evaluate(source);
+            binding.active = value > InputExpr::kConditionThreshold;
+            const ControlInfo& info = kControls[control];
+            if (info.padButton != 0 && binding.active) {
+                statuses[port].button |= info.padButton;
+            }
+            if (info.analog != 0) {
+                const double safe = std::isfinite(value) ? std::clamp(value, 0.0, 1.0) : 0.0;
+                const auto scaled = static_cast<uint8_t>(safe * 255.0);
+                uint8_t& target =
+                    info.analog == 1 ? statuses[port].triggerLeft : statuses[port].triggerRight;
+                target = std::max(target, scaled);
+            }
+        }
+    }
+}
+
+std::string GetExpression(uint32_t port, size_t control) noexcept {
+    if (port >= PAD_CHANMAX || control >= kControls.size()) {
+        return {};
+    }
+    std::lock_guard<std::mutex> lock(g_mutex);
+    return g_bindings[port][control].text;
+}
+
+bool SetExpression(uint32_t port, size_t control, const std::string& text, std::string& error) noexcept {
+    if (port >= PAD_CHANMAX || control >= kControls.size()) {
+        error = "invalid control";
+        return false;
+    }
+    InputExpr::Expression parsed;
+    if (!InputExpr::Expression::Parse(text, parsed, error)) {
+        return false;
+    }
+    {
+        std::lock_guard<std::mutex> lock(g_mutex);
+        Binding& binding = g_bindings[port][control];
+        binding.text = text;
+        binding.expr = std::move(parsed);
+        binding.active = false;
+        RecomputeAnyBoundLocked();
+    }
+    RuntimeConfigFile::SetControllerExpression(ConfigKey(port, control), text);
+    return true;
+}
+
+bool IsActive(uint32_t port, size_t control) noexcept {
+    if (port >= PAD_CHANMAX || control >= kControls.size()) {
+        return false;
+    }
+    std::lock_guard<std::mutex> lock(g_mutex);
+    return g_bindings[port][control].active;
+}
+
+std::string DefaultDolphinConfigPath() noexcept {
+    std::error_code ec;
+    if (const char* appdata = std::getenv("APPDATA"); appdata != nullptr) {
+        const std::filesystem::path roaming =
+            std::filesystem::path(appdata) / "Dolphin Emulator" / "Config" / "GCPadNew.ini";
+        if (std::filesystem::exists(roaming, ec)) {
+            return RuntimeConfigFile::PathToUtf8(roaming);
+        }
+    }
+    const auto executableDirectory = RuntimeConfigFile::ExecutableDirectory();
+    return RuntimeConfigFile::PathToUtf8(executableDirectory ? *executableDirectory / "GCPadNew.ini"
+                                                             : std::filesystem::path("GCPadNew.ini"));
+}
+
+int ImportDolphinConfig(const std::string& path, int padIndex, uint32_t port, std::string& summary,
+                        std::string& error) noexcept {
+    std::vector<std::pair<std::string, std::string>> controls;
+    std::string device;
+    if (!InputExpr::ReadDolphinConfig(RuntimeConfigFile::PathFromUtf8(path), padIndex, controls, device,
+                                      error)) {
+        return -1;
+    }
+
+    int imported = 0;
+    std::vector<std::string> skipped;
+    for (const auto& [name, text] : controls) {
+        const size_t control = ControlIndexForDolphinName(name);
+        if (control == kControls.size()) {
+            if (name.rfind("Main Stick/", 0) == 0 || name.rfind("C-Stick/", 0) == 0) {
+                skipped.push_back(name);
+            }
+            continue;
+        }
+        std::string parseError;
+        if (!SetExpression(port, control, text, parseError)) {
+            skipped.push_back(name);
+            RT_LOG(RT_TAG_CONFIG) << "import " << name << ": " << parseError << std::endl;
+            continue;
+        }
+        ++imported;
+    }
+
+    summary = "Imported " + std::to_string(imported) + " controls";
+    if (!device.empty()) {
+        summary += " from " + device;
+    }
+    if (!skipped.empty()) {
+        summary += "; skipped " + std::to_string(skipped.size()) +
+                   " (stick axes and unsupported inputs keep their existing mapping)";
+    }
+    return imported;
+}
+
+} // namespace InputBindings

runtime/src/input_expr.cpp

@@ -0,0 +1,631 @@
+#include "input_expr.h"
+
+#include <algorithm>
+#include <cctype>
+#include <chrono>
+#include <cmath>
+#include <cstdlib>
+#include <fstream>
+#include <unordered_map>
+
+namespace InputExpr {
+namespace {
+
+using Clock = std::chrono::steady_clock;
+using FSec = std::chrono::duration<double>;
+
+enum class Kind {
+    Literal, Input, Not, Add, Sub, Mul, Div, And, Or, Xor,
+    Greater, Less, Equal,
+    FnIf, FnMin, FnMax, FnClamp, FnAbs, FnSqrt, FnPow, FnSin, FnCos, FnTan,
+    FnDeadzone, FnTimer, FnToggle, FnHold, FnTap, FnPulse, FnSmooth, FnNot,
+};
+
+struct FnInfo {
+    Kind kind;
+    int minArgs;
+    int maxArgs;
+};
+
+const std::unordered_map<std::string, FnInfo>& FunctionTable() {
+    static const std::unordered_map<std::string, FnInfo> table = {
+        {"not", {Kind::FnNot, 1, 1}},       {"if", {Kind::FnIf, 3, 3}},
+        {"min", {Kind::FnMin, 2, 2}},       {"max", {Kind::FnMax, 2, 2}},
+        {"clamp", {Kind::FnClamp, 3, 3}},   {"abs", {Kind::FnAbs, 1, 1}},
+        {"sqrt", {Kind::FnSqrt, 1, 1}},     {"pow", {Kind::FnPow, 2, 2}},
+        {"sin", {Kind::FnSin, 1, 1}},       {"cos", {Kind::FnCos, 1, 1}},
+        {"tan", {Kind::FnTan, 1, 1}},       {"deadzone", {Kind::FnDeadzone, 2, 2}},
+        {"timer", {Kind::FnTimer, 1, 1}},   {"toggle", {Kind::FnToggle, 1, 2}},
+        {"hold", {Kind::FnHold, 2, 2}},     {"tap", {Kind::FnTap, 2, 3}},
+        {"pulse", {Kind::FnPulse, 2, 2}},   {"smooth", {Kind::FnSmooth, 2, 3}},
+    };
+    return table;
+}
+
+} // namespace
+
+struct Node {
+    Kind kind;
+    double literal = 0.0;
+    std::string input;
+    std::vector<std::unique_ptr<Node>> args;
+
+    // Per-instance state for the stateful functions. Mutable because Evaluate
+    // is logically a read of current input state.
+    mutable bool released = false;
+    mutable bool state = false;
+    mutable unsigned taps = 0;
+    mutable double value = 0.0;
+    mutable Clock::time_point mark = Clock::now();
+    mutable bool marked = false;
+};
+
+namespace {
+
+// ---- tokenizer ----------------------------------------------------------
+
+struct Token {
+    enum Type { End, Input, Number, Ident, Op, LParen, RParen, Comma } type = End;
+    std::string text;
+};
+
+class Lexer {
+public:
+    explicit Lexer(const std::string& text) : m_text(text) {}
+
+    bool Next(Token& tok, std::string& error) {
+        while (m_pos < m_text.size() && std::isspace(static_cast<unsigned char>(m_text[m_pos]))) {
+            ++m_pos;
+        }
+        if (m_pos >= m_text.size()) {
+            tok = Token{};
+            return true;
+        }
+        const char c = m_text[m_pos];
+        if (c == '`') {
+            const size_t close = m_text.find('`', m_pos + 1);
+            if (close == std::string::npos) {
+                error = "unterminated ` in expression";
+                return false;
+            }
+            tok.type = Token::Input;
+            tok.text = m_text.substr(m_pos + 1, close - m_pos - 1);
+            m_pos = close + 1;
+            return true;
+        }
+        if (std::isdigit(static_cast<unsigned char>(c)) || c == '.') {
+            size_t end = m_pos;
+            while (end < m_text.size() &&
+                   (std::isdigit(static_cast<unsigned char>(m_text[end])) || m_text[end] == '.')) {
+                ++end;
+            }
+            tok.type = Token::Number;
+            tok.text = m_text.substr(m_pos, end - m_pos);
+            m_pos = end;
+            return true;
+        }
+        if (std::isalpha(static_cast<unsigned char>(c)) || c == '_') {
+            size_t end = m_pos;
+            while (end < m_text.size() &&
+                   (std::isalnum(static_cast<unsigned char>(m_text[end])) || m_text[end] == '_' ||
+                    m_text[end] == ' ')) {
+                ++end;
+            }
+            // Trailing spaces belong to the separator, not the identifier.
+            while (end > m_pos && m_text[end - 1] == ' ') {
+                --end;
+            }
+            tok.type = Token::Ident;
+            tok.text = m_text.substr(m_pos, end - m_pos);
+            m_pos = end;
+            return true;
+        }
+        if (c == '(') { tok.type = Token::LParen; ++m_pos; return true; }
+        if (c == ')') { tok.type = Token::RParen; ++m_pos; return true; }
+        if (c == ',') { tok.type = Token::Comma; ++m_pos; return true; }
+        if (std::string("!&|^+-*/><=").find(c) != std::string::npos) {
+            tok.type = Token::Op;
+            tok.text = std::string(1, c);
+            ++m_pos;
+            return true;
+        }
+        error = std::string("unexpected character '") + c + "' in expression";
+        return false;
+    }
+
+    size_t Position() const { return m_pos; }
+
+private:
+    const std::string& m_text;
+    size_t m_pos = 0;
+};
+
+// ---- parser -------------------------------------------------------------
+
+using NodePtr = std::unique_ptr<Node>;
+
+class Parser {
+public:
+    explicit Parser(const std::string& text) : m_lexer(text) { Advance(); }
+
+    NodePtr ParseExpression(std::string& error) {
+        NodePtr node = ParseBinary(0, error);
+        if (!node) {
+            return nullptr;
+        }
+        if (m_failed) {
+            error = m_lexError;
+            return nullptr;
+        }
+        if (m_tok.type != Token::End) {
+            error = "unexpected trailing input in expression";
+            return nullptr;
+        }
+        return node;
+    }
+
+private:
+    void Advance() {
+        if (!m_lexer.Next(m_tok, m_lexError)) {
+            m_tok = Token{};
+            m_failed = true;
+        }
+    }
+
+    static int Precedence(const std::string& op) {
+        if (op == "|") return 1;
+        if (op == "^") return 2;
+        if (op == "&") return 3;
+        if (op == ">" || op == "<" || op == "=") return 4;
+        if (op == "+" || op == "-") return 5;
+        if (op == "*" || op == "/") return 6;
+        return -1;
+    }
+
+    static Kind BinaryKind(const std::string& op) {
+        if (op == "|") return Kind::Or;
+        if (op == "^") return Kind::Xor;
+        if (op == "&") return Kind::And;
+        if (op == ">") return Kind::Greater;
+        if (op == "<") return Kind::Less;
+        if (op == "=") return Kind::Equal;
+        if (op == "+") return Kind::Add;
+        if (op == "-") return Kind::Sub;
+        if (op == "*") return Kind::Mul;
+        return Kind::Div;
+    }
+
+    NodePtr ParseBinary(int minPrec, std::string& error) {
+        NodePtr lhs = ParseUnary(error);
+        if (!lhs) {
+            return nullptr;
+        }
+        while (m_tok.type == Token::Op) {
+            const int prec = Precedence(m_tok.text);
+            if (prec < 0 || prec < minPrec) {
+                break;
+            }
+            const std::string op = m_tok.text;
+            Advance();
+            NodePtr rhs = ParseBinary(prec + 1, error);
+            if (!rhs) {
+                return nullptr;
+            }
+            auto node = std::make_unique<Node>();
+            node->kind = BinaryKind(op);
+            node->args.push_back(std::move(lhs));
+            node->args.push_back(std::move(rhs));
+            lhs = std::move(node);
+        }
+        return lhs;
+    }
+
+    NodePtr ParseUnary(std::string& error) {
+        if (m_failed) {
+            error = m_lexError;
+            return nullptr;
+        }
+        if (m_tok.type == Token::Op && (m_tok.text == "!" || m_tok.text == "-" || m_tok.text == "+")) {
+            const std::string op = m_tok.text;
+            Advance();
+            NodePtr inner = ParseUnary(error);
+            if (!inner) {
+                return nullptr;
+            }
+            if (op == "+") {
+                return inner;
+            }
+            auto node = std::make_unique<Node>();
+            if (op == "!") {
+                node->kind = Kind::Not;
+                node->args.push_back(std::move(inner));
+            } else {
+                node->kind = Kind::Sub;
+                auto zero = std::make_unique<Node>();
+                zero->kind = Kind::Literal;
+                node->args.push_back(std::move(zero));
+                node->args.push_back(std::move(inner));
+            }
+            return node;
+        }
+        return ParsePrimary(error);
+    }
+
+    NodePtr ParsePrimary(std::string& error) {
+        if (m_failed) {
+            error = m_lexError;
+            return nullptr;
+        }
+        switch (m_tok.type) {
+        case Token::Input: {
+            auto node = std::make_unique<Node>();
+            node->kind = Kind::Input;
+            node->input = m_tok.text;
+            Advance();
+            return node;
+        }
+        case Token::Number: {
+            auto node = std::make_unique<Node>();
+            node->kind = Kind::Literal;
+            node->literal = std::strtod(m_tok.text.c_str(), nullptr);
+            Advance();
+            return node;
+        }
+        case Token::LParen: {
+            Advance();
+            NodePtr inner = ParseBinary(0, error);
+            if (!inner) {
+                return nullptr;
+            }
+            if (m_tok.type != Token::RParen) {
+                error = "expected closing paren";
+                return nullptr;
+            }
+            Advance();
+            return inner;
+        }
+        case Token::Ident: {
+            const std::string name = m_tok.text;
+            Advance();
+            if (m_tok.type != Token::LParen) {
+                // A bare identifier is an input name, as Dolphin allows for
+                // simple cases such as "Start" or "LSHIFT".
+                auto node = std::make_unique<Node>();
+                node->kind = Kind::Input;
+                node->input = name;
+                return node;
+            }
+            const auto it = FunctionTable().find(name);
+            if (it == FunctionTable().end()) {
+                error = "unknown function '" + name + "'";
+                return nullptr;
+            }
+            Advance();
+            auto node = std::make_unique<Node>();
+            node->kind = it->second.kind;
+            if (m_tok.type != Token::RParen) {
+                while (true) {
+                    NodePtr arg = ParseBinary(0, error);
+                    if (!arg) {
+                        return nullptr;
+                    }
+                    node->args.push_back(std::move(arg));
+                    if (m_tok.type != Token::Comma) {
+                        break;
+                    }
+                    Advance();
+                }
+            }
+            if (m_tok.type != Token::RParen) {
+                error = "expected closing paren after " + name + " arguments";
+                return nullptr;
+            }
+            Advance();
+            const int count = static_cast<int>(node->args.size());
+            if (count < it->second.minArgs || count > it->second.maxArgs) {
+                error = name + " takes " + std::to_string(it->second.minArgs) + " to " +
+                        std::to_string(it->second.maxArgs) + " arguments";
+                return nullptr;
+            }
+            return node;
+        }
+        default:
+            error = "expected start of expression";
+            return nullptr;
+        }
+    }
+
+    Lexer m_lexer;
+    Token m_tok;
+    std::string m_lexError;
+    bool m_failed = false;
+};
+
+// ---- evaluator ----------------------------------------------------------
+
+double Eval(const Node& node, const InputSource& source);
+
+double Arg(const Node& node, size_t index, const InputSource& source) {
+    return Eval(*node.args[index], source);
+}
+
+double Eval(const Node& node, const InputSource& source) {
+    switch (node.kind) {
+    case Kind::Literal: return node.literal;
+    case Kind::Input:   return source ? source(node.input) : 0.0;
+    case Kind::Not:
+    case Kind::FnNot:   return 1.0 - Arg(node, 0, source);
+    case Kind::Add:     return Arg(node, 0, source) + Arg(node, 1, source);
+    case Kind::Sub:     return Arg(node, 0, source) - Arg(node, 1, source);
+    case Kind::Mul:     return Arg(node, 0, source) * Arg(node, 1, source);
+    case Kind::Div: {
+        // Both sides are evaluated even when the divisor is zero: the left
+        // subtree may hold stateful functions that need their frame update.
+        const double lhs = Arg(node, 0, source);
+        const double rhs = Arg(node, 1, source);
+        return rhs == 0.0 ? 0.0 : lhs / rhs;
+    }
+    case Kind::And:     return std::min(Arg(node, 0, source), Arg(node, 1, source));
+    case Kind::Or:      return std::max(Arg(node, 0, source), Arg(node, 1, source));
+    case Kind::Xor: {
+        const double a = Arg(node, 0, source);
+        const double b = Arg(node, 1, source);
+        return std::max(std::min(a, 1.0 - b), std::min(b, 1.0 - a));
+    }
+    case Kind::Greater: return Arg(node, 0, source) > Arg(node, 1, source) ? 1.0 : 0.0;
+    case Kind::Less:    return Arg(node, 0, source) < Arg(node, 1, source) ? 1.0 : 0.0;
+    case Kind::Equal:   return Arg(node, 0, source) == Arg(node, 1, source) ? 1.0 : 0.0;
+    case Kind::FnIf:
+        return Arg(node, 0, source) > kConditionThreshold ? Arg(node, 1, source) : Arg(node, 2, source);
+    case Kind::FnMin:   return std::min(Arg(node, 0, source), Arg(node, 1, source));
+    case Kind::FnMax:   return std::max(Arg(node, 0, source), Arg(node, 1, source));
+    case Kind::FnClamp: {
+        const double v = Arg(node, 0, source);
+        double lo = Arg(node, 1, source);
+        double hi = Arg(node, 2, source);
+        if (lo > hi) {
+            std::swap(lo, hi);
+        }
+        return std::clamp(v, lo, hi);
+    }
+    case Kind::FnAbs:   return std::abs(Arg(node, 0, source));
+    case Kind::FnSqrt:  return std::sqrt(Arg(node, 0, source));
+    case Kind::FnPow:   return std::pow(Arg(node, 0, source), Arg(node, 1, source));
+    case Kind::FnSin:   return std::sin(Arg(node, 0, source));
+    case Kind::FnCos:   return std::cos(Arg(node, 0, source));
+    case Kind::FnTan:   return std::tan(Arg(node, 0, source));
+    case Kind::FnDeadzone: {
+        const double v = Arg(node, 0, source);
+        const double dz = std::clamp(Arg(node, 1, source), 0.0, 0.999);
+        return std::copysign(std::max(0.0, std::abs(v) - dz) / (1.0 - dz), v);
+    }
+    case Kind::FnTimer: {
+        const auto now = Clock::now();
+        if (!node.marked) {
+            node.mark = now;
+            node.marked = true;
+        }
+        const double period = Arg(node, 0, source);
+        double progress = std::chrono::duration_cast<FSec>(now - node.mark).count() / period;
+        if (!std::isfinite(progress) || progress < 0.0) {
+            progress = 0.0;
+            node.mark = now;
+        } else if (progress >= 1.0) {
+            const double resets = std::floor(progress);
+            node.mark += std::chrono::duration_cast<Clock::duration>(FSec(period * resets));
+            progress -= resets;
+        }
+        return progress;
+    }
+    case Kind::FnToggle: {
+        const double inner = Arg(node, 0, source);
+        if (inner < kConditionThreshold) {
+            node.released = true;
+        } else if (node.released) {
+            node.released = false;
+            node.state = !node.state;
+        }
+        if (node.args.size() == 2 && Arg(node, 1, source) > kConditionThreshold) {
+            node.state = false;
+        }
+        return node.state ? 1.0 : 0.0;
+    }
+    case Kind::FnHold: {
+        const auto now = Clock::now();
+        if (!node.marked) {
+            node.mark = now;
+            node.marked = true;
+        }
+        const double input = Arg(node, 0, source);
+        if (input < kConditionThreshold) {
+            node.state = false;
+            node.mark = now;
+        } else if (!node.state) {
+            if (std::chrono::duration_cast<FSec>(now - node.mark).count() >= Arg(node, 1, source)) {
+                node.state = true;
+            }
+        }
+        return node.state ? 1.0 : 0.0;
+    }
+    case Kind::FnTap: {
+        const auto now = Clock::now();
+        if (!node.marked) {
+            node.mark = now;
+            node.marked = true;
+        }
+        const double elapsed = std::chrono::duration_cast<FSec>(now - node.mark).count();
+        const double input = Arg(node, 0, source);
+        const bool timeUp = elapsed > Arg(node, 1, source);
+        // The count is user authored, so a negative or huge value must not
+        // reach the unsigned conversion.
+        double requested = node.args.size() == 3 ? Arg(node, 2, source) : 2.0;
+        if (!std::isfinite(requested)) {
+            requested = 2.0;
+        }
+        const auto desired = static_cast<unsigned>(std::clamp(requested + 0.5, 1.0, 64.0));
+        if (input < kConditionThreshold) {
+            node.released = true;
+            if (node.taps > 0 && timeUp) {
+                node.taps = 0;
+            }
+            return 0.0;
+        }
+        if (node.released) {
+            if (node.taps == 0) {
+                node.mark = now;
+            }
+            ++node.taps;
+            node.released = false;
+        }
+        return desired == node.taps ? 1.0 : 0.0;
+    }
+    case Kind::FnPulse: {
+        const auto now = Clock::now();
+        const double input = Arg(node, 0, source);
+        if (input < kConditionThreshold) {
+            node.released = true;
+        } else if (node.released) {
+            node.released = false;
+            const double requested = Arg(node, 1, source);
+            const double safe = std::isfinite(requested) ? std::clamp(requested, 0.0, 3600.0) : 0.0;
+            const auto seconds = std::chrono::duration_cast<Clock::duration>(FSec(safe));
+            if (node.state) {
+                node.mark += seconds;
+            } else {
+                node.state = true;
+                node.mark = now + seconds;
+            }
+        }
+        if (node.state && now >= node.mark) {
+            node.state = false;
+        }
+        return node.state ? 1.0 : 0.0;
+    }
+    case Kind::FnSmooth: {
+        const auto now = Clock::now();
+        if (!node.marked) {
+            node.mark = now;
+            node.marked = true;
+        }
+        const double elapsed = std::chrono::duration_cast<FSec>(now - node.mark).count();
+        node.mark = now;
+        const double desired = Arg(node, 0, source);
+        const double up = Arg(node, 1, source);
+        const double down = node.args.size() == 3 ? Arg(node, 2, source) : up;
+        const double rate = (desired < node.value) ? down : up;
+        const double maxMove = elapsed / rate;
+        if (!std::isfinite(maxMove)) {
+            node.value = desired;
+        } else {
+            const double diff = desired - node.value;
+            node.value += std::copysign(std::min(maxMove, std::abs(diff)), diff);
+        }
+        return node.value;
+    }
+    }
+    return 0.0;
+}
+
+void Collect(const Node& node, std::vector<std::string>& out) {
+    if (node.kind == Kind::Input) {
+        if (std::find(out.begin(), out.end(), node.input) == out.end()) {
+            out.push_back(node.input);
+        }
+    }
+    for (const auto& arg : node.args) {
+        Collect(*arg, out);
+    }
+}
+
+std::string Trim(const std::string& text) {
+    const size_t begin = text.find_first_not_of(" \t\r\n");
+    if (begin == std::string::npos) {
+        return {};
+    }
+    return text.substr(begin, text.find_last_not_of(" \t\r\n") - begin + 1);
+}
+
+} // namespace
+
+Expression::Expression() = default;
+Expression::~Expression() = default;
+Expression::Expression(Expression&&) noexcept = default;
+Expression& Expression::operator=(Expression&&) noexcept = default;
+
+bool Expression::Parse(const std::string& text, Expression& out, std::string& error) {
+    out.m_root.reset();
+    if (Trim(text).empty()) {
+        return true;
+    }
+    Parser parser(text);
+    NodePtr root = parser.ParseExpression(error);
+    if (!root) {
+        return false;
+    }
+    out.m_root = std::move(root);
+    return true;
+}
+
+double Expression::Evaluate(const InputSource& source) const {
+    if (m_root == nullptr) {
+        return 0.0;
+    }
+    const double value = Eval(*m_root, source);
+    return std::isfinite(value) ? value : 0.0;
+}
+
+std::vector<std::string> Expression::ReferencedInputs() const {
+    std::vector<std::string> out;
+    if (m_root) {
+        Collect(*m_root, out);
+    }
+    return out;
+}
+
+bool ReadDolphinConfig(const std::filesystem::path& path, int padIndex,
+                       std::vector<std::pair<std::string, std::string>>& controls,
+                       std::string& deviceName, std::string& error) {
+    std::ifstream file(path);
+    if (!file) {
+        error = "could not open " + path.string();
+        return false;
+    }
+    const std::string wanted = "[GCPad" + std::to_string(padIndex) + "]";
+    bool inSection = false;
+    bool found = false;
+    std::string line;
+    controls.clear();
+    deviceName.clear();
+    while (std::getline(file, line)) {
+        const std::string trimmed = Trim(line);
+        if (trimmed.empty() || trimmed[0] == '#' || trimmed[0] == ';') {
+            continue;
+        }
+        if (trimmed.front() == '[') {
+            inSection = trimmed == wanted;
+            found = found || inSection;
+            continue;
+        }
+        if (!inSection) {
+            continue;
+        }
+        const size_t eq = trimmed.find('=');
+        if (eq == std::string::npos) {
+            continue;
+        }
+        const std::string key = Trim(trimmed.substr(0, eq));
+        const std::string value = Trim(trimmed.substr(eq + 1));
+        if (key == "Device") {
+            deviceName = value;
+        } else if (!value.empty()) {
+            controls.emplace_back(key, value);
+        }
+    }
+    if (!found) {
+        error = wanted + " not found in " + path.string();
+        return false;
+    }
+    return true;
+}
+
+} // namespace InputExpr

runtime/src/settings_overlay.cpp

@@ -1,6 +1,8 @@
 #include "settings_overlay.h"
 #include "audio_backend.h"
+#include "controller_button_names.h"
 #include "controller_mapping_wizard.h"
+#include "input_bindings.h"
 #include "game_graphics_options.h"
 #include "music_attenuation.h"
 #include "runtime_config.h"
@@ -34,6 +36,8 @@
 #endif
 
 #include <dolphin/pad.h>
+
+extern "C" void PAD_HLE_SetRumbleEnabled(bool enabled);
 #include <dolphin/vi.h>
 #include <aurora/aurora.h>
 #include <aurora/gfx.h>
@@ -65,6 +69,7 @@ const char* GraphicsApiDisplayName() {
 }
 
 bool g_topBarVisible = false;
+bool g_rumbleEnabled = RuntimeConfigFile::RumbleEnabled(true);
 int g_controllerPort = 0;
 float g_resolutionScale = RuntimeConfigFile::ResolutionMultiplier(1.0f);
 int g_audioVolumePercent = static_cast<int>(std::lround(RuntimeConfigFile::AudioVolume(1.0f) * 100.0f));
@@ -106,62 +111,9 @@ std::array<int32_t, PAD_MAX_CONTROLLERS> g_configuredControllerIndices = [] {
     return indices;
 }();
 
-struct ControllerButtonItem {
-    const char* configKey;
-    const char* label;
-    PADButton padButton;
-};
-
-constexpr std::array<ControllerButtonItem, PAD_BUTTON_COUNT> kControllerButtons = {{
-    {"a", "A", PAD_BUTTON_A},
-    {"b", "B", PAD_BUTTON_B},
-    {"x", "X", PAD_BUTTON_X},
-    {"y", "Y", PAD_BUTTON_Y},
-    {"start", "Start", PAD_BUTTON_START},
-    {"z", "Z", PAD_TRIGGER_Z},
-    {"l", "L", PAD_TRIGGER_L},
-    {"r", "R", PAD_TRIGGER_R},
-    {"up", "D-pad Up", PAD_BUTTON_UP},
-    {"down", "D-pad Down", PAD_BUTTON_DOWN},
-    {"left", "D-pad Left", PAD_BUTTON_LEFT},
-    {"right", "D-pad Right", PAD_BUTTON_RIGHT},
-}};
-
-struct NativeButtonItem {
-    const char* configName;
-    const char* label;
-    uint32_t nativeButton;
-};
-
-constexpr std::array<NativeButtonItem, SDL_GAMEPAD_BUTTON_COUNT + 1> kNativeButtons = {{
-    {"unmapped", "Unmapped / analog trigger", PAD_NATIVE_BUTTON_INVALID},
-    {"south", "South (A / Cross)", SDL_GAMEPAD_BUTTON_SOUTH},
-    {"east", "East (B / Circle)", SDL_GAMEPAD_BUTTON_EAST},
-    {"west", "West (X / Square)", SDL_GAMEPAD_BUTTON_WEST},
-    {"north", "North (Y / Triangle)", SDL_GAMEPAD_BUTTON_NORTH},
-    {"back", "Back / Select", SDL_GAMEPAD_BUTTON_BACK},
-    {"guide", "Guide / Home", SDL_GAMEPAD_BUTTON_GUIDE},
-    {"start", "Start / Options", SDL_GAMEPAD_BUTTON_START},
-    {"left_stick", "Left stick click", SDL_GAMEPAD_BUTTON_LEFT_STICK},
-    {"right_stick", "Right stick click", SDL_GAMEPAD_BUTTON_RIGHT_STICK},
-    {"left_shoulder", "Left shoulder", SDL_GAMEPAD_BUTTON_LEFT_SHOULDER},
-    {"right_shoulder", "Right shoulder", SDL_GAMEPAD_BUTTON_RIGHT_SHOULDER},
-    {"dpad_up", "D-pad Up", SDL_GAMEPAD_BUTTON_DPAD_UP},
-    {"dpad_down", "D-pad Down", SDL_GAMEPAD_BUTTON_DPAD_DOWN},
-    {"dpad_left", "D-pad Left", SDL_GAMEPAD_BUTTON_DPAD_LEFT},
-    {"dpad_right", "D-pad Right", SDL_GAMEPAD_BUTTON_DPAD_RIGHT},
-    {"misc1", "Misc 1 / Share", SDL_GAMEPAD_BUTTON_MISC1},
-    {"right_paddle1", "Right paddle 1", SDL_GAMEPAD_BUTTON_RIGHT_PADDLE1},
-    {"left_paddle1", "Left paddle 1", SDL_GAMEPAD_BUTTON_LEFT_PADDLE1},
-    {"right_paddle2", "Right paddle 2", SDL_GAMEPAD_BUTTON_RIGHT_PADDLE2},
-    {"left_paddle2", "Left paddle 2", SDL_GAMEPAD_BUTTON_LEFT_PADDLE2},
-    {"touchpad", "Touchpad", SDL_GAMEPAD_BUTTON_TOUCHPAD},
-    {"misc2", "Misc 2", SDL_GAMEPAD_BUTTON_MISC2},
-    {"misc3", "Misc 3 / GC L click", SDL_GAMEPAD_BUTTON_MISC3},
-    {"misc4", "Misc 4 / GC R click", SDL_GAMEPAD_BUTTON_MISC4},
-    {"misc5", "Misc 5", SDL_GAMEPAD_BUTTON_MISC5},
-    {"misc6", "Misc 6", SDL_GAMEPAD_BUTTON_MISC6},
-}};
+using ControllerNames::kNativeButtons;
+using ControllerNames::NativeButtonItem;
+constexpr const auto& kControllerButtons = ControllerNames::kGameCubeButtons;
 
 // Classic Controller Pro layout, indexed like kControllerButtons: the SNES-style
 // diamond (A right, B bottom, X top, Y left) with digital bumpers driving the GC
@@ -178,6 +130,13 @@ constexpr std::array<const char*, PAD_BUTTON_COUNT> kClassicProPreset = {
     "dpad_up", "dpad_down", "dpad_left", "dpad_right",
 };
 
+// PlayStation layout: bumpers drive the GC triggers, Z moves to Create/Share.
+constexpr std::array<const char*, PAD_BUTTON_COUNT> kPlayStationPreset = {
+    "south", "east", "west", "north", "start", "back",
+    "left_shoulder", "right_shoulder",
+    "dpad_up", "dpad_down", "dpad_left", "dpad_right",
+};
+
 struct ResolutionItem {
     const char* label;
     float scale;
@@ -225,43 +184,25 @@ void LimitResolutionForFrameRate() {
     }
 }
 
-const NativeButtonItem* FindNativeButton(std::string value) {
-    const auto it = std::find_if(kNativeButtons.begin(), kNativeButtons.end(), [&](const NativeButtonItem& item) {
-        return value == item.configName;
-    });
-    return it == kNativeButtons.end() ? nullptr : &*it;
-}
+using ControllerNames::FindNativeButton;
 
 struct ControllerBindingPair {
     std::string primary;
     std::string secondary;
 };
 
-std::string TrimBindingToken(const std::string& token) {
-    const size_t begin = token.find_first_not_of(" \t");
-    if (begin == std::string::npos) {
-        return {};
-    }
-    const size_t end = token.find_last_not_of(" \t");
-    return token.substr(begin, end - begin + 1);
-}
 
 // Config values hold up to two comma-separated button names ("dpad_up" or
 // "dpad_up,left_shoulder"); pressing either one counts as the GC button.
 ControllerBindingPair SplitControllerBinding(const std::string& value) {
     const size_t comma = value.find(',');
     if (comma == std::string::npos) {
-        return {TrimBindingToken(value), {}};
+        return {ControllerNames::TrimToken(value), {}};
     }
-    return {TrimBindingToken(value.substr(0, comma)), TrimBindingToken(value.substr(comma + 1))};
+    return {ControllerNames::TrimToken(value.substr(0, comma)), ControllerNames::TrimToken(value.substr(comma + 1))};
 }
 
-const NativeButtonItem& NativeButtonForValue(uint32_t nativeButton) {
-    const auto it = std::find_if(kNativeButtons.begin(), kNativeButtons.end(), [&](const NativeButtonItem& item) {
-        return nativeButton == item.nativeButton;
-    });
-    return it == kNativeButtons.end() ? kNativeButtons.front() : *it;
-}
+using ControllerNames::NativeButtonForValue;
 
 void SetTopBarVisible(bool visible) {
     if (g_topBarVisible == visible) {
@@ -393,10 +334,8 @@ void DrawWiiRemoteSettings(uint32_t selectedGamePort) {
     }
     ImGui::EndDisabled();
     ImGui::SameLine();
-    if (WiiRemoteInput::IsScanning() && WiiRemoteInput::PeriodicRescanEnabled()) {
+    if (WiiRemoteInput::IsScanning()) {
         ImGui::TextDisabled("Scanning... (%u so far) - press 1+2 on the remote", WiiRemoteInput::ScanCount());
-    } else if (WiiRemoteInput::IsScanning()) {
-        ImGui::TextDisabled("Waiting for a remote - press 1+2 on the remote");
     } else {
         ImGui::TextDisabled("Not scanning");
     }
@@ -457,6 +396,105 @@ void DrawWiiRemoteSettings(uint32_t selectedGamePort) {
 }
 
 // Controller settings menu: port selection, controller assignment and button mapping.
+int ExpressionResizeCallback(ImGuiInputTextCallbackData* data) {
+    if (data->EventFlag == ImGuiInputTextFlags_CallbackResize) {
+        auto* text = static_cast<std::string*>(data->UserData);
+        text->resize(static_cast<size_t>(data->BufTextLen));
+        data->Buf = text->data();
+    }
+    return 0;
+}
+
+void DrawExpressionSettings() {
+    ImGui::SeparatorText("Expressions (Dolphin syntax)");
+    ImGui::PushTextWrapPos(ImGui::GetCursorPosX() + 440.0f);
+    ImGui::TextDisabled(
+        "Optional. An expression overrides nothing: its result is combined with the "
+        "button mapping above. Operators ! & | ^ and functions if, min, max, clamp, "
+        "timer, toggle, hold, tap, pulse, smooth, deadzone behave as they do in Dolphin.");
+    ImGui::PopTextWrapPos();
+
+    static std::array<std::string, InputBindings::kControls.size()> errors;
+    static std::array<std::string, InputBindings::kControls.size()> buffers;
+    static std::string importStatus;
+    static int loadedPort = -1;
+    static bool reloadBuffers = true;
+    const auto port = static_cast<uint32_t>(g_controllerPort);
+
+    if (loadedPort != g_controllerPort || reloadBuffers) {
+        for (size_t i = 0; i < buffers.size(); ++i) {
+            buffers[i] = InputBindings::GetExpression(port, i);
+        }
+        errors.fill(std::string());
+        loadedPort = g_controllerPort;
+        reloadBuffers = false;
+    }
+
+    if (ImGui::Button("Import from Dolphin")) {
+        const std::string path = InputBindings::DefaultDolphinConfigPath();
+        std::string summary;
+        std::string error;
+        if (InputBindings::ImportDolphinConfig(path, g_controllerPort + 1, port, summary, error) < 0) {
+            importStatus = error;
+        } else {
+            importStatus = summary;
+            errors.fill(std::string());
+            reloadBuffers = true;
+        }
+    }
+    if (ImGui::IsItemHovered()) {
+        ImGui::SetTooltip("Reads [GCPad%d] from %%APPDATA%%\\Dolphin Emulator\\Config\\GCPadNew.ini,\n"
+                          "or GCPadNew.ini next to the executable.", g_controllerPort + 1);
+    }
+    if (!importStatus.empty()) {
+        ImGui::TextDisabled("%s", importStatus.c_str());
+    }
+
+    for (size_t i = 0; i < InputBindings::kControls.size(); ++i) {
+        ImGui::PushID(static_cast<int>(i) + 2000);
+        std::string& text = buffers[i];
+        ImGui::SetNextItemWidth(300.0f);
+        if (ImGui::InputText(InputBindings::kControls[i].label, text.data(), text.capacity() + 1,
+                             ImGuiInputTextFlags_EnterReturnsTrue | ImGuiInputTextFlags_CallbackResize,
+                             ExpressionResizeCallback, &text)) {
+            std::string error;
+            errors[i] = InputBindings::SetExpression(port, i, text, error) ? std::string() : error;
+        }
+        if (InputBindings::IsActive(port, i)) {
+            ImGui::SameLine();
+            ImGui::TextColored(ImVec4(0.4f, 0.9f, 0.4f, 1.0f), "active");
+        }
+        if (!errors[i].empty()) {
+            ImGui::TextColored(ImVec4(1.0f, 0.65f, 0.3f, 1.0f), "%s", errors[i].c_str());
+        }
+        ImGui::PopID();
+    }
+}
+
+void DrawRumbleSettings() {
+    ImGui::SeparatorText("Vibration");
+    if (ImGui::Checkbox("Controller vibration", &g_rumbleEnabled)) {
+        PAD_HLE_SetRumbleEnabled(g_rumbleEnabled);
+        RuntimeConfigFile::SetRumbleEnabled(g_rumbleEnabled);
+        if (!g_rumbleEnabled) {
+            // Stop whatever is already running: the game will not send another
+            // motor command until its own state machine decides to.
+            constexpr std::array<uint32_t, PAD_MAX_CONTROLLERS> stopAll{
+                PAD_MOTOR_STOP_HARD, PAD_MOTOR_STOP_HARD, PAD_MOTOR_STOP_HARD, PAD_MOTOR_STOP_HARD,
+            };
+            PADControlAllMotors(stopAll.data());
+#if defined(_WIN32)
+            for (uint32_t port = 0; port < PAD_MAX_CONTROLLERS; ++port) {
+                Wup028Adapter::SetRumble(port, false);
+            }
+#endif
+        }
+    }
+    if (ImGui::IsItemHovered()) {
+        ImGui::SetTooltip("Applies to every port.");
+    }
+}
+
 void DrawControllerSettings() {
     for (int port = 0; port < PAD_MAX_CONTROLLERS; ++port) {
         const std::string label = "Port " + std::to_string(port + 1);
@@ -545,20 +583,28 @@ void DrawControllerSettings() {
         PADSerializeMappings();
         mappings = PADGetButtonMappings(port, &mappingCount);
     }
-    ImGui::SameLine();
-    if (ImGui::Button("Classic Controller Pro")) {
+    const auto applyPreset = [&](const std::array<const char*, PAD_BUTTON_COUNT>& preset) {
         const uint32_t port = static_cast<uint32_t>(g_controllerPort);
         for (size_t i = 0; i < kControllerButtons.size(); ++i) {
-            if (const NativeButtonItem* native = FindNativeButton(kClassicProPreset[i])) {
+            if (const NativeButtonItem* native = FindNativeButton(preset[i])) {
                 PADSetButtonMapping(port, PADButtonMapping{native->nativeButton, kControllerButtons[i].padButton});
                 PADSetAltButtonMapping(port,
                                        PADButtonMapping{PAD_NATIVE_BUTTON_INVALID, kControllerButtons[i].padButton});
-                RuntimeConfigFile::SetControllerButton(i, kClassicProPreset[i]);
+                RuntimeConfigFile::SetControllerButton(i, preset[i]);
             }
         }
         altRowExpanded.fill(false);
         PADSerializeMappings();
         mappings = PADGetButtonMappings(port, &mappingCount);
+    };
+
+    ImGui::SameLine();
+    if (ImGui::Button("Classic Controller Pro")) {
+        applyPreset(kClassicProPreset);
+    }
+    ImGui::SameLine();
+    if (ImGui::Button("PlayStation")) {
+        applyPreset(kPlayStationPreset);
     }
 
     ImGui::SeparatorText("Button mapping");
@@ -640,6 +686,8 @@ void DrawControllerSettings() {
         ImGui::TextUnformatted(kControllerButtons[i].label);
         ImGui::PopID();
     }
+    DrawExpressionSettings();
+    DrawRumbleSettings();
 }
 
 void DrawAudioSettings() {
@@ -994,6 +1042,8 @@ void PersistDisplayModeIfChanged() {
 } // namespace
 
 void InitializeRuntimeSettings() noexcept {
+    PAD_HLE_SetRumbleEnabled(g_rumbleEnabled);
+    InputBindings::Reload();
     controller_mapping_wizard::LoadPersistedMappings();
     ApplyConfiguredMappings();
     AudioBackend::Instance().SetMasterVolume(static_cast<float>(g_audioVolumePercent) / 100.0f);
@@ -1014,6 +1064,7 @@ void InitializeRuntimeSettings() noexcept {
     g_strapInputAccepted.store(false, std::memory_order_relaxed);
     g_startupDismissFrame.store(UINT64_MAX, std::memory_order_relaxed);
     PADBlockInput(false);
+    InputBindings::SetInputBlocked(false);
 }
 
 void HandleEvents(const AuroraEvent* events) noexcept {
@@ -1056,7 +1107,9 @@ void Draw() noexcept {
     DrawTopBar();
     controller_mapping_wizard::Draw();
     // The wizard captures raw presses; keep them out of the game.
-    PADBlockInput(controller_mapping_wizard::IsActive());
+    const bool inputBlocked = controller_mapping_wizard::IsActive();
+    PADBlockInput(inputBlocked);
+    InputBindings::SetInputBlocked(inputBlocked);
     DrawStartupScreen();
 }
 

runtime/tests/test_expr.cpp

@@ -0,0 +1,219 @@
+// Verifies the expression engine against Dolphin's documented semantics,
+// including the exact line from the user's GCPadNew.ini.
+
+#include "input_expr.h"
+
+#include <chrono>
+#include <cmath>
+#include <cstdio>
+#include <map>
+#include <string>
+#include <thread>
+
+static int g_failures = 0;
+static std::map<std::string, double> g_inputs;
+
+static InputExpr::InputSource Source() {
+    return [](const std::string& name) {
+        const auto it = g_inputs.find(name);
+        return it == g_inputs.end() ? 0.0 : it->second;
+    };
+}
+
+static void Check(bool ok, const std::string& what) {
+    if (!ok) {
+        std::printf("  FAIL: %s\n", what.c_str());
+        ++g_failures;
+    }
+}
+
+static InputExpr::Expression Compile(const std::string& text) {
+    InputExpr::Expression expr;
+    std::string error;
+    if (!InputExpr::Expression::Parse(text, expr, error)) {
+        std::printf("  FAIL: parse '%s': %s\n", text.c_str(), error.c_str());
+        ++g_failures;
+    }
+    return expr;
+}
+
+static bool Pressed(const InputExpr::Expression& e) {
+    return e.Evaluate(Source()) > InputExpr::kConditionThreshold;
+}
+
+static void Sleep(int ms) { std::this_thread::sleep_for(std::chrono::milliseconds(ms)); }
+
+int main() {
+    std::printf("Dolphin expression engine\n");
+
+    // Operators: & is min, | is max, ! is 1-x, matching Dolphin.
+    g_inputs["A"] = 1.0;
+    g_inputs["B"] = 0.0;
+    Check(Pressed(Compile("`A`")), "bare input");
+    Check(!Pressed(Compile("!`A`")), "not");
+    Check(!Pressed(Compile("`A` & `B`")), "and is min");
+    Check(Pressed(Compile("`A` | `B`")), "or is max");
+    Check(Pressed(Compile("`A` ^ `B`")), "xor");
+    Check(!Pressed(Compile("`A` ^ `A`")), "xor of equal inputs is false");
+
+    // Precedence: & binds tighter than |, so this is A | (B & A).
+    g_inputs["B"] = 0.0;
+    Check(Pressed(Compile("`A` | `B` & `A`")), "& binds tighter than |");
+
+    // Parens and numeric literals.
+    Check(Pressed(Compile("(`B` | 1)")), "literal");
+    Check(Pressed(Compile("min(1, `A`)")), "min");
+    Check(!Pressed(Compile("min(0, `A`)")), "min with zero");
+    Check(Pressed(Compile("if(`A`, 1, 0)")), "if");
+    Check(Pressed(Compile("clamp(5, 0, 1)")), "clamp");
+
+    // toggle flips on each rising edge and holds between them.
+    auto toggle = Compile("toggle(`T`)");
+    g_inputs["T"] = 0.0;
+    toggle.Evaluate(Source());
+    g_inputs["T"] = 1.0;
+    Check(Pressed(toggle), "toggle on after first press");
+    g_inputs["T"] = 0.0;
+    Check(Pressed(toggle), "toggle stays on after release");
+    g_inputs["T"] = 1.0;
+    Check(!Pressed(toggle), "toggle off on second press");
+
+    // hold requires the input to be down for the full duration.
+    auto hold = Compile("hold(`H`, 0.05)");
+    g_inputs["H"] = 1.0;
+    Check(!Pressed(hold), "hold not satisfied immediately");
+    Sleep(70);
+    Check(Pressed(hold), "hold satisfied after the interval");
+    g_inputs["H"] = 0.0;
+    Check(!Pressed(hold), "hold clears on release");
+
+    // pulse fires for the given duration after a rising edge.
+    auto pulse = Compile("pulse(`P`, 0.05)");
+    g_inputs["P"] = 0.0;
+    pulse.Evaluate(Source());
+    g_inputs["P"] = 1.0;
+    Check(Pressed(pulse), "pulse fires on rising edge");
+    Sleep(80);
+    Check(!Pressed(pulse), "pulse expires");
+
+    // The timing-window idiom seen in shared Dolphin configs.
+    auto window = Compile("!pulse(`W`, 0.05) & pulse(`W`, 0.15)");
+    g_inputs["W"] = 0.0;
+    window.Evaluate(Source());
+    g_inputs["W"] = 1.0;
+    Check(!Pressed(window), "window closed before its start");
+    Sleep(90);
+    Check(Pressed(window), "window open between the two pulses");
+    Sleep(90);
+    Check(!Pressed(window), "window closed after its end");
+
+    // timer ramps 0..1 and wraps, so a threshold turns it into a square wave.
+    auto timer = Compile("`X` & timer(0.1)");
+    g_inputs["X"] = 1.0;
+    int high = 0;
+    int low = 0;
+    for (int i = 0; i < 40; ++i) {
+        (Pressed(timer) ? high : low)++;
+        Sleep(5);
+    }
+    Check(high > 5 && low > 5, "timer alternates high and low");
+
+    // The exact D-Pad/Up line from the user's GCPadNew.ini.
+    auto dolphinLine = Compile("`Hat 0 N` | `Button 4` & timer(0.01)");
+    g_inputs["Hat 0 N"] = 0.0;
+    g_inputs["Button 4"] = 0.0;
+    Check(!Pressed(dolphinLine), "idle with nothing held");
+    g_inputs["Hat 0 N"] = 1.0;
+    Check(Pressed(dolphinLine), "hat alone presses");
+    g_inputs["Hat 0 N"] = 0.0;
+    g_inputs["Button 4"] = 1.0;
+    high = low = 0;
+    for (int i = 0; i < 60; ++i) {
+        (Pressed(dolphinLine) ? high : low)++;
+        Sleep(2);
+    }
+    Check(high > 5 && low > 5, "LB alternates via timer(0.01)");
+
+    // Regression tests for the CodeRabbit findings on PR #89.
+    g_inputs["A"] = 1.0;
+    // clamp with reversed bounds: std::clamp is UB when lo > hi.
+    Check(Compile("clamp(0.5, 1, 0)").Evaluate(Source()) == 0.5, "clamp tolerates reversed bounds");
+    // deadzone(v, 1) would divide by zero.
+    {
+        const double v = Compile("deadzone(`A`, 1)").Evaluate(Source());
+        Check(std::isfinite(v), "deadzone with dz=1 stays finite");
+    }
+    // timer with a zero or negative period would produce inf or NaN.
+    for (const char* text : {"timer(0)", "timer(-1)"}) {
+        const double v = Compile(text).Evaluate(Source());
+        Check(std::isfinite(v), std::string(text) + " stays finite");
+    }
+    // Any non-finite result is squashed before it can reach the uint8_t cast.
+    for (const char* text : {"sqrt(0 - 1)", "pow(10, 10000)", "tan(1.5707963267948966)"}) {
+        const double v = Compile(text).Evaluate(Source());
+        Check(std::isfinite(v), std::string(text) + " is sanitised at the boundary");
+    }
+
+    // tap count is user authored; negative, huge and non-finite must not reach
+    // the unsigned conversion.
+    for (const char* text : {"tap(`A`, 0.2, -1)", "tap(`A`, 0.2, 999999999)", "tap(`A`, 0.2, 0)"}) {
+        InputExpr::Expression e;
+        std::string err;
+        Check(InputExpr::Expression::Parse(text, e, err), std::string("parse ") + text);
+        const double v = e.Evaluate(Source());
+        Check(std::isfinite(v), std::string(text) + " evaluates without UB");
+    }
+
+    // Exponent notation is not part of the number syntax, matching Dolphin's
+    // lexer; it is rejected rather than silently misparsed.
+    {
+        InputExpr::Expression e;
+        std::string err;
+        Check(!InputExpr::Expression::Parse("tap(`A`, 0.2, 1e30)", e, err), "exponent notation rejected");
+    }
+
+    // A zero divisor must not skip the left subtree: stateful functions there
+    // still need their per-frame update.
+    {
+        auto divToggle = Compile("toggle(`D`) / `Z`");
+        g_inputs["Z"] = 0.0;
+        g_inputs["D"] = 0.0;
+        divToggle.Evaluate(Source());
+        g_inputs["D"] = 1.0;
+        divToggle.Evaluate(Source());   // rising edge seen even though rhs is 0
+        g_inputs["D"] = 0.0;
+        g_inputs["Z"] = 1.0;
+        Check(divToggle.Evaluate(Source()) > InputExpr::kConditionThreshold,
+              "toggle still latched while the divisor was zero");
+    }
+
+    // smooth with a zero rate divides 0 by 0; NaN must not stick in the node.
+    {
+        auto sm = Compile("smooth(`A`, 0)");
+        g_inputs["A"] = 1.0;
+        sm.Evaluate(Source());
+        Sleep(5);
+        Check(std::isfinite(sm.Evaluate(Source())), "smooth with a zero rate stays finite");
+    }
+
+    // Referenced inputs, used for diagnostics in the UI.
+    const auto refs = dolphinLine.ReferencedInputs();
+    Check(refs.size() == 2, "two referenced inputs");
+
+    // Errors are reported, not silently swallowed.
+    InputExpr::Expression bad;
+    std::string error;
+    Check(!InputExpr::Expression::Parse("`A` & ", bad, error), "trailing operator rejected");
+    Check(!InputExpr::Expression::Parse("nope(1)", bad, error), "unknown function rejected");
+    Check(!InputExpr::Expression::Parse("(`A`", bad, error), "missing paren rejected");
+    Check(!InputExpr::Expression::Parse("`A", bad, error), "unterminated backtick rejected");
+    Check(InputExpr::Expression::Parse("", bad, error) && bad.Empty(), "empty parses to empty");
+    Check(!InputExpr::Expression::Parse("hold(`A`)", bad, error), "wrong arg count rejected");
+
+    if (g_failures == 0) {
+        std::printf("all checks passed\n");
+        return 0;
+    }
+    std::printf("%d check(s) failed\n", g_failures);
+    return 1;
+}