Describe DLSS, FSR 3.1, frame generation, HDR and the build kit in the READMEs; name a null call's caller.

The README takes the name NX2navi as on GitHub and lists the new upscalers, frame generation, the HDR modes, the
higher resolutions and the shader preparation, and points to the build kit for installing. A crash calling address 0
now logs the return address on top of the stack and its module (it was inside sl.common.dll for Streamline).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -27,7 +27,14 @@ Report problems as issues, following [CONTRIBUTING.md](CONTRIBUTING.md).
 - Native code, not emulation
 - 60 fps by default, or a limit of 30 to 240 fps, the display's refresh rate or unlimited
 - Native widescreen and ultrawide (the window's shape, 21:9 or 32:9) with the HUD, menus and movies kept 16:9
-- AMD FSR 1 or bilinear scaling to the window, with a sharpness setting; black bars or stretch
+- Resolutions above the game's 1440p: 1800p, 4K, 5K or the window's own size, sharp on high-DPI displays
+- Upscaling and anti-aliasing: NVIDIA DLSS (DLAA, Quality, Balanced, Performance, Ultra Performance; RTX GPUs) or
+  AMD FSR 3.1 (Native AA and the same modes; any GPU), which render the 3D scene at the mode's share and keep the HUD
+  sharp; or AMD FSR 1 or bilinear scaling to the window, with a sharpness setting; black bars or stretch
+- Frame generation with AMD FSR 3.1 (any GPU): a generated frame between every two the game draws, with the HUD kept
+  out of it, for about twice the frame rate on a fast display
+- HDR on HDR displays: the game's own native HDR, or an enhanced HDR made from its SDR picture
+- Every shader prepared when the game is built, so play does not stop to compile them
 - In-game settings menu (F1, or Minus and Plus together on a gamepad) and performance overlay (F10)
 - Keyboard, mouse and gamepads with remapping, Nintendo or Xbox button layout, rumble and gyro; the game follows
   whichever connected gamepad you press
@@ -38,8 +45,9 @@ Report problems as issues, following [CONTRIBUTING.md](CONTRIBUTING.md).
 
 ## Installing
 
-The setup program for this game is not ready yet. [docs/building.md](docs/building.md) describes building from
-source. Settings are in the in-game menu and in `nx2navi.ini` ([nx2navi.ini.example](nx2navi.ini.example) lists every
+The build kit builds the game on your PC from your own dump (a `.nup` file, or ExeFS and RomFS folders) in about 10 to
+15 minutes: [docs/README-BuildKit.md](docs/README-BuildKit.md). [docs/building.md](docs/building.md) describes building
+from source. Settings are in the in-game menu and in `nx2navi.ini` ([nx2navi.ini.example](nx2navi.ini.example) lists every
 key). Controls: [docs/controls.md](docs/controls.md).
 
 Requirements: Windows 10 or later, an x86-64 CPU with SSE4.2 (AVX2/FMA machines get a faster build), a GPU with Vulkan

docs/README-BuildKit.md

@@ -1,4 +1,4 @@
-# Ocarina Recomp build kit
+# NX2navi build kit
 
 This kit builds *The Legend of Zelda: Ocarina of Time* (Nintendo Switch 2, game version 1.1.1) as a native Windows
 program **on your PC, from your own copy of the game**. The kit contains no game code or data. Everything the build
@@ -34,7 +34,7 @@ writes (`ocarina.exe`, the RomFS image, the shader cache, your saves) comes from
    Answer `Y` when it asks. If MSYS2 is somewhere other than `C:\msys64`, add `--msys <folder>\ucrt64` to the build
    command.
 
-## Build (about 10 to 25 minutes, once)
+## Build (about 10 to 15 minutes, once)
 
 Unpack this kit anywhere, open a Command Prompt in its folder and run:
 
@@ -58,8 +58,13 @@ When it says `finished`, start `C:\Games\Ocarina\ocarina.exe`. You can delete `C
 ## Playing
 
 - **F1** opens the settings menu. Settings are saved in `nx2navi.ini` beside the game; saves go to `profile\`.
-- The first time a shader appears it is translated, which can stutter briefly; it is cached from then on. After an
-  update of the kit or your graphics driver, the next start shows "Preparing shaders" once.
+- Every shader was prepared during the build. After an update of your graphics driver, the next start shows
+  "Preparing shaders" once while the driver rebuilds them.
+- **Screen** in the menu has Upscaling (DLSS on NVIDIA RTX cards, FSR 3.1 on any card), Frame generation (FSR 3.1; it
+  needs DLSS or FSR 3.1 upscaling on), HDR (Native is the game's own HDR; turn HDR on in Windows first) and the
+  resolution. Those marked "after restart" take effect when the game starts again.
+- DLSS needs `nvngx_dlss.dll` from NVIDIA beside `ocarina.exe` (the kit does not include it); FSR 3.1's
+  `amd_fidelityfx_vk.dll` is copied there by the build.
 - Logs are in `logs\`. When reporting a problem, say where you were in the game and which graphics card you have, and
   attach `logs\nx2navi.log`. Never send game files.
 

runtime/platform/win32.c

@@ -681,6 +681,19 @@ static LONG CALLBACK crash_veh(EXCEPTION_POINTERS *ep) {
     if (code == EXCEPTION_ACCESS_VIOLATION || code == EXCEPTION_STACK_OVERFLOW || code == EXCEPTION_ILLEGAL_INSTRUCTION)
         raw_note("crash_veh", code, (uintptr_t)ep->ContextRecord->Rip,
                  ep->ExceptionRecord->NumberParameters >= 2 ? (uintptr_t)ep->ExceptionRecord->ExceptionInformation[1] : 0);
+    if (code == EXCEPTION_ACCESS_VIOLATION && !ep->ContextRecord->Rip) {
+        // a call through a null pointer: the call's return address is on top of the stack, in whichever module made it
+        const uintptr_t *sp = (const uintptr_t *)ep->ContextRecord->Rsp;
+        for (int i = 0; i < 4; i++) {
+            void *base = NULL;
+            if (!RtlPcToFileHeader((void *)sp[i], &base) || !base) continue;
+            char b[200];
+            int n = snprintf(b, sizeof b, "[host] crash_veh: called from %s+%#llx (stack word %d)\n", image_name(base),
+                             (unsigned long long)(sp[i] - (uintptr_t)base), i);
+            DWORD w;
+            if (n > 0) WriteFile(GetStdHandle(STD_ERROR_HANDLE), b, (DWORD)n, &w, NULL);
+        }
+    }
     const char *what = code == EXCEPTION_ACCESS_VIOLATION ? "access violation"
                      : code == EXCEPTION_ILLEGAL_INSTRUCTION ? "illegal instruction"
                      : code == EXCEPTION_INT_DIVIDE_BY_ZERO ? "integer division by zero"