From 4fb1e212c1ca110f8dd47560b2f3afbec8842bb1 Mon Sep 17 00:00:00 2001
From: Benjamin Oldenburg <benjamin.oldenburg@ordis.co.th>
Date: Fri, 20 Mar 2026 16:38:47 +0700
Subject: [PATCH] winnt.h: fix ARM64 CONTEXT V register type

The fallback CONTEXT struct for ARM64 (used when __aarch64__ is defined
but _ARM64_CONTEXT_DECLARED is not set) incorrectly defined V[32] as
DWORD64 (64-bit) instead of ARM64_NT_NEON128 (128-bit).

This caused register corruption when RtlRestoreContext restores NEON/VFP
registers, as the struct size was 256 bytes instead of the correct
512 bytes.

Fixes potential corruption on toolchains that define __aarch64__ but not
_ARM64_ (e.g., clang on macOS or certain cross-compilation scenarios).
---
 win32/include/winapi/winnt.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/win32/include/winapi/winnt.h b/win32/include/winapi/winnt.h
index 0897e2af..37d55483 100644
--- a/win32/include/winapi/winnt.h
+++ b/win32/include/winapi/winnt.h
@@ -2079,7 +2079,7 @@ typedef DWORD LCID;
       DWORD64 Lr;
       DWORD64 Sp;
       DWORD64 Pc;
-      DWORD64 V[32];
+      ARM64_NT_NEON128 V[32];
       DWORD Fpcr;
       DWORD Fpsr;
       DWORD Bcr[8];