SpeedBreaker v0.1.0

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

runtime/game/render_queue.cpp

@@ -0,0 +1,25 @@
+// SpeedBreaker runtime. GPL-3.0-or-later (see COPYING).
+//
+// NFSMW's deferred render-callback queue (state at 0x82909650) is a
+// lock-free single-producer, single-consumer list: while loading and during
+// in-engine cutscenes one thread records render callbacks (sub_823C8210, and
+// the same code inlined in sub_82444520 and sub_82462DC8) and the main
+// thread plays them back (sub_823C8290). It has no barriers: it relies on the
+// entry's stores becoming visible before the write pointer and count that
+// publish it. x86 keeps stores in order; ARM64 doesn't, and the main thread
+// saw a new count with the entry still zero (a call to a null callback at
+// lr 823C82F8, about one run in three on the Mac once game time ran at the
+// right speed). Mid-asm hooks (config/nfsmw.toml) add a release fence before
+// each publish and an acquire fence before an entry is read.
+#include <stdafx.h>
+#include <atomic>
+
+void RenderQueuePublish()
+{
+    std::atomic_thread_fence(std::memory_order_release);
+}
+
+void RenderQueueAcquire()
+{
+    std::atomic_thread_fence(std::memory_order_acquire);
+}