#elif defined(__x86_64__)
#ifdef __FreeBSD__
-#define UCONTEXT_GREGS(ctx) (((ucontext_t*)(ctx))->uc_mcontext)
+#define UCONTEXT_GREGS(ctx) &(((ucontext_t*)(ctx))->uc_mcontext)
#else
-#define UCONTEXT_GREGS(ctx) (((ucontext_t*)(ctx))->uc_mcontext.gregs)
+#define UCONTEXT_GREGS(ctx) &(((ucontext_t*)(ctx))->uc_mcontext.gregs)
#endif
#elif defined(__mono_ppc__)