+#if defined(reg_ALLOC) && defined(LISP_FEATURE_SB_THREAD)
+ /* Put the pseudo-atomic bits and dynamic space free pointer back
+ * into the context (p-a-bits for p-a, and dynamic space free
+ * pointer for ROOM). */
+ *os_context_register_addr(context, reg_ALLOC) =
+ (unsigned long) dynamic_space_free_pointer
+ | (thread->pseudo_atomic_bits & LOWTAG_MASK);
+ /* And clear them so we don't get bit later by call-in/call-out
+ * not updating them. */
+ thread->pseudo_atomic_bits = 0;
+#endif