-#define proc_terminated(proc) (((proc)->state) & PS_GrDT)
-#define proc_hanged(proc) (((proc)->state) & PS_BLOCKED)
-#define proc_runnable(proc) (!(proc)->state || !(((proc)->state) & ~PS_Rn))
+#define proc_terminated(proc) \
+ (!(proc) || ((proc)->state) & PS_GrDT)
+#define proc_hanged(proc) \
+ ((proc) && ((proc)->state) & PS_BLOCKED)
+#define proc_runnable(proc) \
+ ((proc) && (!(proc)->state || !(((proc)->state) & ~PS_Rn)))