181     Int xpivot, x, y, ypivot, p, p2, deg ;  in order_singletons()  local
193 	xpivot = head ;  in order_singletons()
194 	DEBUG1 (("------ Order %s singleton: "ID"\n", xname, xpivot)) ;  in order_singletons()
195 	head = Next [xpivot] ;  in order_singletons()
202 	ASSERT (Xdeg [xpivot] >= 0) ;  in order_singletons()
203 	if (Xdeg [xpivot] != 1)  in order_singletons()
215 	p2 = Xp [xpivot+1] ;  in order_singletons()
216 	for (p = Xp [xpivot] ; p < p2 ; p++)  in order_singletons()
230 	p2 = Xp [xpivot+1] ;  in order_singletons()
231 	for (p = Xp [xpivot] ; p < p2 ; p++)  in order_singletons()
258 	    if (x == xpivot) continue ;  in order_singletons()
286 	Xdeg [xpivot] = FLIP (1) ;  in order_singletons()
290 	Xperm [k] = xpivot ;  in order_singletons()