--- libelwix/src/ring.c	2026/02/11 13:36:09	1.6
+++ libelwix/src/ring.c	2026/02/18 01:34:17	1.7
@@ -3,7 +3,7 @@
 *  by Michael Pounov <misho@elwix.org>
 *
 * $Author: misho $
-* $Id: ring.c,v 1.6 2026/02/11 13:36:09 misho Exp $
+* $Id: ring.c,v 1.7 2026/02/18 01:34:17 misho Exp $
 *
 **************************************************************************
 The ELWIX and AITNET software is distributed under the following
@@ -138,19 +138,13 @@ rbuf_isempty(ringbuf_t *rbuf)
 int
 rbuf_isfull(ringbuf_t *rbuf)
 {
-	int h, t;
-
 	if (!rbuf)
 		return -1;
 	if (!rbuf->rb_bufnum)
 		return 1;
 
-	t = atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire);
-	h = atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_relaxed) + 1;
-	if (h >= rbuf->rb_bufnum)
-		h ^= h;
-
-	return (h == t);
+	return (((atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_relaxed) + 1) % rbuf->rb_bufnum) ==
+			atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire));
 }
 
 /*