diff -ruN porting06/logging.c porting07/logging.c
--- porting06/logging.c	Sun Apr 19 21:53:32 2009
+++ porting07/logging.c	Sun Apr 19 22:19:09 2009
@@ -5,10 +5,19 @@
 int logging_cur = 0;
 int logging_buf[LOGGING_BUF_SIZE];
 
-void logging(int addr)
+void logging_begin(int addr)
 {
   if (!logging_disable) {
     logging_buf[logging_cur++] = addr;
+    if (logging_cur >= LOGGING_BUF_SIZE)
+      logging_cur = 0;
+  }
+}
+
+void logging_end(int addr)
+{
+  if (!logging_disable) {
+    logging_buf[logging_cur++] = addr | (1<<31);
     if (logging_cur >= LOGGING_BUF_SIZE)
       logging_cur = 0;
   }
diff -ruN porting06/mcount.s porting07/mcount.s
--- porting06/mcount.s	Sun Apr 19 21:53:32 2009
+++ porting07/mcount.s	Sun Apr 19 22:19:09 2009
@@ -13,11 +13,9 @@
 	stw	10,44(1)
 	mflr	3
 	stw	3,8(1)
-	bl	logging
+	bl	logging_begin
 
-	lwz	9,8(1)
-	mtctr	9
-	lwz	10,52(1)
+	lwz	10,8(1)
 	mtlr	10
 	lwz	 3,16(1)
 	lwz	 4,20(1)
@@ -27,5 +25,16 @@
 	lwz	 8,36(1)
 	lwz	 9,40(1)
 	lwz	10,44(1)
+	blrl
+
+	stw	3,16(1)
+	stw	4,20(1)
+	lwz	3,8(1)
+	bl	logging_end
+
+	lwz	10,52(1)
+	mtlr	10
+	lwz	 3,16(1)
+	lwz	 4,20(1)
 	addi	1,1,48
-	bctr
+	blr