diff --git a/c/src/lib/libcpu/powerpc/ChangeLog b/c/src/lib/libcpu/powerpc/ChangeLog
index d53193ec07..48537805e5 100644
--- a/c/src/lib/libcpu/powerpc/ChangeLog
+++ b/c/src/lib/libcpu/powerpc/ChangeLog
@@ -1,3 +1,9 @@
+2008-05-14	Till Straumann <strauman@slac.stanford.edu>
+
+	* new-exceptions/bspsupport/ppc_exc_bspsupp.h: added
+	comment about the semantics of the return value of 
+	ppc_exc_handler_t.
+
 2008-05-14	Till Straumann <strauman@slac.stanford.edu>
 
 	* new-exceptions/bspsupport/irq.c: moved malloc/free
diff --git a/c/src/lib/libcpu/powerpc/new-exceptions/bspsupport/ppc_exc_bspsupp.h b/c/src/lib/libcpu/powerpc/new-exceptions/bspsupport/ppc_exc_bspsupp.h
index 636d8b8476..de805c9366 100644
--- a/c/src/lib/libcpu/powerpc/new-exceptions/bspsupport/ppc_exc_bspsupp.h
+++ b/c/src/lib/libcpu/powerpc/new-exceptions/bspsupport/ppc_exc_bspsupp.h
@@ -24,6 +24,16 @@ extern "C" {
 
 /****************************************************/
 
+/*
+ * Exception handlers should return 0 if the exception
+ * was handled and normal execution may resume.
+ *
+ * They should return (-1) to 'rethrow' the exception
+ * resulting in the globalExcHdl() being called.
+ *
+ * Other return values are reserved.
+ */
+
 typedef int (*ppc_exc_handler_t)(BSP_Exception_frame *f, unsigned int vector);
 
 /*