gv.c: Add comment

diff --git a/gv.c b/gv.c
index d3527aa..d6edbfd 100644 (file)
--- a/gv.c
+++ b/gv.c
@@ -1746,7 +1746,13 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
            /* Nothing else to do.
               The compiler will probably turn the switch statement into a
               branch table. Make sure we avoid even that small overhead for
-              the common case of lower case variable names.  */
+               the common case of lower case variable names.  (On EBCDIC
+               platforms, we can't just do:
+                 if (NATIVE_TO_ASCII(*name) > NATIVE_TO_ASCII('V') ) {
+               because cases like '\027' in the switch statement below are
+               C1 (non-ASCII) controls on those platforms, so the remapping
+               would make them larger than 'V')
+             */
        } else
 #endif
        {