--- pp_ctl.c.bak        Tue Mar 21 00:42:26 2000
+++ pp_ctl.c    Tue Apr 25 04:03:36 2000
@@ -736,6 +736,8 @@
        if (diff > PL_markstack_ptr[-1] - PL_markstack_ptr[-2]) {
            shift = diff - (PL_markstack_ptr[-1] - PL_markstack_ptr[-2]);
            count = (SP - PL_stack_base) - PL_markstack_ptr[-1] + 2;
+           if (shift < count)
+               shift = count; /* Avoid shifting too often */

            EXTEND(SP,shift);
            src = SP;