From 8af0e7ca5d9603b3a4f03fe0ee0b4c2e0bdc5fff Mon Sep 17 00:00:00 2001
From: Richard Cornwell <rcornwell@github.com>
Date: Mon, 9 Mar 2020 19:00:26 -0400
Subject: [PATCH] KA10: Fix possible error in FE.

---
 PDP10/kl10_fe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/PDP10/kl10_fe.c b/PDP10/kl10_fe.c
index dfb5dda..b259396 100644
--- a/PDP10/kl10_fe.c
+++ b/PDP10/kl10_fe.c
@@ -1077,7 +1077,7 @@ dte_function(UNIT *uptr)
                        goto cty;
 #if (NUM_DEVS_TTY > 0)
                    ln -= NUM_DLS;
-                   if (ln > 0 && ln >= tty_desc.lines)
+                   if (ln < 0 || ln >= tty_desc.lines)
                        break;
                    otty = &tty_out[ln];
                    if (cmd->sz > 8)