From 9e4a243928d549082c6dd795ee2febfdd05344fc Mon Sep 17 00:00:00 2001
From: nicm <nicm@openbsd.org>
Date: Thu, 12 Jan 2023 12:34:06 +0000
Subject: [PATCH] Add CBT (cursor back tab) sequence, from Crystal Kolipe
 kolipe.c at exoticsilicon dot com.

ok miod
---
 sys/dev/wscons/wsemul_vt100_subr.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/sys/dev/wscons/wsemul_vt100_subr.c b/sys/dev/wscons/wsemul_vt100_subr.c
index b68d94b272c..44f0aefe22f 100644
--- a/sys/dev/wscons/wsemul_vt100_subr.c
+++ b/sys/dev/wscons/wsemul_vt100_subr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: wsemul_vt100_subr.c,v 1.27 2023/01/12 12:28:08 nicm Exp $ */
+/* $OpenBSD: wsemul_vt100_subr.c,v 1.28 2023/01/12 12:34:06 nicm Exp $ */
 /* $NetBSD: wsemul_vt100_subr.c,v 1.7 2000/04/28 21:56:16 mycroft Exp $ */
 
 /*
@@ -217,7 +217,7 @@ int
 wsemul_vt100_handle_csi(struct wsemul_vt100_emuldata *edp,
     struct wsemul_inputstate *instate)
 {
-	int n, help, flags, fgcol, bgcol;
+	int n, m, help, flags, fgcol, bgcol;
 	uint32_t attr, bkgdattr;
 	u_char c;
 	int rc = 0;
@@ -517,6 +517,22 @@ wsemul_vt100_handle_csi(struct wsemul_vt100_emuldata *edp,
 		WSEMULOP(rc, edp, &edp->abortstate, erasecols,
 		    ERASECOLS(edp->ccol, n, edp->bkgdattr));
 		break;
+	case 'Z': /* CBT */
+		if (edp->ccol == 0)
+			break;
+		for (m = 0; m < DEF1_ARG(0); m++) {
+			if (edp->tabs) {
+				for (n = edp->ccol - 1; n > 0; n--) {
+					if (edp->tabs[n])
+						break;
+				}
+			} else
+				n = (edp->ccol - 1) & ~7;
+			edp->ccol = n;
+			if (n == 0)
+				break;
+		}
+		break;
 	case 'c': /* DA primary */
 		if (ARG(0) == 0)
 			wsdisplay_emulinput(edp->cbcookie, WSEMUL_VT_ID1,
-- 
2.20.1