From 1ef3695608acce13dd5c66dbda3ccab865d48a47 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juhani=20Krekel=C3=A4?= <juhani@krekelä.fi>
Date: Thu, 23 Mar 2023 12:25:11 +0200
Subject: [PATCH] Allow moving windows off the left side of screen

---
 shell.asm | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/shell.asm b/shell.asm
index 5c1d792..ec413bc 100644
--- a/shell.asm
+++ b/shell.asm
@@ -158,11 +158,19 @@ paint:
 	mov cx, bx
 	add cx, di
 	cmp cx, COLUMNS
-	jle .no_clipping_width
+	jle .no_clipping_width_right
 	mov cx, COLUMNS
-	.no_clipping_width:
+	.no_clipping_width_right:
 	sub cx, di
 
+	cmp di, 0
+	jge .no_clipping_width_left
+	sub si, di
+	sub si, di
+	add cx, di
+	xor di, di
+	.no_clipping_width_left:
+
 	call PONYDOS_SEG:SYS_DRAW_RECT
 
 	ret
@@ -294,9 +302,6 @@ move:
 	mov [si + window.x], cx
 	mov dx, [si + window.res_x]
 	sub [si + window.x], dx
-	jnc .not_underflow
-
-	mov word [si + window.x], 0
 
 	.not_underflow:
 	pop dx