From c8a6f1d9c609ff4b239e2c190cfcbe4409aabc63 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Oliver=20St=C3=B6neberg?=
 <firewave@users.noreply.github.com>
Date: Mon, 22 Jul 2013 20:29:07 +0000
Subject: [PATCH] added assert in src/mame/video/system1.c (nw)

---
 src/mame/video/system1.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/mame/video/system1.c b/src/mame/video/system1.c
index 68a7bed7d0e..1bdb74ed9b6 100644
--- a/src/mame/video/system1.c
+++ b/src/mame/video/system1.c
@@ -514,6 +514,7 @@ void system1_state::video_update_common(screen_device &screen, bitmap_ind16 &bit
 		for (x = cliprect.min_x; x <= cliprect.max_x; x++)
 		{
 			int bgx = ((x - bgxscroll) / 2) & 0x1ff;
+			assert((x / 2) >= 0 && (x / 2) < 256);
 			UINT16 fgpix = fgbase[x / 2];
 			UINT16 bgpix = bgbase[bgx >> 8][bgx & 0xff];
 			UINT16 sprpix = sprbase[x];