From 59b20dca6ebd52f711ce3b0ad9f28a3e0d1a68e0 Mon Sep 17 00:00:00 2001
From: David Haywood <mamehaze@users.noreply.github.com>
Date: Wed, 6 Mar 2013 17:44:44 +0000
Subject: [PATCH] I imagine there is actually a logic flaw in the new code, but
 for now let's just stop it blowing up.

---
 src/emu/video/stvvdp1.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/emu/video/stvvdp1.c b/src/emu/video/stvvdp1.c
index ccb6957447f..3d181a5afad 100644
--- a/src/emu/video/stvvdp1.c
+++ b/src/emu/video/stvvdp1.c
@@ -196,13 +196,13 @@ void saturn_state::stv_clear_framebuffer( int which_framebuffer )
 	{
 		for(int y=start_y;y<end_y;y++)
 			for(int x=start_x;x<end_x;x++)
-				m_vdp1.framebuffer[ which_framebuffer ][(x+y*1024)] = m_vdp1.ewdr;
+				m_vdp1.framebuffer[ which_framebuffer ][((x&1023)+(y&511)*1024)] = m_vdp1.ewdr;
 	}
 	else
 	{
 		for(int y=start_y;y<end_y;y++)
 			for(int x=start_x;x<end_x;x++)
-				m_vdp1.framebuffer[ which_framebuffer ][(x+y*512)] = m_vdp1.ewdr;
+				m_vdp1.framebuffer[ which_framebuffer ][((x&511)+(y&511)*512)] = m_vdp1.ewdr;
 	}
 
 	if ( VDP1_LOG ) logerror( "Clearing %d framebuffer\n", m_vdp1.framebuffer_current_draw );