From cfe482cd525473641d6025effc1e8fe32905b7ab Mon Sep 17 00:00:00 2001
From: tomcw <tomcw@users.noreply.github.com>
Date: Sun, 11 Oct 2020 21:29:26 +0100
Subject: [PATCH] NTSC: fix rare crash in NTSC_SetVideoMode() after a VM
 restart

---
 source/NTSC.cpp  | 7 +++++++
 source/NTSC.h    | 1 +
 source/Video.cpp | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/source/NTSC.cpp b/source/NTSC.cpp
index d066bcb6..e9fc3171 100644
--- a/source/NTSC.cpp
+++ b/source/NTSC.cpp
@@ -2191,6 +2191,13 @@ _mono:
 void GenerateVideoTables( void );
 void GenerateBaseColors(baseColors_t pBaseNtscColors);
 
+void NTSC_Destroy(void)
+{
+	// After a VM restart, this will point to an old g_pFramebufferbits
+	// - if it's now unmapped then this can cause a crash in NTSC_SetVideoMode()!
+	g_pVideoAddress = 0;
+}
+
 void NTSC_VideoInit( uint8_t* pFramebuffer ) // wsVideoInit
 {
 	make_csbits();
diff --git a/source/NTSC.h b/source/NTSC.h
index a5a61440..26386e4d 100644
--- a/source/NTSC.h
+++ b/source/NTSC.h
@@ -11,6 +11,7 @@
 	extern void     NTSC_VideoClockResync( const DWORD dwCyclesThisFrame );
 	extern uint16_t NTSC_VideoGetScannerAddress( const ULONG uExecutedCycles );
 	extern uint16_t NTSC_VideoGetScannerAddressForDebugger(void);
+	extern void     NTSC_Destroy(void);
 	extern void     NTSC_VideoInit( uint8_t *pFramebuffer );
 	extern void     NTSC_VideoReinitialize( DWORD cyclesThisFrame, bool bInitVideoScannerAddress );
 	extern void     NTSC_VideoInitAppleType();
diff --git a/source/Video.cpp b/source/Video.cpp
index 9831fa14..d3879144 100644
--- a/source/Video.cpp
+++ b/source/Video.cpp
@@ -385,6 +385,8 @@ void VideoDestroy () {
     DeleteObject(g_hLogoBitmap);
     g_hLogoBitmap = (HBITMAP)0;
   }
+
+  NTSC_Destroy();
 }
 
 //===========================================================================