From 2b5416eade556b86776f74cc24fc7959affb7824 Mon Sep 17 00:00:00 2001
From: Christian Speckner <christian.speckner@mayflower.de>
Date: Tue, 5 Dec 2017 20:28:41 +0100
Subject: [PATCH] Don't trap write accesses to datastream pointers & friends in
 CDF / BUS.

---
 src/emucore/Thumbulator.cxx | 45 +++++++++++++++++++------------------
 src/emucore/Thumbulator.hxx |  1 +
 2 files changed, 24 insertions(+), 22 deletions(-)

diff --git a/src/emucore/Thumbulator.cxx b/src/emucore/Thumbulator.cxx
index 986cb7393..36003ab17 100644
--- a/src/emucore/Thumbulator.cxx
+++ b/src/emucore/Thumbulator.cxx
@@ -226,28 +226,7 @@ void Thumbulator::write16(uInt32 addr, uInt32 data)
   if((addr > 0x40001fff) && (addr < 0x50000000))
     fatalError("write16", addr, "abort - out of range");
 
-  switch(configuration)
-  {
-    // this protects 2K Harmony/Melody Drivers
-    // Initial section of driver is the bootstrap which copies the driver
-    // from ROM to RAM, so it can safely be used by the custom ARM code
-    // as additional RAM
-    case ConfigureFor::BUS:
-    case ConfigureFor::CDF:
-    case ConfigureFor::CDF1:
-      if((addr > 0x40000028) && (addr < 0x40000800))
-        fatalError("write16", addr, "to bankswitch code area");
-      break;
-
-    // this protects 3K Harmony/Melody Drivers
-    // Initial section of driver is the bootstrap which copies the driver
-    // from ROM to RAM, so it can safely be used by the custom ARM code
-    // as additional RAM
-    case ConfigureFor::DPCplus:
-      if((addr > 0x40000028) && (addr < 0x40000c00))
-        fatalError("write16", addr, "to bankswitch code area");
-      break;
-  }
+  if (isProtected(addr)) fatalError("write16", addr, "to driver area");
 
   if(addr & 1)
     fatalError("write16", addr, "abort - misaligned");
@@ -281,6 +260,7 @@ void Thumbulator::write32(uInt32 addr, uInt32 data)
   if(addr & 3)
     fatalError("write32", addr, "abort - misaligned");
 
+  if (isProtected(addr)) fatalError("write32", addr, "to driver area");
   DO_DBUG(statusMsg << "write32(" << Base::HEX8 << addr << "," << Base::HEX8 << data << ")" << endl);
 
   switch(addr & 0xF0000000)
@@ -356,6 +336,27 @@ void Thumbulator::write32(uInt32 addr, uInt32 data)
   fatalError("write32", addr, data, "abort");
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+bool Thumbulator::isProtected(uInt32 addr)
+{
+  if (addr < 0x40000000) return false;
+  addr -= 0x40000000;
+
+  switch (configuration) {
+    case ConfigureFor::DPCplus:
+      return (addr < 0x0c00) && (addr > 0x0028);
+
+    case ConfigureFor::CDF:
+      return  (addr < 0x0800) && (addr > 0x0028) && !((addr >= 0x06e0) && (addr < (0x0e60 + 284)));
+
+    case ConfigureFor::CDF1:
+      return  (addr < 0x0800) && (addr > 0x0028) && !((addr >= 0x00a0) && (addr < (0x00a0 + 284)));
+
+    case ConfigureFor::BUS:
+      return  (addr < 0x06d8) && (addr > 0x0028);
+  }
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 uInt32 Thumbulator::read16(uInt32 addr)
 {
diff --git a/src/emucore/Thumbulator.hxx b/src/emucore/Thumbulator.hxx
index 0b1953a28..68ca803e8 100644
--- a/src/emucore/Thumbulator.hxx
+++ b/src/emucore/Thumbulator.hxx
@@ -104,6 +104,7 @@ class Thumbulator
     uInt32 fetch32(uInt32 addr);
     uInt32 read16(uInt32 addr);
     uInt32 read32(uInt32 addr);
+    bool isProtected(uInt32 addr);
     void write16(uInt32 addr, uInt32 data);
     void write32(uInt32 addr, uInt32 data);
     void updateTimer(uInt32 cycles);