new class for Commavid extra RAM carts

git-svn-id: svn://svn.code.sf.net/p/stella/code/trunk@32 8b62c5a3-ac7e-4cc8-8f21-d9a121418aba

stella/src/emucore/CartCV.cxx

@@ -0,0 +1,129 @@
+//============================================================================
+//
+//   SSSS    tt          lll  lll
+//  SS  SS   tt           ll   ll
+//  SS     tttttt  eeee   ll   ll   aaaa
+//   SSSS    tt   ee  ee  ll   ll      aa
+//      SS   tt   eeeeee  ll   ll   aaaaa  --  "An Atari 2600 VCS Emulator"
+//  SS  SS   tt   ee      ll   ll  aa  aa
+//   SSSS     ttt  eeeee llll llll  aaaaa
+//
+// Copyright (c) 1995-1998 by Bradford W. Mott
+//
+// See the file "license" for information on usage and redistribution of
+// this file, and for a DISCLAIMER OF ALL WARRANTIES.
+//
+// $Id: CartCV.cxx,v 1.1 2002-01-18 15:58:46 estolberg Exp $
+//============================================================================
+
+#include <assert.h>
+#include "CartCV.hxx"
+#include "Random.hxx"
+#include "System.hxx"
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+CartridgeCV::CartridgeCV(const uInt8* image, uInt32 size)
+{
+  if(size == 2048)
+  {
+    // Copy the ROM image into my buffer
+    for(uInt32 addr = 0; addr < 2048; ++addr)
+    {
+      myImage[addr] = image[addr];
+    }
+
+    // Initialize RAM with random values
+    Random random;
+    for(uInt32 i = 0; i < 1024; ++i)
+    {
+      myRAM[i] = random.next();
+    }
+  }
+  else if(size == 4096)
+  {
+    // The game has something saved in the RAM
+    // Usefull for MagiCard program listings
+
+    // Copy the ROM image into my buffer
+    for(uInt32 addr = 0; addr < 2048; ++addr)
+    {
+      myImage[addr] = image[addr + 2048];
+    }
+
+    // Copy the RAM image into my buffer
+    for(uInt32 addr = 0; addr < 1024; ++addr)
+    {
+      myRAM[addr] = image[addr];
+    }
+
+  }
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+CartridgeCV::~CartridgeCV()
+{
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+const char* CartridgeCV::name() const
+{
+  return "CartridgeCV";
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void CartridgeCV::reset()
+{
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void CartridgeCV::install(System& system)
+{
+  mySystem = &system;
+  uInt16 shift = mySystem->pageShift();
+  uInt16 mask = mySystem->pageMask();
+
+  // Make sure the system we're being installed in has a page size that'll work
+  assert((0x1800 & mask) == 0);
+
+  System::PageAccess access;
+  access.directPokeBase = 0;
+  access.device = this;
+
+  // Map ROM image into the system
+  for(uInt32 address = 0x1800; address < 0x2000; address += (1 << shift))
+  {
+    access.directPeekBase = &myImage[address & 0x07FF];
+    mySystem->setPageAccess(address >> mySystem->pageShift(), access);
+  }
+
+  // Set the page accessing method for the RAM writing pages
+  for(uInt32 j = 0x1400; j < 0x1800; j += (1 << shift))
+  {
+    access.device = this;
+    access.directPeekBase = 0;
+    access.directPokeBase = &myRAM[j & 0x03FF];
+    mySystem->setPageAccess(j >> shift, access);
+  }
+
+  // Set the page accessing method for the RAM reading pages
+  for(uInt32 k = 0x1000; k < 0x1400; k += (1 << shift))
+  {
+    access.device = this;
+    access.directPeekBase = &myRAM[k & 0x03FF];
+    access.directPokeBase = 0;
+    mySystem->setPageAccess(k >> shift, access);
+  }
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+uInt8 CartridgeCV::peek(uInt16 address)
+{
+  return myImage[address & 0x07FF];
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void CartridgeCV::poke(uInt16, uInt8)
+{
+  // This is ROM so poking has no effect :-)
+}
+