diff --git a/zsnes/src/jma/aribitcd.h b/zsnes/src/jma/aribitcd.h
index 76677027..1fb421ba 100644
--- a/zsnes/src/jma/aribitcd.h
+++ b/zsnes/src/jma/aribitcd.h
@@ -11,6 +11,29 @@ const UINT32 kBitModelTotal = (1 << kNumBitModelTotalBits);
 
 const int kNumMoveReducingBits = 2;
 
+/////////////////////////////
+// CBitModel
+
+template <int aNumMoveBits>
+class CBitModel
+{
+public:
+  UINT32 m_Probability;
+  void UpdateModel(UINT32 aSymbol)
+  {
+    /*
+    m_Probability -= (m_Probability + ((aSymbol - 1) & ((1 << aNumMoveBits) - 1))) >> aNumMoveBits;
+    m_Probability += (1 - aSymbol) << (kNumBitModelTotalBits - aNumMoveBits);
+    */
+    if (aSymbol == 0)
+      m_Probability += (kBitModelTotal - m_Probability) >> aNumMoveBits;
+    else
+      m_Probability -= (m_Probability) >> aNumMoveBits;
+  }
+public:
+  void Init() { m_Probability = kBitModelTotal / 2; }
+};
+
 template <int aNumMoveBits>
 class CBitDecoder: public CBitModel<aNumMoveBits>
 {
diff --git a/zsnes/src/jma/ariconst.h b/zsnes/src/jma/ariconst.h
index d4153bad..43852846 100644
--- a/zsnes/src/jma/ariconst.h
+++ b/zsnes/src/jma/ariconst.h
@@ -22,11 +22,8 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
 #include "aribitcd.h"
 
-typedef NCompression::NArithmetic::CRangeEncoder CMyRangeEncoder;
-typedef NCompression::NArithmetic::CRangeDecoder CMyRangeDecoder;
 
-template <int aNumMoveBits> class CMyBitEncoder: 
-    public NCompression::NArithmetic::CBitEncoder<aNumMoveBits> {};
+typedef NCompression::NArithmetic::CRangeDecoder CMyRangeDecoder;
 template <int aNumMoveBits> class CMyBitDecoder: 
     public NCompression::NArithmetic::CBitDecoder<aNumMoveBits> {};
 
diff --git a/zsnes/src/jma/btreecd.h b/zsnes/src/jma/btreecd.h
index 24ae5849..85f89b29 100644
--- a/zsnes/src/jma/btreecd.h
+++ b/zsnes/src/jma/btreecd.h
@@ -23,44 +23,6 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "aribitcd.h"
 #include "rcdefs.h"
 
-//////////////////////////
-// CBitTreeEncoder
-
-template <int aNumMoveBits, UINT32 m_NumBitLevels>
-class CBitTreeEncoder
-{
-  CMyBitEncoder<aNumMoveBits> m_Models[1 << m_NumBitLevels];
-public:
-  void Init()
-  {
-    for(UINT32 i = 1; i < (1 << m_NumBitLevels); i++)
-      m_Models[i].Init();
-  }
-  void Encode(CMyRangeEncoder *aRangeEncoder, UINT32 aSymbol)
-  {
-    UINT32 aModelIndex = 1;
-    for (UINT32 aBitIndex = m_NumBitLevels; aBitIndex > 0 ;)
-    {
-      aBitIndex--;
-      UINT32 aBit = (aSymbol >> aBitIndex ) & 1;
-      m_Models[aModelIndex].Encode(aRangeEncoder, aBit);
-      aModelIndex = (aModelIndex << 1) | aBit;
-    }
-  };
-  UINT32 GetPrice(UINT32 aSymbol) const
-  {
-    UINT32 aPrice = 0;
-    UINT32 aModelIndex = 1;
-    for (UINT32 aBitIndex = m_NumBitLevels; aBitIndex > 0 ;)
-    {
-      aBitIndex--;
-      UINT32 aBit = (aSymbol >> aBitIndex ) & 1;
-      aPrice += m_Models[aModelIndex].GetPrice(aBit);
-      aModelIndex = (aModelIndex << 1) + aBit;
-    }
-    return aPrice;
-  }
-};
 
 //////////////////////////
 // CBitTreeDecoder
@@ -89,66 +51,6 @@ public:
   };
 };
 
-
-
-////////////////////////////////
-// CReverseBitTreeEncoder
-
-template <int aNumMoveBits>
-class CReverseBitTreeEncoder2
-{
-  CMyBitEncoder<aNumMoveBits> *m_Models;
-  UINT32 m_NumBitLevels;
-public:
-  CReverseBitTreeEncoder2(): m_Models(0) { }
-  ~CReverseBitTreeEncoder2() { delete []m_Models; }
-  bool Create(UINT32 aNumBitLevels)
-  {
-    m_NumBitLevels = aNumBitLevels;
-    m_Models = new CMyBitEncoder<aNumMoveBits>[1 << aNumBitLevels];
-    return (m_Models != 0);
-  }
-  void Init()
-  {
-    UINT32 aNumModels = 1 << m_NumBitLevels;
-    for(UINT32 i = 1; i < aNumModels; i++)
-      m_Models[i].Init();
-  }
-  void Encode(CMyRangeEncoder *aRangeEncoder, UINT32 aSymbol)
-  {
-    UINT32 aModelIndex = 1;
-    for (UINT32 i = 0; i < m_NumBitLevels; i++)
-    {
-      UINT32 aBit = aSymbol & 1;
-      m_Models[aModelIndex].Encode(aRangeEncoder, aBit);
-      aModelIndex = (aModelIndex << 1) | aBit;
-      aSymbol >>= 1;
-    }
-  }
-  UINT32 GetPrice(UINT32 aSymbol) const
-  {
-    UINT32 aPrice = 0;
-    UINT32 aModelIndex = 1;
-    for (UINT32 i = m_NumBitLevels; i > 0; i--)
-    {
-      UINT32 aBit = aSymbol & 1;
-      aSymbol >>= 1;
-      aPrice += m_Models[aModelIndex].GetPrice(aBit);
-      aModelIndex = (aModelIndex << 1) | aBit;
-    }
-    return aPrice;
-  }
-};
-
-/*
-template <int aNumMoveBits, int aNumBitLevels>
-class CReverseBitTreeEncoder: public CReverseBitTreeEncoder2<aNumMoveBits>
-{
-public:
-  CReverseBitTreeEncoder() 
-    { Create(aNumBitLevels); }
-};
-*/
 ////////////////////////////////
 // CReverseBitTreeDecoder
 
@@ -220,90 +122,6 @@ public:
   }
 };
 
-/*
-//////////////////////////
-// CBitTreeEncoder2
-
-template <int aNumMoveBits>
-class CBitTreeEncoder2
-{
-  NCompression::NArithmetic::CBitEncoder<aNumMoveBits> *m_Models;
-  UINT32 m_NumBitLevels;
-public:
-  bool Create(UINT32 aNumBitLevels)
-  { 
-    m_NumBitLevels = aNumBitLevels;
-    m_Models = new NCompression::NArithmetic::CBitEncoder<aNumMoveBits>[1 << aNumBitLevels];
-    return (m_Models != 0);
-  }
-  void Init()
-  {
-    UINT32 aNumModels = 1 << m_NumBitLevels;
-    for(UINT32 i = 1; i < aNumModels; i++)
-      m_Models[i].Init();
-  }
-  void Encode(CMyRangeEncoder *aRangeEncoder, UINT32 aSymbol)
-  {
-    UINT32 aModelIndex = 1;
-    for (UINT32 aBitIndex = m_NumBitLevels; aBitIndex > 0 ;)
-    {
-      aBitIndex--;
-      UINT32 aBit = (aSymbol >> aBitIndex ) & 1;
-      m_Models[aModelIndex].Encode(aRangeEncoder, aBit);
-      aModelIndex = (aModelIndex << 1) | aBit;
-    }
-  }
-  UINT32 GetPrice(UINT32 aSymbol) const
-  {
-    UINT32 aPrice = 0;
-    UINT32 aModelIndex = 1;
-    for (UINT32 aBitIndex = m_NumBitLevels; aBitIndex > 0 ;)
-    {
-      aBitIndex--;
-      UINT32 aBit = (aSymbol >> aBitIndex ) & 1;
-      aPrice += m_Models[aModelIndex].GetPrice(aBit);
-      aModelIndex = (aModelIndex << 1) + aBit;
-    }
-    return aPrice;
-  }
-};
-
-
-//////////////////////////
-// CBitTreeDecoder2
-
-template <int aNumMoveBits>
-class CBitTreeDecoder2
-{
-  NCompression::NArithmetic::CBitDecoder<aNumMoveBits> *m_Models;
-  UINT32 m_NumBitLevels;
-public:
-  bool Create(UINT32 aNumBitLevels)
-  { 
-    m_NumBitLevels = aNumBitLevels;
-    m_Models = new NCompression::NArithmetic::CBitDecoder<aNumMoveBits>[1 << aNumBitLevels];
-    return (m_Models != 0);
-  }
-  void Init()
-  {
-    UINT32 aNumModels = 1 << m_NumBitLevels;
-    for(UINT32 i = 1; i < aNumModels; i++)
-      m_Models[i].Init();
-  }
-  UINT32 Decode(CMyRangeDecoder *aRangeDecoder)
-  {
-    UINT32 aModelIndex = 1;
-    RC_INIT_VAR
-    for(UINT32 aBitIndex = m_NumBitLevels; aBitIndex > 0; aBitIndex--)
-    {
-      // aModelIndex = (aModelIndex << 1) + m_Models[aModelIndex].Decode(aRangeDecoder);
-      RC_GETBIT(aNumMoveBits, m_Models[aModelIndex].m_Probability, aModelIndex)
-    }
-    RC_FLUSH_VAR
-    return aModelIndex - (1 << m_NumBitLevels);
-  }
-};
-*/
 
 
 #endif