diff --git a/oscar64/NativeCodeGenerator.cpp b/oscar64/NativeCodeGenerator.cpp
index a5f5577..a333c4b 100644
--- a/oscar64/NativeCodeGenerator.cpp
+++ b/oscar64/NativeCodeGenerator.cpp
@@ -14815,6 +14815,9 @@ NativeCodeBasicBlock * NativeCodeBasicBlock::SplitMatchingTails(NativeCodeProced
 							nblock->mEntryBlocks.Push(bi);
 							nblock->mNumEntries++;
 
+							nblock->mEntryRequiredRegs = mEntryRequiredRegs;
+							nblock->mExitRequiredRegs = mEntryRequiredRegs;
+
 							bi->mTrueJump = nblock;
 							mEntryBlocks[i] = nullptr;
 							mNumEntries--;
@@ -14863,6 +14866,9 @@ NativeCodeBasicBlock* NativeCodeBasicBlock::AddDominatorBlock(NativeCodeProcedur
 
 		mEntryBlocks[mEntryBlocks.IndexOf(pblock)] = tblock;
 
+		tblock->mEntryRequiredRegs = mEntryRequiredRegs;
+		tblock->mExitRequiredRegs = mEntryRequiredRegs;
+
 		if (pblock->mTrueJump == this)
 			pblock->mTrueJump = tblock;
 		if (pblock->mFalseJump == this)
@@ -26936,8 +26942,10 @@ bool NativeCodeBasicBlock::PeepHoleOptimizer(NativeCodeProcedure* proc, int pass
 						mIns[i + 1].mType == ASMIT_DEC && mIns[i + 1].mMode == ASMIM_ZERO_PAGE && mIns[i + 1].mAddress == mIns[i + 0].mAddress &&
 						!(mIns[i + 2].mLive & LIVE_CPU_REG_C))
 					{
-						mIns[i + 0].mType = ASMIT_SEC; mIns[i + 0].mMode = ASMIM_IMPLIED; mIns[i + 0].mLive |= LIVE_CPU_REG_C;
-						mIns[i + 1].mType = ASMIT_SBC; mIns[i + 1].mMode = ASMIM_IMMEDIATE; mIns[i + 1].mAddress = 1;
+						mIns[i + 0].mType = ASMIT_SEC; mIns[i + 0].mMode = ASMIM_IMPLIED; mIns[i + 0].mLive |= LIVE_CPU_REG_C | LIVE_CPU_REG_A;
+						mIns[i + 1].mType = ASMIT_SBC; mIns[i + 1].mMode = ASMIM_IMMEDIATE; mIns[i + 1].mAddress = 1; mIns[i + 1].mLive |= LIVE_CPU_REG_A;
+						if (mIns[i + 2].mLive & LIVE_CPU_REG_Z)
+							mIns[i + 1].mLive |= LIVE_CPU_REG_Z;
 						mIns[i + 2].mType = ASMIT_STA;
 						progress = true;
 					}
diff --git a/oscar64/Scanner.cpp b/oscar64/Scanner.cpp
index b5d300e..0fa48a3 100644
--- a/oscar64/Scanner.cpp
+++ b/oscar64/Scanner.cpp
@@ -149,8 +149,8 @@ const char* TokenNames[] =
 };
 
 
-Macro::Macro(const Ident* ident)
-	: mIdent(ident), mString(nullptr), mNumArguments(-1)
+Macro::Macro(const Ident* ident, MacroDict * scope)
+	: mIdent(ident), mString(nullptr), mNumArguments(-1), mScope(scope)
 {
 
 }
@@ -389,7 +389,7 @@ static inline int HexValue(char ch)
 
 void Scanner::AddMacro(const Ident* ident, const char* value)
 {
-	Macro* macro = new Macro(ident);
+	Macro* macro = new Macro(ident, nullptr);
 	macro->SetString(value);
 	mDefines->Insert(macro);
 }
@@ -501,7 +501,7 @@ void Scanner::NextToken(void)
 			{
 				if (mToken != TK_IDENT)
 					mTokenIdent = Ident::Unique(TokenNames[mToken]);
-				Macro* macro = new Macro(mTokenIdent);
+				Macro* macro = new Macro(mTokenIdent, nullptr);
 
 				if (mTokenChar == '(')
 				{
@@ -614,7 +614,7 @@ void Scanner::NextToken(void)
 				Macro* macro = mDefines->Lookup(ident);
 				if (!macro)
 				{
-					macro = new Macro(ident);
+					macro = new Macro(ident, nullptr);
 					mDefines->Insert(macro);
 				}
 				char	buffer[20];
@@ -739,6 +739,8 @@ void Scanner::NextToken(void)
 				}
 				else if (def->mNumArguments > 0)
 				{
+					MacroDict* scope = mDefineArguments;
+
 					mDefineArguments = new MacroDict();
 					NextRawToken();
 					if (mToken == TK_OPEN_PARENTHESIS)
@@ -765,7 +767,7 @@ void Scanner::NextToken(void)
 								}
 								offset++;
 							}
-							Macro* arg = new Macro(def->mArguments[i]);
+							Macro* arg = new Macro(def->mArguments[i], scope);
 							arg->SetString(mLine + mOffset, offset - mOffset);
 							mDefineArguments->Insert(arg);
 							mOffset = offset;
@@ -790,7 +792,7 @@ void Scanner::NextToken(void)
 					NextChar();
 				}
 				else
-					mDefineArguments = nullptr;
+					mDefineArguments = def->mScope;
 
 				ex->mLine = mLine;
 				ex->mOffset = mOffset;
@@ -1628,7 +1630,7 @@ bool Scanner::NextChar(void)
 		if (mMacroExpansion)
 		{
 			MacroExpansion* mac = mMacroExpansion->mLink;
-			delete mDefineArguments;
+//			delete mDefineArguments;
 
 			mLine = mMacroExpansion->mLine;
 			mOffset = mMacroExpansion->mOffset;
diff --git a/oscar64/Scanner.h b/oscar64/Scanner.h
index 571ab54..317485c 100644
--- a/oscar64/Scanner.h
+++ b/oscar64/Scanner.h
@@ -150,10 +150,12 @@ enum Token
 
 extern const char* TokenNames[];
 
+class MacroDict;
+
 class Macro
 {
 public:
-	Macro(const Ident* ident);
+	Macro(const Ident* ident, MacroDict* scope);
 	~Macro(void);
 
 	void SetString(const char* str);
@@ -164,6 +166,7 @@ public:
 	const char* mString;
 	int		mNumArguments;
 	const Ident	* mArguments[32];
+	MacroDict* mScope;
 };
 
 typedef Macro* MacroPtr;
@@ -181,6 +184,7 @@ public:
 protected:
 	MacroPtr	*	mHash;
 	int				mHashSize, mHashFill;
+	MacroDict	*	mParent;
 };
 
 class Scanner