From df18dc273ebf1b527c844158a9a54f13d679fd42 Mon Sep 17 00:00:00 2001
From: drmortalwombat <90205530+drmortalwombat@users.noreply.github.com>
Date: Sun, 17 Nov 2024 21:54:55 +0100
Subject: [PATCH] Forward binary op in txax

---
 oscar64/NativeCodeGenerator.cpp | 43 +++++++++++++++++++++++++++++++++
 oscar64/NativeCodeGenerator.h   |  1 +
 2 files changed, 44 insertions(+)

diff --git a/oscar64/NativeCodeGenerator.cpp b/oscar64/NativeCodeGenerator.cpp
index 040fdd3..6688819 100644
--- a/oscar64/NativeCodeGenerator.cpp
+++ b/oscar64/NativeCodeGenerator.cpp
@@ -33827,6 +33827,33 @@ bool NativeCodeBasicBlock::CombineImmediateADCUp(int at)
 	return false;
 }
 
+bool NativeCodeBasicBlock::MoveTXALogicTAXDown(int at)
+{
+	int	i = at + 3;
+	while (i < mIns.Size())
+	{
+		if (mIns[i].ChangesXReg())
+			return false;
+
+		if (mIns[i].mType == ASMIT_TXA)
+		{
+			if (mIns[i].mLive & LIVE_CPU_REG_X)
+				return false;
+			mIns[at + 1].mLive |= mIns[i].mLive;
+			mIns.Insert(i + 1, mIns[at + 1]);
+			mIns.Remove(at, 3);
+			return true;
+		}
+
+		if (mIns[i].RequiresXReg())
+			return false;
+
+		i++;
+	}
+
+	return false;
+}
+
 bool NativeCodeBasicBlock::MoveTXADCDown(int at)
 {
 	int	i = at + 4;
@@ -43827,6 +43854,22 @@ bool NativeCodeBasicBlock::PeepHoleOptimizerShuffle(int pass)
 
 #endif
 
+#if 1
+	for (int i = 0; i + 3 < mIns.Size(); i++)
+	{
+		if (mIns[i + 0].mType == ASMIT_TXA &&
+			mIns[i + 1].IsLogic() && mIns[i + 1].mMode == ASMIM_IMMEDIATE &&
+			mIns[i + 2].mType == ASMIT_TAX && !(mIns[i + 2].mLive & (LIVE_CPU_REG_A | LIVE_CPU_REG_Z)))
+		{
+			if (MoveTXALogicTAXDown(i))
+				changed = true;
+		}
+	}
+
+	CheckLive();
+
+#endif
+
 #if 1
 	for (int i = 0; i + 1 < mIns.Size(); i++)
 	{
diff --git a/oscar64/NativeCodeGenerator.h b/oscar64/NativeCodeGenerator.h
index 21ecf29..811c019 100644
--- a/oscar64/NativeCodeGenerator.h
+++ b/oscar64/NativeCodeGenerator.h
@@ -505,6 +505,7 @@ public:
 	bool CombineImmediateADCUp(int at);
 	bool CombineImmediateADCUpX(int at);
 	bool MoveTXADCDown(int at);
+	bool MoveTXALogicTAXDown(int at);
 	bool FoldShiftORAIntoLoadImmUp(int at);
 
 	bool FindAccuExitValue(int& at);