From 5b2ae228cc79bde96ecfc35f5b55b967a3152f0d Mon Sep 17 00:00:00 2001
From: drmortalwombat <90205530+drmortalwombat@users.noreply.github.com>
Date: Sun, 22 Dec 2024 21:22:05 +0100
Subject: [PATCH] Improve table pointer forwarding

---
 oscar64/NativeCodeGenerator.cpp | 68 +++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/oscar64/NativeCodeGenerator.cpp b/oscar64/NativeCodeGenerator.cpp
index 682cdff..78deeec 100644
--- a/oscar64/NativeCodeGenerator.cpp
+++ b/oscar64/NativeCodeGenerator.cpp
@@ -46786,6 +46786,22 @@ bool NativeCodeBasicBlock::PeepHoleOptimizerIterate4(int i, int pass)
 		mIns[i + 3].mMode = ASMIM_IMPLIED;
 		return true;
 	}
+	else if (
+		mIns[i + 0].mType == ASMIT_CLC &&
+		mIns[i + 1].mType == ASMIT_LDA && HasAsmInstructionMode(ASMIT_LDY, mIns[i + 1].mMode) &&
+		mIns[i + 2].mType == ASMIT_ADC && mIns[i + 2].mMode == ASMIM_IMMEDIATE && mIns[i + 2].mAddress >= 0xfe &&
+		mIns[i + 3].mType == ASMIT_TAY && !(mIns[i + 3].mLive & (LIVE_CPU_REG_A | LIVE_CPU_REG_Z | LIVE_CPU_REG_C)))
+	{
+		mIns[i + 0].mType = ASMIT_NOP; mIns[i + 0].mMode = ASMIM_IMPLIED;
+		mIns[i + 1].mType = ASMIT_LDY; mIns[i + 1].mLive |= LIVE_CPU_REG_Y;
+		mIns[i + 2].mType = ASMIT_DEY; mIns[i + 2].mMode = ASMIM_IMPLIED; mIns[i + 2].mLive |= LIVE_CPU_REG_Y;
+		if (mIns[i + 2].mAddress == 0xfe)
+			mIns[i + 3].mType = ASMIT_DEY;
+		else
+			mIns[i + 3].mType = ASMIT_NOP;
+		mIns[i + 3].mMode = ASMIM_IMPLIED;
+		return true;
+	}
 	else if (
 		mIns[i + 0].mType == ASMIT_SEC &&
 		mIns[i + 1].mType == ASMIT_LDA && HasAsmInstructionMode(ASMIT_LDY, mIns[i + 1].mMode) &&
@@ -46818,6 +46834,22 @@ bool NativeCodeBasicBlock::PeepHoleOptimizerIterate4(int i, int pass)
 		mIns[i + 3].mMode = ASMIM_IMPLIED;
 		return true;
 	}
+	else if (
+		mIns[i + 0].mType == ASMIT_CLC &&
+		mIns[i + 1].mType == ASMIT_LDA && HasAsmInstructionMode(ASMIT_LDX, mIns[i + 1].mMode) &&
+		mIns[i + 2].mType == ASMIT_ADC && mIns[i + 2].mMode == ASMIM_IMMEDIATE && mIns[i + 2].mAddress >= 0xfe &&
+		mIns[i + 3].mType == ASMIT_TAX && !(mIns[i + 3].mLive & (LIVE_CPU_REG_A | LIVE_CPU_REG_Z | LIVE_CPU_REG_C)))
+	{
+		mIns[i + 0].mType = ASMIT_NOP; mIns[i + 0].mMode = ASMIM_IMPLIED;
+		mIns[i + 1].mType = ASMIT_LDX; mIns[i + 1].mLive |= LIVE_CPU_REG_X;
+		mIns[i + 2].mType = ASMIT_DEX; mIns[i + 2].mMode = ASMIM_IMPLIED; mIns[i + 2].mLive |= LIVE_CPU_REG_X;
+		if (mIns[i + 2].mAddress == 0xfe)
+			mIns[i + 3].mType = ASMIT_DEX;
+		else
+			mIns[i + 3].mType = ASMIT_NOP;
+		mIns[i + 3].mMode = ASMIM_IMPLIED;
+		return true;
+	}
 	else if (
 		mIns[i + 0].mType == ASMIT_SEC &&
 		mIns[i + 1].mType == ASMIT_LDA && HasAsmInstructionMode(ASMIT_LDX, mIns[i + 1].mMode) &&
@@ -49163,6 +49195,42 @@ bool NativeCodeBasicBlock::PeepHoleOptimizerIterateN(int i, int pass)
 			}
 		}
 #endif
+#if 1
+		if (
+			mIns[i + 0].mType == ASMIT_CLC &&
+			mIns[i + 1].mType == ASMIT_ADC && mIns[i + 1].mMode == ASMIM_ZERO_PAGE &&
+			mIns[i + 2].mType == ASMIT_STA && mIns[i + 2].mMode == ASMIM_ZERO_PAGE && mIns[i + 2].mAddress == mIns[i + 1].mAddress &&
+			mIns[i + 3].mType == ASMIT_LDA && (mIns[i + 3].mMode == ASMIM_ABSOLUTE_X || mIns[i + 3].mMode == ASMIM_ABSOLUTE_Y || mIns[i + 3].mMode == ASMIM_ABSOLUTE) &&
+			mIns[i + 4].mType == ASMIT_ADC && mIns[i + 4].mMode == ASMIM_IMMEDIATE && mIns[i + 4].mAddress == 0 &&
+			mIns[i + 5].mType == ASMIT_STA && mIns[i + 5].mMode == ASMIM_ZERO_PAGE && mIns[i + 5].mAddress == mIns[i + 2].mAddress + 1)
+		{
+			int yval = RetrieveYValue(i);
+			int reg = FindFreeAccu(i);
+			if (reg >= 0)
+			{
+				NativeCodeInstruction	iins(mIns[i + 0].mIns, ASMIT_STA, ASMIM_ZERO_PAGE, reg);
+
+				mProc->ResetPatched();
+				if (CheckForwardSumYPointer(this, mIns[i + 1].mAddress, mIns[i + 1].mAddress, iins, i + 6, yval, 3))
+				{
+					mIns[i + 0] = iins;
+					mIns[i + 1].mType = ASMIT_NOP; mIns[i + 1].mMode = ASMIM_IMPLIED;
+					mIns[i + 2].mType = ASMIT_NOP; mIns[i + 2].mMode = ASMIM_IMPLIED;
+					mIns[i + 4].mType = ASMIT_NOP; mIns[i + 4].mMode = ASMIM_IMPLIED;
+
+					mProc->ResetPatched();
+					if (PatchForwardSumYPointer(this, mIns[i + 1].mAddress, mIns[i + 1].mAddress, iins, i + 6, yval))
+					{
+						if (mTrueJump)
+							mTrueJump->CheckLive();
+						if (mFalseJump)
+							mFalseJump->CheckLive();
+						return true;
+					}
+				}
+			}
+		}
+#endif
 #if 1
 		if (
 			mLoopHead &&