Add proper "empty" return value to GetEffectiveAddress.

Zero is valid and cannot be used as "empty".

Source/BasicBlock.cpp

@@ -206,6 +206,10 @@ void CBasicBlock::CompileRange(CMipsJitter* jitter)
 			return false;
 		}
 		uint32 target = m_context.m_pArch->GetInstructionEffectiveAddress(&m_context, branchInstAddr, inst);
+		if(target == MIPS_INVALID_PC)
+		{
+			return false;
+		}
 		return target == m_begin;
 	}();
 

Source/GenericMipsExecutor.h

@@ -172,7 +172,7 @@ protected:
 			}
 		}
 
-		if((branchAddress != 0) && block->HasLinkSlot(LINK_SLOT_BRANCH))
+		if((branchAddress != MIPS_INVALID_PC) && block->HasLinkSlot(LINK_SLOT_BRANCH))
 		{
 			branchAddress &= m_addressMask;
 			const auto linkSlot = LINK_SLOT_BRANCH;
@@ -210,7 +210,7 @@ protected:
 	virtual void PartitionFunction(uint32 startAddress)
 	{
 		uint32 endAddress = startAddress + MAX_BLOCK_SIZE;
-		uint32 branchAddress = 0;
+		uint32 branchAddress = MIPS_INVALID_PC;
 		for(uint32 address = startAddress; address < endAddress; address += 4)
 		{
 			uint32 opcode = m_context.m_pMemoryMap->GetInstruction(address);

Source/MA_MIPSIV_Reflection.cpp

@@ -230,7 +230,7 @@ uint32 CMA_MIPSIV::ReflCOPEffeAddr(INSTRUCTION* pInstr, CMIPS* pCtx, uint32 nAdd
 	}
 	else
 	{
-		return 0;
+		return MIPS_INVALID_PC;
 	}
 }
 

Source/MIPSAnalysis.cpp

@@ -269,6 +269,7 @@ void CMIPSAnalysis::ExpandSubroutines(uint32 executableStart, uint32 executableE
 			if(branchType != MIPS_BRANCH_NORMAL) continue;
 
 			uint32 branchTarget = m_ctx->m_pArch->GetInstructionEffectiveAddress(m_ctx, address, opcode);
+			if(branchTarget == MIPS_INVALID_PC) continue;
 
 			//Check if pointing inside our subroutine. If so, don't bother
 			if(branchTarget >= subroutine.start && branchTarget <= subroutine.end) continue;

Source/MIPSReflection.cpp

@@ -1,7 +1,6 @@
 #include "MIPSReflection.h"
 #include <string.h>
-
+#include "MIPS.h"
-class CMIPS;
 
 using namespace MIPSReflection;
 
@@ -64,7 +63,7 @@ uint32 MIPSReflection::SubTableEffAddr(INSTRUCTION* pInstr, CMIPS* pCtx, uint32
 	pInstr = DereferenceInstruction(pInstr->pSubTable, nOpcode);
 	if(pInstr->pGetEffectiveAddress == NULL)
 	{
-		return 0;
+		return MIPS_INVALID_PC;
 	}
 	return pInstr->pGetEffectiveAddress(pInstr, pCtx, nAddress, nOpcode);
 }

Source/ee/EeBasicBlock.cpp

@@ -40,6 +40,7 @@ bool CEeBasicBlock::IsIdleLoopBlock() const
 
 	//Check that the branch target is ourself
 	uint32 branchTarget = m_context.m_pArch->GetInstructionEffectiveAddress(&m_context, endInstructionAddress, endInstruction);
+	if(branchTarget == MIPS_INVALID_PC) return false;
 	if(branchTarget != m_begin) return false;
 
 	uint32 compareRs = 0;

Source/ee/MA_VU_LowerReflection.cpp

@@ -1349,12 +1349,12 @@ uint32 CMA_VU::CLower::GetInstructionEffectiveAddress(CMIPS* context, uint32 add
 {
 	if(IsLOI(context, address))
 	{
-		return 0;
+		return MIPS_INVALID_PC;
 	}
 
 	if(opcode == OPCODE_NOP)
 	{
-		return 0;
+		return MIPS_INVALID_PC;
 	}
 
 	INSTRUCTION instr;

Source/ee/VuAnalysis.cpp

@@ -105,7 +105,7 @@ void CVuAnalysis::Analyse(CMIPS* ctx, uint32 begin, uint32 end)
 		if(branchType == MIPS_BRANCH_NORMAL)
 		{
 			uint32 branchTarget = ctx->m_pArch->GetInstructionEffectiveAddress(ctx, address, lowerInstruction);
-			if(branchTarget != 0)
+			if(branchTarget != MIPS_INVALID_PC)
 			{
 				auto subroutine = ctx->m_analysis->FindSubroutine(branchTarget);
 				if(subroutine)

Source/ee/VuBasicBlock.cpp

@@ -230,9 +230,7 @@ void CVuBasicBlock::CompileRange(CMipsJitter* jitter)
 			return false;
 		}
 		uint32 target = m_context.m_pArch->GetInstructionEffectiveAddress(&m_context, branchInstAddr, inst);
-		//TODO: GetInstructionEffectiveAddress should return something else when the EA can't be computed
+		if(target == MIPS_INVALID_PC)
-		//statically as 0 is a valid address. There's some other implications to this though.
-		if(target == 0)
 		{
 			return false;
 		}
@@ -321,6 +319,7 @@ bool CVuBasicBlock::CheckIsSpecialIntegerLoop(unsigned int regI) const
 		{
 			assert(IsConditionalBranch(opcodeLo));
 			uint32 branchTarget = arch->GetInstructionEffectiveAddress(&m_context, address, opcodeLo);
+			if(branchTarget == MIPS_INVALID_PC) return false;
 			if(branchTarget != m_begin) return false;
 		}
 		else

Source/ee/VuExecutor.cpp

@@ -70,7 +70,7 @@ BasicBlockPtr CVuExecutor::BlockFactory(CMIPS& context, uint32 begin, uint32 end
 void CVuExecutor::PartitionFunction(uint32 startAddress)
 {
 	uint32 endAddress = startAddress + MAX_BLOCK_SIZE - 4;
-	uint32 branchAddress = 0;
+	uint32 branchAddress = MIPS_INVALID_PC;
 	for(uint32 address = startAddress; address < endAddress; address += 8)
 	{
 		uint32 addrLo = address + 0;

Source/ui_qt/DebugSupport/DisAsmWnd.cpp

@@ -186,11 +186,14 @@ void CDisAsmWnd::ShowContextMenu(const QPoint& pos)
 			{
 				char sTemp[256];
 				uint32 nAddress = m_ctx->m_pArch->GetInstructionEffectiveAddress(m_ctx, m_selected, nOpcode);
-				snprintf(sTemp, countof(sTemp), ("Go to 0x%08X"), nAddress);
+				if(nAddress != MIPS_INVALID_PC)
-				QAction* goToEaAction = new QAction(this);
+				{
-				goToEaAction->setText(sTemp);
+					snprintf(sTemp, countof(sTemp), ("Go to 0x%08X"), nAddress);
-				connect(goToEaAction, &QAction::triggered, std::bind(&CDisAsmWnd::GotoEA, this));
+					QAction* goToEaAction = new QAction(this);
-				rightClickMenu->addAction(goToEaAction);
+					goToEaAction->setText(sTemp);
+					connect(goToEaAction, &QAction::triggered, std::bind(&CDisAsmWnd::GotoEA, this));
+					rightClickMenu->addAction(goToEaAction);
+				}
 			}
 		}
 	}
@@ -368,6 +371,7 @@ void CDisAsmWnd::GotoEA()
 	if(m_ctx->m_pArch->IsInstructionBranch(m_ctx, m_selected, nOpcode) == MIPS_BRANCH_NORMAL)
 	{
 		uint32 nAddress = m_ctx->m_pArch->GetInstructionEffectiveAddress(m_ctx, m_selected, nOpcode);
+		assert(nAddress != MIPS_INVALID_PC);
 
 		if(m_address != nAddress)
 		{

Source/ui_qt/DebugSupport/QtDebugger.cpp

@@ -632,6 +632,7 @@ std::vector<uint32> QtDebugger::FindCallers(CMIPS* context, uint32 address)
 	{
 		uint32 opcode = context->m_pMemoryMap->GetInstruction(i);
 		uint32 ea = context->m_pArch->GetInstructionEffectiveAddress(context, i, opcode);
+		if(ea == MIPS_INVALID_PC) continue;
 		if(ea == address)
 		{
 			callers.push_back(i);

Source/ui_qt/DebugSupport/QtDisAsmTableModel.cpp

@@ -312,12 +312,15 @@ std::string CQtDisAsmTableModel::GetInstructionMetadata(uint32 address) const
 		if(m_ctx->m_pArch->IsInstructionBranch(m_ctx, address, opcode) == MIPS_BRANCH_NORMAL)
 		{
 			uint32 effAddr = m_ctx->m_pArch->GetInstructionEffectiveAddress(m_ctx, address, opcode);
-			const char* tag = m_ctx->m_Functions.Find(effAddr);
+			if(effAddr != MIPS_INVALID_PC)
-			if(tag != nullptr)
 			{
-				disAsm += ("-> ");
+				const char* tag = m_ctx->m_Functions.Find(effAddr);
-				disAsm += tag;
+				if(tag != nullptr)
-				commentDrawn = true;
+				{
+					disAsm += ("-> ");
+					disAsm += tag;
+					commentDrawn = true;
+				}
 			}
 		}
 	}