From 71b524519d171067cb1e2ad128ad5c0fba0fbe6e Mon Sep 17 00:00:00 2001
From: Lauchmelder <robert.altner11@gmail.com>
Date: Mon, 28 Feb 2022 17:04:20 +0100
Subject: [PATCH] fixed disassembler

---
 src/CPU.cpp                   |  6 +++---
 src/CPU.hpp                   |  2 +-
 src/debugger/Disassembler.cpp | 27 ++++++++++++++++-----------
 src/debugger/Disassembler.hpp |  2 ++
 4 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/src/CPU.cpp b/src/CPU.cpp
index 8ba1230..adf31eb 100644
--- a/src/CPU.cpp
+++ b/src/CPU.cpp
@@ -56,9 +56,9 @@ uint8_t CPU::Tick()
 	Byte opcode = Read(pc.Raw++);
 	currentInstruction = &(InstructionTable[opcode]);
 
-	pastPCs.push_back(currentInstruction);
-	if (pastPCs.size() > 50)
-		pastPCs.pop_front();
+	pastInstructions.push_back(std::make_pair(pc.Raw - 1, currentInstruction));
+	if (pastInstructions.size() > 50)
+		pastInstructions.pop_front();
 
 	if (currentInstruction->Operation == nullptr || currentInstruction->Mode == nullptr)
 	{
diff --git a/src/CPU.hpp b/src/CPU.hpp
index 38ec0a0..8241d57 100644
--- a/src/CPU.hpp
+++ b/src/CPU.hpp
@@ -240,7 +240,7 @@ private:	// CPU internals
 	uint8_t remainingCycles = 0;
 	uint8_t additionalCycles = 0;	//< E.g. when a page boundary was crossed
 	uint64_t totalCycles = 0;
-	std::deque<Instruction*> pastPCs;	//< For debugging, saves the past 50 instructions
+	std::deque<std::pair<Word, Instruction*>> pastInstructions;	//< For debugging, saves the past 50 instructions
 	bool halted = false;
 
 #ifndef NDEBUG
diff --git a/src/debugger/Disassembler.cpp b/src/debugger/Disassembler.cpp
index 7df3a71..9f8ed49 100644
--- a/src/debugger/Disassembler.cpp
+++ b/src/debugger/Disassembler.cpp
@@ -28,17 +28,17 @@ void Disassembler::OnRender()
 	std::string disassembly;
 
 	ImGui::PushStyleColor(ImGuiCol_Text, ImVec4{ 0.8f, 0.8f, 0.8f, 1.0f });
-	if (cpu->pastPCs.size() < 50)
+	if (cpu->pastInstructions.size() < 50)
 	{
-		for (int i = 0; i < 50 - cpu->pastPCs.size(); i++)
+		for (int i = 0; i < 50 - cpu->pastInstructions.size(); i++)
 		{
 			ImGui::Text("-");
 		}
 	}
 
-	for (Word pc : cpu->pastPCs)
+	for (auto pair : cpu->pastInstructions)
 	{
-		Disassemble(disassembly, pc);
+		Disassemble(disassembly, pair.first, pair.second);
 		ImGui::Text("- %s", disassembly.c_str());
 	}
 	ImGui::PopStyleColor();
@@ -70,18 +70,24 @@ void Disassembler::OnRender()
 
 void Disassembler::Disassemble(std::string& target, uint16_t& pc)
 {
-	std::stringstream ss;
-	ss <<  FORMAT << pc << ": ";
 	Instruction* currentInstr = &cpu->InstructionTable[cpu->Read(pc)];
+	Disassemble(target, pc, currentInstr);
+	pc += currentInstr->Size;
+}
 
-	for (int i = 0; i < currentInstr->Size; i++)
+void Disassembler::Disassemble(std::string& target, uint16_t pc, const Instruction* instr)
+{
+	std::stringstream ss;
+	ss << FORMAT << pc << ": ";
+
+	for (int i = 0; i < instr->Size; i++)
 	{
 		ss << FORMAT << std::setw(2) << (Word)cpu->Read(pc + i) << " ";
 	}
-	ss << std::string(15 - ss.str().size(), ' ') << currentInstr->Mnemonic << " ";
+	ss << std::string(15 - ss.str().size(), ' ') << instr->Mnemonic << " ";
 
 	Address absoluteAddress;
-	switch (currentInstr->AddrType)
+	switch (instr->AddrType)
 	{
 	case Addressing::ACC:
 		ss << "A";
@@ -118,7 +124,7 @@ void Disassembler::Disassemble(std::string& target, uint16_t& pc)
 		ss << "#$" << FORMAT << std::setw(2) << value;
 	} break;
 
-	case Addressing::IMP: 
+	case Addressing::IMP:
 		break;
 
 	case Addressing::IND:
@@ -172,6 +178,5 @@ void Disassembler::Disassemble(std::string& target, uint16_t& pc)
 	} break;
 	}
 
-	pc += currentInstr->Size;
 	target = ss.str();
 }
diff --git a/src/debugger/Disassembler.hpp b/src/debugger/Disassembler.hpp
index 68dc21f..e0b9a5d 100644
--- a/src/debugger/Disassembler.hpp
+++ b/src/debugger/Disassembler.hpp
@@ -3,6 +3,7 @@
 #include "DebugWindow.hpp"
 
 class CPU;
+struct Instruction;
 
 class Disassembler :
 	public DebugWindow
@@ -14,6 +15,7 @@ public:
 
 private:
 	void Disassemble(std::string& target, uint16_t& pc);
+	void Disassemble(std::string& target, uint16_t pc, const Instruction* instr);
 
 private:
 	CPU* cpu;