From 20c126adfc015fec86894558570081751358b2ad Mon Sep 17 00:00:00 2001
From: "Adrian.Conlon" <adrian.conlon@gmail.com>
Date: Thu, 31 Aug 2017 01:19:51 +0100
Subject: [PATCH] Correct a couple of cycle counting issues.

Signed-off-by: Adrian.Conlon <adrian.conlon@gmail.com>
---
 LR35902/src/LR35902.cpp | 12 ++++++------
 M6502/src/mos6502.cpp   | 16 +++++++++-------
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/LR35902/src/LR35902.cpp b/LR35902/src/LR35902.cpp
index c74e9ca..28e717d 100644
--- a/LR35902/src/LR35902.cpp
+++ b/LR35902/src/LR35902.cpp
@@ -335,10 +335,10 @@ void EightBit::LR35902::ccf(uint8_t& a, uint8_t& f) {
 
 int EightBit::LR35902::runRasterLines() {
 	m_bus.resetLY();
-	int cycles = 0;
+	int count = 0;
 	for (int line = 0; line < Display::RasterHeight; ++line)
-		cycles += runRasterLine();
-	return cycles;
+		count += runRasterLine();
+	return count;
 }
 
 int EightBit::LR35902::runRasterLine() {
@@ -351,10 +351,10 @@ int EightBit::LR35902::runRasterLine() {
 
 int EightBit::LR35902::runVerticalBlankLines() {
 	m_bus.triggerInterrupt(Bus::Interrupts::VerticalBlank);
-	int cycles = 0;
+	int count = 0;
 	for (int line = 0; line < (Bus::TotalLineCount - Display::RasterHeight); ++line)
-		cycles += runRasterLine();
-	return cycles;
+		count += runRasterLine();
+	return count;
 }
 
 int EightBit::LR35902::singleStep() {
diff --git a/M6502/src/mos6502.cpp b/M6502/src/mos6502.cpp
index 13e5759..cac272e 100644
--- a/M6502/src/mos6502.cpp
+++ b/M6502/src/mos6502.cpp
@@ -33,13 +33,11 @@ void EightBit::MOS6502::initialise() {
 	}
 
 	PC().word = 0;
+
 	X() = Bit7;
 	Y() = 0;
 	A() = 0;
-
-	P() = 0;
-	setFlag(P(), RF);
-
+	P() = RF;
 	S() = Mask8;
 
 	MEMPTR().word = 0;
@@ -47,7 +45,8 @@ void EightBit::MOS6502::initialise() {
 
 int EightBit::MOS6502::step() {
 	ExecutingInstruction.fire(*this);
-	auto returned = execute(fetchByte());
+	cycles = 0;
+	auto returned = fetchExecute();
 	ExecutedInstruction.fire(*this);
 	return returned;
 }
@@ -344,6 +343,9 @@ int EightBit::MOS6502::execute(uint8_t cell) {
 		__assume(0);
 	}
 
+	if (cycles == 0)
+		throw std::logic_error("Unhandled opcode");
+
 	return cycles;
 }
 
@@ -483,7 +485,7 @@ void EightBit::MOS6502::ADC_d(uint8_t data) {
 ////
 
 void EightBit::MOS6502::Branch(int8_t displacement) {
-	auto page = PC().high;
+	const auto page = PC().high;
 	PC().word += displacement;
 	if (PC().high != page)
 		cycles++;
@@ -491,7 +493,7 @@ void EightBit::MOS6502::Branch(int8_t displacement) {
 }
 
 void EightBit::MOS6502::Branch(bool flag) {
-	int8_t displacement = AM_Immediate();
+	const int8_t displacement = AM_Immediate();
 	if (flag)
 		Branch(displacement);
 }