From 7432e602f86de1bcfb7adc34245780ff2687f640 Mon Sep 17 00:00:00 2001
From: Adrian Conlon <Adrian.conlon@gmail.com>
Date: Thu, 28 Dec 2017 16:15:22 +0000
Subject: [PATCH] Correct a 6502 bug in absolute indirect addressing mode
 (unchanging page on address resolution).

Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
---
 M6502/inc/mos6502.h   | 3 ++-
 M6502/src/mos6502.cpp | 8 ++++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/M6502/inc/mos6502.h b/M6502/inc/mos6502.h
index c924c9f..5b487ea 100644
--- a/M6502/inc/mos6502.h
+++ b/M6502/inc/mos6502.h
@@ -75,6 +75,7 @@ namespace EightBit {
 			adjustNegative(datum);
 		}
 
+		void getWord(uint8_t page, uint8_t offset, register16_t& output);
 		void getWord(uint8_t offset, register16_t& output);
 
 		void getWord(register16_t& output);
@@ -104,7 +105,7 @@ namespace EightBit {
 
 		void Address_Indirect() {
 			Address_Absolute();
-			getWord(MEMPTR(), MEMPTR());
+			getWord(MEMPTR().high, MEMPTR().low, MEMPTR());
 		}
 
 		void Address_ZeroPageX() {
diff --git a/M6502/src/mos6502.cpp b/M6502/src/mos6502.cpp
index 462fec3..46b4406 100644
--- a/M6502/src/mos6502.cpp
+++ b/M6502/src/mos6502.cpp
@@ -63,14 +63,18 @@ void EightBit::MOS6502::reset() {
 	getWord(RSTvector, PC());
 }
 
-void EightBit::MOS6502::getWord(uint8_t offset, register16_t& output) {
+void EightBit::MOS6502::getWord(uint8_t page, uint8_t offset, register16_t& output) {
 	BUS().ADDRESS().low = offset;
-	BUS().ADDRESS().high = 0;
+	BUS().ADDRESS().high = page;
 	output.low = getByte();
 	BUS().ADDRESS().low++;
 	output.high = getByte();
 }
 
+void EightBit::MOS6502::getWord(uint8_t offset, register16_t& output) {
+	getWord(0, offset, output);
+}
+
 void EightBit::MOS6502::getWord(register16_t& output) {
 	output.low = getByte();
 	BUS().ADDRESS().word++;