From 2be817a6a11746c91e97c7c627bba80b74f5eca0 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Fri, 30 Oct 2020 21:42:43 -0400
Subject: [PATCH] Maps in "the interrupt ROM addresses".

---
 Machines/Apple/AppleIIgs/AppleIIgs.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Machines/Apple/AppleIIgs/AppleIIgs.cpp b/Machines/Apple/AppleIIgs/AppleIIgs.cpp
index eb31333da..a1c86d891 100644
--- a/Machines/Apple/AppleIIgs/AppleIIgs.cpp
+++ b/Machines/Apple/AppleIIgs/AppleIIgs.cpp
@@ -191,6 +191,14 @@ class ConcreteMachine:
 					case 0xc054: case 0xc055: case 0xc056: case 0xc057:
 					break;
 
+					// Interrupt ROM addresses; Cf. P25 of the Hardware Reference.
+					case 0xc071: case 0xc072: case 0xc073: case 0xc074: case 0xc075: case 0xc076: case 0xc077:
+					case 0xc078: case 0xc079: case 0xc07a: case 0xc07b: case 0xc07c: case 0xc07d: case 0xc07e: case 0xc07f:
+						if(isReadOperation(operation)) {
+							*value = rom_[rom_.size() - 65536 + (address & 0xffff)];
+						}
+					break;
+
 					default:
 						if((address & 0xffff) < 0xc100) {
 							// TODO: all other IO accesses.