From 952891d1b62b4727fff61985aebcbf494b5df63b Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 16 Nov 2020 21:46:35 -0500
Subject: [PATCH] Improves commentary.
---
Machines/Apple/AppleIIgs/MemoryMap.hpp | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/Machines/Apple/AppleIIgs/MemoryMap.hpp b/Machines/Apple/AppleIIgs/MemoryMap.hpp
index 2ad3e9662..512f0b96c 100644
--- a/Machines/Apple/AppleIIgs/MemoryMap.hpp
+++ b/Machines/Apple/AppleIIgs/MemoryMap.hpp
@@ -414,6 +414,10 @@ class MemoryMap {
// Hi-res graphics Page 1, main and auxiliary — $2000–$4000;
// also part of the super high-res graphics page.
+ //
+ // Test applied: both the graphics page inhibit and, on odd
+ // pages, the super high-res inhibit must be applied to inhibit
+ // this area.
apply(shadow_register_ & 0x02, 0x0020);
apply((shadow_register_ & 0x12) && (shadow_register_ & 0x08), 0x0120);
apply((shadow_register_ & 0x02) || inhibit_all_pages, 0x0220);
@@ -425,6 +429,10 @@ class MemoryMap {
// Hi-res graphics Page 2, main and auxiliary — $4000–$6000;
// also part of the super high-res graphics page.
+ //
+ // Test applied: both the graphics page inhibit and, on odd
+ // pages, the super high-res inhibit must be applied to inhibit
+ // this area.
apply(shadow_register_ & 0x04, 0x0040);
apply((shadow_register_ & 0x14) && (shadow_register_ & 0x08), 0x0140);
apply((shadow_register_ & 0x04) || inhibit_all_pages, 0x0240);
@@ -434,7 +442,7 @@ class MemoryMap {
assert(region_map[0x0260] == region_map[0x0240]+1);
assert(region_map[0x0360] == region_map[0x0340]+1);
- // Residue of Super Hi-Res — $6000–$a000
+ // Residue of Super Hi-Res — $6000–$a000 (odd pages only).
apply(shadow_register_ & 0x08, 0x0160);
apply((shadow_register_ & 0x08) || inhibit_all_pages, 0x0360);
assert(region_map[0x01a0] == region_map[0x0160]+1);