6502/CLK
1
0
Fork 0
mirror of https://github.com/TomHarte/CLK.git synced 2025-04-06 10:38:16 +00:00
Code Issues Projects Releases Wiki Activity

Takes a repeat shot at proper shadowing.

Browse Source 
I think the Apple IIgs Technical Reference explains how these bits interact, and I just had inhibit_all_pages off all on my own.
This commit is contained in:
Thomas Harte 2020-11-16 19:54:12 -05:00
parent da8563733b
commit e4c5bfdd5c
1 changed files with 53 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

72
Machines/Apple/AppleIIgs/MemoryMap.hpp
View File

@ -366,8 +366,10 @@ class MemoryMap {
}
void set_shadowing() {
const bool inhibit_all_pages = speed_register_ & 0x10;
const bool inhibit_all_pages = !(speed_register_ & 0x10);
// Disables shadowing for the region starting from @c zone if @c flag is true;
// otherwise enables it.
#define apply(flag, zone) \
if(flag) { \
regions[region_map[zone]].flags &= ~Region::IsShadowed; \
@ -375,36 +377,68 @@ class MemoryMap {
regions[region_map[zone]].flags |= Region::IsShadowed; \
}
// Text Page 1, main and auxiliary.
printf("Shadowing: %02x\n", shadow_register_);
// Relevant bits:
//
// b5: inhibit shadowing, text page 2 [if ROM 03; as if always set otherwise]
// b4: inhibit shadowing, auxiliary high-res graphics
// b3: inhibit shadowing, super high-res graphics
// b2: inhibit shadowing, high-res graphics page 2
// b1: inhibit shadowing, high-res graphics page 1
// b0: inhibit shadowing, text page 1
//
// The interpretations of how the overlapping high-res and super high-res inhibit
// bits apply used below is taken from The Apple IIgs Technical Reference, P. 178.
// Text Page 1, main and auxiliary — $0400–$0800.
apply(shadow_register_ & 0x01, 0x0004);
apply(shadow_register_ & 0x01, 0x0104);
apply((shadow_register_ & 0x01) && inhibit_all_pages, 0x0204);
apply((shadow_register_ & 0x01) && inhibit_all_pages, 0x0304);
apply((shadow_register_ & 0x01) || inhibit_all_pages, 0x0204); // All other pages uses the same shadowing flags.
apply((shadow_register_ & 0x01) || inhibit_all_pages, 0x0304);
assert(region_map[0x0008] == region_map[0x0004]+1);
assert(region_map[0x0108] == region_map[0x0104]+1);
assert(region_map[0x0208] == region_map[0x0204]+1);
assert(region_map[0x0308] == region_map[0x0304]+1);
// Text Page 2, main and auxiliary.
// Text Page 2, main and auxiliary — 0x0800–0x0c00.
// TODO: on a ROM03 machine only.
apply(shadow_register_ & 0x20, 0x0008);
apply(shadow_register_ & 0x20, 0x0108);
apply((shadow_register_ & 0x20) && inhibit_all_pages, 0x0208);
apply((shadow_register_ & 0x20) && inhibit_all_pages, 0x0308);
apply((shadow_register_ & 0x20) || inhibit_all_pages, 0x0208);
apply((shadow_register_ & 0x20) || inhibit_all_pages, 0x0308);
assert(region_map[0x000c] == region_map[0x0008]+1);
assert(region_map[0x010c] == region_map[0x0108]+1);
assert(region_map[0x020c] == region_map[0x0208]+1);
assert(region_map[0x030c] == region_map[0x0308]+1);
// Hi-res graphics Page 1, main and auxiliary.
// Hi-res graphics Page 1, main and auxiliary — $2000–$4000;
// also part of the super high-res graphics page.
apply(shadow_register_ & 0x02, 0x0020);
apply(shadow_register_ & 0x12, 0x0120);
apply((shadow_register_ & 0x02) && inhibit_all_pages, 0x0220);
apply((shadow_register_ & 0x12) && inhibit_all_pages, 0x0320);
apply((shadow_register_ & 0x12) && (shadow_register_ & 0x08), 0x0120);
apply((shadow_register_ & 0x02) || inhibit_all_pages, 0x0220);
apply(((shadow_register_ & 0x12) && (shadow_register_ & 0x08)) || inhibit_all_pages, 0x0320);
assert(region_map[0x0040] == region_map[0x0020]+1);
assert(region_map[0x0140] == region_map[0x0120]+1);
assert(region_map[0x0240] == region_map[0x0220]+1);
assert(region_map[0x0340] == region_map[0x0320]+1);
// Hi-res graphics Page 2, main and auxiliary.
// Hi-res graphics Page 2, main and auxiliary — $4000–$6000;
// also part of the super high-res graphics page.
apply(shadow_register_ & 0x04, 0x0040);
apply(shadow_register_ & 0x14, 0x0140);
apply((shadow_register_ & 0x04) && inhibit_all_pages, 0x0240);
apply((shadow_register_ & 0x14) && inhibit_all_pages, 0x0340);
apply((shadow_register_ & 0x14) && (shadow_register_ & 0x08), 0x0140);
apply((shadow_register_ & 0x04) || inhibit_all_pages, 0x0240);
apply(((shadow_register_ & 0x14) && (shadow_register_ & 0x08)) || inhibit_all_pages, 0x0340);
assert(region_map[0x0060] == region_map[0x0040]+1);
assert(region_map[0x0160] == region_map[0x0140]+1);
assert(region_map[0x0260] == region_map[0x0240]+1);
assert(region_map[0x0360] == region_map[0x0340]+1);
// Residue of Super Hi-Res.
// Residue of Super Hi-Res — $6000–$a000
apply(shadow_register_ & 0x08, 0x0160);
apply((shadow_register_ & 0x08) && inhibit_all_pages, 0x0360);
// TODO: does inhibiting Super Hi-Res also affect the regular hi-res pages?
apply((shadow_register_ & 0x08) || inhibit_all_pages, 0x0360);
assert(region_map[0x01a0] == region_map[0x0160]+1);
assert(region_map[0x03a0] == region_map[0x0360]+1);
#undef apply
}