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Merge pull request #423 from TomHarte/LanguageCard

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Implements the Apple II language card
This commit is contained in:
Thomas Harte 2018-05-06 16:18:15 -04:00 committed by GitHub
commit 1139caa83f
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 139 additions and 63 deletions
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2
Analyser/Static/DiskII/StaticAnalyser.cpp
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@ -69,6 +69,7 @@ Analyser::Static::TargetList Analyser::Static::DiskII::GetTargets(const Media &m
return targets;
} else {
targets.push_back(std::unique_ptr<Analyser::Static::Target>(AppleTarget(nullptr)));
targets.back()->media = media;
return targets;
}
}
@ -119,5 +120,6 @@ Analyser::Static::TargetList Analyser::Static::DiskII::GetTargets(const Media &m
} else {
targets.push_back(std::unique_ptr<Analyser::Static::Target>(AppleTarget(sector_zero)));
}
targets.back()->media = media;
return targets;
}

114
Machines/AppleII/AppleII.cpp
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@ -69,10 +69,9 @@ class ConcreteMachine:
stretched_cycles_since_card_update_ = 0;
}
uint8_t ram_[48*1024];
uint8_t ram_[65536], aux_ram_[65536];
std::vector<uint8_t> apple2_rom_, apple2plus_rom_, rom_;
std::vector<uint8_t> character_rom_;
uint16_t rom_start_address_;
uint8_t keyboard_input_ = 0x00;
Concurrency::DeferringAsyncTaskQueue audio_queue_;
@ -85,6 +84,36 @@ class ConcreteMachine:
Cycles cycles_since_card_update_;
int stretched_cycles_since_card_update_ = 0;
struct MemoryBlock {
uint8_t *read_pointer = nullptr;
uint8_t *write_pointer = nullptr;
} memory_blocks_[4]; // The IO page isn't included.
// MARK: - The language card.
struct {
bool bank1 = false;
bool read = false;
bool pre_write = false;
bool write = false;
} language_card_;
bool has_language_card_ = true;
void set_language_card_paging() {
if(has_language_card_ && !language_card_.write) {
memory_blocks_[2].write_pointer = &ram_[48*1024 + (language_card_.bank1 ? 0x1000 : 0x0000)];
memory_blocks_[3].write_pointer = &ram_[56*1024];
} else {
memory_blocks_[2].write_pointer = memory_blocks_[3].write_pointer = nullptr;
}
if(has_language_card_ && language_card_.read) {
memory_blocks_[2].read_pointer = &ram_[48*1024 + (language_card_.bank1 ? 0x1000 : 0x0000)];
memory_blocks_[3].read_pointer = &ram_[56*1024];
} else {
memory_blocks_[2].read_pointer = rom_.data();
memory_blocks_[3].read_pointer = rom_.data() + 0x1000;
}
}
public:
ConcreteMachine():
m6502_(*this),
@ -107,6 +136,10 @@ class ConcreteMachine:
Memory::Fuzz(ram_, sizeof(ram_));
}
~ConcreteMachine() {
audio_queue_.flush();
}
void setup_output(float aspect_ratio) override {
video_.reset(new AppleII::Video::Video<VideoBusHandler>(video_bus_handler_));
video_->set_character_rom(character_rom_);
@ -129,34 +162,43 @@ class ConcreteMachine:
++ cycles_since_card_update_;
cycles_since_audio_update_ += Cycles(7);
switch(address) {
default:
if(isReadOperation(operation)) {
if(address < sizeof(ram_)) {
*value = ram_[address];
} else if(address >= rom_start_address_) {
*value = rom_[address - rom_start_address_];
/*
There are five distinct zones of memory on an Apple II:
0000 — 0200 : the zero and stack pages, which can be paged independently on a IIe
0200 — c000 : the main block of RAM, which can be paged on a IIe
c000 — d000 : the IO area, including card ROMs
d000 — e000 : the low ROM area, which can contain indepdently-paged RAM with a language card
e000 — : the rest of ROM, also potentially replaced with RAM by a language card
*/
MemoryBlock *block = nullptr;
if(address < 0x200) block = &memory_blocks_[0];
else if(address < 0xc000) {update_video(); block = &memory_blocks_[1]; address -= 0x200; }
else if(address < 0xd000) block = nullptr;
else if(address < 0xe000) {block = &memory_blocks_[2]; address -= 0xd000; }
else {block = &memory_blocks_[3]; address -= 0xe000; }
if(block) {
if(isReadOperation(operation)) *value = block->read_pointer[address];
else if(block->write_pointer) block->write_pointer[address] = *value;
} else {
switch(address) {
default:
// printf("Unknown access to %04x\n", address);
break;
if(isReadOperation(operation)) {
// Read-only switches.
switch(address) {
default: break;
case 0xc000:
*value = keyboard_input_;
break;
}
}
} else {
if(address < sizeof(ram_)) {
if(address >= 0x400) {
// TODO: be more selective.
update_video();
}
ram_[address] = *value;
}
// Write-only switches.
}
break;
/* Read-write switches. */
case 0xc050: update_video(); video_->set_graphics_mode(); break;
case 0xc051: update_video(); video_->set_text_mode(); break;
case 0xc052: update_video(); video_->set_mixed_mode(false); break;
@ -174,6 +216,33 @@ class ConcreteMachine:
update_audio();
audio_toggle_.set_output(!audio_toggle_.get_output());
break;
case 0xc080: case 0xc084: case 0xc088: case 0xc08c:
case 0xc081: case 0xc085: case 0xc089: case 0xc08d:
case 0xc082: case 0xc086: case 0xc08a: case 0xc08e:
case 0xc083: case 0xc087: case 0xc08b: case 0xc08f:
// Quotes below taken from Understanding the Apple II, p. 5-28 and 5-29.
// "A3 controls the 4K bank selection"
language_card_.bank1 = (address&8);
// "Access to $C080, $C083, $C084, $0087, $C088, $C08B, $C08C, or $C08F sets the READ ENABLE flip-flop"
// (other accesses reset it)
language_card_.read = !(((address&2) >> 1) ^ (address&1));
// "The WRITE ENABLE' flip-flop is reset by an odd read access to the $C08X range when the PRE-WRITE flip-flop is set."
if(language_card_.pre_write && isReadOperation(operation) && (address&1)) language_card_.write = false;
// "[The WRITE ENABLE' flip-flop] is set by an even access in the $C08X range."
if(!(address&1)) language_card_.write = true;
// ("Any other type of access causes the WRITE ENABLE' flip-flop to hold its current state.")
// "The PRE-WRITE flip-flop is set by an odd read access in the $C08X range. It is reset by an even access or a write access."
language_card_.pre_write = isReadOperation(operation) ? (address&1) : false;
set_language_card_paging();
break;
}
if(address >= 0xc100 && address < 0xc800) {
@ -197,6 +266,7 @@ class ConcreteMachine:
cards_[card_number]->perform_bus_operation(operation, 0x100 | (address&0xf), value);
}
}
}
// The Apple II has a slightly weird timing pattern: every 65th CPU cycle is stretched
// by an extra 1/7th. That's because one cycle lasts 3.5 NTSC colour clocks, so after
@ -283,7 +353,11 @@ class ConcreteMachine:
if(rom_.size() > 12*1024) {
rom_.erase(rom_.begin(), rom_.begin() + static_cast<off_t>(rom_.size()) - 12*1024);
}
rom_start_address_ = 0xd000;//static_cast<uint16_t>(0x10000 - rom_.size());
// Set up the default memory blocks.
memory_blocks_[0].read_pointer = memory_blocks_[0].write_pointer = ram_;
memory_blocks_[1].read_pointer = memory_blocks_[1].write_pointer = &ram_[0x200];
set_language_card_paging();
insert_media(apple_target->media);
}

4
Storage/Disk/Encodings/AppleGCR/SegmentParser.cpp
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@ -56,11 +56,11 @@ std::map<std::size_t, Sector> Storage::Encodings::AppleGCR::sectors_from_segment
const uint_fast8_t value = shift_register;
shift_register = 0;
if(pointer == scanning_sentinel) {
scanner[0] = scanner[1];
scanner[1] = scanner[2];
scanner[2] = value;
if(pointer == scanning_sentinel) {
if(
scanner[0] == header_prologue[0] &&
scanner[1] == header_prologue[1] &&
@ -83,7 +83,7 @@ std::map<std::size_t, Sector> Storage::Encodings::AppleGCR::sectors_from_segment
if(new_sector) {
// If this is an epilogue, make sense of this whole sector;
// otherwise just keep the byte for later.
if(value == epilogue[1]) {
if(scanner[1] == epilogue[0] && scanner[2] == epilogue[1]) {
std::unique_ptr<Sector> sector = std::move(new_sector);
new_sector.reset();
pointer = scanning_sentinel;