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Adds an implementation of the language card.

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This commit is contained in:
Thomas Harte 2018-05-06 16:17:11 -04:00
parent 36f8b165cf
commit d613c3c187
1 changed files with 58 additions and 3 deletions
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61
Machines/AppleII/AppleII.cpp
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@ -69,7 +69,7 @@ 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_;
uint8_t keyboard_input_ = 0x00;
@ -89,6 +89,31 @@ class ConcreteMachine:
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),
@ -111,6 +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_);
@ -187,6 +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) {
@ -301,8 +357,7 @@ class ConcreteMachine:
// 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];
memory_blocks_[2].read_pointer = rom_.data();
memory_blocks_[3].read_pointer = rom_.data() + 0x1000;
set_language_card_paging();
insert_media(apple_target->media);
}