mirror of
https://github.com/TomHarte/CLK.git
synced 2024-07-28 09:29:07 +00:00
Attempts to rationalise Apple II address decoding.
This commit is contained in:
Thomas Harte
parent
9ff34d90f4
commit
4c4ab25d0e
@ -72,7 +72,6 @@ class ConcreteMachine:
|
||||
uint8_t ram_[48*1024];
|
||||
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 +84,11 @@ 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.
|
||||
|
||||
public:
|
||||
ConcreteMachine():
|
||||
m6502_(*this),
|
||||
@ -129,72 +133,82 @@ 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_];
|
||||
} else {
|
||||
/*
|
||||
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:
|
||||
if(isReadOperation(operation)) {
|
||||
// Read-only switches.
|
||||
switch(address) {
|
||||
default:
|
||||
// printf("Unknown access to %04x\n", address);
|
||||
break;
|
||||
default: break;
|
||||
|
||||
case 0xc000:
|
||||
*value = keyboard_input_;
|
||||
break;
|
||||
}
|
||||
} else {
|
||||
// Write-only switches.
|
||||
}
|
||||
} else {
|
||||
if(address < sizeof(ram_)) {
|
||||
if(address >= 0x400) {
|
||||
// TODO: be more selective.
|
||||
update_video();
|
||||
}
|
||||
ram_[address] = *value;
|
||||
}
|
||||
}
|
||||
break;
|
||||
break;
|
||||
|
||||
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;
|
||||
case 0xc053: update_video(); video_->set_mixed_mode(true); break;
|
||||
case 0xc054: update_video(); video_->set_video_page(0); break;
|
||||
case 0xc055: update_video(); video_->set_video_page(1); break;
|
||||
case 0xc056: update_video(); video_->set_low_resolution(); break;
|
||||
case 0xc057: update_video(); video_->set_high_resolution(); 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;
|
||||
case 0xc053: update_video(); video_->set_mixed_mode(true); break;
|
||||
case 0xc054: update_video(); video_->set_video_page(0); break;
|
||||
case 0xc055: update_video(); video_->set_video_page(1); break;
|
||||
case 0xc056: update_video(); video_->set_low_resolution(); break;
|
||||
case 0xc057: update_video(); video_->set_high_resolution(); break;
|
||||
|
||||
case 0xc010:
|
||||
keyboard_input_ &= 0x7f;
|
||||
break;
|
||||
case 0xc010:
|
||||
keyboard_input_ &= 0x7f;
|
||||
break;
|
||||
|
||||
case 0xc030:
|
||||
update_audio();
|
||||
audio_toggle_.set_output(!audio_toggle_.get_output());
|
||||
break;
|
||||
}
|
||||
|
||||
if(address >= 0xc100 && address < 0xc800) {
|
||||
/*
|
||||
Decode the area conventionally used by cards for ROMs:
|
||||
0xCn00 — 0xCnff: card n.
|
||||
*/
|
||||
const int card_number = (address - 0xc100) >> 8;
|
||||
if(cards_[card_number]) {
|
||||
update_cards();
|
||||
cards_[card_number]->perform_bus_operation(operation, address & 0xff, value);
|
||||
case 0xc030:
|
||||
update_audio();
|
||||
audio_toggle_.set_output(!audio_toggle_.get_output());
|
||||
break;
|
||||
}
|
||||
} else if(address >= 0xc090 && address < 0xc100) {
|
||||
/*
|
||||
Decode the area conventionally used by cards for registers:
|
||||
C0n0--C0nF: card n - 8.
|
||||
*/
|
||||
const int card_number = (address - 0xc090) >> 4;
|
||||
if(cards_[card_number]) {
|
||||
update_cards();
|
||||
cards_[card_number]->perform_bus_operation(operation, 0x100 | (address&0xf), value);
|
||||
|
||||
if(address >= 0xc100 && address < 0xc800) {
|
||||
/*
|
||||
Decode the area conventionally used by cards for ROMs:
|
||||
0xCn00 — 0xCnff: card n.
|
||||
*/
|
||||
const int card_number = (address - 0xc100) >> 8;
|
||||
if(cards_[card_number]) {
|
||||
update_cards();
|
||||
cards_[card_number]->perform_bus_operation(operation, address & 0xff, value);
|
||||
}
|
||||
} else if(address >= 0xc090 && address < 0xc100) {
|
||||
/*
|
||||
Decode the area conventionally used by cards for registers:
|
||||
C0n0--C0nF: card n - 8.
|
||||
*/
|
||||
const int card_number = (address - 0xc090) >> 4;
|
||||
if(cards_[card_number]) {
|
||||
update_cards();
|
||||
cards_[card_number]->perform_bus_operation(operation, 0x100 | (address&0xf), value);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
@ -283,7 +297,12 @@ 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];
|
||||
memory_blocks_[2].read_pointer = rom_.data();
|
||||
memory_blocks_[3].read_pointer = rom_.data() + 0x1000;
|
||||
|
||||
insert_media(apple_target->media);
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user