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Implements the alternative zero page soft switch.

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This commit is contained in:
Thomas Harte 2018-07-25 22:10:21 -04:00
parent 5c4506a9db
commit 5f2b9b2d5a
1 changed files with 34 additions and 7 deletions
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41
Machines/AppleII/AppleII.cpp
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@ -155,16 +155,18 @@ template <bool is_iie> class ConcreteMachine:
} language_card_;
bool has_language_card_ = true;
void set_language_card_paging() {
uint8_t *const ram = alternative_zero_page_ ? aux_ram_ : ram_;
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];
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];
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() + (is_iie ? 3840 : 0);
memory_blocks_[3].read_pointer = memory_blocks_[2].read_pointer + 0x1000;
@ -174,7 +176,10 @@ template <bool is_iie> class ConcreteMachine:
// MARK - The IIe's ROM controls.
bool internal_CX_rom_ = false;
bool slot_C3_rom_ = false;
bool internal_c8_rom_ = false;
// bool internal_c8_rom_ = false;
// MARK - The IIe's auxiliary RAM controls.
bool alternative_zero_page_ = false;
// MARK - typing
std::unique_ptr<Utility::StringSerialiser> string_serialiser_;
@ -257,6 +262,7 @@ template <bool is_iie> class ConcreteMachine:
// Also, start with randomised memory contents.
Memory::Fuzz(ram_, sizeof(ram_));
Memory::Fuzz(aux_ram_, sizeof(aux_ram_));
// Add a couple of joysticks.
joysticks_.emplace_back(new Joystick);
@ -296,10 +302,15 @@ template <bool is_iie> class ConcreteMachine:
install_card(6, new AppleII::DiskIICard(rom_fetcher, target.disk_controller == Target::DiskController::SixteenSector));
}
// Set up the default memory blocks.
// Set up the block that will provide CX ROM access on a IIe.
cx_rom_block_.read_pointer = rom_.data();
// Set up the default memory blocks. On a II or II+ these values will never change.
// On a IIe they'll be affected by selection of auxiliary RAM.
memory_blocks_[0].read_pointer = memory_blocks_[0].write_pointer = ram_;
memory_blocks_[1].read_pointer = memory_blocks_[1].write_pointer = &ram_[0x200];
cx_rom_block_.read_pointer = rom_.data();
// Set proper values for the language card/ROM area.
set_language_card_paging();
insert_media(target.media);
@ -512,6 +523,7 @@ template <bool is_iie> class ConcreteMachine:
// The IIe-only state reads follow...
case 0xc015: if(is_iie) *value = (*value & 0x7f) | internal_CX_rom_ ? 0x80 : 0x00; break;
case 0xc016: if(is_iie) *value = (*value & 0x7f) | alternative_zero_page_ ? 0x80 : 0x00; break;
case 0xc017: if(is_iie) *value = (*value & 0x7f) | slot_C3_rom_ ? 0x80 : 0x00; break;
case 0xc018: if(is_iie) *value = (*value & 0x7f) | video_->get_80_store() ? 0x80 : 0x00; break;
case 0xc01a: if(is_iie) *value = (*value & 0x7f) | video_->get_text() ? 0x80 : 0x00; break;
@ -547,6 +559,15 @@ template <bool is_iie> class ConcreteMachine:
case 0xc05e:
case 0xc05f: video_->set_double_high_resolution(!(address&1)); break;
case 0xc008:
case 0xc009:
// The alternative zero page setting affects both bank 0 and any RAM
// that's paged as though it were on a language card.
alternative_zero_page_ = !!(address&1);
memory_blocks_[0].read_pointer = memory_blocks_[0].write_pointer = alternative_zero_page_ ? aux_ram_ : ram_;
set_language_card_paging();
break;
}
}
}
@ -580,6 +601,12 @@ template <bool is_iie> class ConcreteMachine:
if(!string_serialiser_->advance())
string_serialiser_.reset();
}
// On the IIe, reading C010 returns additional key info.
if(is_iie && isReadOperation(operation)) {
// TODO!
*value = 0;
}
break;
case 0xc030: