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Corrects IIe text display.

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This commit is contained in:
Thomas Harte 2018-08-04 16:52:29 -04:00
parent e97cc40a2c
commit 558b96bc05
4 changed files with 30 additions and 8 deletions
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9
Machines/AppleII/AppleII.cpp
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@ -62,7 +62,7 @@ template <bool is_iie> class ConcreteMachine:
CPU::MOS6502::Processor<ConcreteMachine, false> m6502_;
VideoBusHandler video_bus_handler_;
std::unique_ptr<AppleII::Video::Video<VideoBusHandler>> video_;
std::unique_ptr<AppleII::Video::Video<VideoBusHandler, is_iie>> video_;
int cycles_into_current_line_ = 0;
Cycles cycles_since_video_update_;
@ -329,17 +329,20 @@ template <bool is_iie> class ConcreteMachine:
// Pick the required ROMs.
using Target = Analyser::Static::AppleII::Target;
std::vector<std::string> rom_names = {"apple2-character.rom"};
std::vector<std::string> rom_names;
size_t rom_size = 12*1024;
switch(target.model) {
default:
rom_names.push_back("apple2-character.rom");
rom_names.push_back("apple2o.rom");
break;
case Target::Model::IIplus:
rom_names.push_back("apple2-character.rom");
rom_names.push_back("apple2.rom");
break;
case Target::Model::IIe:
rom_size += 3840;
rom_names.push_back("apple2eu-character.rom");
rom_names.push_back("apple2eu.rom");
break;
}
@ -380,7 +383,7 @@ template <bool is_iie> class ConcreteMachine:
}
void setup_output(float aspect_ratio) override {
video_.reset(new AppleII::Video::Video<VideoBusHandler>(video_bus_handler_));
video_.reset(new AppleII::Video::Video<VideoBusHandler, is_iie>(video_bus_handler_));
video_->set_character_rom(character_rom_);
}

14
Machines/AppleII/Video.cpp
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@ -100,4 +100,18 @@ bool VideoBase::get_double_high_resolution() {
void VideoBase::set_character_rom(const std::vector<uint8_t> &character_rom) {
character_rom_ = character_rom;
// Flip all character contents based on the second line of the $ graphic.
if(character_rom_[0x121] == 0x3c || character_rom_[0x122] == 0x3c) {
for(auto &graphic : character_rom_) {
graphic =
((graphic & 0x01) ? 0x40 : 0x00) |
((graphic & 0x02) ? 0x20 : 0x00) |
((graphic & 0x04) ? 0x10 : 0x00) |
((graphic & 0x08) ? 0x08 : 0x00) |
((graphic & 0x10) ? 0x04 : 0x00) |
((graphic & 0x20) ? 0x02 : 0x00) |
((graphic & 0x40) ? 0x01 : 0x00);
}
}
}

14
Machines/AppleII/Video.hpp
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@ -191,7 +191,7 @@ class VideoBase {
std::vector<uint8_t> character_rom_;
};
template <class BusHandler> class Video: public VideoBase {
template <class BusHandler, bool is_iie> class Video: public VideoBase {
public:
/// Constructs an instance of the video feed; a CRT is also created.
Video(BusHandler &bus_handler) :
@ -262,15 +262,19 @@ template <class BusHandler> class Video: public VideoBase {
case GraphicsMode::Text: {
const uint8_t inverses[] = {
0xff,
static_cast<uint8_t>((flash_ / flash_length) * 0xff),
alternative_character_set_ ? static_cast<uint8_t>(0xff) : static_cast<uint8_t>((flash_ / flash_length) * 0xff),
0x00,
0x00
};
const uint8_t masks[] = {
alternative_character_set_ ? static_cast<uint8_t>(0x7f) : static_cast<uint8_t>(0x3f),
is_iie ? 0x7f : 0x3f,
};
for(int c = column_; c < pixel_end; ++c) {
const uint8_t character = bus_handler_.perform_read(static_cast<uint16_t>(text_address + c));
const std::size_t character_address = static_cast<std::size_t>(((character & 0x3f) << 3) + pixel_row);
const uint8_t character_pattern = character_rom_[character_address] ^ inverses[character >> 6];
const uint8_t xor_mask = inverses[character >> 6];
const std::size_t character_address = static_cast<std::size_t>(((character & masks[character >> 7]) << 3) + pixel_row);
const uint8_t character_pattern = character_rom_[character_address] ^ xor_mask;
// The character ROM is output MSB to LSB rather than LSB to MSB.
pixel_pointer_[0] = character_pattern & 0x40;

1
ROMImages/AppleII/readme.txt
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@ -8,5 +8,6 @@ apple2e.rom — a file at least 15.75kb big, in which the final 12kb is the main
apple2eu.rom — as per apple2e.rom, but for the Unenhanced Apple II.
apple2-character.rom — a 2kb image of the Apple IIe's character ROM.
apple2eu-character.rom — a 4kb image of the Unenhanced IIe's character ROM.
Apologies for the wackiness around "at least xkb big", it's to allow for use of files such as those on ftp.apple.asimov.net, which tend to be a bunch of other things, then the system ROM.