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Completes first draft of Apple II video hardware.

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This commit is contained in:
Thomas Harte 2018-04-17 22:04:02 -04:00
parent 1c605d58e3
commit a07c99d778
3 changed files with 193 additions and 106 deletions
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5
Machines/AppleII/AppleII.cpp
View File

@ -104,7 +104,10 @@ class ConcreteMachine:
}
} else {
if(address < sizeof(ram_)) {
update_video(); // TODO: be more selective.
if(address >= 0x400) {
// TODO: be more selective.
update_video();
}
ram_[address] = *value;
// printf("%04x <- %02x\n", address, *value);
}

120
Machines/AppleII/Video.cpp
View File

@ -10,26 +10,100 @@
using namespace AppleII::Video;
//void Video::set_graphics_mode() {
// printf("Graphics mode\n");
//}
//
//void Video::set_text_mode() {
// printf("Text mode\n");
//}
//
//void Video::set_mixed_mode(bool mixed_mode) {
// printf("Mixed mode: %s\n", mixed_mode ? "true" : "false");
//}
//
//void Video::set_video_page(int page) {
// printf("Video page: %d\n", page);
//}
//
//void Video::set_low_resolution() {
// printf("Low resolution\n");
//}
//
//void Video::set_high_resolution() {
// printf("High resolution\n");
//}
namespace {
struct ScaledByteFiller {
ScaledByteFiller() {
VideoBase::setup_tables();
}
} throwaway;
}
VideoBase::VideoBase() :
crt_(new Outputs::CRT::CRT(455, 1, Outputs::CRT::DisplayType::NTSC60, 1)) {
// Set a composite sampling function that assumes 1bpp input, and uses just 7 bits per byte.
crt_->set_composite_sampling_function(
"float composite_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate, float phase, float amplitude)"
"{"
"uint texValue = texture(sampler, coordinate).r;"
"texValue <<= uint(icoordinate.x * 7.0) % 7u;"
"return float(texValue & 64u);"
"}");
// TODO: the above has precision issues. Fix!
// Show only the centre 75% of the TV frame.
crt_->set_video_signal(Outputs::CRT::VideoSignal::Composite);
crt_->set_visible_area(Outputs::CRT::Rect(0.115f, 0.117f, 0.77f, 0.77f));
}
Outputs::CRT::CRT *VideoBase::get_crt() {
return crt_.get();
}
uint16_t VideoBase::scaled_byte[256];
uint16_t VideoBase::low_resolution_patterns[2][16];
void VideoBase::setup_tables() {
for(int c = 0; c < 128; ++c) {
const uint16_t value =
((c & 0x01) ? 0x0003 : 0x0000) |
((c & 0x02) ? 0x000c : 0x0000) |
((c & 0x04) ? 0x0030 : 0x0000) |
((c & 0x08) ? 0x0140 : 0x0000) |
((c & 0x10) ? 0x0600 : 0x0000) |
((c & 0x20) ? 0x1800 : 0x0000) |
((c & 0x40) ? 0x6000 : 0x0000);
uint8_t *const table_entry = reinterpret_cast<uint8_t *>(&scaled_byte[c]);
table_entry[1] = static_cast<uint8_t>(value & 0xff);
table_entry[0] = static_cast<uint8_t>(value >> 8);
}
for(int c = 128; c < 256; ++c) {
uint8_t *const source_table_entry = reinterpret_cast<uint8_t *>(&scaled_byte[c & 0x7f]);
uint8_t *const destination_table_entry = reinterpret_cast<uint8_t *>(&scaled_byte[c]);
destination_table_entry[0] = static_cast<uint8_t>(source_table_entry[0] >> 1);
destination_table_entry[1] = static_cast<uint8_t>((source_table_entry[1] >> 1) | ((source_table_entry[0]&1) << 6));
}
for(int c = 0; c < 16; ++c) {
uint8_t *table_entry = reinterpret_cast<uint8_t *>(&low_resolution_patterns[0][c]);
table_entry[1] = static_cast<uint8_t>(c | (c << 4));
table_entry[0] = static_cast<uint8_t>((c >> 3) | (c << 1) | (c << 5));
table_entry = reinterpret_cast<uint8_t *>(&low_resolution_patterns[1][c]);
table_entry[1] = static_cast<uint8_t>((c >> 2) | (c << 2) | (c << 6));
table_entry[0] = static_cast<uint8_t>((c >> 1) | (c << 3));
}
}
void VideoBase::set_graphics_mode() {
use_graphics_mode_ = true;
}
void VideoBase::set_text_mode() {
use_graphics_mode_ = false;
}
void VideoBase::set_mixed_mode(bool mixed_mode) {
mixed_mode_ = mixed_mode;
}
void VideoBase::set_video_page(int page) {
video_page_ = page;
}
void VideoBase::set_low_resolution() {
graphics_mode_ = GraphicsMode::LowRes;
}
void VideoBase::set_high_resolution() {
graphics_mode_ = GraphicsMode::HighRes;
}
void VideoBase::set_character_rom(const std::vector<uint8_t> &character_rom) {
character_rom_ = character_rom;
}

174
Machines/AppleII/Video.hpp
View File

@ -24,41 +24,52 @@ class BusHandler {
}
};
template <class BusHandler> class Video {
class VideoBase {
public:
VideoBase();
static void setup_tables();
/// @returns The CRT this video feed is feeding.
Outputs::CRT::CRT *get_crt();
// Inputs for the various soft switches.
void set_graphics_mode();
void set_text_mode();
void set_mixed_mode(bool);
void set_video_page(int);
void set_low_resolution();
void set_high_resolution();
// Setup for text mode.
void set_character_rom(const std::vector<uint8_t> &);
protected:
std::unique_ptr<Outputs::CRT::CRT> crt_;
int video_page_ = 0;
int row_ = 0, column_ = 0;
uint16_t *pixel_pointer_ = nullptr;
std::vector<uint8_t> character_rom_;
enum class GraphicsMode {
LowRes,
HighRes,
Text
} graphics_mode_ = GraphicsMode::LowRes;
bool use_graphics_mode_ = false;
bool mixed_mode_ = false;
uint16_t graphics_carry_ = 0;
static uint16_t scaled_byte[256];
static uint16_t low_resolution_patterns[2][16];
};
template <class BusHandler> class Video: public VideoBase {
public:
/// Constructs an instance of the video feed; a CRT is also created.
Video(BusHandler &bus_handler) :
bus_handler_(bus_handler),
crt_(new Outputs::CRT::CRT(455, 1, Outputs::CRT::DisplayType::NTSC60, 1)) {
// Set a composite sampling function that assumes 1bpp input, and uses just 7 bits per byte.
crt_->set_composite_sampling_function(
"float composite_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate, float phase, float amplitude)"
"{"
// "uint texValue = texture(sampler, coordinate).r;"
// "texValue <<= int(icoordinate.x * 8) & 7;"
// "return float(texValue & 128u);"
"uint texValue = texture(sampler, coordinate).r;"
"texValue <<= uint(icoordinate.x * 7.0) % 7u;"
"return float(texValue & 64u);"
// "uint texValue = texture(sampler, coordinate).r;"
// "texValue <<= uint(mod(icoordinate.x, 1.0) * 7.0);"
// "return float(texValue & 64u);"
"}");
// TODO: the above has precision issues. Fix!
// Show only the centre 75% of the TV frame.
crt_->set_video_signal(Outputs::CRT::VideoSignal::Composite);
crt_->set_visible_area(Outputs::CRT::Rect(0.115f, 0.117f, 0.77f, 0.77f));
}
/// @returns The CRT this video feed is feeding.
Outputs::CRT::CRT *get_crt() {
return crt_.get();
}
VideoBase(),
bus_handler_(bus_handler) {}
/*!
Advances time by @c cycles; expects to be fed by the CPU clock.
@ -83,6 +94,9 @@ template <class BusHandler> class Video {
crt_->output_sync(static_cast<unsigned int>(cycles_this_line) * 7);
} else {
const int ending_column = column_ + cycles_this_line;
GraphicsMode line_mode = graphics_mode_;
if(!use_graphics_mode_ || (mixed_mode_ && row_ >= 160))
line_mode = GraphicsMode::Text;
// The first 40 columns are submitted to the CRT only upon completion;
// they'll be either graphics or blank, depending on which side we are
@ -90,27 +104,49 @@ template <class BusHandler> class Video {
if(column_ < 40) {
if(row_ < 192) {
if(!column_) {
pixel_pointer_ = crt_->allocate_write_area(40);
pixel_pointer_ = reinterpret_cast<uint16_t *>(crt_->allocate_write_area(80, 2));
}
const int pixel_end = std::min(40, ending_column);
const int character_row = row_ >> 3;
const int pixel_row = row_ & 7;
const uint16_t line_address = static_cast<uint16_t>(0x400 + (video_page_ * 0x400) + (character_row >> 3) * 40 + ((character_row&7) << 7));
const uint16_t row_address = static_cast<uint16_t>((character_row >> 3) * 40 + ((character_row&7) << 7));
const uint16_t text_address = static_cast<uint16_t>(((video_page_+1) * 0x400) + row_address);
const uint16_t graphics_address = static_cast<uint16_t>(((video_page_+1) * 0x1000) + row_address + ((pixel_row&7) << 9));
const int row_shift = (row_&4);
for(int c = column_; c < pixel_end; ++c) {
const uint16_t address = static_cast<uint16_t>(line_address + c);
const uint8_t character = bus_handler_.perform_read(address);
const int index = (character & 0x7f) << 3;
switch(line_mode) {
case GraphicsMode::Text:
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 & 0x7f) << 3) + pixel_row);
const std::size_t character_address = static_cast<std::size_t>(index + pixel_row);
pixel_pointer_[c] = character_rom_[character_address] ^ ((character & 0x80) ? 0x00 : 0xff);
const uint8_t character_pattern = character_rom_[character_address] ^ ((character & 0x80) ? 0x00 : 0xff);
pixel_pointer_[c] = scaled_byte[character_pattern & 0x7f];
}
break;
case GraphicsMode::LowRes:
for(int c = column_; c < pixel_end; ++c) {
const uint8_t character = bus_handler_.perform_read(static_cast<uint16_t>(text_address + c));
pixel_pointer_[c] = low_resolution_patterns[column_&1][(character >> row_shift)&0xf];
}
break;
case GraphicsMode::HighRes:
for(int c = column_; c < pixel_end; ++c) {
const uint8_t graphic = bus_handler_.perform_read(static_cast<uint16_t>(graphics_address + c));
pixel_pointer_[c] = scaled_byte[graphic];
if(graphic & 0x80) {
reinterpret_cast<uint8_t *>(&pixel_pointer_[c])[0] |= graphics_carry_ << 7;
}
graphics_carry_ = pixel_pointer_[c] & 1;
}
break;
}
// TODO: graphics; 0x2000+ for high resolution
if(ending_column >= 40) {
crt_->output_data(280, 40);
crt_->output_data(280, 80);
}
} else {
if(ending_column >= 40) {
@ -130,15 +166,25 @@ template <class BusHandler> class Video {
crt_->output_blank(static_cast<unsigned int>(first_blank_end - first_blank_start) * 7);
}
// TODO: colour burst.
const int sync_start = std::max(first_sync_column, column_);
const int sync_end = std::min(first_sync_column + 4, ending_column);
if(sync_end > sync_start) {
crt_->output_sync(static_cast<unsigned int>(sync_end - sync_start) * 7);
}
const int second_blank_start = std::max(first_sync_column + 4, column_);
int second_blank_start;
if(line_mode != GraphicsMode::Text) {
const int colour_burst_start = std::max(first_sync_column + 4, column_);
const int colour_burst_end = std::min(first_sync_column + 7, ending_column);
if(colour_burst_end > colour_burst_start) {
crt_->output_default_colour_burst(static_cast<unsigned int>(colour_burst_end - colour_burst_start) * 7);
}
second_blank_start = std::max(first_sync_column + 7, column_);
} else {
second_blank_start = std::max(first_sync_column + 4, column_);
}
if(ending_column > second_blank_start) {
crt_->output_blank(static_cast<unsigned int>(ending_column - second_blank_start) * 7);
}
@ -156,44 +202,8 @@ template <class BusHandler> class Video {
}
}
// Inputs for the various soft switches.
void set_graphics_mode() {
printf("Graphics mode\n");
}
void set_text_mode() {
printf("Text mode\n");
}
void set_mixed_mode(bool mixed_mode) {
printf("Mixed mode: %s\n", mixed_mode ? "true" : "false");
}
void set_video_page(int page) {
video_page_ = page;
printf("Video page: %d\n", page);
}
void set_low_resolution() {
printf("Low resolution\n");
}
void set_high_resolution() {
printf("High resolution\n");
}
void set_character_rom(const std::vector<uint8_t> &character_rom) {
character_rom_ = character_rom;
}
private:
BusHandler &bus_handler_;
std::unique_ptr<Outputs::CRT::CRT> crt_;
int video_page_ = 0;
int row_ = 0, column_ = 0;
uint8_t *pixel_pointer_ = nullptr;
std::vector<uint8_t> character_rom_;
};
}