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Made an attempt to reintroduce the basic horizontal loop.

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This commit is contained in:
Thomas Harte 2017-01-29 15:43:57 -05:00
parent 2390358c24
commit d51f185dc7
3 changed files with 73 additions and 3 deletions
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73
Machines/Atari2600/TIA.cpp
View File

@ -14,7 +14,9 @@ namespace {
}
TIA::TIA() :
horizontal_counter_(0)
horizontal_counter_(0),
output_cursor_(0),
pixel_target_(nullptr)
{
crt_.reset(new Outputs::CRT::CRT(cycles_per_line * 2 + 1, 1, Outputs::CRT::DisplayType::NTSC60, 1));
crt_->set_output_device(Outputs::CRT::Television);
@ -76,7 +78,6 @@ void TIA::run_for_cycles(int number_of_cycles)
{
int cycles = std::min(number_of_cycles, cycles_per_line - horizontal_counter_);
output_for_cycles(cycles);
horizontal_counter_ = (horizontal_counter_ + cycles) % cycles_per_line;
number_of_cycles -= cycles;
}
@ -91,7 +92,6 @@ void TIA::run_for_cycles(int number_of_cycles)
if(number_of_cycles)
{
output_for_cycles(number_of_cycles);
horizontal_counter_ = (horizontal_counter_ + number_of_cycles) % cycles_per_line;
}
}
@ -205,10 +205,77 @@ void TIA::clear_collision_flags()
{
}
// case 0: case 1: case 2: case 3: state = OutputState::Blank; break;
// case 4: case 5: case 6: case 7: state = OutputState::Sync; break;
// case 8: case 9: case 10: case 11: state = OutputState::ColourBurst; break;
// case 12: case 13: case 14:
// case 15: case 16: state = OutputState::Blank; break;
//
// case 17: case 18: state = vbextend ? OutputState::Blank : OutputState::Pixel; break;
// default: state = OutputState::Pixel; break;
void TIA::output_for_cycles(int number_of_cycles)
{
/*
Line timing is oriented around 0 being the start of the right-hand side vertical blank;
a wsync synchronises the CPU to horizontal_counter_ = 0. All timing below is in terms of the
NTSC colour clock.
Therefore, each line is composed of:
16 cycles: blank ; -> 16
16 cycles: sync ; -> 32
16 cycles: colour burst ; -> 48
20 cycles: blank ; -> 68
8 cycles: blank or pixels, depending on whether the blank extend bit is set
152 cycles: pixels
*/
horizontal_counter_ += number_of_cycles;
if(!output_cursor_ && horizontal_counter_ >= 16)
{
crt_->output_blank(32);
output_cursor_ = 16;
}
if(output_cursor_ == 16 && horizontal_counter_ >= 32)
{
crt_->output_sync(32);
output_cursor_ = 32;
}
if(output_cursor_ == 32 && horizontal_counter_ >= 48)
{
crt_->output_default_colour_burst(32);
output_cursor_ = 48;
}
if(output_cursor_ == 48 && horizontal_counter_ >= 68)
{
crt_->output_default_colour_burst(40);
output_cursor_ = 68;
}
if(horizontal_counter_ > 68)
{
if(output_cursor_ == 68)
{
pixel_target_ = crt_->allocate_write_area(160);
}
if(pixel_target_)
{
while(output_cursor_ < horizontal_counter_)
{
pixel_target_[output_cursor_ - 68] = (output_cursor_&1) ? 0xff : 0x00;
output_cursor_++;
}
} else output_cursor_ = horizontal_counter_;
if(horizontal_counter_ == cycles_per_line)
{
crt_->output_data(320, 2);
pixel_target_ = nullptr;
}
}
horizontal_counter_ %= cycles_per_line;
}
void TIA::output_line()
{
// TODO: optimise special case
output_for_cycles(cycles_per_line);
}

2
Machines/Atari2600/TIA.hpp
View File

@ -68,6 +68,8 @@ class TIA {
std::shared_ptr<Outputs::CRT::CRT> crt_;
int horizontal_counter_;
int output_cursor_;
uint8_t *pixel_target_;
void output_for_cycles(int number_of_cycles);
void output_line();

1
OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme
View File

@ -69,6 +69,7 @@
useCustomWorkingDirectory = "NO"
ignoresPersistentStateOnLaunch = "NO"
debugDocumentVersioning = "YES"
enableAddressSanitizer = "YES"
debugServiceExtension = "internal"
allowLocationSimulation = "NO">
<BuildableProductRunnable