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Made complete attempt at sync discrimination. But I seem somehow to be locking such that horizontal sync is in the middle of the line. Obviously my flywheel is at fault somehow.

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This commit is contained in:
Thomas Harte 2015-07-20 21:43:00 -04:00
parent 4e4c082a05
commit 4695295dd1
2 changed files with 110 additions and 118 deletions
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210
Outputs/CRT.cpp
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@ -14,6 +14,9 @@ static const int bufferHeight = 512;
static const int syncCapacityLineChargeThreshold = 3; static const int syncCapacityLineChargeThreshold = 3;
static const int millisecondsHorizontalRetraceTime = 16; static const int millisecondsHorizontalRetraceTime = 16;
static const int scanlinesVerticalRetraceTime = 26;
#define kEmergencyRetraceTime (_expected_next_hsync + _hsync_error_window)
using namespace Outputs; using namespace Outputs;
@ -42,7 +45,6 @@ CRT::CRT(int cycles_per_line, int number_of_buffers, ...)
_horizontal_counter = 0; _horizontal_counter = 0;
_sync_capacitor_charge_level = 0; _sync_capacitor_charge_level = 0;
_hretrace_counter = -1;
_is_in_sync = false; _is_in_sync = false;
_vsync_is_proposed = false; _vsync_is_proposed = false;
} }
@ -57,148 +59,128 @@ CRT::~CRT()
delete[] _buffers; delete[] _buffers;
} }
#pragma mark - Sync decisions #pragma mark - Sync loop
#define hretrace_period() ((millisecondsHorizontalRetraceTime * _cycles_per_line) >> 6) CRT::SyncEvent CRT::advance_to_next_sync_event(bool hsync_is_requested, bool vsync_is_charging, int cycles_to_run_for, int *cycles_advanced)
void CRT::propose_hsync()
{ {
if (_horizontal_counter >= _expected_next_hsync - _hsync_error_window) // do we recognise this hsync, thereby adjusting time expectations?
{ if (_horizontal_counter >= _expected_next_hsync - _hsync_error_window && hsync_is_requested) {
_expected_next_hsync = (_horizontal_counter + _expected_next_hsync) >> 1; _did_detect_hsync = true;
do_hsync(); _expected_next_hsync = (_expected_next_hsync + _horizontal_counter) >> 1;
} }
else
{
printf("r %d\n", _horizontal_counter);
}
}
void CRT::charge_vsync(int number_of_cycles) SyncEvent proposedEvent = SyncEvent::None;
{ int proposedSyncTime = cycles_to_run_for;
// will we start indicating hsync during this charge?
const int final_capacitor_charge_level = _sync_capacitor_charge_level + number_of_cycles;
const int required_capacitor_charge_level = syncCapacityLineChargeThreshold*_cycles_per_line;
if(_sync_capacitor_charge_level < required_capacitor_charge_level && final_capacitor_charge_level >= required_capacitor_charge_level)
{
const int cycles_until_vsync_starts = required_capacitor_charge_level - _sync_capacitor_charge_level;
run_line_for_cycles(cycles_until_vsync_starts);
_vsync_is_proposed = true;
run_line_for_cycles(number_of_cycles - cycles_until_vsync_starts);
}
else
{
run_line_for_cycles(number_of_cycles);
}
_sync_capacitor_charge_level += number_of_cycles;
}
void CRT::drain_vsync(int number_of_cycles) // will we end an ongoing hsync?
{ const int endOfHSyncTime = (millisecondsHorizontalRetraceTime*_cycles_per_line) >> 6;
// will we stop indicating hsync during this charge? if (_horizontal_counter < endOfHSyncTime && _horizontal_counter+proposedSyncTime >= endOfHSyncTime) {
const int required_capacitor_charge_level = syncCapacityLineChargeThreshold*_cycles_per_line; proposedSyncTime = endOfHSyncTime - _horizontal_counter;
if(_sync_capacitor_charge_level >= required_capacitor_charge_level && _sync_capacitor_charge_level - number_of_cycles < required_capacitor_charge_level) proposedEvent = SyncEvent::EndHSync;
{
const int cycles_until_vsync_ends = _sync_capacitor_charge_level - required_capacitor_charge_level;
run_line_for_cycles(cycles_until_vsync_ends);
_vsync_is_proposed = false;
run_line_for_cycles(number_of_cycles - cycles_until_vsync_ends);
} }
else
{ // will we start an hsync?
run_line_for_cycles(number_of_cycles); if (_horizontal_counter + proposedSyncTime >= _expected_next_hsync) {
proposedSyncTime = _expected_next_hsync - _horizontal_counter;
proposedEvent = SyncEvent::StartHSync;
} }
_sync_capacitor_charge_level = std::max(0, _sync_capacitor_charge_level - number_of_cycles);
}
void CRT::run_line_for_cycles(int number_of_cycles) // will an acceptable vertical sync be triggered?
{ if (vsync_is_charging && !_vretrace_counter) {
// we're guaranteed not to see any vertical sync events during this run_for_cycles; const int startOfVSyncTime = syncCapacityLineChargeThreshold*_cycles_per_line;
// will we see a horizontal?
if(!_hretrace_counter) if (_sync_capacitor_charge_level < startOfVSyncTime && _sync_capacitor_charge_level + proposedSyncTime >= startOfVSyncTime) {
{ proposedSyncTime = startOfVSyncTime - _sync_capacitor_charge_level;
const int end_counter = _horizontal_counter + number_of_cycles; proposedEvent = SyncEvent::StartVSync;
const int last_allowed_retrace_time = _expected_next_hsync + _hsync_error_window; }
if(end_counter >= last_allowed_retrace_time) }
{
// there'll be a forced retrace, and we didn't detect a sync pulse so we'll // TODO: will a late-in-the-day vertical sync be forced?
// push back towards the default period
const int cycles_before_retrace = end_counter - last_allowed_retrace_time; // will an ongoing vertical sync end?
run_hline_for_cycles(cycles_before_retrace); if (_vretrace_counter > 0) {
do_hsync(); if (_vretrace_counter < proposedSyncTime) {
_hretrace_counter = hretrace_period(); proposedSyncTime = _vretrace_counter;
_expected_next_hsync = (_expected_next_hsync + _cycles_per_line) >> 1; proposedEvent = SyncEvent::EndVSync;
run_hline_for_cycles(number_of_cycles - cycles_before_retrace);
} }
}
*cycles_advanced = proposedSyncTime;
return proposedEvent;
}
void CRT::advance_cycles(int number_of_cycles, bool hsync_requested, const bool vsync_charging, const CRTRun::Type type)
{
while(number_of_cycles) {
int next_run_length;
SyncEvent next_event = advance_to_next_sync_event(hsync_requested, vsync_charging, number_of_cycles, &next_run_length);
for(int c = 0; c < next_run_length; c++)
{
switch(type)
{
case CRTRun::Type::Data: putc('-', stdout); break;
case CRTRun::Type::Blank: putc(' ', stdout); break;
case CRTRun::Type::Level: putc('_', stdout); break;
case CRTRun::Type::Sync: putc('<', stdout); break;
}
}
// printf("[[%d]%d:%d]", type, next_event, next_run_length);
hsync_requested = false;
number_of_cycles -= next_run_length;
_horizontal_counter += next_run_length;
if (vsync_charging)
_sync_capacitor_charge_level += next_run_length;
else else
{ _sync_capacitor_charge_level = std::max(_sync_capacitor_charge_level - next_run_length, 0);
// we'll just output, no big deal
run_hline_for_cycles(number_of_cycles); _vretrace_counter = std::max(_vretrace_counter - next_run_length, 0);
switch(next_event) {
default: break;
case SyncEvent::StartHSync:
_horizontal_counter = 0;
if (!_did_detect_hsync) {
_expected_next_hsync = (_expected_next_hsync + _cycles_per_line) >> 1;
}
_did_detect_hsync = false;
printf("\n");
break;
case SyncEvent::StartVSync:
_vretrace_counter = scanlinesVerticalRetraceTime * _cycles_per_line;
printf("\n\n===\n\n");
break;
} }
} }
else
{
if(_hretrace_counter - number_of_cycles < 0)
{
// we'll fully retrace and exit
number_of_cycles -= _hretrace_counter;
run_hline_for_cycles(number_of_cycles - _hretrace_counter);
_hretrace_counter = 0;
}
else
{
// we'll spend this whole period retracing
_hretrace_counter -= number_of_cycles;
}
_hretrace_counter = std::max(0, _hretrace_counter - number_of_cycles);
}
} }
void CRT::run_hline_for_cycles(int number_of_cycles)
{
_horizontal_counter += number_of_cycles;
}
void CRT::do_hsync()
{
printf("%d\n", _horizontal_counter);
_hretrace_counter = hretrace_period();
_horizontal_counter = 0;
}
#pragma mark - stream feeding methods #pragma mark - stream feeding methods
void CRT::output_sync(int number_of_cycles) void CRT::output_sync(int number_of_cycles)
{ {
// printf("[%d]\n", number_of_cycles); bool _hsync_requested = !_is_in_sync;
// _is_in_sync = true;
// if(number_of_cycles > 16) advance_cycles(number_of_cycles, _hsync_requested, true, CRTRun::Type::Sync);
// {
// printf("!!!\n");
// }
// horizontal sync is edge triggered
if(!_is_in_sync)
{
_is_in_sync = true;
propose_hsync();
}
charge_vsync(number_of_cycles);
} }
void CRT::output_level(int number_of_cycles, std::string type) void CRT::output_level(int number_of_cycles, std::string type)
{ {
_is_in_sync = false; _is_in_sync = false;
drain_vsync(number_of_cycles); advance_cycles(number_of_cycles, false, false, CRTRun::Type::Level);
} }
void CRT::output_data(int number_of_cycles, std::string type) void CRT::output_data(int number_of_cycles, std::string type)
{ {
_is_in_sync = false; _is_in_sync = false;
drain_vsync(number_of_cycles); advance_cycles(number_of_cycles, false, false, CRTRun::Type::Data);
}
void CRT::output_blank(int number_of_cycles, std::string type)
{
_is_in_sync = false;
advance_cycles(number_of_cycles, false, false, CRTRun::Type::Blank);
} }
#pragma mark - Buffer supply #pragma mark - Buffer supply

18
Outputs/CRT.hpp
View File

@ -22,6 +22,7 @@ class CRT {
void output_sync(int number_of_cycles); void output_sync(int number_of_cycles);
void output_level(int number_of_cycles, std::string type); void output_level(int number_of_cycles, std::string type);
void output_blank(int number_of_cycles, std::string type);
void output_data(int number_of_cycles, std::string type); void output_data(int number_of_cycles, std::string type);
struct CRTRun { struct CRTRun {
@ -30,7 +31,7 @@ class CRT {
} start_point, end_point; } start_point, end_point;
enum Type { enum Type {
Sync, Level, Data Sync, Level, Data, Blank
} type; } type;
std::string data_type; std::string data_type;
@ -49,7 +50,6 @@ class CRT {
private: private:
CRTDelegate *_delegate; CRTDelegate *_delegate;
int _sync_capacitor_charge_level;
float _horizontalOffset, _verticalOffset; float _horizontalOffset, _verticalOffset;
uint8_t **_buffers; uint8_t **_buffers;
@ -68,11 +68,21 @@ class CRT {
void do_hsync(); void do_hsync();
void do_vsync(); void do_vsync();
int _horizontal_counter, _expected_next_hsync, _hsync_error_window, _hretrace_counter;
int _cycles_per_line; int _cycles_per_line;
bool _is_in_sync, _vsync_is_proposed; bool _is_in_sync, _vsync_is_proposed, _did_detect_hsync;
enum SyncEvent {
None,
StartHSync, EndHSync,
StartVSync, EndVSync
};
SyncEvent advance_to_next_sync_event(bool hsync_is_requested, bool vsync_is_charging, int cycles_to_run_for, int *cycles_advanced);
int _sync_capacitor_charge_level, _vretrace_counter;
int _horizontal_counter, _expected_next_hsync, _hsync_error_window;
void advance_cycles(int number_of_cycles, bool hsync_requested, bool vsync_charging, CRTRun::Type type);
}; };
} }