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Consolidate StandardTiming into LineLayout.

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This commit is contained in:
Thomas Harte 2023-05-11 23:49:12 -04:00
parent 7f5d129b13
commit 7e319374b6
3 changed files with 38 additions and 38 deletions
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2
Components/9918/9918.hpp
View File

@ -18,6 +18,8 @@ namespace TI::TMS {
enum Personality {
TMS9918A, // includes the 9928 and 9929; set TV standard and output device as desired.
// Yamaha extensions.
V9938,
V9958,

44
Components/9918/Implementation/9918.cpp
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@ -35,7 +35,7 @@ Base<personality>::Base() :
// "For a line interrupt, /INT is pulled low 608 mclks into the appropriate scanline relative to pixel 0.
// This is 3 mclks before the rising edge of /HSYNC which starts the next scanline."
mode_timing_.line_interrupt_position = (LineLayout<personality>::EndOfLeftBorder + 304) % Timing<personality>::CyclesPerLine;
mode_timing_.line_interrupt_position = (LineLayout<personality>::EndOfLeftBorder + 304) % LineLayout<personality>::CyclesPerLine;
// For a frame interrupt, /INT is pulled low 607 mclks into scanline 192 (of scanlines 0 through 261) relative to pixel 0.
// This is 4 mclks before the rising edge of /HSYNC which starts the next scanline.
@ -197,7 +197,7 @@ void TMS9918<personality>::run_for(const HalfCycles cycles) {
if(fetch_cycles_pool) {
// Determine how much writing to do; at the absolute most go to the end of this line.
const int fetch_cycles = std::min(
Timing<personality>::CyclesPerLine - this->fetch_pointer_.column,
LineLayout<personality>::CyclesPerLine - this->fetch_pointer_.column,
fetch_cycles_pool
);
const int end_column = this->fetch_pointer_.column + fetch_cycles;
@ -319,7 +319,7 @@ void TMS9918<personality>::run_for(const HalfCycles cycles) {
fetch_cycles_pool -= fetch_cycles;
// Check for end of line.
if(this->fetch_pointer_.column == Timing<personality>::CyclesPerLine) {
if(this->fetch_pointer_.column == LineLayout<personality>::CyclesPerLine) {
this->fetch_pointer_.column = 0;
this->fetch_pointer_.row = (this->fetch_pointer_.row + 1) % this->mode_timing_.total_lines;
@ -341,13 +341,13 @@ void TMS9918<personality>::run_for(const HalfCycles cycles) {
this->minimum_access_column_ =
std::max(
0,
this->minimum_access_column_ - Timing<personality>::CyclesPerLine
this->minimum_access_column_ - LineLayout<personality>::CyclesPerLine
);
if constexpr (is_yamaha_vdp(personality)) {
Storage<personality>::minimum_command_column_ =
std::max(
0,
Storage<personality>::minimum_command_column_ - Timing<personality>::CyclesPerLine
Storage<personality>::minimum_command_column_ - LineLayout<personality>::CyclesPerLine
);
}
@ -457,7 +457,7 @@ void TMS9918<personality>::run_for(const HalfCycles cycles) {
if(output_cycles_pool) {
// Determine how much time has passed in the remainder of this line, and proceed.
const int target_output_cycles = std::min(
Timing<personality>::CyclesPerLine - this->output_pointer_.column,
LineLayout<personality>::CyclesPerLine - this->output_pointer_.column,
output_cycles_pool
);
int output_cycles_performed = 0;
@ -522,8 +522,8 @@ void TMS9918<personality>::run_for(const HalfCycles cycles) {
};
const auto right_blank = [&]() {
if(end_column == Timing<personality>::CyclesPerLine) {
output_blank(Timing<personality>::CyclesPerLine - LineLayout<personality>::EndOfRightBorder);
if(end_column == LineLayout<personality>::CyclesPerLine) {
output_blank(LineLayout<personality>::CyclesPerLine - LineLayout<personality>::EndOfRightBorder);
}
};
@ -534,8 +534,8 @@ void TMS9918<personality>::run_for(const HalfCycles cycles) {
) {
// Vertical sync.
// TODO: the Yamaha and Mega Drive both support interlaced video.
if(end_column == Timing<personality>::CyclesPerLine) {
output_sync(Timing<personality>::CyclesPerLine);
if(end_column == LineLayout<personality>::CyclesPerLine) {
output_sync(LineLayout<personality>::CyclesPerLine);
}
} else {
left_blank();
@ -610,14 +610,14 @@ void TMS9918<personality>::run_for(const HalfCycles cycles) {
// Advance time.
// -------------
this->output_pointer_.column = end_column;
if(end_column == Timing<personality>::CyclesPerLine) {
if(end_column == LineLayout<personality>::CyclesPerLine) {
// Advance line buffer.
this->advance(this->draw_line_buffer_);
}
}
output_cycles_pool -= target_output_cycles;
if(this->output_pointer_.column == Timing<personality>::CyclesPerLine) {
if(this->output_pointer_.column == LineLayout<personality>::CyclesPerLine) {
this->output_pointer_.column = 0;
this->output_pointer_.row = (this->output_pointer_.row + 1) % this->mode_timing_.total_lines;
}
@ -685,7 +685,7 @@ void Base<personality>::write_vram(uint8_t value) {
// Enqueue the write to occur at the next available slot.
read_ahead_buffer_ = value;
queued_access_ = MemoryAccess::Write;
minimum_access_column_ = fetch_pointer_.column + Timing<personality>::VRAMAccessDelay;
minimum_access_column_ = fetch_pointer_.column + LineLayout<personality>::VRAMAccessDelay;
}
template <Personality personality>
@ -1034,7 +1034,7 @@ void Base<personality>::write_register(uint8_t value) {
// A read request is enqueued upon setting the address; conversely a write
// won't be enqueued unless and until some actual data is supplied.
queued_access_ = MemoryAccess::Read;
minimum_access_column_ = fetch_pointer_.column + Timing<personality>::VRAMAccessDelay;
minimum_access_column_ = fetch_pointer_.column + LineLayout<personality>::VRAMAccessDelay;
}
if constexpr (is_sega_vdp(personality)) {
@ -1242,11 +1242,11 @@ HalfCycles TMS9918<personality>::get_next_sequence_point() const {
if(get_interrupt_line()) return HalfCycles::max();
// Calculate the amount of time until the next end-of-frame interrupt.
const int frame_length = Timing<personality>::CyclesPerLine * this->mode_timing_.total_lines;
const int frame_length = LineLayout<personality>::CyclesPerLine * this->mode_timing_.total_lines;
int time_until_frame_interrupt =
(
((this->mode_timing_.end_of_frame_interrupt_position.row * Timing<personality>::CyclesPerLine) + this->mode_timing_.end_of_frame_interrupt_position.column + frame_length) -
((this->fetch_pointer_.row * Timing<personality>::CyclesPerLine) + this->fetch_pointer_.column)
((this->mode_timing_.end_of_frame_interrupt_position.row * LineLayout<personality>::CyclesPerLine) + this->mode_timing_.end_of_frame_interrupt_position.column + frame_length) -
((this->fetch_pointer_.row * LineLayout<personality>::CyclesPerLine) + this->fetch_pointer_.column)
) % frame_length;
if(!time_until_frame_interrupt) time_until_frame_interrupt = frame_length;
@ -1260,7 +1260,7 @@ HalfCycles TMS9918<personality>::get_next_sequence_point() const {
int cycles_to_next_interrupt_threshold = this->mode_timing_.line_interrupt_position - this->fetch_pointer_.column;
int line_of_next_interrupt_threshold = this->fetch_pointer_.row;
if(cycles_to_next_interrupt_threshold <= 0) {
cycles_to_next_interrupt_threshold += Timing<personality>::CyclesPerLine;
cycles_to_next_interrupt_threshold += LineLayout<personality>::CyclesPerLine;
++line_of_next_interrupt_threshold;
}
@ -1291,7 +1291,7 @@ HalfCycles TMS9918<personality>::get_next_sequence_point() const {
// Figure out the number of internal cycles until the next line interrupt, which is the amount
// of time to the next tick over and then next_line_interrupt_row - row_ lines further.
const int lines_until_interrupt = (next_line_interrupt_row - line_of_next_interrupt_threshold + this->mode_timing_.total_lines) % this->mode_timing_.total_lines;
const int local_cycles_until_line_interrupt = cycles_to_next_interrupt_threshold + lines_until_interrupt * Timing<personality>::CyclesPerLine;
const int local_cycles_until_line_interrupt = cycles_to_next_interrupt_threshold + lines_until_interrupt * LineLayout<personality>::CyclesPerLine;
if(!this->generate_interrupts_) return this->clock_converter_.half_cycles_before_internal_cycles(local_cycles_until_line_interrupt);
// Return whichever interrupt is closer.
@ -1305,7 +1305,7 @@ HalfCycles TMS9918<personality>::get_time_until_line(int line) {
int cycles_to_next_interrupt_threshold = this->mode_timing_.line_interrupt_position - this->fetch_pointer_.column;
int line_of_next_interrupt_threshold = this->fetch_pointer_.row;
if(cycles_to_next_interrupt_threshold <= 0) {
cycles_to_next_interrupt_threshold += Timing<personality>::CyclesPerLine;
cycles_to_next_interrupt_threshold += LineLayout<personality>::CyclesPerLine;
++line_of_next_interrupt_threshold;
}
@ -1313,7 +1313,7 @@ HalfCycles TMS9918<personality>::get_time_until_line(int line) {
line += this->mode_timing_.total_lines;
}
return this->clock_converter_.half_cycles_before_internal_cycles(cycles_to_next_interrupt_threshold + (line - line_of_next_interrupt_threshold)*Timing<personality>::CyclesPerLine);
return this->clock_converter_.half_cycles_before_internal_cycles(cycles_to_next_interrupt_threshold + (line - line_of_next_interrupt_threshold)*LineLayout<personality>::CyclesPerLine);
}
template <Personality personality>
@ -1329,7 +1329,7 @@ template <Personality personality>uint8_t TMS9918<personality>::get_latched_hori
// which counts the 256 pixels as items 0–255, starts
// counting at -48, and returns only the top 8 bits of the number.
int public_counter = this->latched_column_ - LineLayout<personality>::EndOfLeftBorder;
if(public_counter < -46) public_counter += Timing<personality>::CyclesPerLine;
if(public_counter < -46) public_counter += LineLayout<personality>::CyclesPerLine;
return uint8_t(public_counter >> 1);
}

30
Components/9918/Implementation/ClockConverter.hpp
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@ -51,20 +51,6 @@ template <Personality personality, Clock clock> constexpr int from_internal(int
return length * clock_rate<personality, clock>() / clock_rate<personality, Clock::Internal>();
}
/// Provides default timing measurements that duplicate the layout of a TMS9928's line,
/// scaled to the clock rate specified.
template <Personality personality> struct StandardTiming {
/// The total number of internal cycles per line of output.
constexpr static int CyclesPerLine = clock_rate<personality, Clock::Internal>();
/// The number of internal cycles that must elapse between a request to read or write and
/// it becoming a candidate for action.
constexpr static int VRAMAccessDelay = 6;
};
/// Provides concrete, specific timing for the nominated personality.
template <Personality personality> struct Timing: public StandardTiming<personality> {};
/*!
Provides a [potentially-]stateful conversion between the external and internal clocks.
Unlike the other clock conversions, this one may be non-integral, requiring that
@ -174,9 +160,15 @@ template <Personality personality> struct LineLayout<personality, std::enable_if
constexpr static int EndOfLeftBorder = 63;
constexpr static int EndOfPixels = 319;
constexpr static int EndOfRightBorder = 334;
constexpr static int CyclesPerLine = 342;
constexpr static int TextModeEndOfLeftBorder = 69;
constexpr static int TextModeEndOfPixels = 309;
/// The number of internal cycles that must elapse between a request to read or write and
/// it becoming a candidate for action.
constexpr static int VRAMAccessDelay = 6;
};
template <Personality personality> struct LineLayout<personality, std::enable_if_t<is_yamaha_vdp(personality)>> {
@ -187,9 +179,15 @@ template <Personality personality> struct LineLayout<personality, std::enable_if
constexpr static int EndOfLeftBorder = 258;
constexpr static int EndOfPixels = 1282;
constexpr static int EndOfRightBorder = 1341;
constexpr static int CyclesPerLine = 1368;
constexpr static int TextModeEndOfLeftBorder = 294;
constexpr static int TextModeEndOfPixels = 1254;
/// The number of internal cycles that must elapse between a request to read or write and
/// it becoming a candidate for action.
constexpr static int VRAMAccessDelay = 16;
};
}