mirror of
https://github.com/TomHarte/CLK.git
synced 2024-11-07 19:05:38 +00:00
482 lines
14 KiB
C++
482 lines
14 KiB
C++
//
|
|
//
|
|
// Storage.hpp
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 12/02/2023.
|
|
// Copyright © 2023 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#ifndef Storage_h
|
|
#define Storage_h
|
|
|
|
#include "LineBuffer.hpp"
|
|
#include "YamahaCommands.hpp"
|
|
|
|
#include <optional>
|
|
|
|
namespace TI {
|
|
namespace TMS {
|
|
|
|
/// A container for personality-specific storage; see specific instances below.
|
|
template <Personality personality, typename Enable = void> struct Storage {
|
|
};
|
|
|
|
template <> struct Storage<Personality::TMS9918A> {
|
|
using AddressT = uint16_t;
|
|
|
|
void begin_line(ScreenMode, bool) {}
|
|
};
|
|
|
|
// Yamaha-specific storage.
|
|
template <Personality personality> struct Storage<personality, std::enable_if_t<is_yamaha_vdp(personality)>> {
|
|
using AddressT = uint32_t;
|
|
|
|
int selected_status_ = 0;
|
|
|
|
int indirect_register_ = 0;
|
|
bool increment_indirect_register_ = false;
|
|
|
|
std::array<uint32_t, 16> palette_{};
|
|
uint8_t new_colour_ = 0;
|
|
uint8_t palette_entry_ = 0;
|
|
bool palette_write_phase_ = false;
|
|
|
|
uint8_t mode_ = 0;
|
|
|
|
uint8_t vertical_offset_ = 0;
|
|
|
|
/// Describes an _observable_ memory access event. i.e. anything that it is safe
|
|
/// (and convenient) to treat as atomic in between external slots.
|
|
struct Event {
|
|
/// Offset of the _beginning_ of the event. Not completely arbitrarily: this is when
|
|
/// external data must be ready by in order to take part in those slots.
|
|
uint16_t offset = 1368;
|
|
enum class Type: uint8_t {
|
|
/// A slot for reading or writing data on behalf of the CPU or the command engine.
|
|
External,
|
|
|
|
//
|
|
// Sprites.
|
|
//
|
|
SpriteY,
|
|
SpriteLocation,
|
|
SpritePattern,
|
|
|
|
//
|
|
// Backgrounds.
|
|
//
|
|
Name,
|
|
Colour,
|
|
Pattern,
|
|
} type = Type::External;
|
|
uint8_t id = 0;
|
|
|
|
constexpr Event(Type type, uint8_t id = 0) noexcept :
|
|
type(type),
|
|
id(id) {}
|
|
|
|
constexpr Event() noexcept {}
|
|
};
|
|
|
|
// State that tracks fetching position within a line.
|
|
const Event *next_event_ = nullptr;
|
|
|
|
// Text blink colours.
|
|
uint8_t blink_text_colour_ = 0;
|
|
uint8_t blink_background_colour_ = 0;
|
|
|
|
// Blink state (which is also affects even/odd page display in applicable modes).
|
|
int in_blink_ = 1;
|
|
uint8_t blink_periods_ = 0;
|
|
uint8_t blink_counter_ = 0;
|
|
|
|
// Sprite collection state.
|
|
bool sprites_enabled_ = true;
|
|
|
|
/// Resets line-ephemeral state for a new line.
|
|
void begin_line(ScreenMode mode, bool is_refresh) {
|
|
if(is_refresh) {
|
|
next_event_ = refresh_events.data();
|
|
return;
|
|
}
|
|
|
|
switch(mode) {
|
|
case ScreenMode::YamahaText80:
|
|
case ScreenMode::Text:
|
|
next_event_ = text_events.data();
|
|
break;
|
|
|
|
case ScreenMode::MultiColour:
|
|
case ScreenMode::YamahaGraphics1:
|
|
case ScreenMode::YamahaGraphics2:
|
|
next_event_ = character_events.data();
|
|
break;
|
|
|
|
case ScreenMode::YamahaGraphics3: // TODO: verify; my guess is that G3 is timed like a bitmap mode
|
|
// in order to fit the pattern for sprite mode 2. Just a guess.
|
|
default:
|
|
next_event_ = sprites_enabled_ ? sprites_events.data() : no_sprites_events.data();
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Command engine state.
|
|
CommandContext command_context_;
|
|
std::unique_ptr<Command> command_ = nullptr;
|
|
|
|
enum class CommandStep {
|
|
None,
|
|
|
|
ReadSourcePixel,
|
|
ReadDestinationPixel,
|
|
WritePixel,
|
|
|
|
ReadSourceByte,
|
|
WriteByte,
|
|
};
|
|
CommandStep next_command_step_ = CommandStep::None;
|
|
int minimum_command_column_ = 0;
|
|
uint8_t command_latch_ = 0;
|
|
|
|
void update_command_step(int current_column) {
|
|
if(!command_) {
|
|
next_command_step_ = CommandStep::None;
|
|
return;
|
|
}
|
|
if(command_->done()) {
|
|
command_ = nullptr;
|
|
next_command_step_ = CommandStep::None;
|
|
return;
|
|
}
|
|
|
|
minimum_command_column_ = current_column + command_->cycles;
|
|
switch(command_->access) {
|
|
case Command::AccessType::CopyPoint:
|
|
next_command_step_ = CommandStep::ReadSourcePixel;
|
|
break;
|
|
case Command::AccessType::PlotPoint:
|
|
next_command_step_ = CommandStep::ReadDestinationPixel;
|
|
break;
|
|
|
|
case Command::AccessType::WaitForColourReceipt:
|
|
// i.e. nothing to do until a colour is received.
|
|
next_command_step_ = CommandStep::None;
|
|
break;
|
|
|
|
case Command::AccessType::CopyByte:
|
|
next_command_step_ = CommandStep::ReadSourceByte;
|
|
break;
|
|
case Command::AccessType::WriteByte:
|
|
next_command_step_ = CommandStep::WriteByte;
|
|
break;
|
|
}
|
|
}
|
|
|
|
Storage() noexcept {
|
|
// Perform sanity checks on the event lists.
|
|
#ifndef NDEBUG
|
|
const Event *lists[] = { no_sprites_events.data(), sprites_events.data(), text_events.data(), character_events.data(), refresh_events.data(), nullptr };
|
|
const Event **list = lists;
|
|
while(*list) {
|
|
const Event *cursor = *list;
|
|
++list;
|
|
|
|
while(cursor[1].offset != 1368) {
|
|
assert(cursor[1].offset > cursor[0].offset);
|
|
++cursor;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
// Seed to _something_ meaningful.
|
|
//
|
|
// TODO: this is a workaround [/hack], in effect, for the main TMS' habit of starting
|
|
// in a randomised position, which means that start-of-line isn't announced.
|
|
//
|
|
// Do I really want that behaviour?
|
|
next_event_ = refresh_events.data();
|
|
}
|
|
|
|
private:
|
|
// This emulator treats position 0 as being immediately after the standard pixel area.
|
|
// i.e. offset 1282 on Grauw's http://map.grauw.nl/articles/vdp-vram-timing/vdp-timing.png
|
|
static constexpr int ZeroAsGrauwIndex = 1282;
|
|
constexpr static int grauw_to_internal(int offset) {
|
|
return (offset + 1368 - ZeroAsGrauwIndex) % 1368;
|
|
}
|
|
constexpr static int internal_to_grauw(int offset) {
|
|
return (offset + ZeroAsGrauwIndex) % 1368;
|
|
}
|
|
|
|
template <typename GeneratorT> static constexpr size_t events_size() {
|
|
size_t size = 0;
|
|
for(int c = 0; c < 1368; c++) {
|
|
const auto event_type = GeneratorT::event(internal_to_grauw(c));
|
|
size += event_type.has_value();
|
|
}
|
|
return size + 1;
|
|
}
|
|
|
|
template <typename GeneratorT, size_t size = events_size<GeneratorT>()>
|
|
static constexpr std::array<Event, size> events() {
|
|
std::array<Event, size> result{};
|
|
size_t index = 0;
|
|
for(int c = 0; c < 1368; c++) {
|
|
const auto event = GeneratorT::event(internal_to_grauw(c));
|
|
if(!event) {
|
|
continue;
|
|
}
|
|
result[index] = *event;
|
|
result[index].offset = uint16_t(c);
|
|
++index;
|
|
}
|
|
result[index] = Event();
|
|
return result;
|
|
}
|
|
|
|
struct StandardGenerators {
|
|
static constexpr std::optional<Event> external_every_eight(int index) {
|
|
if(index & 7) return std::nullopt;
|
|
return Event::Type::External;
|
|
}
|
|
};
|
|
|
|
struct RefreshGenerator {
|
|
static constexpr std::optional<Event> event(int grauw_index) {
|
|
// From 0 to 126: CPU/CMD slots at every cycle divisible by 8.
|
|
if(grauw_index < 126) {
|
|
return StandardGenerators::external_every_eight(grauw_index - 0);
|
|
}
|
|
|
|
// From 164 to 1234: eight-cycle windows, the first 15 of each 16 being
|
|
// CPU/CMD and the final being refresh.
|
|
if(grauw_index >= 164 && grauw_index < 1234) {
|
|
const int offset = grauw_index - 164;
|
|
if(offset & 7) return std::nullopt;
|
|
if(((offset >> 3) & 15) == 15) return std::nullopt;
|
|
return Event::Type::External;
|
|
}
|
|
|
|
// From 1268 to 1330: CPU/CMD slots at every cycle divisible by 8.
|
|
if(grauw_index >= 1268 && grauw_index < 1330) {
|
|
return StandardGenerators::external_every_eight(grauw_index - 1268);
|
|
}
|
|
|
|
// A CPU/CMD at 1334.
|
|
if(grauw_index == 1334) {
|
|
return Event::Type::External;
|
|
}
|
|
|
|
// From 1344 to 1366: CPU/CMD slots every cycle divisible by 8.
|
|
if(grauw_index >= 1344 && grauw_index < 1366) {
|
|
return StandardGenerators::external_every_eight(grauw_index - 1344);
|
|
}
|
|
|
|
// Otherwise: nothing.
|
|
return std::nullopt;
|
|
}
|
|
};
|
|
static constexpr auto refresh_events = events<RefreshGenerator>();
|
|
|
|
template <bool include_sprites> struct BitmapGenerator {
|
|
static constexpr std::optional<Event> event(int grauw_index) {
|
|
if(!include_sprites) {
|
|
// Various standard zones of one-every-eight external slots.
|
|
if(grauw_index < 124) {
|
|
return StandardGenerators::external_every_eight(grauw_index + 2);
|
|
}
|
|
if(grauw_index > 1266) {
|
|
return StandardGenerators::external_every_eight(grauw_index - 1266);
|
|
}
|
|
} else {
|
|
// This records collection points for all data for selected sprites.
|
|
// There's only four of them (each site covering two sprites),
|
|
// so it's clearer just to be explicit.
|
|
//
|
|
// There's also a corresponding number of extra external slots to spell out.
|
|
switch(grauw_index) {
|
|
default: break;
|
|
case 1238: return Event(Event::Type::SpriteLocation, 0);
|
|
case 1302: return Event(Event::Type::SpriteLocation, 2);
|
|
case 2: return Event(Event::Type::SpriteLocation, 4);
|
|
case 66: return Event(Event::Type::SpriteLocation, 6);
|
|
case 1270: return Event(Event::Type::SpritePattern, 0);
|
|
case 1338: return Event(Event::Type::SpritePattern, 2);
|
|
case 34: return Event(Event::Type::SpritePattern, 4);
|
|
case 98: return Event(Event::Type::SpritePattern, 6);
|
|
case 1264: case 1330: case 28: case 92:
|
|
return Event::Type::External;
|
|
}
|
|
}
|
|
|
|
if(grauw_index >= 162 && grauw_index < 176) {
|
|
return StandardGenerators::external_every_eight(grauw_index - 162);
|
|
}
|
|
|
|
// Everywhere else the pattern is:
|
|
//
|
|
// external or sprite y, external, data block
|
|
//
|
|
// Subject to caveats:
|
|
//
|
|
// 1) the first data block is just a dummy fetch with no side effects,
|
|
// so this emulator declines to record it; and
|
|
// 2) every fourth block, the second external is actually a refresh.
|
|
//
|
|
if(grauw_index >= 182 && grauw_index < 1238) {
|
|
const int offset = grauw_index - 182;
|
|
const int block = offset / 32;
|
|
const int sub_block = offset & 31;
|
|
|
|
switch(sub_block) {
|
|
default: return std::nullopt;
|
|
case 0:
|
|
if(include_sprites) {
|
|
// Don't include the sprite post-amble (i.e. a spurious read with no side effects).
|
|
if(block < 32) {
|
|
return Event::Type::SpriteY;
|
|
}
|
|
} else {
|
|
return Event::Type::External;
|
|
}
|
|
case 6:
|
|
if((block & 3) != 3) {
|
|
return Event::Type::External;
|
|
}
|
|
break;
|
|
case 12:
|
|
if(block) {
|
|
return Event(Event::Type::Pattern, uint8_t(block - 1));
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
return std::nullopt;
|
|
}
|
|
};
|
|
static constexpr auto no_sprites_events = events<BitmapGenerator<false>>();
|
|
static constexpr auto sprites_events = events<BitmapGenerator<true>>();
|
|
|
|
struct TextGenerator {
|
|
static constexpr std::optional<Event> event(int grauw_index) {
|
|
// Capture various one-in-eight zones.
|
|
if(grauw_index < 72) {
|
|
return StandardGenerators::external_every_eight(grauw_index - 2);
|
|
}
|
|
if(grauw_index >= 166 && grauw_index < 228) {
|
|
return StandardGenerators::external_every_eight(grauw_index - 166);
|
|
}
|
|
if(grauw_index >= 1206 && grauw_index < 1332) {
|
|
return StandardGenerators::external_every_eight(grauw_index - 1206);
|
|
}
|
|
if(grauw_index == 1336) {
|
|
return Event::Type::External;
|
|
}
|
|
if(grauw_index >= 1346) {
|
|
return StandardGenerators::external_every_eight(grauw_index - 1346);
|
|
}
|
|
|
|
// Elsewhere...
|
|
if(grauw_index >= 246) {
|
|
const int offset = grauw_index - 246;
|
|
const int block = offset / 48;
|
|
const int sub_block = offset % 48;
|
|
switch(sub_block) {
|
|
default: break;
|
|
case 0: return Event(Event::Type::Name, uint8_t(block));
|
|
case 18: return (block & 1) ? Event::Type::External : Event(Event::Type::Colour, uint8_t(block >> 1));
|
|
case 24: return Event(Event::Type::Pattern, uint8_t(block));
|
|
}
|
|
}
|
|
|
|
return std::nullopt;
|
|
}
|
|
};
|
|
static constexpr auto text_events = events<TextGenerator>();
|
|
|
|
struct CharacterGenerator {
|
|
static constexpr std::optional<Event> event(int grauw_index) {
|
|
// Grab sprite events.
|
|
switch(grauw_index) {
|
|
default: break;
|
|
case 1242: return Event(Event::Type::SpriteLocation, 0);
|
|
case 1306: return Event(Event::Type::SpriteLocation, 1);
|
|
case 6: return Event(Event::Type::SpriteLocation, 2);
|
|
case 70: return Event(Event::Type::SpriteLocation, 3);
|
|
case 1274: return Event(Event::Type::SpritePattern, 0);
|
|
case 1342: return Event(Event::Type::SpritePattern, 1);
|
|
case 38: return Event(Event::Type::SpritePattern, 2);
|
|
case 102: return Event(Event::Type::SpritePattern, 3);
|
|
case 1268: case 1334: case 32: case 96: return Event::Type::External;
|
|
}
|
|
|
|
if(grauw_index >= 166 && grauw_index < 180) {
|
|
return StandardGenerators::external_every_eight(grauw_index - 166);
|
|
}
|
|
|
|
if(grauw_index >= 182 && grauw_index < 1238) {
|
|
const int offset = grauw_index - 182;
|
|
const int block = offset / 32;
|
|
const int sub_block = offset & 31;
|
|
switch(sub_block) {
|
|
case 0: if(block > 0) return Event(Event::Type::Name, uint8_t(block - 1));
|
|
case 6: if((sub_block & 3) != 3) return Event::Type::External;
|
|
case 12: if(block < 32) return Event(Event::Type::SpriteY, uint8_t(block));
|
|
case 18: if(block > 0) return Event(Event::Type::Pattern, uint8_t(block - 1));
|
|
case 24: if(block > 0) return Event(Event::Type::Colour, uint8_t(block - 1));
|
|
}
|
|
}
|
|
|
|
return std::nullopt;
|
|
}
|
|
};
|
|
static constexpr auto character_events = events<CharacterGenerator>();
|
|
};
|
|
|
|
// Master System-specific storage.
|
|
template <Personality personality> struct Storage<personality, std::enable_if_t<is_sega_vdp(personality)>> {
|
|
using AddressT = uint16_t;
|
|
|
|
// The SMS VDP has a programmer-set colour palette, with a dedicated patch of RAM. But the RAM is only exactly
|
|
// fast enough for the pixel clock. So when the programmer writes to it, that causes a one-pixel glitch; there
|
|
// isn't the bandwidth for the read both write to occur simultaneously. The following buffer therefore keeps
|
|
// track of pending collisions, for visual reproduction.
|
|
struct CRAMDot {
|
|
LineBufferPointer location;
|
|
uint32_t value;
|
|
};
|
|
std::vector<CRAMDot> upcoming_cram_dots_;
|
|
|
|
// The Master System's additional colour RAM.
|
|
uint32_t colour_ram_[32];
|
|
bool cram_is_selected_ = false;
|
|
|
|
// Programmer-set flags.
|
|
bool vertical_scroll_lock_ = false;
|
|
bool horizontal_scroll_lock_ = false;
|
|
bool hide_left_column_ = false;
|
|
bool shift_sprites_8px_left_ = false;
|
|
bool mode4_enable_ = false;
|
|
uint8_t horizontal_scroll_ = 0;
|
|
uint8_t vertical_scroll_ = 0;
|
|
|
|
// Holds the vertical scroll position for this frame; this is latched
|
|
// once and cannot dynamically be changed until the next frame.
|
|
uint8_t latched_vertical_scroll_ = 0;
|
|
|
|
// Various resource addresses with VDP-version-specific modifications
|
|
// built in.
|
|
AddressT pattern_name_address_;
|
|
AddressT sprite_attribute_table_address_;
|
|
AddressT sprite_generator_table_address_;
|
|
|
|
void begin_line(ScreenMode, bool) {}
|
|
};
|
|
|
|
}
|
|
}
|
|
|
|
#endif /* Storage_h */
|