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2003b514aa
CLK/Machines/Electron/Electron.cpp
Thomas Harte 2003b514aa Switched the typer to postfix underscores.
2016-12-03 10:55:50 -05:00

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//
// Electron.cpp
// Clock Signal
//
// Created by Thomas Harte on 03/01/2016.
// Copyright © 2016 Thomas Harte. All rights reserved.
//
#include "Electron.hpp"
#include "TapeUEF.hpp"
#include <algorithm>
#include <cassert>
using namespace Electron;
namespace {
static const unsigned int cycles_per_line = 128;
static const unsigned int lines_per_frame = 625;
static const unsigned int cycles_per_frame = lines_per_frame * cycles_per_line;
static const unsigned int crt_cycles_multiplier = 8;
static const unsigned int crt_cycles_per_line = crt_cycles_multiplier * cycles_per_line;
static const unsigned int field_divider_line = 312; // i.e. the line, simultaneous with which, the first field's sync ends. So if
// the first line with pixels in field 1 is the 20th in the frame, the first line
// with pixels in field 2 will be 20+field_divider_line
static const unsigned int first_graphics_line = 31;
static const unsigned int first_graphics_cycle = 33;
static const unsigned int display_end_interrupt_line = 256;
static const unsigned int real_time_clock_interrupt_1 = 16704;
static const unsigned int real_time_clock_interrupt_2 = 56704;
static const unsigned int clock_rate_audio_divider = 8;
}
#define graphics_line(v) ((((v) >> 7) - first_graphics_line + field_divider_line) % field_divider_line)
#define graphics_column(v) ((((v) & 127) - first_graphics_cycle + 128) & 127)
Machine::Machine() :
_interrupt_control(0),
_interrupt_status(Interrupt::PowerOnReset | Interrupt::TransmitDataEmpty | 0x80),
_frameCycles(0),
_displayOutputPosition(0),
_audioOutputPosition(0),
_current_pixel_line(-1),
_use_fast_tape_hack(false),
_crt(nullptr),
_phase(0)
{
memset(_key_states, 0, sizeof(_key_states));
memset(_palette, 0xf, sizeof(_palette));
for(int c = 0; c < 16; c++)
memset(_roms[c], 0xff, 16384);
_tape.set_delegate(this);
set_clock_rate(2000000);
}
void Machine::setup_output(float aspect_ratio)
{
_speaker.reset(new Speaker);
_crt.reset(new Outputs::CRT::CRT(crt_cycles_per_line, 8, Outputs::CRT::DisplayType::PAL50, 1));
_crt->set_rgb_sampling_function(
"vec3 rgb_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate)"
"{"
"uint texValue = texture(sampler, coordinate).r;"
"texValue >>= 4 - (int(icoordinate.x * 8) & 4);"
"return vec3( uvec3(texValue) & uvec3(4u, 2u, 1u));"
"}");
// TODO: as implied below, I've introduced a clock's latency into the graphics pipeline somehow. Investigate.
_crt->set_visible_area(_crt->get_rect_for_area(first_graphics_line - 3, 256, (first_graphics_cycle+1) * crt_cycles_multiplier, 80 * crt_cycles_multiplier, 4.0f / 3.0f));
// The maximum output frequency is 62500Hz and all other permitted output frequencies are integral divisions of that;
// however setting the speaker on or off can happen on any 2Mhz cycle, and probably (?) takes effect immediately. So
// run the speaker at a 2000000Hz input rate, at least for the time being.
_speaker->set_input_rate(2000000 / clock_rate_audio_divider);
}
void Machine::close_output()
{
_crt = nullptr;
}
unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uint16_t address, uint8_t *value)
{
unsigned int cycles = 1;
if(address < 0x8000)
{
if(isReadOperation(operation))
{
*value = _ram[address];
}
else
{
if(
(
((_frameCycles >= first_graphics_line * cycles_per_line) && (_frameCycles < (first_graphics_line + 256) * cycles_per_line)) ||
((_frameCycles >= (first_graphics_line + field_divider_line) * cycles_per_line) && (_frameCycles < (first_graphics_line + 256 + field_divider_line) * cycles_per_line))
)
)
update_display();
_ram[address] = *value;
}
// for the entire frame, RAM is accessible only on odd cycles; in modes below 4
// it's also accessible only outside of the pixel regions
cycles += 1 + (_frameCycles&1);
if(_screen_mode < 4)
{
const int current_line = graphics_line(_frameCycles + (_frameCycles&1));
const int current_column = graphics_column(_frameCycles + (_frameCycles&1));
if(current_line < 256 && current_column < 80 && !_isBlankLine)
cycles += (unsigned int)(80 - current_column);
}
}
else
{
// if((address >> 8) == 0xfc)
// {
// printf("d");
// }
switch(address & 0xff0f)
{
case 0xfe00:
if(isReadOperation(operation))
{
*value = _interrupt_status;
_interrupt_status &= ~PowerOnReset;
}
else
{
_interrupt_control = (*value) & ~1;
evaluate_interrupts();
}
break;
case 0xfe02:
if(!isReadOperation(operation))
{
_startScreenAddress = (_startScreenAddress & 0xfe00) | (uint16_t)(((*value) & 0xe0) << 1);
if(!_startScreenAddress) _startScreenAddress |= 0x8000;
}
break;
case 0xfe03:
if(!isReadOperation(operation))
{
_startScreenAddress = (_startScreenAddress & 0x01ff) | (uint16_t)(((*value) & 0x3f) << 9);
if(!_startScreenAddress) _startScreenAddress |= 0x8000;
}
break;
case 0xfe04:
if(isReadOperation(operation))
{
*value = _tape.get_data_register();
_tape.clear_interrupts(Interrupt::ReceiveDataFull);
}
else
{
_tape.set_data_register(*value);
_tape.clear_interrupts(Interrupt::TransmitDataEmpty);
}
break;
case 0xfe05:
if(!isReadOperation(operation))
{
const uint8_t interruptDisable = (*value)&0xf0;
if( interruptDisable )
{
if( interruptDisable&0x10 ) _interrupt_status &= ~Interrupt::DisplayEnd;
if( interruptDisable&0x20 ) _interrupt_status &= ~Interrupt::RealTimeClock;
if( interruptDisable&0x40 ) _interrupt_status &= ~Interrupt::HighToneDetect;
evaluate_interrupts();
// TODO: NMI
}
// latch the paged ROM in case external hardware is being emulated
_active_rom = (Electron::ROMSlot)(*value & 0xf);
// apply the ULA's test
if(*value & 0x08)
{
if(*value & 0x04)
{
_keyboard_is_active = false;
_basic_is_active = false;
}
else
{
_keyboard_is_active = !(*value & 0x02);
_basic_is_active = !_keyboard_is_active;
}
}
}
break;
case 0xfe06:
if(!isReadOperation(operation))
{
update_audio();
_speaker->set_divider(*value);
_tape.set_counter(*value);
}
break;
case 0xfe07:
if(!isReadOperation(operation))
{
// update screen mode
uint8_t new_screen_mode = ((*value) >> 3)&7;
if(new_screen_mode == 7) new_screen_mode = 4;
if(new_screen_mode != _screen_mode)
{
update_display();
_screen_mode = new_screen_mode;
switch(_screen_mode)
{
case 0: case 1: case 2: _screenModeBaseAddress = 0x3000; break;
case 3: _screenModeBaseAddress = 0x4000; break;
case 4: case 5: _screenModeBaseAddress = 0x5800; break;
case 6: _screenModeBaseAddress = 0x6000; break;
}
}
// update speaker mode
bool new_speaker_is_enabled = (*value & 6) == 2;
if(new_speaker_is_enabled != speaker_is_enabled_)
{
update_audio();
_speaker->set_is_enabled(new_speaker_is_enabled);
speaker_is_enabled_ = new_speaker_is_enabled;
}
_tape.set_is_enabled((*value & 6) != 6);
_tape.set_is_in_input_mode((*value & 6) == 0);
_tape.set_is_running(((*value)&0x40) ? true : false);
// TODO: caps lock LED
}
break;
case 0xfe08: case 0xfe09: case 0xfe0a: case 0xfe0b: case 0xfe0c: case 0xfe0d: case 0xfe0e: case 0xfe0f:
{
if(!isReadOperation(operation))
{
update_display();
static const int registers[4][4] = {
{10, 8, 2, 0},
{14, 12, 6, 4},
{15, 13, 7, 5},
{11, 9, 3, 1},
};
const int index = (address >> 1)&3;
const uint8_t colour = ~(*value);
if(address&1)
{
_palette[registers[index][0]] = (_palette[registers[index][0]]&3) | ((colour >> 1)&4);
_palette[registers[index][1]] = (_palette[registers[index][1]]&3) | ((colour >> 0)&4);
_palette[registers[index][2]] = (_palette[registers[index][2]]&3) | ((colour << 1)&4);
_palette[registers[index][3]] = (_palette[registers[index][3]]&3) | ((colour << 2)&4);
_palette[registers[index][2]] = (_palette[registers[index][2]]&5) | ((colour >> 4)&2);
_palette[registers[index][3]] = (_palette[registers[index][3]]&5) | ((colour >> 3)&2);
}
else
{
_palette[registers[index][0]] = (_palette[registers[index][0]]&6) | ((colour >> 7)&1);
_palette[registers[index][1]] = (_palette[registers[index][1]]&6) | ((colour >> 6)&1);
_palette[registers[index][2]] = (_palette[registers[index][2]]&6) | ((colour >> 5)&1);
_palette[registers[index][3]] = (_palette[registers[index][3]]&6) | ((colour >> 4)&1);
_palette[registers[index][0]] = (_palette[registers[index][0]]&5) | ((colour >> 2)&2);
_palette[registers[index][1]] = (_palette[registers[index][1]]&5) | ((colour >> 1)&2);
}
// regenerate all palette tables for now
#define pack(a, b) (uint8_t)((a << 4) | (b))
for(int byte = 0; byte < 256; byte++)
{
uint8_t *target = (uint8_t *)&_paletteTables.forty1bpp[byte];
target[0] = pack(_palette[(byte&0x80) >> 4], _palette[(byte&0x40) >> 3]);
target[1] = pack(_palette[(byte&0x20) >> 2], _palette[(byte&0x10) >> 1]);
target = (uint8_t *)&_paletteTables.eighty2bpp[byte];
target[0] = pack(_palette[((byte&0x80) >> 4) | ((byte&0x08) >> 2)], _palette[((byte&0x40) >> 3) | ((byte&0x04) >> 1)]);
target[1] = pack(_palette[((byte&0x20) >> 2) | ((byte&0x02) >> 0)], _palette[((byte&0x10) >> 1) | ((byte&0x01) << 1)]);
target = (uint8_t *)&_paletteTables.eighty1bpp[byte];
target[0] = pack(_palette[(byte&0x80) >> 4], _palette[(byte&0x40) >> 3]);
target[1] = pack(_palette[(byte&0x20) >> 2], _palette[(byte&0x10) >> 1]);
target[2] = pack(_palette[(byte&0x08) >> 0], _palette[(byte&0x04) << 1]);
target[3] = pack(_palette[(byte&0x02) << 2], _palette[(byte&0x01) << 3]);
_paletteTables.forty2bpp[byte] = pack(_palette[((byte&0x80) >> 4) | ((byte&0x08) >> 2)], _palette[((byte&0x40) >> 3) | ((byte&0x04) >> 1)]);
_paletteTables.eighty4bpp[byte] = pack( _palette[((byte&0x80) >> 4) | ((byte&0x20) >> 3) | ((byte&0x08) >> 2) | ((byte&0x02) >> 1)],
_palette[((byte&0x40) >> 3) | ((byte&0x10) >> 2) | ((byte&0x04) >> 1) | ((byte&0x01) >> 0)]);
}
#undef pack
}
}
break;
case 0xfc04: case 0xfc05: case 0xfc06: case 0xfc07:
if(_plus3 && (address&0x00f0) == 0x00c0)
{
if(is_holding_shift_ && address == 0xfcc4)
{
is_holding_shift_ = false;
set_key_state(KeyShift, false);
}
if(isReadOperation(operation))
*value = _plus3->get_register(address);
else
_plus3->set_register(address, *value);
}
break;
case 0xfc00:
if(_plus3 && (address&0x00f0) == 0x00c0)
{
if(!isReadOperation(operation))
{
_plus3->set_control_register(*value);
}
else
*value = 1;
}
break;
default:
if(address >= 0xc000)
{
if(isReadOperation(operation))
{
if(
_use_fast_tape_hack &&
_tape.has_tape() &&
(operation == CPU6502::BusOperation::ReadOpcode) &&
(
(address == 0xf4e5) || (address == 0xf4e6) || // double NOPs at 0xf4e5, 0xf6de, 0xf6fa and 0xfa51
(address == 0xf6de) || (address == 0xf6df) || // act to disable the normal branch into tape-handling
(address == 0xf6fa) || (address == 0xf6fb) || // code, forcing the OS along the serially-accessed ROM
(address == 0xfa51) || (address == 0xfa52) || // pathway.
(address == 0xf0a8) // 0xf0a8 is from where a service call would normally be
// dispatched; we can check whether it would be call 14
// (i.e. read byte) and, if so, whether the OS was about to
// issue a read byte call to a ROM despite being the tape
// FS being selected. If so then this is a get byte that
// we should service synthetically. Put the byte into Y
// and set A to zero to report that action was taken, then
// allow the PC read to return an RTS.
)
)
{
uint8_t service_call = (uint8_t)get_value_of_register(CPU6502::Register::X);
if(address == 0xf0a8)
{
if(!_ram[0x247] && service_call == 14)
{
_tape.set_delegate(nullptr);
// TODO: handle tape wrap around.
int cycles_left_while_plausibly_in_data = 50;
_tape.clear_interrupts(Interrupt::ReceiveDataFull);
while(!_tape.get_tape()->is_at_end())
{
_tape.run_for_input_pulse();
cycles_left_while_plausibly_in_data--;
if(!cycles_left_while_plausibly_in_data) _fast_load_is_in_data = false;
if( (_tape.get_interrupt_status() & Interrupt::ReceiveDataFull) &&
(_fast_load_is_in_data || _tape.get_data_register() == 0x2a)
) break;
}
_tape.set_delegate(this);
_tape.clear_interrupts(Interrupt::ReceiveDataFull);
_interrupt_status |= _tape.get_interrupt_status();
_fast_load_is_in_data = true;
set_value_of_register(CPU6502::Register::A, 0);
set_value_of_register(CPU6502::Register::Y, _tape.get_data_register());
*value = 0x60; // 0x60 is RTS
}
else
*value = _os[address & 16383];
}
else
*value = 0xea;
}
else
{
*value = _os[address & 16383];
}
}
}
else
{
if(isReadOperation(operation))
{
*value = _roms[_active_rom][address & 16383];
if(_keyboard_is_active)
{
*value &= 0xf0;
for(int address_line = 0; address_line < 14; address_line++)
{
if(!(address&(1 << address_line))) *value |= _key_states[address_line];
}
}
if(_basic_is_active)
{
*value &= _roms[ROMSlotBASIC][address & 16383];
}
} else if(_rom_write_masks[_active_rom])
{
_roms[_active_rom][address & 16383] = *value;
}
}
break;
}
}
// if(operation == CPU6502::BusOperation::ReadOpcode)
// {
// printf("%04x: %02x (%d)\n", address, *value, _fieldCycles);
// }
// const int end_of_field =
// if(_frameCycles < (256 + first_graphics_line) << 7))
const unsigned int pixel_line_clock = _frameCycles;// + 128 - first_graphics_cycle + 80;
const unsigned int line_before_cycle = graphics_line(pixel_line_clock);
const unsigned int line_after_cycle = graphics_line(pixel_line_clock + cycles);
// implicit assumption here: the number of 2Mhz cycles this bus operation will take
// is never longer than a line. On the Electron, it's a safe one.
if(line_before_cycle != line_after_cycle)
{
switch(line_before_cycle)
{
// case real_time_clock_interrupt_line: signal_interrupt(Interrupt::RealTimeClock); break;
// case real_time_clock_interrupt_line+1: clear_interrupt(Interrupt::RealTimeClock); break;
case display_end_interrupt_line: signal_interrupt(Interrupt::DisplayEnd); break;
// case display_end_interrupt_line+1: clear_interrupt(Interrupt::DisplayEnd); break;
}
}
if(
(pixel_line_clock < real_time_clock_interrupt_1 && pixel_line_clock + cycles >= real_time_clock_interrupt_1) ||
(pixel_line_clock < real_time_clock_interrupt_2 && pixel_line_clock + cycles >= real_time_clock_interrupt_2))
{
signal_interrupt(Interrupt::RealTimeClock);
}
_frameCycles += cycles;
if(!(_frameCycles&127)) _phase += 64;
// deal with frame wraparound by updating the two dependent subsystems
// as though the exact end of frame had been hit, then reset those
// and allow the frame cycle counter to assume its real value
if(_frameCycles >= cycles_per_frame)
{
unsigned int nextFrameCycles = _frameCycles - cycles_per_frame;
_frameCycles = cycles_per_frame;
update_display();
update_audio();
_displayOutputPosition = 0;
_audioOutputPosition = 0;
_frameCycles = nextFrameCycles;
}
if(!(_frameCycles&16383))
update_audio();
_tape.run_for_cycles(cycles);
if(typer_) typer_->update((int)cycles);
if(_plus3) _plus3->run_for_cycles(4*cycles);
return cycles;
}
void Machine::synchronise()
{
update_display();
update_audio();
_speaker->flush();
}
void Machine::configure_as_target(const StaticAnalyser::Target &target)
{
if(target.tapes.size())
{
_tape.set_tape(target.tapes.front());
}
if(target.disks.size())
{
_plus3.reset(new Plus3);
if(target.acorn.has_dfs)
{
set_rom(ROMSlot0, _dfs, true);
}
if(target.acorn.has_adfs)
{
set_rom(ROMSlot4, _adfs, true);
set_rom(ROMSlot5, std::vector<uint8_t>(_adfs.begin() + 16384, _adfs.end()), true);
}
_plus3->set_disk(target.disks.front(), 0);
}
ROMSlot slot = ROMSlot12;
for(std::shared_ptr<Storage::Cartridge::Cartridge> cartridge : target.cartridges)
{
set_rom(slot, cartridge->get_segments().front().data, false);
slot = (ROMSlot)(((int)slot + 1)&15);
}
if(target.loadingCommand.length()) // TODO: and automatic loading option enabled
{
set_typer_for_string(target.loadingCommand.c_str());
}
if(target.acorn.should_hold_shift)
{
set_key_state(KeyShift, true);
is_holding_shift_ = true;
}
}
void Machine::set_rom(ROMSlot slot, std::vector<uint8_t> data, bool is_writeable)
{
uint8_t *target = nullptr;
switch(slot)
{
case ROMSlotDFS: _dfs = data; return;
case ROMSlotADFS: _adfs = data; return;
case ROMSlotOS: target = _os; break;
default:
target = _roms[slot];
_rom_write_masks[slot] = is_writeable;
break;
}
memcpy(target, &data[0], std::min((size_t)16384, data.size()));
}
inline void Machine::signal_interrupt(Electron::Interrupt interrupt)
{
_interrupt_status |= interrupt;
evaluate_interrupts();
}
inline void Machine::clear_interrupt(Electron::Interrupt interrupt)
{
_interrupt_status &= ~interrupt;
evaluate_interrupts();
}
void Machine::tape_did_change_interrupt_status(Tape *tape)
{
_interrupt_status = (_interrupt_status & ~(Interrupt::TransmitDataEmpty | Interrupt::ReceiveDataFull | Interrupt::HighToneDetect)) | _tape.get_interrupt_status();
evaluate_interrupts();
}
inline void Machine::evaluate_interrupts()
{
if(_interrupt_status & _interrupt_control)
{
_interrupt_status |= 1;
}
else
{
_interrupt_status &= ~1;
}
set_irq_line(_interrupt_status & 1);
}
inline void Machine::update_audio()
{
unsigned int difference = _frameCycles - _audioOutputPosition;
_audioOutputPosition = _frameCycles;
_speaker->run_for_cycles(difference / clock_rate_audio_divider);
_audioOutputPositionError = difference % clock_rate_audio_divider;
}
inline void Machine::start_pixel_line()
{
_current_pixel_line = (_current_pixel_line+1)&255;
if(!_current_pixel_line)
{
_startLineAddress = _startScreenAddress;
_current_character_row = 0;
_isBlankLine = false;
}
else
{
bool mode_has_blank_lines = (_screen_mode == 6) || (_screen_mode == 3);
_isBlankLine = (mode_has_blank_lines && ((_current_character_row > 7 && _current_character_row < 10) || (_current_pixel_line > 249)));
if(!_isBlankLine)
{
_startLineAddress++;
if(_current_character_row > 7)
{
_startLineAddress += ((_screen_mode < 4) ? 80 : 40) * 8 - 8;
_current_character_row = 0;
}
}
}
_currentScreenAddress = _startLineAddress;
_current_pixel_column = 0;
_initial_output_target = _current_output_target = nullptr;
}
inline void Machine::end_pixel_line()
{
if(_current_output_target) _crt->output_data((unsigned int)((_current_output_target - _initial_output_target) * _current_output_divider), _current_output_divider);
_current_character_row++;
}
inline void Machine::output_pixels(unsigned int number_of_cycles)
{
if(!number_of_cycles) return;
if(_isBlankLine)
{
_crt->output_blank(number_of_cycles * crt_cycles_multiplier);
}
else
{
unsigned int divider = 0;
switch(_screen_mode)
{
case 0: case 3: divider = 2; break;
case 1: case 4: case 6: divider = 4; break;
case 2: case 5: divider = 8; break;
}
if(!_initial_output_target || divider != _current_output_divider)
{
if(_current_output_target) _crt->output_data((unsigned int)((_current_output_target - _initial_output_target) * _current_output_divider), _current_output_divider);
_current_output_divider = divider;
_initial_output_target = _current_output_target = _crt->allocate_write_area(640 / _current_output_divider);
}
#define get_pixel() \
if(_currentScreenAddress&32768)\
{\
_currentScreenAddress = (_screenModeBaseAddress + _currentScreenAddress)&32767;\
}\
_last_pixel_byte = _ram[_currentScreenAddress];\
_currentScreenAddress = _currentScreenAddress+8
switch(_screen_mode)
{
case 0: case 3:
if(_initial_output_target)
{
while(number_of_cycles--)
{
get_pixel();
*(uint32_t *)_current_output_target = _paletteTables.eighty1bpp[_last_pixel_byte];
_current_output_target += 4;
_current_pixel_column++;
}
} else _current_output_target += 4*number_of_cycles;
break;
case 1:
if(_initial_output_target)
{
while(number_of_cycles--)
{
get_pixel();
*(uint16_t *)_current_output_target = _paletteTables.eighty2bpp[_last_pixel_byte];
_current_output_target += 2;
_current_pixel_column++;
}
} else _current_output_target += 2*number_of_cycles;
break;
case 2:
if(_initial_output_target)
{
while(number_of_cycles--)
{
get_pixel();
*_current_output_target = _paletteTables.eighty4bpp[_last_pixel_byte];
_current_output_target += 1;
_current_pixel_column++;
}
} else _current_output_target += number_of_cycles;
break;
case 4: case 6:
if(_initial_output_target)
{
if(_current_pixel_column&1)
{
_last_pixel_byte <<= 4;
*(uint16_t *)_current_output_target = _paletteTables.forty1bpp[_last_pixel_byte];
_current_output_target += 2;
number_of_cycles--;
_current_pixel_column++;
}
while(number_of_cycles > 1)
{
get_pixel();
*(uint16_t *)_current_output_target = _paletteTables.forty1bpp[_last_pixel_byte];
_current_output_target += 2;
_last_pixel_byte <<= 4;
*(uint16_t *)_current_output_target = _paletteTables.forty1bpp[_last_pixel_byte];
_current_output_target += 2;
number_of_cycles -= 2;
_current_pixel_column+=2;
}
if(number_of_cycles)
{
get_pixel();
*(uint16_t *)_current_output_target = _paletteTables.forty1bpp[_last_pixel_byte];
_current_output_target += 2;
_current_pixel_column++;
}
} else _current_output_target += 2 * number_of_cycles;
break;
case 5:
if(_initial_output_target)
{
if(_current_pixel_column&1)
{
_last_pixel_byte <<= 2;
*_current_output_target = _paletteTables.forty2bpp[_last_pixel_byte];
_current_output_target += 1;
number_of_cycles--;
_current_pixel_column++;
}
while(number_of_cycles > 1)
{
get_pixel();
*_current_output_target = _paletteTables.forty2bpp[_last_pixel_byte];
_current_output_target += 1;
_last_pixel_byte <<= 2;
*_current_output_target = _paletteTables.forty2bpp[_last_pixel_byte];
_current_output_target += 1;
number_of_cycles -= 2;
_current_pixel_column+=2;
}
if(number_of_cycles)
{
get_pixel();
*_current_output_target = _paletteTables.forty2bpp[_last_pixel_byte];
_current_output_target += 1;
_current_pixel_column++;
}
} else _current_output_target += number_of_cycles;
break;
}
#undef get_pixel
}
}
inline void Machine::update_display()
{
/*
Odd field: Even field:
|--S--| -S-|
|--S--| |--S--|
|-S-B-| = 3 |--S--| = 2.5
|--B--| |--B--|
|--P--| |--P--|
|--B--| = 312 |--B--| = 312.5
|-B-
*/
int final_line = _frameCycles >> 7;
while(_displayOutputPosition < _frameCycles)
{
int line = _displayOutputPosition >> 7;
// Priority one: sync.
// ===================
// full sync lines are 0, 1, field_divider_line+1 and field_divider_line+2
if(line == 0 || line == 1 || line == field_divider_line+1 || line == field_divider_line+2)
{
// wait for the line to complete before signalling
if(final_line == line) return;
_crt->output_sync(128 * crt_cycles_multiplier);
_displayOutputPosition += 128;
continue;
}
// line 2 is a left-sync line
if(line == 2)
{
// wait for the line to complete before signalling
if(final_line == line) return;
_crt->output_sync(64 * crt_cycles_multiplier);
_crt->output_blank(64 * crt_cycles_multiplier);
_displayOutputPosition += 128;
continue;
}
// line field_divider_line is a right-sync line
if(line == field_divider_line)
{
// wait for the line to complete before signalling
if(final_line == line) return;
_crt->output_sync(9 * crt_cycles_multiplier);
_crt->output_blank(55 * crt_cycles_multiplier);
_crt->output_sync(64 * crt_cycles_multiplier);
_displayOutputPosition += 128;
continue;
}
// Priority two: blank lines.
// ==========================
//
// Given that it is not a sync line, this is a blank line if it is less than first_graphics_line, or greater
// than first_graphics_line+255 and less than first_graphics_line+field_divider_line, or greater than
// first_graphics_line+field_divider_line+255 (TODO: or this is Mode 3 or 6 and this should be blank)
if(
line < first_graphics_line ||
(line > first_graphics_line+255 && line < first_graphics_line+field_divider_line) ||
line > first_graphics_line+field_divider_line+255)
{
if(final_line == line) return;
_crt->output_sync(9 * crt_cycles_multiplier);
_crt->output_blank(119 * crt_cycles_multiplier);
_displayOutputPosition += 128;
continue;
}
// Final possibility: this is a pixel line.
// ========================================
// determine how far we're going from left to right
unsigned int this_cycle = _displayOutputPosition&127;
unsigned int final_cycle = _frameCycles&127;
if(final_line > line)
{
final_cycle = 128;
}
// output format is:
// 9 cycles: sync
// ... to 24 cycles: colour burst
// ... to first_graphics_cycle: blank
// ... for 80 cycles: pixels
// ... until end of line: blank
while(this_cycle < final_cycle)
{
if(this_cycle < 9)
{
if(final_cycle < 9) return;
_crt->output_sync(9 * crt_cycles_multiplier);
_displayOutputPosition += 9;
this_cycle = 9;
}
if(this_cycle < 24)
{
if(final_cycle < 24) return;
_crt->output_colour_burst((24-9) * crt_cycles_multiplier, _phase, 12);
_displayOutputPosition += 24-9;
this_cycle = 24;
// TODO: phase shouldn't be zero on every line
}
if(this_cycle < first_graphics_cycle)
{
if(final_cycle < first_graphics_cycle) return;
_crt->output_blank((first_graphics_cycle - 24) * crt_cycles_multiplier);
_displayOutputPosition += first_graphics_cycle - 24;
this_cycle = first_graphics_cycle;
start_pixel_line();
}
if(this_cycle < first_graphics_cycle + 80)
{
unsigned int length_to_output = std::min(final_cycle, (first_graphics_cycle + 80)) - this_cycle;
output_pixels(length_to_output);
_displayOutputPosition += length_to_output;
this_cycle += length_to_output;
}
if(this_cycle >= first_graphics_cycle + 80)
{
if(final_cycle < 128) return;
end_pixel_line();
_crt->output_blank((128 - (first_graphics_cycle + 80)) * crt_cycles_multiplier);
_displayOutputPosition += 128 - (first_graphics_cycle + 80);
this_cycle = 128;
}
}
}
}
void Machine::clear_all_keys()
{
memset(_key_states, 0, sizeof(_key_states));
}
void Machine::set_key_state(uint16_t key, bool isPressed)
{
if(key == KeyBreak)
{
set_reset_line(isPressed);
}
else
{
if(isPressed)
_key_states[key >> 4] |= key&0xf;
else
_key_states[key >> 4] &= ~(key&0xf);
}
}
/*
Speaker
*/
void Speaker::get_samples(unsigned int number_of_samples, int16_t *target)
{
if(_is_enabled)
{
while(number_of_samples--)
{
*target = (int16_t)((_counter / (_divider+1)) * 8192);
target++;
_counter = (_counter + 1) % ((_divider+1) * 2);
}
}
else
{
memset(target, 0, sizeof(int16_t) * number_of_samples);
}
}
void Speaker::skip_samples(unsigned int number_of_samples)
{
_counter = (_counter + number_of_samples) % ((_divider+1) * 2);
}
void Speaker::set_divider(uint8_t divider)
{
enqueue([=]() {
_divider = divider * 32 / clock_rate_audio_divider;
});
}
void Speaker::set_is_enabled(bool is_enabled)
{
enqueue([=]() {
_is_enabled = is_enabled;
_counter = 0;
});
}
/*
Tape
*/
Tape::Tape() :
TapePlayer(2000000),
_is_running(false),
_data_register(0),
_delegate(nullptr),
_output({.bits_remaining_until_empty = 0, .cycles_into_pulse = 0}),
_last_posted_interrupt_status(0),
_interrupt_status(0)
{}
inline void Tape::push_tape_bit(uint16_t bit)
{
_data_register = (uint16_t)((_data_register >> 1) | (bit << 10));
if(_input.minimum_bits_until_full) _input.minimum_bits_until_full--;
if(_input.minimum_bits_until_full == 8) _interrupt_status &= ~Interrupt::ReceiveDataFull;
if(!_input.minimum_bits_until_full)
{
if((_data_register&0x3) == 0x1)
{
_interrupt_status |= Interrupt::ReceiveDataFull;
if(_is_in_input_mode) _input.minimum_bits_until_full = 9;
}
}
if(_output.bits_remaining_until_empty) _output.bits_remaining_until_empty--;
if(!_output.bits_remaining_until_empty) _interrupt_status |= Interrupt::TransmitDataEmpty;
if(_data_register == 0x3ff) _interrupt_status |= Interrupt::HighToneDetect;
else _interrupt_status &= ~Interrupt::HighToneDetect;
evaluate_interrupts();
}
inline void Tape::evaluate_interrupts()
{
if(_last_posted_interrupt_status != _interrupt_status)
{
_last_posted_interrupt_status = _interrupt_status;
if(_delegate) _delegate->tape_did_change_interrupt_status(this);
}
}
inline void Tape::clear_interrupts(uint8_t interrupts)
{
_interrupt_status &= ~interrupts;
evaluate_interrupts();
}
inline void Tape::set_is_in_input_mode(bool is_in_input_mode)
{
_is_in_input_mode = is_in_input_mode;
}
inline void Tape::set_counter(uint8_t value)
{
_output.cycles_into_pulse = 0;
_output.bits_remaining_until_empty = 0;
}
inline void Tape::set_data_register(uint8_t value)
{
_data_register = (uint16_t)((value << 2) | 1);
_output.bits_remaining_until_empty = 9;
}
inline uint8_t Tape::get_data_register()
{
return (uint8_t)(_data_register >> 2);
}
inline void Tape::process_input_pulse(Storage::Tape::Tape::Pulse pulse)
{
_crossings[0] = _crossings[1];
_crossings[1] = _crossings[2];
_crossings[2] = _crossings[3];
_crossings[3] = Tape::Unrecognised;
if(pulse.type != Storage::Tape::Tape::Pulse::Zero)
{
float pulse_length = (float)pulse.length.length / (float)pulse.length.clock_rate;
if(pulse_length >= 0.35 / 2400.0 && pulse_length < 0.7 / 2400.0) _crossings[3] = Tape::Short;
if(pulse_length >= 0.35 / 1200.0 && pulse_length < 0.7 / 1200.0) _crossings[3] = Tape::Long;
}
if(_crossings[0] == Tape::Long && _crossings[1] == Tape::Long)
{
push_tape_bit(0);
_crossings[0] = _crossings[1] = Tape::Recognised;
}
else
{
if(_crossings[0] == Tape::Short && _crossings[1] == Tape::Short && _crossings[2] == Tape::Short && _crossings[3] == Tape::Short)
{
push_tape_bit(1);
_crossings[0] = _crossings[1] =
_crossings[2] = _crossings[3] = Tape::Recognised;
}
}
}
inline void Tape::run_for_cycles(unsigned int number_of_cycles)
{
if(_is_enabled)
{
if(_is_in_input_mode)
{
if(_is_running)
{
TapePlayer::run_for_cycles((int)number_of_cycles);
}
}
else
{
_output.cycles_into_pulse += number_of_cycles;
while(_output.cycles_into_pulse > 1664) // 1664 = the closest you can get to 1200 baud if you're looking for something
{ // that divides the 125,000Hz clock that the sound divider runs off.
_output.cycles_into_pulse -= 1664;
push_tape_bit(1);
}
}
}
}
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