1
0
mirror of https://github.com/TomHarte/CLK.git synced 2024-07-04 18:29:40 +00:00
CLK/Components/6560/6560.cpp

481 lines
18 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

//
// 6560.cpp
// Clock Signal
//
// Created by Thomas Harte on 05/06/2016.
// Copyright © 2016 Thomas Harte. All rights reserved.
//
#include "6560.hpp"
using namespace MOS;
MOS6560::MOS6560() :
_crt(new Outputs::CRT::CRT(65*4, 4, Outputs::CRT::NTSC60, 1)),
_horizontal_counter(0),
_vertical_counter(0),
_cycles_since_speaker_update(0),
_is_odd_frame(false)
{
_crt->set_composite_sampling_function(
"float composite_sample(usampler2D texID, vec2 coordinate, vec2 iCoordinate, float phase, float amplitude)"
"{"
"uint c = texture(texID, coordinate).r;"
"float y = float(c >> 4) / 4.0;"
"uint yC = c & 15u;"
"float phaseOffset = 6.283185308 * float(yC) / 16.0;"
"float chroma = cos(phase + phaseOffset);"
"return mix(y, step(yC, 14) * chroma, amplitude);"
"}");
// default to NTSC
set_output_mode(OutputMode::NTSC);
// show only the centre
_crt->set_visible_area(_crt->get_rect_for_area(16, 237, 11*4, 55*4, 4.0f / 3.0f));
_speaker.set_input_rate(255681.75); // assuming NTSC; clock rate / 4
}
void MOS6560::set_output_mode(OutputMode output_mode)
{
uint8_t luminances[16] = { // range is 04
0, 4, 1, 3, 2, 2, 1, 3,
2, 1, 2, 1, 2, 3, 2, 3
};
uint8_t pal_chrominances[16] = { // range is 015; 15 is a special case meaning "no chrominance"
15, 15, 5, 13, 2, 10, 0, 8,
6, 7, 5, 13, 2, 10, 0, 8,
};
uint8_t ntsc_chrominances[16] = {
15, 15, 2, 10, 4, 12, 6, 14,
0, 8, 2, 10, 4, 12, 6, 14,
};
uint8_t *chrominances;
Outputs::CRT::DisplayType display_type;
switch(output_mode)
{
case OutputMode::PAL:
chrominances = pal_chrominances;
display_type = Outputs::CRT::PAL50;
_timing.cycles_per_line = 71;
_timing.lines_per_progressive_field = 312;
_timing.supports_interlacing = false;
break;
case OutputMode::NTSC:
chrominances = ntsc_chrominances;
display_type = Outputs::CRT::NTSC60;
_timing.cycles_per_line = 65;
_timing.lines_per_progressive_field = 261;
_timing.supports_interlacing = true;
break;
}
_crt->set_new_display_type((unsigned int)(_timing.cycles_per_line*4), display_type);
for(int c = 0; c < 16; c++)
{
_colours[c] = (uint8_t)((luminances[c] << 4) | chrominances[c]);
}
}
// TODO: set clock rate
void MOS6560::set_register(int address, uint8_t value)
{
address &= 0xf;
_registers.direct_values[address] = value;
switch(address)
{
case 0x0:
_registers.interlaced = !!(value&0x80) && _timing.supports_interlacing;
_registers.first_column_location = value & 0x7f;
break;
case 0x1:
_registers.first_row_location = value;
break;
case 0x2:
_registers.number_of_columns = value & 0x7f;
_registers.video_matrix_start_address = (uint16_t)((_registers.video_matrix_start_address & 0x3c00) | ((value & 0x80) << 2));
break;
case 0x3:
_registers.number_of_rows = (value >> 1)&0x3f;
_registers.tall_characters = !!(value&0x01);
break;
case 0x5:
_registers.character_cell_start_address = (uint16_t)((value & 0x0f) << 10);
_registers.video_matrix_start_address = (uint16_t)((_registers.video_matrix_start_address & 0x0200) | ((value & 0xf0) << 6));
break;
case 0xa:
case 0xb:
case 0xc:
case 0xd:
update_audio();
_speaker.set_control(address - 0xa, value);
break;
case 0xe:
update_audio();
_registers.auxiliary_colour = _colours[value >> 4];
_speaker.set_volume(value & 0xf);
break;
case 0xf:
if(_this_state == State::Border)
{
output_border(_cycles_in_state * 4);
_cycles_in_state = 0;
}
_registers.invertedCells = !((value >> 3)&1);
_registers.borderColour = _colours[value & 0x07];
_registers.backgroundColour = _colours[value >> 4];
break;
// TODO: audio, primarily
default:
break;
}
}
uint8_t MOS6560::get_register(int address)
{
address &= 0xf;
switch(address)
{
default: return _registers.direct_values[address];
case 0x03: return (uint8_t)(_vertical_counter << 7) | (_registers.direct_values[3] & 0x7f);
case 0x04: return (_vertical_counter >> 1) & 0xff;
}
}
void MOS6560::output_border(unsigned int number_of_cycles)
{
uint8_t *colour_pointer = _crt->allocate_write_area(1);
if(colour_pointer) *colour_pointer = _registers.borderColour;
_crt->output_level(number_of_cycles);
}
uint16_t MOS6560::get_address()
{
// keep track of the amount of time since the speaker was updated; lazy updates are applied
_cycles_since_speaker_update++;
// keep an old copy of the vertical count because that test is a cycle later than the actual changes
int previous_vertical_counter = _vertical_counter;
// keep track of internal time relative to this scanline
_horizontal_counter++;
if(_horizontal_counter == _timing.cycles_per_line)
{
if(_horizontal_drawing_latch)
{
_current_character_row++;
if(
(_current_character_row == 16) ||
(_current_character_row == 8 && !_registers.tall_characters)
) {
_current_character_row = 0;
_current_row++;
}
_pixel_line_cycle = -1;
_columns_this_line = -1;
_column_counter = -1;
}
_horizontal_counter = 0;
_horizontal_drawing_latch = false;
_vertical_counter ++;
if(_vertical_counter == (_registers.interlaced ? (_is_odd_frame ? 262 : 263) : _timing.lines_per_progressive_field))
{
_vertical_counter = 0;
_is_odd_frame ^= true;
_current_row = 0;
_rows_this_field = -1;
_vertical_drawing_latch = false;
_base_video_matrix_address_counter = 0;
_current_character_row = 0;
}
}
// check for vertical starting events
_vertical_drawing_latch |= _registers.first_row_location == (previous_vertical_counter >> 1);
_horizontal_drawing_latch |= _vertical_drawing_latch && (_horizontal_counter == _registers.first_column_location);
if(_pixel_line_cycle >= 0) _pixel_line_cycle++;
switch(_pixel_line_cycle)
{
case -1:
if(_horizontal_drawing_latch)
{
_pixel_line_cycle = 0;
_video_matrix_address_counter = _base_video_matrix_address_counter;
}
break;
case 1: _columns_this_line = _registers.number_of_columns; break;
case 2: if(_rows_this_field < 0) _rows_this_field = _registers.number_of_rows; break;
case 3: if(_current_row < _rows_this_field) _column_counter = 0; break;
}
uint16_t fetch_address = 0x1c;
if(_column_counter >= 0 && _column_counter < _columns_this_line*2)
{
if(_column_counter&1)
{
fetch_address = _registers.character_cell_start_address + (_character_code*(_registers.tall_characters ? 16 : 8)) + _current_character_row;
}
else
{
fetch_address = (uint16_t)(_registers.video_matrix_start_address + _video_matrix_address_counter);
_video_matrix_address_counter++;
if(
(_current_character_row == 15) ||
(_current_character_row == 7 && !_registers.tall_characters)
) {
_base_video_matrix_address_counter = _video_matrix_address_counter;
}
}
}
return fetch_address;
}
void MOS6560::set_graphics_value(uint8_t value, uint8_t colour_value)
{
// determine output state; colour burst and sync timing are currently a guess
if(_horizontal_counter > _timing.cycles_per_line-4) _this_state = State::ColourBurst;
else if(_horizontal_counter > _timing.cycles_per_line-7) _this_state = State::Sync;
else
{
_this_state = (_column_counter >= 0 && _column_counter < _columns_this_line*2) ? State::Pixels : State::Border;
}
// apply vertical sync
if(
(_vertical_counter < 3 && (_is_odd_frame || !_registers.interlaced)) ||
(_registers.interlaced &&
(
(_vertical_counter == 0 && _horizontal_counter > 32) ||
(_vertical_counter == 1) || (_vertical_counter == 2) ||
(_vertical_counter == 3 && _horizontal_counter <= 32)
)
))
_this_state = State::Sync;
// update the CRT
if(_this_state != _output_state)
{
switch(_output_state)
{
case State::Sync: _crt->output_sync(_cycles_in_state * 4); break;
case State::ColourBurst: _crt->output_colour_burst(_cycles_in_state * 4, _is_odd_frame ? 128 : 0, 0); break;
case State::Border: output_border(_cycles_in_state * 4); break;
case State::Pixels: _crt->output_data(_cycles_in_state * 4, 1); break;
}
_output_state = _this_state;
_cycles_in_state = 0;
pixel_pointer = nullptr;
if(_output_state == State::Pixels)
{
pixel_pointer = _crt->allocate_write_area(260);
}
}
_cycles_in_state++;
if(_this_state == State::Pixels)
{
if(_column_counter&1)
{
_character_value = value;
if(pixel_pointer)
{
uint8_t cell_colour = _colours[_character_colour & 0x7];
if(!(_character_colour&0x8))
{
uint8_t colours[2];
if(_registers.invertedCells)
{
colours[0] = cell_colour;
colours[1] = _registers.backgroundColour;
}
else
{
colours[0] = _registers.backgroundColour;
colours[1] = cell_colour;
}
pixel_pointer[0] = colours[(_character_value >> 7)&1];
pixel_pointer[1] = colours[(_character_value >> 6)&1];
pixel_pointer[2] = colours[(_character_value >> 5)&1];
pixel_pointer[3] = colours[(_character_value >> 4)&1];
pixel_pointer[4] = colours[(_character_value >> 3)&1];
pixel_pointer[5] = colours[(_character_value >> 2)&1];
pixel_pointer[6] = colours[(_character_value >> 1)&1];
pixel_pointer[7] = colours[(_character_value >> 0)&1];
}
else
{
uint8_t colours[4] = {_registers.backgroundColour, _registers.borderColour, cell_colour, _registers.auxiliary_colour};
pixel_pointer[0] =
pixel_pointer[1] = colours[(_character_value >> 6)&3];
pixel_pointer[2] =
pixel_pointer[3] = colours[(_character_value >> 4)&3];
pixel_pointer[4] =
pixel_pointer[5] = colours[(_character_value >> 2)&3];
pixel_pointer[6] =
pixel_pointer[7] = colours[(_character_value >> 0)&3];
}
pixel_pointer += 8;
}
}
else
{
_character_code = value;
_character_colour = colour_value;
}
_column_counter++;
}
}
void MOS6560::update_audio()
{
_speaker.run_for_cycles(_cycles_since_speaker_update >> 2);
_cycles_since_speaker_update &= 3;
}
#pragma mark - Audio
MOS6560::Speaker::Speaker() :
_volume(0),
_control_registers{0, 0, 0, 0},
_shift_registers{0, 0, 0, 0},
_counters{2, 1, 0, 0} // create a slight phase offset for the three channels
{}
void MOS6560::Speaker::set_volume(uint8_t volume)
{
_volume = volume;
}
void MOS6560::Speaker::set_control(int channel, uint8_t value)
{
_control_registers[channel] = value;
}
// Source: VICE. Not original.
static uint8_t noise_pattern[] = {
0x07, 0x1e, 0x1e, 0x1c, 0x1c, 0x3e, 0x3c, 0x38, 0x78, 0xf8, 0x7c, 0x1e, 0x1f, 0x8f, 0x07, 0x07,
0xc1, 0xc0, 0xe0, 0xf1, 0xe0, 0xf0, 0xe3, 0xe1, 0xc0, 0xe0, 0x78, 0x7e, 0x3c, 0x38, 0xe0, 0xe1,
0xc3, 0xc3, 0x87, 0xc7, 0x07, 0x1e, 0x1c, 0x1f, 0x0e, 0x0e, 0x1e, 0x0e, 0x0f, 0x0f, 0xc3, 0xc3,
0xf1, 0xe1, 0xe3, 0xc1, 0xe3, 0xc3, 0xc3, 0xfc, 0x3c, 0x1e, 0x0f, 0x83, 0xc3, 0xc1, 0xc1, 0xc3,
0xc3, 0xc7, 0x87, 0x87, 0xc7, 0x0f, 0x0e, 0x3c, 0x7c, 0x78, 0x3c, 0x3c, 0x3c, 0x38, 0x3e, 0x1c,
0x7c, 0x1e, 0x3c, 0x0f, 0x0e, 0x3e, 0x78, 0xf0, 0xf0, 0xe0, 0xe1, 0xf1, 0xc1, 0xc3, 0xc7, 0xc3,
0xe1, 0xf1, 0xe0, 0xe1, 0xf0, 0xf1, 0xe3, 0xc0, 0xf0, 0xe0, 0xf8, 0x70, 0xe3, 0x87, 0x87, 0xc0,
0xf0, 0xe0, 0xf1, 0xe1, 0xe1, 0xc7, 0x83, 0x87, 0x83, 0x8f, 0x87, 0x87, 0xc7, 0x83, 0xc3, 0x83,
0xc3, 0xf1, 0xe1, 0xc3, 0xc7, 0x81, 0xcf, 0x87, 0x03, 0x87, 0xc7, 0xc7, 0x87, 0x83, 0xe1, 0xc3,
0x07, 0xc3, 0x87, 0x87, 0x07, 0x87, 0xc3, 0x87, 0x83, 0xe1, 0xc3, 0xc7, 0xc3, 0x87, 0x87, 0x8f,
0x0f, 0x87, 0x87, 0x0f, 0xcf, 0x1f, 0x87, 0x8e, 0x0e, 0x07, 0x81, 0xc3, 0xe3, 0xc1, 0xe0, 0xf0,
0xe0, 0xe3, 0x83, 0x87, 0x07, 0x87, 0x8e, 0x1e, 0x0f, 0x07, 0x87, 0x8f, 0x1f, 0x07, 0x87, 0xc1,
0xf0, 0xe1, 0xe1, 0xe3, 0xc7, 0x0f, 0x03, 0x8f, 0x87, 0x0e, 0x1e, 0x1e, 0x0f, 0x87, 0x87, 0x0f,
0x87, 0x1f, 0x0f, 0xc3, 0xc3, 0xf0, 0xf8, 0xf0, 0x70, 0xf1, 0xf0, 0xf0, 0xe1, 0xf0, 0xe0, 0x78,
0x7c, 0x78, 0x7c, 0x70, 0x71, 0xe1, 0xe1, 0xc3, 0xc3, 0xc7, 0x87, 0x1c, 0x3c, 0x3c, 0x1c, 0x3c,
0x7c, 0x1e, 0x1e, 0x1e, 0x1c, 0x3c, 0x78, 0xf8, 0xf8, 0xe1, 0xc3, 0x87, 0x1e, 0x1e, 0x3c, 0x3e,
0x0f, 0x0f, 0x87, 0x1f, 0x8e, 0x0f, 0x0f, 0x8e, 0x1e, 0x1e, 0x1e, 0x1e, 0x0f, 0x0f, 0x8f, 0x87,
0x87, 0xc3, 0x83, 0xc1, 0xe1, 0xc3, 0xc1, 0xc3, 0xc7, 0x8f, 0x0f, 0x0f, 0x0f, 0x0f, 0x83, 0xc7,
0xc3, 0xc1, 0xe1, 0xe0, 0xf8, 0x3e, 0x3c, 0x3c, 0x3c, 0x3c, 0x3c, 0x78, 0x3e, 0x1e, 0x1e, 0x1e,
0x0f, 0x0f, 0x0f, 0x1e, 0x0e, 0x1e, 0x1e, 0x0f, 0x0f, 0x87, 0x1f, 0x87, 0x87, 0x1c, 0x3e, 0x1f,
0x0f, 0x0f, 0x8e, 0x3e, 0x0e, 0x3e, 0x1e, 0x1c, 0x3c, 0x7c, 0xfc, 0x38, 0x78, 0x78, 0x38, 0x78,
0x70, 0xf8, 0x7c, 0x1e, 0x3c, 0x3c, 0x30, 0xf1, 0xf0, 0x70, 0x70, 0xe0, 0xf8, 0xf0, 0xf8, 0x78,
0x78, 0x71, 0xe1, 0xf0, 0xe3, 0xc1, 0xf0, 0x71, 0xe3, 0xc7, 0x87, 0x8e, 0x3e, 0x0e, 0x1e, 0x3e,
0x0f, 0x07, 0x87, 0x0c, 0x3e, 0x0f, 0x87, 0x0f, 0x1e, 0x3c, 0x3c, 0x38, 0x78, 0xf1, 0xe7, 0xc3,
0xc3, 0xc7, 0x8e, 0x3c, 0x38, 0xf0, 0xe0, 0x7e, 0x1e, 0x3e, 0x0e, 0x0f, 0x0f, 0x0f, 0x03, 0xc3,
0xc3, 0xc7, 0x87, 0x1f, 0x0e, 0x1e, 0x1c, 0x3c, 0x3c, 0x0f, 0x07, 0x07, 0xc7, 0xc7, 0x87, 0x87,
0x8f, 0x0f, 0xc0, 0xf0, 0xf8, 0x60, 0xf0, 0xf0, 0xe1, 0xe3, 0xe3, 0xc3, 0xc3, 0xc3, 0x87, 0x0f,
0x87, 0x8e, 0x1e, 0x1e, 0x3f, 0x1e, 0x0e, 0x1c, 0x3c, 0x7e, 0x1e, 0x3c, 0x38, 0x78, 0x78, 0x78,
0x38, 0x78, 0x3c, 0xe1, 0xe3, 0x8f, 0x1f, 0x1c, 0x78, 0x70, 0x7e, 0x0f, 0x87, 0x07, 0xc3, 0xc7,
0x0f, 0x1e, 0x3c, 0x0e, 0x0f, 0x0e, 0x1e, 0x03, 0xf0, 0xf0, 0xf1, 0xe3, 0xc1, 0xc7, 0xc0, 0xe1,
0xe1, 0xe1, 0xe1, 0xe0, 0x70, 0xe1, 0xf0, 0x78, 0x70, 0xe3, 0xc7, 0x0f, 0xc1, 0xe1, 0xe3, 0xc3,
0xc0, 0xf0, 0xfc, 0x1c, 0x3c, 0x70, 0xf8, 0x70, 0xf8, 0x78, 0x3c, 0x70, 0xf0, 0x78, 0x70, 0x7c,
0x7c, 0x3c, 0x38, 0x1e, 0x3e, 0x3c, 0x7e, 0x07, 0x83, 0xc7, 0xc1, 0xc1, 0xe1, 0xc3, 0xc3, 0xc3,
0xe1, 0xe1, 0xf0, 0x78, 0x7c, 0x3e, 0x0f, 0x1f, 0x07, 0x8f, 0x0f, 0x83, 0x87, 0xc1, 0xe3, 0xe3,
0xc3, 0xc3, 0xe1, 0xf0, 0xf8, 0xf0, 0x3c, 0x7c, 0x3c, 0x0f, 0x8e, 0x0e, 0x1f, 0x1f, 0x0e, 0x3c,
0x38, 0x78, 0x70, 0x70, 0xf0, 0xf0, 0xf8, 0x70, 0x70, 0x78, 0x38, 0x3c, 0x70, 0xe0, 0xf0, 0x78,
0xf1, 0xf0, 0x78, 0x3e, 0x3c, 0x0f, 0x07, 0x0e, 0x3e, 0x1e, 0x3f, 0x1e, 0x0e, 0x0f, 0x87, 0x87,
0x07, 0x0f, 0x07, 0xc7, 0x8f, 0x0f, 0x87, 0x1e, 0x1e, 0x1f, 0x1e, 0x1e, 0x3c, 0x1e, 0x1c, 0x3e,
0x0f, 0x03, 0xc3, 0x81, 0xe0, 0xf0, 0xfc, 0x38, 0x3c, 0x3e, 0x0e, 0x1e, 0x1c, 0x7c, 0x1e, 0x1f,
0x0e, 0x3e, 0x1c, 0x78, 0x78, 0x7c, 0x1e, 0x3e, 0x1e, 0x3c, 0x1f, 0x0f, 0x1f, 0x0f, 0x0f, 0x8f,
0x1c, 0x3c, 0x78, 0xf8, 0xf0, 0xf8, 0x70, 0xf0, 0x78, 0x78, 0x3c, 0x3c, 0x78, 0x3c, 0x1f, 0x0f,
0x07, 0x86, 0x1c, 0x1e, 0x1c, 0x1e, 0x1e, 0x1f, 0x03, 0xc3, 0xc7, 0x8e, 0x3c, 0x3c, 0x1c, 0x18,
0xf0, 0xe1, 0xc3, 0xe1, 0xc1, 0xe1, 0xe3, 0xc3, 0xc3, 0xe3, 0xc3, 0x83, 0x87, 0x83, 0x87, 0x0f,
0x07, 0x07, 0xe1, 0xe1, 0xe0, 0x7c, 0x78, 0x38, 0x78, 0x78, 0x3c, 0x1f, 0x0f, 0x8f, 0x0e, 0x07,
0x0f, 0x07, 0x83, 0xc3, 0xc3, 0x81, 0xf0, 0xf8, 0xf1, 0xe0, 0xe3, 0xc7, 0x1c, 0x3e, 0x1e, 0x0f,
0x0f, 0xc3, 0xf0, 0xf0, 0xe3, 0x83, 0xc3, 0xc7, 0x07, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x07, 0x87,
0x0f, 0x0f, 0x0e, 0x0f, 0x0f, 0x1e, 0x0f, 0x0f, 0x87, 0x87, 0x87, 0x8f, 0xc7, 0xc7, 0x83, 0x83,
0xc3, 0xc7, 0x8f, 0x87, 0x07, 0xc3, 0x8e, 0x1e, 0x38, 0x3e, 0x3c, 0x38, 0x7c, 0x1f, 0x1c, 0x38,
0x3c, 0x78, 0x7c, 0x1e, 0x1c, 0x3c, 0x3f, 0x1e, 0x0e, 0x3e, 0x1c, 0x3c, 0x1f, 0x0f, 0x07, 0xc3,
0xe3, 0x83, 0x87, 0x81, 0xc1, 0xe3, 0xcf, 0x0e, 0x0f, 0x1e, 0x3e, 0x1e, 0x1f, 0x0f, 0x8f, 0xc3,
0x87, 0x0e, 0x03, 0xf0, 0xf0, 0x70, 0xe0, 0xe1, 0xe1, 0xc7, 0x8e, 0x0f, 0x0f, 0x1e, 0x0e, 0x1e,
0x1f, 0x1c, 0x78, 0xf0, 0xf1, 0xf1, 0xe0, 0xf1, 0xe1, 0xe1, 0xe0, 0xe0, 0xf1, 0xc1, 0xf0, 0x71,
0xe1, 0xc3, 0x83, 0xc7, 0x83, 0xe1, 0xe1, 0xf8, 0x70, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0x70, 0xf8,
0x70, 0x70, 0x61, 0xe0, 0xf0, 0xe1, 0xe0, 0x78, 0x71, 0xe0, 0xf0, 0xf8, 0x38, 0x1e, 0x1c, 0x38,
0x70, 0xf8, 0x60, 0x78, 0x38, 0x3c, 0x3f, 0x1f, 0x0f, 0x1f, 0x0f, 0x1f, 0x87, 0x87, 0x83, 0x87,
0x83, 0xe1, 0xe1, 0xf0, 0x78, 0xf1, 0xf0, 0x70, 0x38, 0x38, 0x70, 0xe0, 0xe3, 0xc0, 0xe0, 0xf8,
0x78, 0x78, 0xf8, 0x38, 0xf1, 0xe1, 0xe1, 0xc3, 0x87, 0x87, 0x0e, 0x1e, 0x1f, 0x0e, 0x0e, 0x0f,
0x0f, 0x87, 0xc3, 0x87, 0x07, 0x83, 0xc0, 0xf0, 0x38, 0x3c, 0x3c, 0x38, 0xf0, 0xfc, 0x3e, 0x1e,
0x1c, 0x1c, 0x38, 0x70, 0xf0, 0xf1, 0xe0, 0xf0, 0xe0, 0xe0, 0xf1, 0xe3, 0xe0, 0xe1, 0xf0, 0xf0,
0x78, 0x7c, 0x78, 0x3c, 0x78, 0x78, 0x38, 0x78, 0x78, 0x78, 0x78, 0x70, 0xe3, 0x83, 0x83, 0xe0,
0xc3, 0xc1, 0xe1, 0xc1, 0xc1, 0xc1, 0xe3, 0xc3, 0xc7, 0x1e, 0x0e, 0x1f, 0x1e, 0x1e, 0x0f, 0x0f,
0x0e, 0x0e, 0x0e, 0x07, 0x83, 0x87, 0x87, 0x0e, 0x07, 0x8f, 0x0f, 0x0f, 0x0f, 0x0e, 0x1c, 0x70,
0xe1, 0xe0, 0x71, 0xc1, 0x83, 0x83, 0x87, 0x0f, 0x1e, 0x18, 0x78, 0x78, 0x7c, 0x3e, 0x1c, 0x38,
0xf0, 0xe1, 0xe0, 0x78, 0x70, 0x38, 0x3c, 0x3e, 0x1e, 0x3c, 0x1e, 0x1c, 0x70, 0x3c, 0x38, 0x3f,
};
#define shift(r) _shift_registers[r] = (_shift_registers[r] << 1) | (((_shift_registers[r]^0x80)&_control_registers[r]) >> 7);
#define increment(r) _shift_registers[r] = (_shift_registers[r]+1)%8191;
#define update(r, m, up) _counters[r]++; if((_counters[r] >> m) == 0x7f) { up(r); _counters[r] = _control_registers[r]&0x7f; }
void MOS6560::Speaker::get_samples(unsigned int number_of_samples, int16_t *target)
{
for(unsigned int c = 0; c < number_of_samples; c++)
{
update(0, 2, shift);
update(1, 1, shift);
update(2, 0, shift);
update(3, 1, increment);
// this sums the output of all three sounds channels plus a DC offset for volume;
// TODO: what's the real ratio of this stuff?
target[c] = (
(_shift_registers[0]&1) +
(_shift_registers[1]&1) +
(_shift_registers[2]&1) +
((noise_pattern[_shift_registers[3] >> 3] >> (_shift_registers[3]&7))&(_control_registers[3] >> 7)&1)
) * _volume * 700 + _volume * 44;
}
}
void MOS6560::Speaker::skip_samples(unsigned int number_of_samples)
{
for(unsigned int c = 0; c < number_of_samples; c++)
{
update(0, 2, shift);
update(1, 1, shift);
update(2, 0, shift);
update(3, 1, increment);
}
}
#undef shift
#undef increment
#undef update