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1054 lines
31 KiB
C++
1054 lines
31 KiB
C++
//
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// Electron.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 03/01/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#include "Electron.hpp"
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#include "TapeUEF.hpp"
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#include <algorithm>
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#include <cassert>
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using namespace Electron;
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namespace {
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static const unsigned int cycles_per_line = 128;
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static const unsigned int lines_per_frame = 625;
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static const unsigned int cycles_per_frame = lines_per_frame * cycles_per_line;
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static const unsigned int crt_cycles_multiplier = 8;
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static const unsigned int crt_cycles_per_line = crt_cycles_multiplier * cycles_per_line;
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static const unsigned int field_divider_line = 312; // i.e. the line, simultaneous with which, the first field's sync ends. So if
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// the first line with pixels in field 1 is the 20th in the frame, the first line
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// with pixels in field 2 will be 20+field_divider_line
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static const unsigned int first_graphics_line = 31;
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static const unsigned int first_graphics_cycle = 33;
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static const unsigned int display_end_interrupt_line = 256;
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static const unsigned int real_time_clock_interrupt_1 = 16704;
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static const unsigned int real_time_clock_interrupt_2 = 56704;
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static const unsigned int clock_rate_audio_divider = 8;
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}
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#define graphics_line(v) ((((v) >> 7) - first_graphics_line + field_divider_line) % field_divider_line)
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#define graphics_column(v) ((((v) & 127) - first_graphics_cycle + 128) & 127)
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Machine::Machine() :
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_interrupt_control(0),
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_interrupt_status(Interrupt::PowerOnReset),
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_frameCycles(0),
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_displayOutputPosition(0),
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_audioOutputPosition(0),
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_current_pixel_line(-1),
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_use_fast_tape_hack(false),
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_crt(nullptr),
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_phase(0)
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{
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memset(_key_states, 0, sizeof(_key_states));
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memset(_palette, 0xf, sizeof(_palette));
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for(int c = 0; c < 16; c++)
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memset(_roms[c], 0xff, 16384);
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_tape.set_delegate(this);
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set_reset_line(true);
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}
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void Machine::setup_output(float aspect_ratio)
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{
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_crt = std::unique_ptr<Outputs::CRT::CRT>(new Outputs::CRT::CRT(crt_cycles_per_line, 8, Outputs::CRT::DisplayType::PAL50, 1));
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_crt->set_rgb_sampling_function(
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"vec3 rgb_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate)"
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"{"
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"uint texValue = texture(sampler, coordinate).r;"
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"texValue >>= 4 - (int(icoordinate.x * 8) & 4);"
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"return vec3( uvec3(texValue) & uvec3(4u, 2u, 1u));"
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"}");
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// TODO: as implied below, I've introduced a clock's latency into the graphics pipeline somehow. Investigate.
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_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));
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// The maximum output frequency is 62500Hz and all other permitted output frequencies are integral divisions of that;
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// however setting the speaker on or off can happen on any 2Mhz cycle, and probably (?) takes effect immediately. So
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// run the speaker at a 2000000Hz input rate, at least for the time being.
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_speaker.set_input_rate(2000000 / clock_rate_audio_divider);
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}
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void Machine::close_output()
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{
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_crt = nullptr;
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}
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unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uint16_t address, uint8_t *value)
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{
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unsigned int cycles = 1;
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set_reset_line(false);
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if(address < 0x8000)
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{
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if(isReadOperation(operation))
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{
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*value = _ram[address];
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}
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else
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{
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if(
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(
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((_frameCycles >= first_graphics_line * cycles_per_line) && (_frameCycles < (first_graphics_line + 256) * cycles_per_line)) ||
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((_frameCycles >= (first_graphics_line + field_divider_line) * cycles_per_line) && (_frameCycles < (first_graphics_line + 256 + field_divider_line) * cycles_per_line))
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)
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)
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update_display();
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_ram[address] = *value;
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}
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// for the entire frame, RAM is accessible only on odd cycles; in modes below 4
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// it's also accessible only outside of the pixel regions
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cycles += 1 + (_frameCycles&1);
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if(_screen_mode < 4)
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{
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const int current_line = graphics_line(_frameCycles + (_frameCycles&1));
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const int current_column = graphics_column(_frameCycles + (_frameCycles&1));
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if(current_line < 256 && current_column < 80 && !_isBlankLine)
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cycles += (unsigned int)(80 - current_column);
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}
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}
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else
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{
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if(address >= 0xc000)
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{
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if((address & 0xff00) == 0xfe00)
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{
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switch(address&0xf)
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{
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case 0x0:
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if(isReadOperation(operation))
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{
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*value = _interrupt_status;
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_interrupt_status &= ~PowerOnReset;
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}
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else
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{
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_interrupt_control = (*value) & ~1;
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evaluate_interrupts();
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}
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break;
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case 0x1:
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break;
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case 0x2:
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if(!isReadOperation(operation))
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{
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_startScreenAddress = (_startScreenAddress & 0xfe00) | (uint16_t)(((*value) & 0xe0) << 1);
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if(!_startScreenAddress) _startScreenAddress |= 0x8000;
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}
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break;
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case 0x3:
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if(!isReadOperation(operation))
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{
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_startScreenAddress = (_startScreenAddress & 0x01ff) | (uint16_t)(((*value) & 0x3f) << 9);
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if(!_startScreenAddress) _startScreenAddress |= 0x8000;
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}
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break;
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case 0x4:
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if(isReadOperation(operation))
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{
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*value = _tape.get_data_register();
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_tape.clear_interrupts(Interrupt::ReceiveDataFull);
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}
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else
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{
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_tape.set_data_register(*value);
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_tape.clear_interrupts(Interrupt::TransmitDataEmpty);
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}
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break;
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case 0x5:
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if(!isReadOperation(operation))
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{
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const uint8_t interruptDisable = (*value)&0xf0;
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if( interruptDisable )
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{
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if( interruptDisable&0x10 ) _interrupt_status &= ~Interrupt::DisplayEnd;
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if( interruptDisable&0x20 ) _interrupt_status &= ~Interrupt::RealTimeClock;
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if( interruptDisable&0x40 ) _interrupt_status &= ~Interrupt::HighToneDetect;
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evaluate_interrupts();
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// TODO: NMI
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}
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// latch the paged ROM in case external hardware is being emulated
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_active_rom = (Electron::ROMSlot)(*value & 0xf);
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// apply the ULA's test
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if(*value & 0x08)
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{
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if(*value & 0x04)
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{
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_keyboard_is_active = false;
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_basic_is_active = false;
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}
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else
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{
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_keyboard_is_active = !(*value & 0x02);
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_basic_is_active = !_keyboard_is_active;
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}
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}
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}
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break;
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case 0x6:
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if(!isReadOperation(operation))
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{
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update_audio();
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_speaker.set_divider(*value);
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_tape.set_counter(*value);
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}
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break;
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case 0x7:
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if(!isReadOperation(operation))
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{
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// update screen mode
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uint8_t new_screen_mode = ((*value) >> 3)&7;
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if(new_screen_mode == 7) new_screen_mode = 4;
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if(new_screen_mode != _screen_mode)
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{
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// printf("To mode %d, at %d cycles into field (%d)\n", new_screen_mode, _fieldCycles, _fieldCycles >> 7);
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update_display();
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_screen_mode = new_screen_mode;
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switch(_screen_mode)
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{
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case 0: case 1: case 2: _screenModeBaseAddress = 0x3000; break;
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case 3: _screenModeBaseAddress = 0x4000; break;
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case 4: case 5: _screenModeBaseAddress = 0x5800; break;
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case 6: _screenModeBaseAddress = 0x6000; break;
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}
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}
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// update speaker mode
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bool new_speaker_is_enabled = (*value & 6) == 2;
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if(new_speaker_is_enabled != _speaker.get_is_enabled())
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{
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update_audio();
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_speaker.set_is_enabled(new_speaker_is_enabled);
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_tape.set_is_enabled(!new_speaker_is_enabled);
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}
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_tape.set_is_running(((*value)&0x40) ? true : false);
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_tape.set_is_in_input_mode(((*value)&0x04) ? false : true);
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// TODO: caps lock LED
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}
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break;
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default:
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{
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if(!isReadOperation(operation))
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{
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update_display();
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static const int registers[4][4] = {
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{10, 8, 2, 0},
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{14, 12, 6, 4},
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{15, 13, 7, 5},
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{11, 9, 3, 1},
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};
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const int index = (address >> 1)&3;
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const uint8_t colour = ~(*value);
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if(address&1)
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{
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_palette[registers[index][0]] = (_palette[registers[index][0]]&3) | ((colour >> 1)&4);
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_palette[registers[index][1]] = (_palette[registers[index][1]]&3) | ((colour >> 0)&4);
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_palette[registers[index][2]] = (_palette[registers[index][2]]&3) | ((colour << 1)&4);
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_palette[registers[index][3]] = (_palette[registers[index][3]]&3) | ((colour << 2)&4);
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_palette[registers[index][2]] = (_palette[registers[index][2]]&5) | ((colour >> 4)&2);
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_palette[registers[index][3]] = (_palette[registers[index][3]]&5) | ((colour >> 3)&2);
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}
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else
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{
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_palette[registers[index][0]] = (_palette[registers[index][0]]&6) | ((colour >> 7)&1);
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_palette[registers[index][1]] = (_palette[registers[index][1]]&6) | ((colour >> 6)&1);
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_palette[registers[index][2]] = (_palette[registers[index][2]]&6) | ((colour >> 5)&1);
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_palette[registers[index][3]] = (_palette[registers[index][3]]&6) | ((colour >> 4)&1);
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_palette[registers[index][0]] = (_palette[registers[index][0]]&5) | ((colour >> 2)&2);
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_palette[registers[index][1]] = (_palette[registers[index][1]]&5) | ((colour >> 1)&2);
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}
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// regenerate all palette tables for now
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#define pack(a, b) (uint8_t)((a << 4) | (b))
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for(int byte = 0; byte < 256; byte++)
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{
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uint8_t *target = (uint8_t *)&_paletteTables.forty1bpp[byte];
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target[0] = pack(_palette[(byte&0x80) >> 4], _palette[(byte&0x40) >> 3]);
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target[1] = pack(_palette[(byte&0x20) >> 2], _palette[(byte&0x10) >> 1]);
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target = (uint8_t *)&_paletteTables.eighty2bpp[byte];
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target[0] = pack(_palette[((byte&0x80) >> 4) | ((byte&0x08) >> 2)], _palette[((byte&0x40) >> 3) | ((byte&0x04) >> 1)]);
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target[1] = pack(_palette[((byte&0x20) >> 2) | ((byte&0x02) >> 0)], _palette[((byte&0x10) >> 1) | ((byte&0x01) << 1)]);
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target = (uint8_t *)&_paletteTables.eighty1bpp[byte];
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target[0] = pack(_palette[(byte&0x80) >> 4], _palette[(byte&0x40) >> 3]);
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target[1] = pack(_palette[(byte&0x20) >> 2], _palette[(byte&0x10) >> 1]);
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target[2] = pack(_palette[(byte&0x08) >> 0], _palette[(byte&0x04) << 1]);
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target[3] = pack(_palette[(byte&0x02) << 2], _palette[(byte&0x01) << 3]);
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_paletteTables.forty2bpp[byte] = pack(_palette[((byte&0x80) >> 4) | ((byte&0x08) >> 2)], _palette[((byte&0x40) >> 3) | ((byte&0x04) >> 1)]);
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_paletteTables.eighty4bpp[byte] = pack( _palette[((byte&0x80) >> 4) | ((byte&0x20) >> 3) | ((byte&0x08) >> 2) | ((byte&0x02) >> 1)],
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_palette[((byte&0x40) >> 3) | ((byte&0x10) >> 2) | ((byte&0x04) >> 1) | ((byte&0x01) >> 0)]);
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}
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#undef pack
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}
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}
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break;
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}
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}
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else
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{
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if(isReadOperation(operation))
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{
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if(
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_use_fast_tape_hack &&
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_tape.has_tape() &&
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(operation == CPU6502::BusOperation::ReadOpcode) &&
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(
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(address == 0xf4e5) || (address == 0xf4e6) || // double NOPs at 0xf4e5, 0xf6de, 0xf6fa and 0xfa51
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(address == 0xf6de) || (address == 0xf6df) || // act to disable the normal branch into tape-handling
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(address == 0xf6fa) || (address == 0xf6fb) || // code, forcing the OS along the serially-accessed ROM
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(address == 0xfa51) || (address == 0xfa52) || // pathway.
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(address == 0xf0a8) // 0xf0a8 is from where a service call would normally be
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// dispatched; we can check whether it would be call 14
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// (i.e. read byte) and, if so, whether the OS was about to
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// issue a read byte call to a ROM despite being the tape
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// FS being selected. If so then this is a get byte that
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// we should service synthetically. Put the byte into Y
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// and set A to zero to report that action was taken, then
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// allow the PC read to return an RTS.
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)
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)
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{
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uint8_t service_call = (uint8_t)get_value_of_register(CPU6502::Register::X);
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if(address == 0xf0a8)
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{
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if(!_ram[0x247] && service_call == 14)
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{
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_tape.set_delegate(nullptr);
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// TODO: handle tape wrap around.
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int cycles_left_while_plausibly_in_data = 50;
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_tape.clear_interrupts(Interrupt::ReceiveDataFull);
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while(1)
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{
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_tape.run_for_input_pulse();
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cycles_left_while_plausibly_in_data--;
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if(!cycles_left_while_plausibly_in_data) _fast_load_is_in_data = false;
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if( (_tape.get_interrupt_status() & Interrupt::ReceiveDataFull) &&
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(_fast_load_is_in_data || _tape.get_data_register() == 0x2a)
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) break;
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}
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_tape.set_delegate(this);
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_tape.clear_interrupts(Interrupt::ReceiveDataFull);
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_interrupt_status |= _tape.get_interrupt_status();
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_fast_load_is_in_data = true;
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set_value_of_register(CPU6502::Register::A, 0);
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set_value_of_register(CPU6502::Register::Y, _tape.get_data_register());
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*value = 0x60; // 0x60 is RTS
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}
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else
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*value = _os[address & 16383];
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}
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else
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*value = 0xea;
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}
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else
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{
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*value = _os[address & 16383];
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}
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}
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}
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}
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else
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{
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if(isReadOperation(operation))
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{
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*value = _roms[_active_rom][address & 16383];
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if(_keyboard_is_active)
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{
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*value &= 0xf0;
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for(int address_line = 0; address_line < 14; address_line++)
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{
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if(!(address&(1 << address_line))) *value |= _key_states[address_line];
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}
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}
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if(_basic_is_active)
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{
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*value &= _roms[ROMSlotBASIC][address & 16383];
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}
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}
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}
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}
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// if(operation == CPU6502::BusOperation::ReadOpcode)
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// {
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// printf("%04x: %02x (%d)\n", address, *value, _fieldCycles);
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// }
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// const int end_of_field =
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// if(_frameCycles < (256 + first_graphics_line) << 7))
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const unsigned int pixel_line_clock = _frameCycles;// + 128 - first_graphics_cycle + 80;
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const unsigned int line_before_cycle = graphics_line(pixel_line_clock);
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const unsigned int line_after_cycle = graphics_line(pixel_line_clock + cycles);
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// implicit assumption here: the number of 2Mhz cycles this bus operation will take
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// is never longer than a line. On the Electron, it's a safe one.
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if(line_before_cycle != line_after_cycle)
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{
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switch(line_before_cycle)
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{
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// case real_time_clock_interrupt_line: signal_interrupt(Interrupt::RealTimeClock); break;
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// case real_time_clock_interrupt_line+1: clear_interrupt(Interrupt::RealTimeClock); break;
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case display_end_interrupt_line: signal_interrupt(Interrupt::DisplayEnd); break;
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// case display_end_interrupt_line+1: clear_interrupt(Interrupt::DisplayEnd); break;
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}
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}
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if(
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(pixel_line_clock < real_time_clock_interrupt_1 && pixel_line_clock + cycles >= real_time_clock_interrupt_1) ||
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(pixel_line_clock < real_time_clock_interrupt_2 && pixel_line_clock + cycles >= real_time_clock_interrupt_2))
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{
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signal_interrupt(Interrupt::RealTimeClock);
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}
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_frameCycles += cycles;
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if(!(_frameCycles&127)) _phase += 64;
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// deal with frame wraparound by updating the two dependent subsystems
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// as though the exact end of frame had been hit, then reset those
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// and allow the frame cycle counter to assume its real value
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if(_frameCycles >= cycles_per_frame)
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{
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unsigned int nextFrameCycles = _frameCycles - cycles_per_frame;
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_frameCycles = cycles_per_frame;
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update_display();
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update_audio();
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_displayOutputPosition = 0;
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_audioOutputPosition = 0;
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_frameCycles = nextFrameCycles;
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}
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if(!(_frameCycles&16383))
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update_audio();
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_tape.run_for_cycles(cycles);
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return cycles;
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}
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|
|
void Machine::update_output()
|
|
{
|
|
update_display();
|
|
update_audio();
|
|
}
|
|
|
|
void Machine::set_tape(std::shared_ptr<Storage::Tape> tape)
|
|
{
|
|
_tape.set_tape(tape);
|
|
}
|
|
|
|
void Machine::set_rom(ROMSlot slot, size_t length, const uint8_t *data)
|
|
{
|
|
uint8_t *target = nullptr;
|
|
switch(slot)
|
|
{
|
|
case ROMSlotOS: target = _os; break;
|
|
default: target = _roms[slot]; break;
|
|
}
|
|
|
|
memcpy(target, data, std::min((size_t)16384, length));
|
|
}
|
|
|
|
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(Key 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)
|
|
{
|
|
_divider = divider * 32 / clock_rate_audio_divider;
|
|
}
|
|
|
|
void Speaker::set_is_enabled(bool is_enabled)
|
|
{
|
|
_is_enabled = is_enabled;
|
|
_counter = 0;
|
|
}
|
|
|
|
/*
|
|
Tape
|
|
*/
|
|
|
|
Tape::Tape() :
|
|
_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) {}
|
|
|
|
void Tape::set_tape(std::shared_ptr<Storage::Tape> tape)
|
|
{
|
|
_tape = tape;
|
|
get_next_tape_pulse();
|
|
}
|
|
|
|
inline void Tape::get_next_tape_pulse()
|
|
{
|
|
_input.time_into_pulse = 0;
|
|
if(_tape)
|
|
_input.current_pulse = _tape->get_next_pulse();
|
|
else
|
|
{
|
|
_input.current_pulse.length.length = 1;
|
|
_input.current_pulse.length.clock_rate = 1;
|
|
_input.current_pulse.type = Storage::Tape::Pulse::Zero;
|
|
}
|
|
if(_input.pulse_stepper == nullptr || _input.current_pulse.length.clock_rate != _input.pulse_stepper->get_output_rate())
|
|
{
|
|
_input.pulse_stepper = std::unique_ptr<SignalProcessing::Stepper>(new SignalProcessing::Stepper(_input.current_pulse.length.clock_rate, 2000000));
|
|
}
|
|
}
|
|
|
|
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::run_for_input_pulse()
|
|
{
|
|
get_next_tape_pulse();
|
|
|
|
_crossings[0] = _crossings[1];
|
|
_crossings[1] = _crossings[2];
|
|
_crossings[2] = _crossings[3];
|
|
|
|
_crossings[3] = Tape::Unrecognised;
|
|
if(_input.current_pulse.type != Storage::Tape::Pulse::Zero)
|
|
{
|
|
float pulse_length = (float)_input.current_pulse.length.length / (float)_input.current_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 && _tape != nullptr)
|
|
{
|
|
while(number_of_cycles--)
|
|
{
|
|
_input.time_into_pulse += (unsigned int)_input.pulse_stepper->step();
|
|
if(_input.time_into_pulse == _input.current_pulse.length.length)
|
|
{
|
|
run_for_input_pulse();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
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);
|
|
}
|
|
}
|
|
}
|
|
}
|