CLK/Machines/Atari2600/Atari2600.cpp

//
//  Atari2600.cpp
//  CLK
//
//  Created by Thomas Harte on 14/07/2015.
//  Copyright © 2015 Thomas Harte. All rights reserved.
//

#include "Atari2600.hpp"
#include <algorithm>
#include <stdio.h>

#include "CartridgeUnpaged.hpp"
#include "CartridgeCommaVid.hpp"
#include "CartridgeAtari8k.hpp"

using namespace Atari2600;
namespace {
	static const double NTSC_clock_rate = 1194720;
	static const double PAL_clock_rate = 1182298;
}

Machine::Machine() :
	rom_(nullptr),
	rom_pages_{nullptr, nullptr, nullptr, nullptr},
	frame_record_pointer_(0),
	is_ntsc_(true) {
	set_clock_rate(NTSC_clock_rate);
}

void Machine::setup_output(float aspect_ratio) {
	bus_->tia_.reset(new TIA);
	bus_->speaker_.reset(new Speaker);
	bus_->speaker_->set_input_rate((float)(get_clock_rate() / 38.0));
	bus_->tia_->get_crt()->set_delegate(this);
}

void Machine::close_output() {
	bus_.reset();
}

Machine::~Machine() {
	close_output();
}

void Machine::set_digital_input(Atari2600DigitalInput input, bool state) {
	switch (input) {
		case Atari2600DigitalInputJoy1Up:		bus_->mos6532_.update_port_input(0, 0x10, state);	break;
		case Atari2600DigitalInputJoy1Down:		bus_->mos6532_.update_port_input(0, 0x20, state);	break;
		case Atari2600DigitalInputJoy1Left:		bus_->mos6532_.update_port_input(0, 0x40, state);	break;
		case Atari2600DigitalInputJoy1Right:	bus_->mos6532_.update_port_input(0, 0x80, state);	break;

		case Atari2600DigitalInputJoy2Up:		bus_->mos6532_.update_port_input(0, 0x01, state);	break;
		case Atari2600DigitalInputJoy2Down:		bus_->mos6532_.update_port_input(0, 0x02, state);	break;
		case Atari2600DigitalInputJoy2Left:		bus_->mos6532_.update_port_input(0, 0x04, state);	break;
		case Atari2600DigitalInputJoy2Right:	bus_->mos6532_.update_port_input(0, 0x08, state);	break;

		// TODO: latching
		case Atari2600DigitalInputJoy1Fire:		if(state) bus_->tia_input_value_[0] &= ~0x80; else bus_->tia_input_value_[0] |= 0x80; break;
		case Atari2600DigitalInputJoy2Fire:		if(state) bus_->tia_input_value_[1] &= ~0x80; else bus_->tia_input_value_[1] |= 0x80; break;

		default: break;
	}
}

void Machine::set_switch_is_enabled(Atari2600Switch input, bool state) {
	switch(input) {
		case Atari2600SwitchReset:					bus_->mos6532_.update_port_input(1, 0x01, state);	break;
		case Atari2600SwitchSelect:					bus_->mos6532_.update_port_input(1, 0x02, state);	break;
		case Atari2600SwitchColour:					bus_->mos6532_.update_port_input(1, 0x08, state);	break;
		case Atari2600SwitchLeftPlayerDifficulty:	bus_->mos6532_.update_port_input(1, 0x40, state);	break;
		case Atari2600SwitchRightPlayerDifficulty:	bus_->mos6532_.update_port_input(1, 0x80, state);	break;
	}
}

void Machine::configure_as_target(const StaticAnalyser::Target &target) {
	switch(target.atari.paging_model) {
		case StaticAnalyser::Atari2600PagingModel::None:
			bus_.reset(new CartridgeUnpaged(target.cartridges.front()->get_segments().front().data));
		break;
		case StaticAnalyser::Atari2600PagingModel::CommaVid:
			bus_.reset(new CartridgeCommaVid(target.cartridges.front()->get_segments().front().data));
		break;
		case StaticAnalyser::Atari2600PagingModel::Atari8k:
			if(target.atari.uses_superchip) {
				bus_.reset(new CartridgeAtari8kSuperChip(target.cartridges.front()->get_segments().front().data));
			} else {
				bus_.reset(new CartridgeAtari8k(target.cartridges.front()->get_segments().front().data));
			}
		break;
	}

/*	if(!target.cartridges.front()->get_segments().size()) return;
	Storage::Cartridge::Cartridge::Segment segment = target.cartridges.front()->get_segments().front();
	size_t length = segment.data.size();

	rom_size_ = length;
	delete[] rom_;
	rom_ = new uint8_t[rom_size_];

	size_t offset = 0;
	const size_t copy_step = std::min(rom_size_, length);
	while(offset < rom_size_) {
		size_t copy_length = std::min(copy_step, rom_size_ - offset);
		memcpy(&rom_[offset], &segment.data[0], copy_length);
		offset += copy_length;
	}

	// On a real paged cartridge, any page may initially be visible. Various homebrew authors appear to have
	// decided the last page will always be initially visible. So do that.
	size_t rom_mask = rom_size_ - 1;
	uint8_t *rom_base = rom_;
	if(rom_size_ > 4096) rom_base = &rom_[rom_size_ - 4096];
	rom_pages_[0] = rom_base;
	rom_pages_[1] = &rom_base[1024 & rom_mask];
	rom_pages_[2] = &rom_base[2048 & rom_mask];
	rom_pages_[3] = &rom_base[3072 & rom_mask];

	// By default, throw all stores away, and don't ever read from RAM
	for(int c = 0; c < sizeof(ram_write_targets_) / sizeof(*ram_write_targets_); c++) {
		ram_write_targets_[c] = throwaway_ram_;
		ram_read_targets_[c] = nullptr;
	}

	switch(target.atari.paging_model) {
		default:
			if(target.atari.uses_superchip) {
				// allocate 128 bytes of RAM; allow writing from 0x1000, reading from 0x1080
				ram_.resize(128);
				ram_write_targets_[0] = ram_.data();
				ram_read_targets_[1] = ram_write_targets_[0];
			}
		break;
		case StaticAnalyser::Atari2600PagingModel::CBSRamPlus:
			// allocate 256 bytes of RAM; allow writing from 0x1000, reading from 0x1100
			ram_.resize(256);
			ram_write_targets_[0] = ram_.data();
			ram_write_targets_[1] = ram_write_targets_[0] + 128;
			ram_read_targets_[2] = ram_write_targets_[0];
			ram_read_targets_[3] = ram_write_targets_[1];
		break;
		case StaticAnalyser::Atari2600PagingModel::CommaVid:
			// allocate 1kb of RAM; allow reading from 0x1000, writing from 0x1400
			ram_.resize(1024);
			for(int c = 0; c < 8; c++) {
				ram_read_targets_[c] = ram_.data() + 128 * c;
				ram_write_targets_[c + 8] = ram_.data() + 128 * c;
			}
		break;
		case StaticAnalyser::Atari2600PagingModel::MegaBoy:
			mega_boy_page_ = 15;
		break;
		case StaticAnalyser::Atari2600PagingModel::MNetwork:
			ram_.resize(2048);
			// Put 256 bytes of RAM for writing at 0x1800 and reading at 0x1900
			ram_write_targets_[16] = ram_.data();
			ram_write_targets_[17] = ram_write_targets_[16] + 128;
			ram_read_targets_[18] = ram_write_targets_[16];
			ram_read_targets_[19] = ram_write_targets_[17];

			rom_pages_[0] = rom_;
			rom_pages_[1] = rom_pages_[0] + 1024;
			rom_pages_[2] = rom_pages_[0] + 2048;
			rom_pages_[3] = rom_pages_[0] + 3072;
		break;
	}

	paging_model_ = target.atari.paging_model;*/
}

#pragma mark - CRT delegate

void Machine::crt_did_end_batch_of_frames(Outputs::CRT::CRT *crt, unsigned int number_of_frames, unsigned int number_of_unexpected_vertical_syncs) {
	const size_t number_of_frame_records = sizeof(frame_records_) / sizeof(frame_records_[0]);
	frame_records_[frame_record_pointer_ % number_of_frame_records].number_of_frames = number_of_frames;
	frame_records_[frame_record_pointer_ % number_of_frame_records].number_of_unexpected_vertical_syncs = number_of_unexpected_vertical_syncs;
	frame_record_pointer_ ++;

	if(frame_record_pointer_ >= 6) {
		unsigned int total_number_of_frames = 0;
		unsigned int total_number_of_unexpected_vertical_syncs = 0;
		for(size_t c = 0; c < number_of_frame_records; c++) {
			total_number_of_frames += frame_records_[c].number_of_frames;
			total_number_of_unexpected_vertical_syncs += frame_records_[c].number_of_unexpected_vertical_syncs;
		}

		if(total_number_of_unexpected_vertical_syncs >= total_number_of_frames >> 1) {
			for(size_t c = 0; c < number_of_frame_records; c++) {
				frame_records_[c].number_of_frames = 0;
				frame_records_[c].number_of_unexpected_vertical_syncs = 0;
			}
			is_ntsc_ ^= true;

			double clock_rate;
			if(is_ntsc_) {
				clock_rate = NTSC_clock_rate;
				bus_->tia_->set_output_mode(TIA::OutputMode::NTSC);
			} else {
				clock_rate = PAL_clock_rate;
				bus_->tia_->set_output_mode(TIA::OutputMode::PAL);
			}

			bus_->speaker_->set_input_rate((float)(clock_rate / 38.0));
			bus_->speaker_->set_high_frequency_cut_off((float)(clock_rate / (38.0 * 2.0)));
			set_clock_rate(clock_rate);
		}
	}
}