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CLK/Machines/ZX8081/ZX8081.cpp

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//
// ZX8081.cpp
// Clock Signal
//
// Created by Thomas Harte on 04/06/2017.
// Copyright © 2017 Thomas Harte. All rights reserved.
//
#include "ZX8081.hpp"
#include "../../Processors/Z80/Z80.hpp"
#include "../../Storage/Tape/Tape.hpp"
#include "../../Storage/Tape/Parsers/ZX8081.hpp"
#include "../MemoryFuzzer.hpp"
#include "../Typer.hpp"
#include "Video.hpp"
namespace {
// The clock rate is 3.25Mhz.
const unsigned int ZX8081ClockRate = 3250000;
}
namespace ZX8081 {
class ConcreteMachine:
public Utility::TypeRecipient,
public CPU::Z80::BusHandler,
public Machine {
public:
ConcreteMachine() :
z80_(*this),
vsync_(false),
hsync_(false),
nmi_is_enabled_(false),
tape_player_(ZX8081ClockRate),
use_fast_tape_hack_(false),
tape_advance_delay_(0),
has_latched_video_byte_(false) {
set_clock_rate(ZX8081ClockRate);
clear_all_keys();
}
HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
HalfCycles previous_counter = horizontal_counter_;
horizontal_counter_ += cycle.length;
if(previous_counter < vsync_start_ && horizontal_counter_ >= vsync_start_) {
video_->run_for(vsync_start_ - previous_counter);
set_hsync(true);
line_counter_ = (line_counter_ + 1) & 7;
if(nmi_is_enabled_) {
z80_.set_non_maskable_interrupt_line(true);
}
video_->run_for(horizontal_counter_ - vsync_start_);
} else if(previous_counter < vsync_end_ && horizontal_counter_ >= vsync_end_) {
video_->run_for(vsync_end_ - previous_counter);
set_hsync(false);
if(nmi_is_enabled_) {
z80_.set_non_maskable_interrupt_line(false);
z80_.set_wait_line(false);
}
video_->run_for(horizontal_counter_ - vsync_end_);
} else {
video_->run_for(cycle.length);
}
if(is_zx81_) horizontal_counter_ %= HalfCycles(Cycles(207));
if(!tape_advance_delay_) {
tape_player_.run_for(cycle.length);
} else {
tape_advance_delay_ = std::max(tape_advance_delay_ - cycle.length, HalfCycles(0));
}
if(nmi_is_enabled_ && !z80_.get_halt_line() && z80_.get_non_maskable_interrupt_line()) {
z80_.set_wait_line(true);
}
if(!cycle.is_terminal()) {
return Cycles(0);
}
uint16_t address = cycle.address ? *cycle.address : 0;
bool is_opcode_read = false;
switch(cycle.operation) {
case CPU::Z80::PartialMachineCycle::Output:
if(!(address & 2)) nmi_is_enabled_ = false;
if(!(address & 1)) nmi_is_enabled_ = is_zx81_;
if(!nmi_is_enabled_) {
// Line counter reset is held low while vsync is active; simulate that lazily by performing
// an instant reset upon the transition from active to inactive.
if(vsync_) line_counter_ = 0;
set_vsync(false);
}
break;
case CPU::Z80::PartialMachineCycle::Input: {
uint8_t value = 0xff;
if(!(address&1)) {
if(!nmi_is_enabled_) set_vsync(true);
uint16_t mask = 0x100;
for(int c = 0; c < 8; c++) {
if(!(address & mask)) value &= key_states_[c];
mask <<= 1;
}
value &= ~(tape_player_.get_input() ? 0x00 : 0x80);
}
*cycle.value = value;
} break;
case CPU::Z80::PartialMachineCycle::Interrupt:
// resetting event is M1 and IOREQ both simultaneously having leading edges;
// that happens 2 cycles before the end of INTACK. So the timer was reset and
// now has advanced twice.
horizontal_counter_ = HalfCycles(2);
*cycle.value = 0xff;
break;
case CPU::Z80::PartialMachineCycle::Refresh:
// The ZX80 and 81 signal an interrupt while refresh is active and bit 6 of the refresh
// address is low. The Z80 signals a refresh, providing the refresh address during the
// final two cycles of an opcode fetch. Therefore communicate a transient signalling
// of the IRQ line if necessary.
if(!(address & 0x40)) {
z80_.set_interrupt_line(true, Cycles(-2));
z80_.set_interrupt_line(false);
}
if(has_latched_video_byte_) {
size_t char_address = (size_t)((address & 0xfe00) | ((latched_video_byte_ & 0x3f) << 3) | line_counter_);
uint8_t mask = (latched_video_byte_ & 0x80) ? 0x00 : 0xff;
if(char_address < ram_base_) {
latched_video_byte_ = rom_[char_address & rom_mask_] ^ mask;
} else {
latched_video_byte_ = ram_[address & ram_mask_] ^ mask;
}
video_->output_byte(latched_video_byte_);
has_latched_video_byte_ = false;
}
break;
case CPU::Z80::PartialMachineCycle::ReadOpcode:
// Check for use of the fast tape hack.
if(use_fast_tape_hack_ && address == tape_trap_address_ && tape_player_.has_tape()) {
uint64_t prior_offset = tape_player_.get_tape()->get_offset();
int next_byte = parser_.get_next_byte(tape_player_.get_tape());
if(next_byte != -1) {
uint16_t hl = z80_.get_value_of_register(CPU::Z80::Register::HL);
ram_[hl & ram_mask_] = (uint8_t)next_byte;
*cycle.value = 0x00;
z80_.set_value_of_register(CPU::Z80::Register::ProgramCounter, tape_return_address_ - 1);
// Assume that having read one byte quickly, we're probably going to be asked to read
// another shortly. Therefore, temporarily disable the tape motor for 1000 cycles in order
// to avoid fighting with real time. This is a stop-gap fix.
tape_advance_delay_ = 1000;
return 0;
} else {
tape_player_.get_tape()->set_offset(prior_offset);
}
}
// Check for automatic tape control.
if(use_automatic_tape_motor_control_) {
tape_player_.set_motor_control((address >= automatic_tape_motor_start_address_) && (address < automatic_tape_motor_end_address_));
}
is_opcode_read = true;
case CPU::Z80::PartialMachineCycle::Read:
if(address < ram_base_) {
*cycle.value = rom_[address & rom_mask_];
} else {
uint8_t value = ram_[address & ram_mask_];
// If this is an M1 cycle reading from above the 32kb mark and HALT is not
// currently active, latch for video output and return a NOP. Otherwise,
// just return the value as read.
if(is_opcode_read && address&0x8000 && !(value & 0x40) && !z80_.get_halt_line()) {
latched_video_byte_ = value;
has_latched_video_byte_ = true;
*cycle.value = 0;
} else *cycle.value = value;
}
break;
case CPU::Z80::PartialMachineCycle::Write:
if(address >= ram_base_) {
ram_[address & ram_mask_] = *cycle.value;
}
break;
default: break;
}
if(typer_) typer_->run_for(cycle.length);
return HalfCycles(0);
}
void flush() {
video_->flush();
}
void setup_output(float aspect_ratio) {
video_.reset(new Video);
}
void close_output() {
video_.reset();
}
std::shared_ptr<Outputs::CRT::CRT> get_crt() {
return video_->get_crt();
}
std::shared_ptr<Outputs::Speaker> get_speaker() {
return nullptr;
}
void run_for(const Cycles cycles) {
z80_.run_for(cycles);
}
void configure_as_target(const StaticAnalyser::Target &target) {
is_zx81_ = target.zx8081.isZX81;
if(is_zx81_) {
rom_ = zx81_rom_;
tape_trap_address_ = 0x37c;
tape_return_address_ = 0x380;
vsync_start_ = HalfCycles(32);
vsync_end_ = HalfCycles(64);
automatic_tape_motor_start_address_ = 0x0340;
automatic_tape_motor_end_address_ = 0x03c3;
} else {
rom_ = zx80_rom_;
tape_trap_address_ = 0x220;
tape_return_address_ = 0x248;
vsync_start_ = HalfCycles(26);
vsync_end_ = HalfCycles(66);
automatic_tape_motor_start_address_ = 0x0206;
automatic_tape_motor_end_address_ = 0x024d;
}
rom_mask_ = (uint16_t)(rom_.size() - 1);
switch(target.zx8081.memory_model) {
case StaticAnalyser::ZX8081MemoryModel::Unexpanded:
ram_.resize(1024);
ram_base_ = 16384;
ram_mask_ = 1023;
break;
case StaticAnalyser::ZX8081MemoryModel::SixteenKB:
ram_.resize(16384);
ram_base_ = 16384;
ram_mask_ = 16383;
break;
case StaticAnalyser::ZX8081MemoryModel::SixtyFourKB:
ram_.resize(65536);
ram_base_ = 8192;
ram_mask_ = 65535;
break;
}
Memory::Fuzz(ram_);
if(target.tapes.size()) {
tape_player_.set_tape(target.tapes.front());
}
if(target.loadingCommand.length()) {
set_typer_for_string(target.loadingCommand.c_str());
}
}
void set_rom(ROMType type, std::vector<uint8_t> data) {
switch(type) {
case ZX80: zx80_rom_ = data; break;
case ZX81: zx81_rom_ = data; break;
}
}
#pragma mark - Keyboard
void set_key_state(uint16_t key, bool isPressed) {
if(isPressed)
key_states_[key >> 8] &= (uint8_t)(~key);
else
key_states_[key >> 8] |= (uint8_t)key;
}
void clear_all_keys() {
memset(key_states_, 0xff, 8);
}
#pragma mark - Tape control
void set_use_fast_tape_hack(bool activate) {
use_fast_tape_hack_ = activate;
}
void set_use_automatic_tape_motor_control(bool enabled) {
use_automatic_tape_motor_control_ = enabled;
if(!enabled) {
tape_player_.set_motor_control(false);
}
}
void set_tape_is_playing(bool is_playing) {
tape_player_.set_motor_control(is_playing);
}
#pragma mark - Typer
// for Utility::TypeRecipient::Delegate
HalfCycles get_typer_delay() { return Cycles(7000000); }
HalfCycles get_typer_frequency() { return Cycles(390000); }
uint16_t *sequence_for_character(Utility::Typer *typer, char character) {
#define KEYS(...) {__VA_ARGS__, EndSequence}
#define SHIFT(...) {KeyShift, __VA_ARGS__, EndSequence}
#define X {NotMapped}
static KeySequence zx81_key_sequences[] = {
/* NUL */ X, /* SOH */ X,
/* STX */ X, /* ETX */ X,
/* EOT */ X, /* ENQ */ X,
/* ACK */ X, /* BEL */ X,
/* BS */ SHIFT(Key0), /* HT */ X,
/* LF */ KEYS(KeyEnter), /* VT */ X,
/* FF */ X, /* CR */ X,
/* SO */ X, /* SI */ X,
/* DLE */ X, /* DC1 */ X,
/* DC2 */ X, /* DC3 */ X,
/* DC4 */ X, /* NAK */ X,
/* SYN */ X, /* ETB */ X,
/* CAN */ X, /* EM */ X,
/* SUB */ X, /* ESC */ X,
/* FS */ X, /* GS */ X,
/* RS */ X, /* US */ X,
/* space */ KEYS(KeySpace), /* ! */ X,
/* " */ SHIFT(KeyP), /* # */ X,
/* $ */ SHIFT(KeyU), /* % */ X,
/* & */ X, /* ' */ X,
/* ( */ SHIFT(KeyI), /* ) */ SHIFT(KeyO),
/* * */ SHIFT(KeyB), /* + */ SHIFT(KeyK),
/* , */ SHIFT(KeyDot), /* - */ SHIFT(KeyJ),
/* . */ KEYS(KeyDot), /* / */ SHIFT(KeyV),
/* 0 */ KEYS(Key0), /* 1 */ KEYS(Key1),
/* 2 */ KEYS(Key2), /* 3 */ KEYS(Key3),
/* 4 */ KEYS(Key4), /* 5 */ KEYS(Key5),
/* 6 */ KEYS(Key6), /* 7 */ KEYS(Key7),
/* 8 */ KEYS(Key8), /* 9 */ KEYS(Key9),
/* : */ SHIFT(KeyZ), /* ; */ SHIFT(KeyX),
/* < */ SHIFT(KeyN), /* = */ SHIFT(KeyL),
/* > */ SHIFT(KeyM), /* ? */ SHIFT(KeyC),
/* @ */ X, /* A */ KEYS(KeyA),
/* B */ KEYS(KeyB), /* C */ KEYS(KeyC),
/* D */ KEYS(KeyD), /* E */ KEYS(KeyE),
/* F */ KEYS(KeyF), /* G */ KEYS(KeyG),
/* H */ KEYS(KeyH), /* I */ KEYS(KeyI),
/* J */ KEYS(KeyJ), /* K */ KEYS(KeyK),
/* L */ KEYS(KeyL), /* M */ KEYS(KeyM),
/* N */ KEYS(KeyN), /* O */ KEYS(KeyO),
/* P */ KEYS(KeyP), /* Q */ KEYS(KeyQ),
/* R */ KEYS(KeyR), /* S */ KEYS(KeyS),
/* T */ KEYS(KeyT), /* U */ KEYS(KeyU),
/* V */ KEYS(KeyV), /* W */ KEYS(KeyW),
/* X */ KEYS(KeyX), /* Y */ KEYS(KeyY),
/* Z */ KEYS(KeyZ), /* [ */ X,
/* \ */ X, /* ] */ X,
/* ^ */ X, /* _ */ X,
/* ` */ X, /* a */ KEYS(KeyA),
/* b */ KEYS(KeyB), /* c */ KEYS(KeyC),
/* d */ KEYS(KeyD), /* e */ KEYS(KeyE),
/* f */ KEYS(KeyF), /* g */ KEYS(KeyG),
/* h */ KEYS(KeyH), /* i */ KEYS(KeyI),
/* j */ KEYS(KeyJ), /* k */ KEYS(KeyK),
/* l */ KEYS(KeyL), /* m */ KEYS(KeyM),
/* n */ KEYS(KeyN), /* o */ KEYS(KeyO),
/* p */ KEYS(KeyP), /* q */ KEYS(KeyQ),
/* r */ KEYS(KeyR), /* s */ KEYS(KeyS),
/* t */ KEYS(KeyT), /* u */ KEYS(KeyU),
/* v */ KEYS(KeyV), /* w */ KEYS(KeyW),
/* x */ KEYS(KeyX), /* y */ KEYS(KeyY),
/* z */ KEYS(KeyZ), /* { */ X,
/* | */ X, /* } */ X,
};
static KeySequence zx80_key_sequences[] = {
/* NUL */ X, /* SOH */ X,
/* STX */ X, /* ETX */ X,
/* EOT */ X, /* ENQ */ X,
/* ACK */ X, /* BEL */ X,
/* BS */ SHIFT(Key0), /* HT */ X,
/* LF */ KEYS(KeyEnter), /* VT */ X,
/* FF */ X, /* CR */ X,
/* SO */ X, /* SI */ X,
/* DLE */ X, /* DC1 */ X,
/* DC2 */ X, /* DC3 */ X,
/* DC4 */ X, /* NAK */ X,
/* SYN */ X, /* ETB */ X,
/* CAN */ X, /* EM */ X,
/* SUB */ X, /* ESC */ X,
/* FS */ X, /* GS */ X,
/* RS */ X, /* US */ X,
/* space */ KEYS(KeySpace), /* ! */ X,
/* " */ SHIFT(KeyY), /* # */ X,
/* $ */ SHIFT(KeyU), /* % */ X,
/* & */ X, /* ' */ X,
/* ( */ SHIFT(KeyI), /* ) */ SHIFT(KeyO),
/* * */ SHIFT(KeyP), /* + */ SHIFT(KeyK),
/* , */ SHIFT(KeyDot), /* - */ SHIFT(KeyJ),
/* . */ KEYS(KeyDot), /* / */ SHIFT(KeyV),
/* 0 */ KEYS(Key0), /* 1 */ KEYS(Key1),
/* 2 */ KEYS(Key2), /* 3 */ KEYS(Key3),
/* 4 */ KEYS(Key4), /* 5 */ KEYS(Key5),
/* 6 */ KEYS(Key6), /* 7 */ KEYS(Key7),
/* 8 */ KEYS(Key8), /* 9 */ KEYS(Key9),
/* : */ SHIFT(KeyZ), /* ; */ SHIFT(KeyX),
/* < */ SHIFT(KeyN), /* = */ SHIFT(KeyL),
/* > */ SHIFT(KeyM), /* ? */ SHIFT(KeyC),
/* @ */ X, /* A */ KEYS(KeyA),
/* B */ KEYS(KeyB), /* C */ KEYS(KeyC),
/* D */ KEYS(KeyD), /* E */ KEYS(KeyE),
/* F */ KEYS(KeyF), /* G */ KEYS(KeyG),
/* H */ KEYS(KeyH), /* I */ KEYS(KeyI),
/* J */ KEYS(KeyJ), /* K */ KEYS(KeyK),
/* L */ KEYS(KeyL), /* M */ KEYS(KeyM),
/* N */ KEYS(KeyN), /* O */ KEYS(KeyO),
/* P */ KEYS(KeyP), /* Q */ KEYS(KeyQ),
/* R */ KEYS(KeyR), /* S */ KEYS(KeyS),
/* T */ KEYS(KeyT), /* U */ KEYS(KeyU),
/* V */ KEYS(KeyV), /* W */ KEYS(KeyW),
/* X */ KEYS(KeyX), /* Y */ KEYS(KeyY),
/* Z */ KEYS(KeyZ), /* [ */ X,
/* \ */ X, /* ] */ X,
/* ^ */ X, /* _ */ X,
/* ` */ X, /* a */ KEYS(KeyA),
/* b */ KEYS(KeyB), /* c */ KEYS(KeyC),
/* d */ KEYS(KeyD), /* e */ KEYS(KeyE),
/* f */ KEYS(KeyF), /* g */ KEYS(KeyG),
/* h */ KEYS(KeyH), /* i */ KEYS(KeyI),
/* j */ KEYS(KeyJ), /* k */ KEYS(KeyK),
/* l */ KEYS(KeyL), /* m */ KEYS(KeyM),
/* n */ KEYS(KeyN), /* o */ KEYS(KeyO),
/* p */ KEYS(KeyP), /* q */ KEYS(KeyQ),
/* r */ KEYS(KeyR), /* s */ KEYS(KeyS),
/* t */ KEYS(KeyT), /* u */ KEYS(KeyU),
/* v */ KEYS(KeyV), /* w */ KEYS(KeyW),
/* x */ KEYS(KeyX), /* y */ KEYS(KeyY),
/* z */ KEYS(KeyZ), /* { */ X,
/* | */ X, /* } */ X,
};
#undef KEYS
#undef SHIFT
#undef X
if(is_zx81_)
return table_lookup_sequence_for_character(zx81_key_sequences, sizeof(zx81_key_sequences), character);
else
return table_lookup_sequence_for_character(zx80_key_sequences, sizeof(zx80_key_sequences), character);
}
private:
CPU::Z80::Processor<ConcreteMachine> z80_;
std::shared_ptr<Video> video_;
std::vector<uint8_t> zx81_rom_, zx80_rom_;
uint16_t tape_trap_address_, tape_return_address_;
uint16_t automatic_tape_motor_start_address_, automatic_tape_motor_end_address_;
std::vector<uint8_t> ram_;
uint16_t ram_mask_, ram_base_;
std::vector<uint8_t> rom_;
uint16_t rom_mask_;
bool vsync_, hsync_;
int line_counter_;
uint8_t key_states_[8];
HalfClockReceiver<Storage::Tape::BinaryTapePlayer> tape_player_;
Storage::Tape::ZX8081::Parser parser_;
bool is_zx81_;
bool nmi_is_enabled_;
HalfCycles vsync_start_, vsync_end_;
HalfCycles horizontal_counter_;
uint8_t latched_video_byte_;
bool has_latched_video_byte_;
bool use_fast_tape_hack_;
bool use_automatic_tape_motor_control_;
HalfCycles tape_advance_delay_;
#pragma mark - Video
void set_vsync(bool sync) {
vsync_ = sync;
update_sync();
}
void set_hsync(bool sync) {
hsync_ = sync;
update_sync();
}
void update_sync() {
video_->set_sync(vsync_ || hsync_);
}
};
}
using namespace ZX8081;
// See header; constructs and returns an instance of the ZX80/81.
Machine *Machine::ZX8081() {
return new ZX8081::ConcreteMachine;
}
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