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Merge pull request #363 from TomHarte/ZonX
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Introduces ZonX emulation and corrects a minor ColecoVision AY timing issue.
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@TomHarte
TomHarte authored Mar 7, 2018
2 parents dfcc502 + 9abc020 commit a942e13
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Showing 2 changed files with 75 additions and 13 deletions.
3 changes: 3 additions & 0 deletions Machines/ColecoVision/ColecoVision.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -252,6 +252,7 @@ class ConcreteMachine:
default: *cycle.value = 0xff; break;
case 0x52:
// Read AY data.
update_audio();
ay_.set_control_lines(GI::AY38910::ControlLines(GI::AY38910::BC2 | GI::AY38910::BC1));
*cycle.value = ay_.get_data_output();
ay_.set_control_lines(GI::AY38910::ControlLines(0));
Expand Down Expand Up @@ -289,12 +290,14 @@ class ConcreteMachine:
break;
case 0x50:
// Set AY address.
update_audio();
ay_.set_control_lines(GI::AY38910::BC1);
ay_.set_data_input(*cycle.value);
ay_.set_control_lines(GI::AY38910::ControlLines(0));
break;
case 0x51:
// Set AY data.
update_audio();
ay_.set_control_lines(GI::AY38910::ControlLines(GI::AY38910::BC2 | GI::AY38910::BDIR));
ay_.set_data_input(*cycle.value);
ay_.set_control_lines(GI::AY38910::ControlLines(0));
Expand Down
85 changes: 72 additions & 13 deletions Machines/ZX8081/ZX8081.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@

#include "ZX8081.hpp"

#include "../../Components/AY38910/AY38910.hpp"
#include "../../Processors/Z80/Z80.hpp"
#include "../../Storage/Tape/Tape.hpp"
#include "../../Storage/Tape/Parsers/ZX8081.hpp"
Expand All @@ -18,6 +19,8 @@
#include "../Utility/MemoryFuzzer.hpp"
#include "../Utility/Typer.hpp"

#include "../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"

#include "Keyboard.hpp"
#include "Video.hpp"

Expand All @@ -31,6 +34,11 @@ namespace {
const unsigned int ZX8081ClockRate = 3250000;
}

// TODO:
// Quiksilva sound support:
// 7FFFh.W PSG index
// 7FFEh.R/W PSG data

namespace ZX8081 {

enum ROMType: uint8_t {
Expand All @@ -50,14 +58,18 @@ template<bool is_zx81> class ConcreteMachine:
public:
ConcreteMachine() :
z80_(*this),
tape_player_(ZX8081ClockRate) {
tape_player_(ZX8081ClockRate),
ay_(audio_queue_),
speaker_(ay_) {
set_clock_rate(ZX8081ClockRate);
speaker_.set_input_rate(static_cast<float>(ZX8081ClockRate) / 2.0f);
clear_all_keys();
}

forceinline HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
HalfCycles previous_counter = horizontal_counter_;
const HalfCycles previous_counter = horizontal_counter_;
horizontal_counter_ += cycle.length;
time_since_ay_update_ += cycle.length;

if(previous_counter < vsync_start_ && horizontal_counter_ >= vsync_start_) {
video_->run_for(vsync_start_ - previous_counter);
Expand Down Expand Up @@ -94,7 +106,7 @@ template<bool is_zx81> class ConcreteMachine:
return Cycles(0);
}

uint16_t address = cycle.address ? *cycle.address : 0;
const uint16_t address = cycle.address ? *cycle.address : 0;
bool is_opcode_read = false;
switch(cycle.operation) {
case CPU::Z80::PartialMachineCycle::Output:
Expand All @@ -106,6 +118,15 @@ template<bool is_zx81> class ConcreteMachine:
if(vsync_) line_counter_ = 0;
set_vsync(false);
}

// The below emulates the ZonX AY expansion device.
if(is_zx81) {
if((address&0xef) == 0xcf) {
ay_set_register(*cycle.value);
} else if((address&0xef) == 0x0f) {
ay_set_data(*cycle.value);
}
}
break;

case CPU::Z80::PartialMachineCycle::Input: {
Expand All @@ -121,6 +142,13 @@ template<bool is_zx81> class ConcreteMachine:

value &= ~(tape_player_.get_input() ? 0x00 : 0x80);
}

// The below emulates the ZonX AY expansion device.
if(is_zx81) {
if((address&0xef) == 0x0f) {
value &= ay_read_data();
}
}
*cycle.value = value;
} break;

Expand All @@ -144,7 +172,7 @@ template<bool is_zx81> class ConcreteMachine:
}
if(has_latched_video_byte_) {
std::size_t char_address = static_cast<std::size_t>((address & 0xfe00) | ((latched_video_byte_ & 0x3f) << 3) | line_counter_);
uint8_t mask = (latched_video_byte_ & 0x80) ? 0x00 : 0xff;
const uint8_t mask = (latched_video_byte_ & 0x80) ? 0x00 : 0xff;
if(char_address < ram_base_) {
latched_video_byte_ = rom_[char_address & rom_mask_] ^ mask;
} else {
Expand All @@ -159,10 +187,10 @@ template<bool is_zx81> class ConcreteMachine:
case CPU::Z80::PartialMachineCycle::ReadOpcode:
// Check for use of the fast tape hack.
if(use_fast_tape_hack_ && address == tape_trap_address_) {
uint64_t prior_offset = tape_player_.get_tape()->get_offset();
int next_byte = parser_.get_next_byte(tape_player_.get_tape());
const uint64_t prior_offset = tape_player_.get_tape()->get_offset();
const 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);
const uint16_t hl = z80_.get_value_of_register(CPU::Z80::Register::HL);
ram_[hl & ram_mask_] = static_cast<uint8_t>(next_byte);
*cycle.value = 0x00;
z80_.set_value_of_register(CPU::Z80::Register::ProgramCounter, tape_return_address_ - 1);
Expand All @@ -187,7 +215,7 @@ template<bool is_zx81> class ConcreteMachine:
if(address < ram_base_) {
*cycle.value = rom_[address & rom_mask_];
} else {
uint8_t value = ram_[address & ram_mask_];
const 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,
Expand All @@ -210,12 +238,15 @@ template<bool is_zx81> class ConcreteMachine:
}

if(typer_) typer_->run_for(cycle.length);

return HalfCycles(0);
}

forceinline void flush() {
video_->flush();
if(is_zx81) {
update_audio();
audio_queue_.perform();
}
}

void setup_output(float aspect_ratio) override final {
Expand All @@ -231,7 +262,7 @@ template<bool is_zx81> class ConcreteMachine:
}

Outputs::Speaker::Speaker *get_speaker() override final {
return nullptr;
return is_zx81 ? &speaker_ : nullptr;
}

void run_for(const Cycles cycles) override final {
Expand Down Expand Up @@ -301,7 +332,7 @@ template<bool is_zx81> class ConcreteMachine:

// Obtains the system ROMs.
bool set_rom_fetcher(const std::function<std::vector<std::unique_ptr<std::vector<uint8_t>>>(const std::string &machine, const std::vector<std::string> &names)> &roms_with_names) override {
auto roms = roms_with_names(
const auto roms = roms_with_names(
"ZX8081",
{
"zx80.rom", "zx81.rom",
Expand All @@ -320,8 +351,8 @@ template<bool is_zx81> class ConcreteMachine:
}

// MARK: - Keyboard
void set_key_state(uint16_t key, bool isPressed) override final {
if(isPressed)
void set_key_state(uint16_t key, bool is_pressed) override final {
if(is_pressed)
key_states_[key >> 8] &= static_cast<uint8_t>(~key);
else
key_states_[key >> 8] |= static_cast<uint8_t>(key);
Expand Down Expand Up @@ -443,6 +474,34 @@ template<bool is_zx81> class ConcreteMachine:
inline void update_sync() {
video_->set_sync(vsync_ || hsync_);
}

// MARK: - Audio
Concurrency::DeferringAsyncTaskQueue audio_queue_;
GI::AY38910::AY38910 ay_;
Outputs::Speaker::LowpassSpeaker<GI::AY38910::AY38910> speaker_;
HalfCycles time_since_ay_update_;
inline void ay_set_register(uint8_t value) {
update_audio();
ay_.set_control_lines(GI::AY38910::BC1);
ay_.set_data_input(value);
ay_.set_control_lines(GI::AY38910::ControlLines(0));
}
inline void ay_set_data(uint8_t value) {
update_audio();
ay_.set_control_lines(GI::AY38910::ControlLines(GI::AY38910::BC2 | GI::AY38910::BDIR));
ay_.set_data_input(value);
ay_.set_control_lines(GI::AY38910::ControlLines(0));
}
inline uint8_t ay_read_data() {
update_audio();
ay_.set_control_lines(GI::AY38910::ControlLines(GI::AY38910::BC2 | GI::AY38910::BC1));
const uint8_t value = ay_.get_data_output();
ay_.set_control_lines(GI::AY38910::ControlLines(0));
return value;
}
inline void update_audio() {
speaker_.run_for(audio_queue_, time_since_ay_update_.divide_cycles(Cycles(2)));
}
};

}
Expand Down

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