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Added a decent portion of documentation. But started feeling like I should address my various ownership decisions. Which would justify a separate pull request.

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This commit is contained in:
Thomas Harte 2017-08-16 16:23:33 -04:00
parent 4c15e46fd1
commit 925e774015
2 changed files with 54 additions and 14 deletions
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60
Machines/Commodore/Vic-20/Vic20.cpp
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@ -27,24 +27,36 @@
namespace Commodore {
namespace Vic20 {
/*!
Models the user-port VIA, which is the Vic's connection point for controlling its tape recorder —
sensing the presence or absence of a tape and controlling the tape motor — and reading the current
state from its serial port. Most of the joystick input is also exposed here.
*/
class UserPortVIA: public MOS::MOS6522<UserPortVIA>, public MOS::MOS6522IRQDelegate {
public:
UserPortVIA() : port_a_(0xbf) {}
using MOS6522IRQDelegate::set_interrupt_status;
/// Reports the current input to the 6522 port @c port.
uint8_t get_port_input(Port port) {
// Port A provides information about the presence or absence of a tape, and parts of
// the joystick and serial port state, both of which have been statefully collected
// into port_a_.
if(!port) {
return port_a_ | (tape_->has_tape() ? 0x00 : 0x40);
}
return 0xff;
}
/// Receives announcements of control line output change from the 6522.
void set_control_line_output(Port port, Line line, bool value) {
// The CA2 output is used to control the tape motor.
if(port == Port::A && line == Line::Two) {
tape_->set_motor_control(!value);
}
}
/// Receives announcements of changes in the serial bus connected to the serial port and propagates them into Port A.
void set_serial_line_state(::Commodore::Serial::Line line, bool value) {
switch(line) {
default: break;
@ -53,25 +65,28 @@ class UserPortVIA: public MOS::MOS6522<UserPortVIA>, public MOS::MOS6522IRQDeleg
}
}
/// Allows the current joystick input to be set.
void set_joystick_state(JoystickInput input, bool value) {
if(input != JoystickInput::Right) {
port_a_ = (port_a_ & ~input) | (value ? 0 : input);
}
}
/// Receives announcements from the 6522 of user-port output, which might affect what's currently being presented onto the serial bus.
void set_port_output(Port port, uint8_t value, uint8_t mask) {
// Line 7 of port A is inverted and output as serial ATN
// Line 7 of port A is inverted and output as serial ATN.
if(!port) {
std::shared_ptr<::Commodore::Serial::Port> serialPort = serial_port_.lock();
if(serialPort)
serialPort->set_output(::Commodore::Serial::Line::Attention, (::Commodore::Serial::LineLevel)!(value&0x80));
if(serialPort) serialPort->set_output(::Commodore::Serial::Line::Attention, (::Commodore::Serial::LineLevel)!(value&0x80));
}
}
void set_serial_port(std::shared_ptr<::Commodore::Serial::Port> serialPort) {
serial_port_ = serialPort;
/// Sets @serial_port as this VIA's connection to the serial bus.
void set_serial_port(std::shared_ptr<::Commodore::Serial::Port> serial_port) {
serial_port_ = serial_port;
}
/// Sets @tape as the tape player connected to this VIA.
void set_tape(std::shared_ptr<Storage::Tape::BinaryTapePlayer> tape) {
tape_ = tape;
}
@ -82,6 +97,10 @@ class UserPortVIA: public MOS::MOS6522<UserPortVIA>, public MOS::MOS6522IRQDeleg
std::shared_ptr<Storage::Tape::BinaryTapePlayer> tape_;
};
/*!
Models the keyboard VIA, which is used by the Vic for reading its keyboard, to output to its serial port,
and for the small portion of joystick input not connected to the user-port VIA.
*/
class KeyboardVIA: public MOS::MOS6522<KeyboardVIA>, public MOS::MOS6522IRQDelegate {
public:
KeyboardVIA() : port_b_(0xff) {
@ -90,17 +109,20 @@ class KeyboardVIA: public MOS::MOS6522<KeyboardVIA>, public MOS::MOS6522IRQDeleg
using MOS6522IRQDelegate::set_interrupt_status;
void set_key_state(uint16_t key, bool isPressed) {
if(isPressed)
/// Sets whether @c key @c is_pressed.
void set_key_state(uint16_t key, bool is_pressed) {
if(is_pressed)
columns_[key & 7] &= ~(key >> 3);
else
columns_[key & 7] |= (key >> 3);
}
/// Sets all keys as unpressed.
void clear_all_keys() {
memset(columns_, 0xff, sizeof(columns_));
}
/// Called by the 6522 to get input. Reads the keyboard on Port A, returns a small amount of joystick state on Port B.
uint8_t get_port_input(Port port) {
if(!port) {
uint8_t result = 0xff;
@ -114,11 +136,12 @@ class KeyboardVIA: public MOS::MOS6522<KeyboardVIA>, public MOS::MOS6522IRQDeleg
return port_b_;
}
/// Called by the 6522 to set output. The value of Port B selects which part of the keyboard to read.
void set_port_output(Port port, uint8_t value, uint8_t mask) {
if(port)
activation_mask_ = (value & mask) | (~mask);
if(port) activation_mask_ = (value & mask) | (~mask);
}
/// Called by the 6522 to set control line output. Which affects the serial port.
void set_control_line_output(Port port, Line line, bool value) {
if(line == Line::Two) {
std::shared_ptr<::Commodore::Serial::Port> serialPort = serial_port_.lock();
@ -132,12 +155,14 @@ class KeyboardVIA: public MOS::MOS6522<KeyboardVIA>, public MOS::MOS6522IRQDeleg
}
}
/// Sets whether the joystick input @c input is pressed.
void set_joystick_state(JoystickInput input, bool value) {
if(input == JoystickInput::Right) {
port_b_ = (port_b_ & ~input) | (value ? 0 : input);
}
}
/// Sets the serial port to which this VIA is connected.
void set_serial_port(std::shared_ptr<::Commodore::Serial::Port> serialPort) {
serial_port_ = serialPort;
}
@ -149,13 +174,18 @@ class KeyboardVIA: public MOS::MOS6522<KeyboardVIA>, public MOS::MOS6522IRQDeleg
std::weak_ptr<::Commodore::Serial::Port> serial_port_;
};
/*!
Models the Vic's serial port, providing the receipticle for input.
*/
class SerialPort : public ::Commodore::Serial::Port {
public:
/// Receives an input change from the base serial port class, and communicates it to the user-port VIA.
void set_input(::Commodore::Serial::Line line, ::Commodore::Serial::LineLevel level) {
std::shared_ptr<UserPortVIA> userPortVIA = user_port_via_.lock();
if(userPortVIA) userPortVIA->set_serial_line_state(line, (bool)level);
}
/// Sets the user-port VIA with which this serial port communicates.
void set_user_port_via(std::shared_ptr<UserPortVIA> userPortVIA) {
user_port_via_ = userPortVIA;
}
@ -164,15 +194,20 @@ class SerialPort : public ::Commodore::Serial::Port {
std::weak_ptr<UserPortVIA> user_port_via_;
};
/*!
Provides the bus over which the Vic 6560 fetches memory in a Vic-20.
*/
class Vic6560: public MOS::MOS6560<Vic6560> {
public:
/// Performs a read on behalf of the 6560; in practice uses @c video_memory_map and @c colour_memory to find data.
inline void perform_read(uint16_t address, uint8_t *pixel_data, uint8_t *colour_data) {
*pixel_data = video_memory_map[address >> 10] ? video_memory_map[address >> 10][address & 0x3ff] : 0xff; // TODO
*colour_data = colour_memory[address & 0x03ff];
}
uint8_t *video_memory_map[16];
uint8_t *colour_memory;
// It is assumed that these pointers have been filled in by the machine.
uint8_t *video_memory_map[16]; // Segments video memory into 1kb portions.
uint8_t *colour_memory; // Colour memory must be contiguous.
};
class ConcreteMachine:
@ -212,9 +247,6 @@ class ConcreteMachine:
// set the NTSC clock rate
set_region(NTSC);
// _debugPort.reset(new ::Commodore::Serial::DebugPort);
// _debugPort->set_serial_bus(serial_bus_);
// serial_bus_->add_port(_debugPort);
}
~ConcreteMachine() {

8
Machines/Commodore/Vic-20/Vic20.hpp
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@ -72,15 +72,23 @@ class Machine:
public:
virtual ~Machine();
/// Creates and returns a Vic-20.
static Machine *Vic20();
/// Sets the contents of the rom in @c slot to the buffer @c data of length @c length.
virtual void set_rom(ROMSlot slot, size_t length, const uint8_t *data) = 0;
// TODO: take a std::vector<uint8_t> to collapse length and data.
/// Sets the state of joystick input @c input.
virtual void set_joystick_state(JoystickInput input, bool isPressed) = 0;
/// Sets the memory size of this Vic-20.
virtual void set_memory_size(MemorySize size) = 0;
/// Sets the region of this Vic-20.
virtual void set_region(Region region) = 0;
/// Enables or disables turbo-speed tape loading.
virtual void set_use_fast_tape_hack(bool activate) = 0;
};