org.razvan.jzx
Class BaseIO

java.lang.Object
  org.razvan.jzx.BaseComponent
      org.razvan.jzx.BaseIO

Direct Known Subclasses:

IO, IO

public class BaseIO
extends BaseComponent

Base class extended by all I/O components that comprise the emulator.

This class provides basic, common I/O functionality for the I/O subsystem of the emulator. Specific methods are overriden or implemented so as to comply with the Spectrum 48k and the Spectrum 128k models.

Author:

Razvan Surdulescu (c) 2001 - 2006, Erik Kunze (c) 1995, 1996, 1997, Des Herriott (c) 1993, 1994
You may use and distribute this software for free provided you include this copyright notice. You may not sell this software, use my name for publicity reasons or modify the code without permission from me.

See Also:

IO, IO

Field Summary

static int	B_BORDER Bit mask used to determine the border color value.
static int	B_DOWN Bit mask for "joystick down" event.
static int	B_EAR Bit mask used to determien the "tape in" bit.
static int	B_FIRE Bit mask for "joystick fire" event.
static int	B_KEMPSTON Bit mask used to determine if the Kempston joystick is selected.
static int	B_KEYBOARD Bit mask used to determine the keyboard value.
static int	B_LEFT Bit mask for "joystick left" event.
static int	B_MIC Bit mask used to determine the "tape out" bit.
static int	B_RIGHT Bit mask for "joystick right" event.
static int	B_SPEAKER Bit mask used to determine the speaker value.
static int	B_ULA Bit mask used to detemine if the specified port will cause a "select" on the ULA.
static int	B_UP Bit mask for "joystick up" event.
static int	LINE_BUF_SIZE The size of the buffer used for generating sounds.
protected byte[]	m_buffer The sound buffer as it is currently being filled and played.
protected Z80	m_cpu Cached reference to the Z80 component.
protected int	m_index The current index into the sound buffer.
protected int[]	m_inPorts The input port array.
protected int[]	m_keyPorts The keyboard port array.
protected int	m_lastBorderColor Last border color.
protected BaseMemory	m_memory Cached reference to the memory component.
protected int[]	m_outPorts The output port array.
protected BaseScreen	m_screen Cached reference to the screen component.
protected int	m_speakerLevel
static int	P_KEMPSTON Kempston joystick address.
static int	P_SINCLAIR1 Port address for the Sinclair1 joystick (Interface II).
static int	P_SINCLAIR2 Port address for the Sinclair2 joystick (Interface II).
static int	P_ULA Port address for the ULA.
static float	SAMPLE_FREQ The sampling frequency for playing sounds with the speaker or AY chip.

Fields inherited from class org.razvan.jzx.BaseComponent

m_logger, m_spectrum

Constructor Summary

BaseIO()

Method Summary

void	advance(int tStates)
void	andIn(int port16, int mask8) INport(port16) = INport(port16) AND mask8
void	andKey(int port16, int mask8) KEYport(port16) = KEYport(port16) AND mask8
void	andOut(int port16, int mask8) OUTport(port16) = OUTport(port16) AND mask8
static int	getAudioSamplesForTStates(int tStates)
int	in8(int port16) Process an I/O "in" request.
void	init(BaseSpectrum spectrum, ILogger logger) Allocate the port arrays and cache the Z80, memory and screen components.
void	load(BaseLoader loader) Extracts the saved border color and outputs it to the appropriate I/O port.
protected int	mixSound(int tStates, int val8)
void	orIn(int port16, int mask8) INport(port16) = INport(port16) OR mask8
void	orKey(int port16, int mask8) KEYport(port16) = KEYport(port16) OR mask8
void	orOut(int port16, int mask8) OUTport(port16) = OUTport(port16) OR mask8
void	out(int port16, int val8) Process an I/O "out" request.
void	reset() Set the port arrays to zero.
void	terminate() Release references to all cached components and port arrays.

Methods inherited from class org.razvan.jzx.BaseComponent

getSpectrum

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SAMPLE_FREQ

public static final float SAMPLE_FREQ

The sampling frequency for playing sounds with the speaker or AY chip.

See Also:

Constant Field Values

LINE_BUF_SIZE

public static final int LINE_BUF_SIZE

The size of the buffer used for generating sounds.

See Also:

Constant Field Values

m_buffer

protected byte[] m_buffer

The sound buffer as it is currently being filled and played.

m_index

protected int m_index

The current index into the sound buffer.

P_ULA

public static final int P_ULA

Port address for the ULA.

See Also:

Constant Field Values

B_ULA

public static final int B_ULA

Bit mask used to detemine if the specified port will cause a "select" on the ULA.

See Also:

Constant Field Values

B_BORDER

public static final int B_BORDER

Bit mask used to determine the border color value.

See Also:

Constant Field Values

B_MIC

public static final int B_MIC

Bit mask used to determine the "tape out" bit.

See Also:

Constant Field Values

B_SPEAKER

public static final int B_SPEAKER

Bit mask used to determine the speaker value.

See Also:

Constant Field Values

B_KEYBOARD

public static final int B_KEYBOARD

Bit mask used to determine the keyboard value.

See Also:

Constant Field Values

B_EAR

public static final int B_EAR

Bit mask used to determien the "tape in" bit.

See Also:

Constant Field Values

P_KEMPSTON

public static final int P_KEMPSTON

Kempston joystick address.

See Also:

Constant Field Values

B_KEMPSTON

public static final int B_KEMPSTON

Bit mask used to determine if the Kempston joystick is selected.

See Also:

Constant Field Values

B_RIGHT

public static final int B_RIGHT

Bit mask for "joystick right" event.

See Also:

Constant Field Values

B_LEFT

public static final int B_LEFT

Bit mask for "joystick left" event.

See Also:

Constant Field Values

B_DOWN

public static final int B_DOWN

Bit mask for "joystick down" event.

See Also:

Constant Field Values

B_UP

public static final int B_UP

Bit mask for "joystick up" event.

See Also:

Constant Field Values

B_FIRE

public static final int B_FIRE

Bit mask for "joystick fire" event.

See Also:

Constant Field Values

P_SINCLAIR1

public static final int P_SINCLAIR1

Port address for the Sinclair1 joystick (Interface II).

See Also:

Constant Field Values

P_SINCLAIR2

public static final int P_SINCLAIR2

Port address for the Sinclair2 joystick (Interface II).

See Also:

Constant Field Values

m_lastBorderColor

protected int m_lastBorderColor

Last border color.

This is used to determine if the newly specified border color should trigger a screen update.

m_inPorts

protected int[] m_inPorts

The input port array.

This array is modified by the Z80 I/O instructions.

m_outPorts

protected int[] m_outPorts

The output port array.

This array is modified by the Z80 I/O instructions.

m_keyPorts

protected int[] m_keyPorts

The keyboard port array.

This array is modified by the Keyboard component directly.

m_cpu

protected Z80 m_cpu

Cached reference to the Z80 component.

This is used to increment the CPU T-states after I/O instructions.

m_memory

protected BaseMemory m_memory

Cached reference to the memory component.

This is used for all memory page modifications that are triggered by I/O instructions.

m_screen

protected BaseScreen m_screen

Cached reference to the screen component.

This is used to alter the border color.

m_speakerLevel

protected int m_speakerLevel

Constructor Detail

BaseIO

public BaseIO()

Method Detail

getAudioSamplesForTStates

public static int getAudioSamplesForTStates(int tStates)

init

public void init(BaseSpectrum spectrum,
                 ILogger logger)

Allocate the port arrays and cache the Z80, memory and screen components.

Overrides:

init in class BaseComponent

reset

public void reset()

Set the port arrays to zero.

Specified by:

reset in class BaseComponent

terminate

public void terminate()

Release references to all cached components and port arrays.

Overrides:

terminate in class BaseComponent

in8

public int in8(int port16)

Process an I/O "in" request.

The flow of this call is as follows:

• If you read from both the joystick and keyboard ports, the joystick takes priority.
• Read keyboard ports and increment CPU T-states.
• Return random value or memory value for all other unrecognized ports.

See the explicit code comments for specific details.

Parameters:

port16 - The 16-bit I/O input port.

Returns:

The 8-bit value read from the I/O port.

out

public void out(int port16,
                int val8)

Process an I/O "out" request.

The flow of this call is as follows:

• Set new border color, if appropriate.
• Output speaker sound, if appropriate.
• Insert appropriate delay if ULA is busy with video update.

See the explicit code comments for specific details.

Parameters:

port16 - The 16-bit I/O output port.

val8 - The 8-bit value to write to the I/O port.

advance

public void advance(int tStates)

mixSound

protected int mixSound(int tStates,
                       int val8)

orIn

public void orIn(int port16,
                 int mask8)

INport(port16) = INport(port16) OR mask8

andIn

public void andIn(int port16,
                  int mask8)

INport(port16) = INport(port16) AND mask8

orOut

public void orOut(int port16,
                  int mask8)

OUTport(port16) = OUTport(port16) OR mask8

andOut

public void andOut(int port16,
                   int mask8)

OUTport(port16) = OUTport(port16) AND mask8

orKey

public void orKey(int port16,
                  int mask8)

KEYport(port16) = KEYport(port16) OR mask8

andKey

public void andKey(int port16,
                   int mask8)

KEYport(port16) = KEYport(port16) AND mask8

load

public void load(BaseLoader loader)

Extracts the saved border color and outputs it to the appropriate I/O port.

Specified by:

load in class BaseComponent