openmsx::SN76489 Class Reference

This class implements the Texas Instruments SN76489 sound chip. More...

#include <SN76489.hh>

Inheritance diagram for openmsx::SN76489:

Collaboration diagram for openmsx::SN76489:

Public Member Functions
	SN76489 (const DeviceConfig &config)
	~SN76489 ()
void	generateChannels (std::span< float * > buffers, unsigned num) override
	Abstract method to generate the actual sound data.
void	reset (EmuTime::param time)
void	write (byte value, EmuTime::param time)
template<typename Archive >
void	serialize (Archive &ar, unsigned version)
Public Member Functions inherited from openmsx::ResampledSoundDevice
bool	generateInput (float *buffer, size_t num)
	Note: To enable various optimizations (like SSE), this method is allowed to generate up to 3 extra sample.
DynamicClock &	getEmuClock ()
Public Member Functions inherited from openmsx::SoundDevice
	SoundDevice (const SoundDevice &)=delete
SoundDevice &	operator= (const SoundDevice &)=delete
const std::string &	getName () const
	Get the unique name that identifies this sound device.
std::string_view	getDescription () const
	Gets a description of this sound device, to be presented to the user.
bool	isStereo () const
	Is this a stereo device? This is set in the constructor and cannot be changed anymore.
AmplificationFactors	getAmplificationFactor () const
void	setSoftwareVolume (float volume, EmuTime::param time)
	Change the 'software volume' of this sound device.
void	setSoftwareVolume (float left, float right, EmuTime::param time)
void	recordChannel (unsigned channel, const Filename &filename)
void	muteChannel (unsigned channel, bool muted)

Additional Inherited Members
Public Types inherited from openmsx::ResampledSoundDevice
enum	ResampleType { RESAMPLE_HQ , RESAMPLE_LQ , RESAMPLE_BLIP }
Static Public Attributes inherited from openmsx::SoundDevice
static constexpr unsigned	MAX_CHANNELS = 24
Protected Member Functions inherited from openmsx::ResampledSoundDevice
	ResampledSoundDevice (MSXMotherBoard &motherBoard, std::string_view name, static_string_view description, unsigned channels, unsigned inputSampleRate, bool stereo)
	~ResampledSoundDevice ()
void	setOutputRate (unsigned hostSampleRate, double speed) override
	When a SoundDevice registers itself with the Mixer, the Mixer sets the required sampleRate through this method.
bool	updateBuffer (size_t length, float *buffer, EmuTime::param time) override
	Generate sample data.
void	update (const Setting &setting) noexcept override
void	createResampler ()
Protected Member Functions inherited from openmsx::SoundDevice
	SoundDevice (MSXMixer &mixer, std::string_view name, static_string_view description, unsigned numChannels, unsigned inputRate, bool stereo)
	Constructor.
	~SoundDevice ()
virtual float	getAmplificationFactorImpl () const
	Get amplification/attenuation factor for this device.
void	registerSound (const DeviceConfig &config)
	Registers this sound device with the Mixer.
void	unregisterSound ()
	Unregisters this sound device with the Mixer.
void	updateStream (EmuTime::param time)
void	setInputRate (unsigned sampleRate)
unsigned	getInputRate () const
bool	mixChannels (float *dataOut, size_t samples)
	Calls generateChannels() and combines the output to a single channel.
const DynamicClock &	getHostSampleClock () const
	See MSXMixer::getHostSampleClock().
double	getEffectiveSpeed () const
Protected Member Functions inherited from openmsx::Observer< Setting >
	Observer ()=default
	~Observer ()=default
	Observer (const Observer &)=delete
Observer &	operator= (const Observer &)=delete
virtual void	subjectDeleted (const Setting &)
Static Protected Member Functions inherited from openmsx::SoundDevice
static void	addFill (float *&buffer, float value, unsigned num)
	Adds a number of samples that all have the same value.

Detailed Description

This class implements the Texas Instruments SN76489 sound chip.

Unlike the AY-3-8910, this chip only performs sound synthesis.

Resources used:

• SN76489AN data sheet http://map.grauw.nl/resources/sound/texas_instruments_sn76489an.pdf
• Developer documentation on SMS Power! http://www.smspower.org/Development/SN76489
• John Kortink's reverse engineering results http://www.zeridajh.org/articles/various/sn76489/index.htm
• MAME's implementation https://github.com/mamedev/mame/blob/master/src/devices/sound/sn76496.cpp
• blueMSX's implementation https://sourceforge.net/p/bluemsx/code/HEAD/tree/trunk/blueMSX/Src/SoundChips/SN76489.c

Definition at line 26 of file SN76489.hh.

Constructor & Destructor Documentation

SN76489()

openmsx::SN76489::SN76489 ( const DeviceConfig &  config )

explicit

Definition at line 92 of file SN76489.cc.

References openmsx::SoundDevice::registerSound().

~SN76489()

openmsx::SN76489::~SN76489

(

)

Definition at line 106 of file SN76489.cc.

References openmsx::SoundDevice::unregisterSound().

Member Function Documentation

generateChannels()

void openmsx::SN76489::generateChannels ( std::span< float * >  buffers, unsigned  num  )

overridevirtual

Abstract method to generate the actual sound data.

Parameters

buffers	An array of pointer to buffers. Each buffer must be big enough to hold 'num' samples.
num	The number of samples.

This method should fill each buffer with sound data that corresponds to one channel of the sound device. The same channel should each time be written to the same buffer (needed for record).

If a certain channel is muted it is allowed to set the buffer pointer to nullptr. This has exactly the same effect as filling the buffer completely with zeros, but it can be more efficient.

Implements openmsx::SoundDevice.

Definition at line 287 of file SN76489.cc.

References xrange().

reset()

void openmsx::SN76489::reset

(

EmuTime::param

time

)

Definition at line 141 of file SN76489.cc.

References openmsx::SoundDevice::updateStream().

Referenced by openmsx::MusicalMemoryMapper::reset(), and openmsx::SNPSG::reset().

serialize()

template<typename Archive >

void openmsx::SN76489::serialize	(	Archive &	ar,
		unsigned	version
	)

Definition at line 309 of file SN76489.cc.

write()

void openmsx::SN76489::write	(	byte	value,
		EmuTime::param	time
	)

Definition at line 147 of file SN76489.cc.

References UNREACHABLE.

Referenced by openmsx::MusicalMemoryMapper::writeIO(), and openmsx::SNPSG::writeIO().

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The documentation for this class was generated from the following files:

• SN76489.hh
• SN76489.cc