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// license: GPL-2.0+
// copyright-holders: Dirk Best
/***************************************************************************
PMI DAC-76 COMDAC
Companding D/A Converter
***************************************************************************/
#include "dac76.h"
//**************************************************************************
// CONSTEXPR DEFINITIONS
//**************************************************************************
constexpr int dac76_device::m_level[];
//**************************************************************************
// DEVICE DEFINITIONS
//**************************************************************************
const device_type DAC76 = &device_creator<dac76_device>;
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// dac76_device - constructor
//-------------------------------------------------
dac76_device::dac76_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
device_t(mconfig, DAC76, "DAC-76 COMDAC", tag, owner, clock, "dac76", __FILE__),
device_sound_interface(mconfig, *this),
m_stream(nullptr),
m_chord(0),
m_step(0),
m_sb(false)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void dac76_device::device_start()
{
// create sound stream
m_stream = machine().sound().stream_alloc(*this, 0, 1, machine().sample_rate() * 8);
// register for save states
save_item(NAME(m_chord));
save_item(NAME(m_step));
save_item(NAME(m_sb));
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void dac76_device::device_reset()
{
m_chord = 0;
m_step = 0;
m_sb = false;
}
//-------------------------------------------------
// sound_stream_update - handle update requests for
// our sound stream
//-------------------------------------------------
void dac76_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples)
{
// get current output level
int step_size = (2 << m_chord);
stream_sample_t vout = m_level[m_chord] + m_step * step_size;
// apply sign bit
vout *= (m_sb ? +1 : -1);
// range is 0-8031, normalize to about 0-32768 range
vout *= 4;
for (int i = 0; i < samples; i++)
outputs[0][i] = vout;
}
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