// license:BSD-3-Clause
// copyright-holders:Krzysztof Strzecha
/***************************************************************************
audio/dai_snd.c
Functions to emulate sound hardware of DAI Personal Computer
Krzysztof Strzecha
****************************************************************************/
#include "emu.h"
#include "dai_snd.h"
// device type definition
DEFINE_DEVICE_TYPE(DAI_SOUND, dai_sound_device, "dai_sound", "DAI Custom Sound")
//-------------------------------------------------
// dai_sound_device - constructor
//-------------------------------------------------
dai_sound_device::dai_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, DAI_SOUND, tag, owner, clock)
, device_sound_interface(mconfig, *this)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void dai_sound_device::device_start()
{
m_mixer_channel = stream_alloc(0, 2, machine().sample_rate());
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void dai_sound_device::device_reset()
{
memset(m_dai_input, 0, sizeof(m_dai_input));
memset(m_osc_volume, 0, sizeof(m_osc_volume));
m_noise_volume = 0;
}
//-------------------------------------------------
// channels 0/1/2 volume table
//-------------------------------------------------
const uint16_t dai_sound_device::s_osc_volume_table[] = {
0, 500, 1000, 1500,
2000, 2500, 3000, 3500,
4000, 4500, 5000, 5500,
6000, 6500, 7000, 7500
};
//-------------------------------------------------
// noise volume table
//-------------------------------------------------
const uint16_t dai_sound_device::s_noise_volume_table[] = {
0, 0, 0, 0,
0, 0, 0, 0,
500, 1000, 1500, 2000,
2500, 3000, 3500, 4000
};
//-------------------------------------------------
// set_volume
//-------------------------------------------------
void dai_sound_device::set_volume(offs_t offset, uint8_t data)
{
m_mixer_channel->update();
switch (offset & 1)
{
case 0x00:
m_osc_volume[0] = data&0x0f;
m_osc_volume[1] = (data&0xf0)>>4;
break;
case 0x01:
m_osc_volume[2] = data&0x0f;
m_noise_volume = (data&0xf0)>>4;
}
}
//-------------------------------------------------
// PIT callbacks
//-------------------------------------------------
WRITE_LINE_MEMBER(dai_sound_device::set_input_ch0)
{
m_mixer_channel->update();
m_dai_input[0] = state;
}
WRITE_LINE_MEMBER(dai_sound_device::set_input_ch1)
{
m_mixer_channel->update();
m_dai_input[1] = state;
}
WRITE_LINE_MEMBER(dai_sound_device::set_input_ch2)
{
m_mixer_channel->update();
m_dai_input[2] = state;
}
//-------------------------------------------------
// sound_stream_update - handle update requests for
// our sound stream
//-------------------------------------------------
void dai_sound_device::sound_stream_update(sound_stream &stream, std::vector<read_stream_view> const &inputs, std::vector<write_stream_view> &outputs)
{
auto &sample_left = outputs[0];
auto &sample_right = outputs[1];
int16_t channel_0_signal = m_dai_input[0] ? s_osc_volume_table[m_osc_volume[0]] : -s_osc_volume_table[m_osc_volume[0]];
int16_t channel_1_signal = m_dai_input[1] ? s_osc_volume_table[m_osc_volume[1]] : -s_osc_volume_table[m_osc_volume[1]];
int16_t channel_2_signal = m_dai_input[2] ? s_osc_volume_table[m_osc_volume[2]] : -s_osc_volume_table[m_osc_volume[2]];
for (int sampindex = 0; sampindex < sample_left.samples(); sampindex++)
{
int16_t noise = machine().rand()&0x01 ? s_noise_volume_table[m_noise_volume] : -s_noise_volume_table[m_noise_volume];
/* channel 0 + channel 1 + noise */
sample_left.put_int(sampindex, channel_0_signal + channel_1_signal + noise, 32768);
/* channel 1 + channel 2 + noise */
sample_right.put_int(sampindex, channel_1_signal + channel_2_signal + noise, 32768);
}
}