// license:GPL-2.0+
// copyright-holders:Juergen Buchmueller
/****************************************************************************
*
* warpwarp.cpp
*
* sound driver
* juergen buchmueller <pullmoll@t-online.de>, jan 2000
*
****************************************************************************/
#include "emu.h"
#include "audio/warpwarp.h"
DEFINE_DEVICE_TYPE(WARPWARP_SOUND, warpwarp_sound_device, "warpwarp_sound", "Warp Warp Custom Sound")
warpwarp_sound_device::warpwarp_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, WARPWARP_SOUND, tag, owner, clock),
device_sound_interface(mconfig, *this),
m_decay(nullptr),
m_channel(nullptr),
m_sound_latch(0),
m_music1_latch(0),
m_music2_latch(0),
m_sound_signal(0),
m_sound_volume(0),
m_sound_volume_timer(nullptr),
m_music_signal(0),
m_music_volume(0),
m_music_volume_timer(nullptr),
m_noise(0),
m_vcarry(0),
m_vcount(0),
m_mcarry(0),
m_mcount(0)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void warpwarp_sound_device::device_start()
{
m_decay = std::make_unique<int16_t[]>(32768);
for (int i = 0; i < 0x8000; i++)
m_decay[0x7fff - i] = (int16_t) (0x7fff/exp(1.0*i/4096));
m_clock_16h = clock() / 3 / 2 / 16;
m_clock_1v = clock() / 3 / 2 / 384;
m_channel = machine().sound().stream_alloc(*this, 0, 1, m_clock_16h);
m_sound_volume_timer = timer_alloc(TIMER_SOUND_VOLUME_DECAY);
m_music_volume_timer = timer_alloc(TIMER_MUSIC_VOLUME_DECAY);
save_item(NAME(m_sound_latch));
save_item(NAME(m_music1_latch));
save_item(NAME(m_music2_latch));
save_item(NAME(m_sound_signal));
save_item(NAME(m_sound_volume));
save_item(NAME(m_music_signal));
save_item(NAME(m_music_volume));
save_item(NAME(m_noise));
save_item(NAME(m_vcarry));
save_item(NAME(m_vcount));
save_item(NAME(m_mcarry));
save_item(NAME(m_mcount));
}
void warpwarp_sound_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
{
switch (id)
{
case TIMER_SOUND_VOLUME_DECAY:
if (--m_sound_volume < 0)
m_sound_volume = 0;
break;
case TIMER_MUSIC_VOLUME_DECAY:
if (--m_music_volume < 0)
m_music_volume = 0;
break;
default:
throw emu_fatalerror("Unknown id in warpwarp_sound_device::device_timer");
}
}
void warpwarp_sound_device::sound_w(u8 data)
{
m_channel->update();
m_sound_latch = data & 0x0f;
m_sound_volume = 0x7fff; /* set sound_volume */
m_noise = 0x0000; /* reset noise shifter */
/* faster decay enabled? */
if( m_sound_latch & 8 )
{
/*
* R85(?) is 10k, Rb is 0, C92 is 1uF
* charge time t1 = 0.693 * (R24 + Rb) * C57 -> 0.22176s
* discharge time t2 = 0.693 * (Rb) * C57 -> 0
* C90(?) is only charged via D17 (1N914), no discharge!
* Decay:
* discharge C90(?) (1uF) through R13||R14 (22k||47k)
* 0.639 * 15k * 1uF -> 0.9585s
*/
attotime period = attotime::from_hz(32768) * 95850 / 100000;
m_sound_volume_timer->adjust(period, 0, period);
}
else
{
/*
* discharge only after R93 (100k) and through the 10k
* potentiometerin the amplifier section.
* 0.639 * 110k * 1uF -> 7.0290s
* ...but this is not very realistic for the game sound :(
* maybe there _is_ a discharge through the diode D17?
*/
//attotime period = attotime::from_hz(32768) * 702900 / 100000;
attotime period = attotime::from_hz(32768) * 191700 / 100000;
m_sound_volume_timer->adjust(period, 0, period);
}
}
void warpwarp_sound_device::music1_w(u8 data)
{
m_channel->update();
m_music1_latch = data & 0x3f;
}
void warpwarp_sound_device::music2_w(u8 data)
{
m_channel->update();
m_music2_latch = data & 0x3f;
m_music_volume = 0x7fff;
/* fast decay enabled? */
if( m_music2_latch & 0x10 )
{
/*
* Ra (R83?) is 10k, Rb is 0, C92 is 1uF
* charge time t1 = 0.693 * (Ra + Rb) * C -> 0.22176s
* discharge time is (nearly) zero, because Rb is zero
* C95(?) is only charged via D17, not discharged!
* Decay:
* discharge C95(?) (10uF) through R13||R14 (22k||47k)
* 0.639 * 15k * 10uF -> 9.585s
* ...I'm sure this is off by one number of magnitude :/
*/
attotime period = attotime::from_hz(32768) * 95850 / 100000;
m_music_volume_timer->adjust(period, 0, period);
}
else
{
/*
* discharge through R14 (47k),
* discharge C95(?) (10uF) through R14 (47k)
* 0.639 * 47k * 10uF -> 30.033s
*/
//attotime period = attotime::from_hz(32768) * 3003300 / 100000;
attotime period = attotime::from_hz(32768) * 300330 / 100000;
m_music_volume_timer->adjust(period, 0, period);
}
}
//-------------------------------------------------
// sound_stream_update - handle a stream update
//-------------------------------------------------
void warpwarp_sound_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples)
{
stream_sample_t *buffer = outputs[0];
while (samples--)
{
*buffer++ = (m_sound_signal + m_music_signal) / 2;
/*
* The music signal is selected at a rate of 2H (1.536MHz) from the
* four bits of a 4 bit binary counter which is clocked with 16H,
* which is 192kHz, and is divided by 4 times (64 - music1_latch).
* 0 = 256 steps -> 750 Hz
* 1 = 252 steps -> 761.9 Hz
* ...
* 32 = 128 steps -> 1500 Hz
* ...
* 48 = 64 steps -> 3000 Hz
* ...
* 63 = 4 steps -> 48 kHz
*/
m_mcarry -= m_clock_16h / (4 * (64 - m_music1_latch));
while( m_mcarry < 0 )
{
m_mcarry += m_clock_16h;
m_mcount++;
m_music_signal = (m_mcount & ~m_music2_latch & 15) ? m_decay[m_music_volume] : 0;
/* override by noise gate? */
if( (m_music2_latch & 32) && (m_noise & 0x8000) )
m_music_signal = m_decay[m_music_volume];
}
/* clock 1V = 8kHz */
m_vcarry -= m_clock_1v;
while (m_vcarry < 0)
{
m_vcarry += m_clock_16h;
m_vcount++;
/* noise is clocked with raising edge of 2V */
if ((m_vcount & 3) == 2)
{
/* bit0 = bit0 ^ !bit10 */
if ((m_noise & 1) == ((m_noise >> 10) & 1))
m_noise = (m_noise << 1) | 1;
else
m_noise = m_noise << 1;
}
switch (m_sound_latch & 7)
{
case 0: /* 4V */
m_sound_signal = (m_vcount & 0x04) ? m_decay[m_sound_volume] : 0;
break;
case 1: /* 8V */
m_sound_signal = (m_vcount & 0x08) ? m_decay[m_sound_volume] : 0;
break;
case 2: /* 16V */
m_sound_signal = (m_vcount & 0x10) ? m_decay[m_sound_volume] : 0;
break;
case 3: /* 32V */
m_sound_signal = (m_vcount & 0x20) ? m_decay[m_sound_volume] : 0;
break;
case 4: /* TONE1 */
m_sound_signal = !(m_vcount & 0x01) && !(m_vcount & 0x10) ? m_decay[m_sound_volume] : 0;
break;
case 5: /* TONE2 */
m_sound_signal = !(m_vcount & 0x02) && !(m_vcount & 0x20) ? m_decay[m_sound_volume] : 0;
break;
case 6: /* TONE3 */
m_sound_signal = !(m_vcount & 0x04) && !(m_vcount & 0x40) ? m_decay[m_sound_volume] : 0;
break;
default: /* NOISE */
/* QH of 74164 #4V */
m_sound_signal = (m_noise & 0x8000) ? m_decay[m_sound_volume] : 0;
}
}
}
}