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-rw-r--r--src/mame/audio/tvc_snd.cpp142
1 files changed, 142 insertions, 0 deletions
diff --git a/src/mame/audio/tvc_snd.cpp b/src/mame/audio/tvc_snd.cpp
new file mode 100644
index 00000000000..29d61b5dc7c
--- /dev/null
+++ b/src/mame/audio/tvc_snd.cpp
@@ -0,0 +1,142 @@
+// license:BSD-3-Clause
+// copyright-holders:Sandro Ronco
+/***************************************************************************
+
+ Videotone TVC 32/64 sound emulation
+
+***************************************************************************/
+
+#include "emu.h"
+#include "tvc_snd.h"
+
+// device type definition
+const device_type TVC_SOUND = &device_creator<tvc_sound_device>;
+
+//-------------------------------------------------
+// tvc_sound_device - constructor
+//-------------------------------------------------
+
+tvc_sound_device::tvc_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
+ device_t(mconfig, TVC_SOUND, "TVC 64 Audio Custom", tag, owner, clock, "tvc_sound", __FILE__),
+ device_sound_interface(mconfig, *this),
+ m_write_sndint(*this)
+{
+}
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+void tvc_sound_device::device_start()
+{
+ // resolve callbacks
+ m_write_sndint.resolve_safe();
+
+ m_stream = machine().sound().stream_alloc(*this, 0, 1, machine().sample_rate());
+ m_sndint_timer = timer_alloc(TIMER_SNDINT);
+}
+
+//-------------------------------------------------
+// device_reset - device-specific reset
+//-------------------------------------------------
+void tvc_sound_device::device_reset()
+{
+ m_enabled = 0;
+ m_freq = 0;
+ m_incr = 0;
+ m_signal = 1;
+ m_sndint_timer->reset();
+}
+
+
+//-------------------------------------------------
+// device_timer - handler timer events
+//-------------------------------------------------
+
+void tvc_sound_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
+{
+ m_write_sndint(1);
+}
+
+//-------------------------------------------------
+// sound_stream_update - handle update requests for
+// our sound stream
+//-------------------------------------------------
+
+void tvc_sound_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples)
+{
+ int rate = machine().sample_rate() / 2;
+
+ if (m_enabled && m_freq)
+ {
+ while( samples-- > 0 )
+ {
+ *outputs[0]++ = m_signal * (m_volume * 0x0800);
+ m_incr -= m_freq;
+ while(m_incr < 0)
+ {
+ m_incr += rate;
+ m_signal = -m_signal;
+ }
+ }
+ }
+ else
+ {
+ // fill output with 0 if the sound is disabled
+ memset(outputs[0], 0, samples * sizeof(stream_sample_t));
+ }
+}
+
+
+
+//-------------------------------------------------
+// ports write
+//-------------------------------------------------
+
+WRITE8_MEMBER(tvc_sound_device::write)
+{
+ m_stream->update();
+
+ m_ports[offset] = data;
+
+ switch(offset)
+ {
+ case 1:
+ m_enabled = BIT(data, 4);
+ // fall through
+
+ case 0:
+ {
+ UINT16 pitch = (m_ports[0] | (m_ports[1]<<8)) & 0x0fff;
+ m_freq = (pitch == 0x0fff) ? 0 : (int)(195312.5 / (4096 - pitch));
+
+ if ((m_ports[1] & 0x20) && m_freq != 0)
+ m_sndint_timer->adjust(attotime::from_hz(m_freq), 0, attotime::from_hz(m_freq));
+ else
+ m_sndint_timer->reset();
+
+ break;
+ }
+
+ case 2:
+ m_volume = (data>>2) & 0x0f;
+ break;
+ }
+}
+
+
+//-------------------------------------------------
+// tvc_sound_device::reset_divider
+//-------------------------------------------------
+
+void tvc_sound_device::reset_divider()
+{
+ m_stream->update();
+
+ m_incr = 0;
+ m_signal = 1;
+
+ if (m_ports[1] & 0x20 && m_freq != 0)
+ m_sndint_timer->adjust(attotime::from_hz(m_freq), 0, attotime::from_hz(m_freq));
+ else
+ m_sndint_timer->reset();
+}