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-rw-r--r--src/devices/sound/beep.c147
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diff --git a/src/devices/sound/beep.c b/src/devices/sound/beep.c
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+// license:BSD-3-Clause
+// copyright-holders:Kevin Thacker
+/***************************************************************************
+
+ beep.c
+
+ This is used for computers/systems which can only output a constant tone.
+ This tone can be turned on and off.
+ e.g. PCW and PCW16 computer systems
+ KT - 25-Jun-2000
+
+ Sound handler
+
+****************************************************************************/
+
+#include "emu.h"
+#include "sound/beep.h"
+
+#define BEEP_RATE (48000)
+
+
+// device type definition
+const device_type BEEP = &device_creator<beep_device>;
+
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+// beep_device - constructor
+//-------------------------------------------------
+
+beep_device::beep_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+ : device_t(mconfig, BEEP, "Beep", tag, owner, clock, "beep", __FILE__),
+ device_sound_interface(mconfig, *this),
+ m_stream(NULL),
+ m_enable(0),
+ m_frequency(0),
+ m_incr(0),
+ m_signal(0)
+{
+}
+
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void beep_device::device_start()
+{
+ m_stream = stream_alloc(0, 1, BEEP_RATE);
+ m_enable = 0;
+ m_frequency = 3250;
+ m_incr = 0;
+ m_signal = 0x07fff;
+}
+
+
+//-------------------------------------------------
+// sound_stream_update - handle a stream update
+//-------------------------------------------------
+
+void beep_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples)
+{
+ stream_sample_t *buffer = outputs[0];
+ INT16 signal = m_signal;
+ int clock = 0, rate = BEEP_RATE / 2;
+
+ /* get progress through wave */
+ int incr = m_incr;
+
+ if (m_frequency > 0)
+ clock = m_frequency;
+
+ /* if we're not enabled, just fill with 0 */
+ if ( !m_enable || clock == 0 )
+ {
+ memset( buffer, 0, samples * sizeof(*buffer) );
+ return;
+ }
+
+ /* fill in the sample */
+ while( samples-- > 0 )
+ {
+ *buffer++ = signal;
+ incr -= clock;
+ while( incr < 0 )
+ {
+ incr += rate;
+ signal = -signal;
+ }
+ }
+
+ /* store progress through wave */
+ m_incr = incr;
+ m_signal = signal;
+}
+
+
+//-------------------------------------------------
+// changing state to on from off will restart tone
+//-------------------------------------------------
+
+void beep_device::set_state(int on)
+{
+ /* only update if new state is not the same as old state */
+ if (m_enable == on)
+ return;
+
+ m_stream->update();
+ m_enable = on;
+
+ /* restart wave from beginning */
+ m_incr = 0;
+ m_signal = 0x07fff;
+}
+
+
+
+//-------------------------------------------------
+// setting new frequency starts from beginning
+//-------------------------------------------------
+
+void beep_device::set_frequency(int frequency)
+{
+ if (m_frequency == frequency)
+ return;
+
+ m_stream->update();
+ m_frequency = frequency;
+ m_signal = 0x07fff;
+ m_incr = 0;
+}
+
+
+
+//-------------------------------------------------
+// change a channel volume
+//-------------------------------------------------
+
+void beep_device::set_volume(int volume)
+{
+ m_stream->update();
+ volume = 100 * volume / 7;
+ set_output_gain(0, volume);
+}