mirror of
https://github.com/holub/mame
synced 2025-06-01 18:41:47 +03:00
be0e3a784f
It is quite clear nobody understands how the dac device works. unsigned_write8 (formerly dac_data_w) accepts a value from 0..255 and scales it to 0..32768. signed_write8 (formated dac_signed_data_w) accepts a value from 0..255 and scales it to -32767..32768. So signed/unsigned applies to the output. The input values are always full-range unsigned data. Same goes for 16-bit variants.
101 lines
3.6 KiB
C++
101 lines
3.6 KiB
C++
/***************************************************************************
|
|
|
|
dac.h
|
|
|
|
DAC device emulator.
|
|
|
|
****************************************************************************
|
|
|
|
Copyright Aaron Giles
|
|
All rights reserved.
|
|
|
|
Redistribution and use in source and binary forms, with or without
|
|
modification, are permitted provided that the following conditions are
|
|
met:
|
|
|
|
* Redistributions of source code must retain the above copyright
|
|
notice, this list of conditions and the following disclaimer.
|
|
* Redistributions in binary form must reproduce the above copyright
|
|
notice, this list of conditions and the following disclaimer in
|
|
the documentation and/or other materials provided with the
|
|
distribution.
|
|
* Neither the name 'MAME' nor the names of its contributors may be
|
|
used to endorse or promote products derived from this software
|
|
without specific prior written permission.
|
|
|
|
THIS SOFTWARE IS PROVIDED BY AARON GILES ''AS IS'' AND ANY EXPRESS OR
|
|
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
|
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
|
DISCLAIMED. IN NO EVENT SHALL AARON GILES BE LIABLE FOR ANY DIRECT,
|
|
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
|
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
|
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
|
|
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
|
|
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
***************************************************************************/
|
|
|
|
#ifndef __DAC_H__
|
|
#define __DAC_H__
|
|
|
|
|
|
//**************************************************************************
|
|
// INTERFACE CONFIGURATION MACROS
|
|
//**************************************************************************
|
|
|
|
#define MCFG_DAC_ADD(_tag) \
|
|
MCFG_DEVICE_ADD(_tag, DAC, 0) \
|
|
|
|
|
|
|
|
//**************************************************************************
|
|
// TYPE DEFINITIONS
|
|
//**************************************************************************
|
|
|
|
|
|
// ======================> dac_device
|
|
|
|
class dac_device : public device_t,
|
|
public device_sound_interface
|
|
{
|
|
// default to 4x oversampling
|
|
static const UINT32 DEFAULT_SAMPLE_RATE = 48000 * 4;
|
|
|
|
public:
|
|
// construction/destruction
|
|
dac_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock);
|
|
|
|
// public interface
|
|
INT16 output() const { return m_output; }
|
|
void write(INT16 data) { m_stream->update(); m_output = data; }
|
|
void write_unsigned8(UINT8 data) { write(data * 32767 / 255); } // 0..255, mapped to 0..32767
|
|
void write_signed8(UINT8 data) { write((data - 0x80) * 32767 / 128); } // 0..255, mapped to -32767..32767
|
|
void write_unsigned16(UINT16 data) { write(data / 2); } // 0..65535, mapped to 0..32767
|
|
void write_signed16(UINT16 data) { write(data - 0x8000); } // 0..65535, mapped to -32768..32767
|
|
|
|
// wrappers
|
|
DECLARE_WRITE8_MEMBER( write_unsigned8 );
|
|
DECLARE_WRITE8_MEMBER( write_signed8 );
|
|
|
|
protected:
|
|
// device-level overrides
|
|
virtual void device_start();
|
|
virtual void device_reset();
|
|
|
|
// device_sound_interface overrides
|
|
virtual void sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples);
|
|
|
|
// internal state
|
|
sound_stream * m_stream;
|
|
INT16 m_output;
|
|
};
|
|
|
|
|
|
// device type definition
|
|
extern const device_type DAC;
|
|
|
|
|
|
#endif /* __DAC_H__ */
|