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// license:BSD-3-Clause
// copyright-holders:Antoine Mine
/**********************************************************************
Copyright (C) Antoine Mine' 2006
Philips MEA 8000 emulation.
**********************************************************************/
#ifndef MAME_SOUND_MEA8000_H
#define MAME_SOUND_MEA8000_H
#pragma once
/* define to use double instead of int (slow but useful for debugging) */
#undef MEA8000_FLOAT_MODE
class mea8000_device : public device_t, public device_sound_interface
{
public:
mea8000_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
auto req() { return m_write_req.bind(); }
DECLARE_READ8_MEMBER(read);
DECLARE_WRITE8_MEMBER(write);
protected:
// device-level overrides
virtual void device_start() override;
virtual void sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples) override;
private:
/* filter coefficients from frequencies */
static constexpr unsigned TABLE_LEN = 3600;
/* noise generator table */
static constexpr unsigned NOISE_LEN = 8192;
/* finite machine state controlling frames */
enum class mea8000_state : u8
{
STOPPED, /* nothing to do, timer disabled */
WAIT_FIRST, /* received pitch, wait for first full frame, timer disabled */
STARTED, /* playing a frame, timer on */
SLOWING /* repeating last frame with decreasing amplitude, timer on */
};
struct filter_t
{
#ifdef MEA8000_FLOAT_MODE
double fm, last_fm; /* frequency, in Hz */
double bw, last_bw; /* bandwidth, in Hz */
double output, last_output; /* filter state */
#else
uint16_t fm = 0, last_fm = 0;
uint16_t bw = 0, last_bw = 0;
int32_t output = 0, last_output = 0;
#endif
};
int accept_byte();
void update_req();
void init_tables();
#ifndef MEA8000_FLOAT_MODE /* uint16_t version */
int interp(uint16_t org, uint16_t dst);
int filter_step(int i, int input);
int noise_gen();
int freq_gen();
int compute_sample();
#else /* float version */
double interp(double org, double dst);
double filter_step(int i, double input);
double noise_gen();
double freq_gen();
double compute_sample();
#endif
void shift_frame();
void decode_frame();
void start_frame();
void stop_frame();
TIMER_CALLBACK_MEMBER(timer_expire);
devcb_write8 m_write_req;
/* state */
mea8000_state m_state = mea8000_state::STOPPED; /* current state */
uint8_t m_buf[4] = { 0, 0, 0, 0 }; /* store 4 consecutive data to form a frame info */
uint8_t m_bufpos = 0; /* new byte to write in frame info buffer */
uint8_t m_cont = 0; /* if no data 0=stop 1=repeat last frame */
uint8_t m_roe = 0; /* enable req output, now unimplemented */
uint16_t m_framelength = 0; /* in samples */
uint16_t m_framepos = 0; /* in samples */
uint16_t m_framelog = 0; /* log2 of framelength */
int16_t m_lastsample = 0, m_sample = 0; /* output samples are interpolated */
uint32_t m_phi = 0; /* absolute phase for frequency / noise generator */
filter_t m_f[4]; /* filters */
uint16_t m_last_ampl = 0, m_ampl = 0; /* amplitude * 1000 */
uint16_t m_last_pitch = 0, m_pitch = 0; /* pitch of sawtooth signal, in Hz */
uint8_t m_noise = 0;
emu_timer *m_timer = nullptr;
sound_stream * m_stream = nullptr;
stream_sample_t m_output = 0;
int m_cos_table[TABLE_LEN]; /* fm => cos coefficient */
int m_exp_table[TABLE_LEN]; /* bw => exp coefficient */
int m_exp2_table[TABLE_LEN]; /* bw => 2*exp coefficient */
int m_noise_table[NOISE_LEN];
};
DECLARE_DEVICE_TYPE(MEA8000, mea8000_device)
#endif // MAME_SOUND_MEA8000_H
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