summaryrefslogtreecommitdiffstatshomepage
path: root/src/emu/sound/msm5205.c
blob: 071a4d69214b3415c965e552bf3ebe50c0aafc7e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
/*
 *   streaming ADPCM driver
 *   by Aaron Giles
 *
 *   Library to transcode from an ADPCM source to raw PCM.
 *   Written by Buffoni Mirko in 08/06/97
 *   References: various sources and documents.
 *
 *   HJB 08/31/98
 *   modified to use an automatically selected oversampling factor
 *   for the current sample rate
 *
 *   01/06/99
 *  separate MSM5205 emulator form adpcm.c and some fix
 */

#include "emu.h"
#include "streams.h"
#include "msm5205.h"

/*
 *
 *  MSM 5205 ADPCM chip:
 *
 *  Data is streamed from a CPU by means of a clock generated on the chip.
 *
 *  A reset signal is set high or low to determine whether playback (and interrupts) are occuring
 *
 */

typedef struct _msm5205_state msm5205_state;
struct _msm5205_state
{
	const msm5205_interface *intf;
	running_device *device;
	sound_stream * stream;  /* number of stream system      */
	INT32 clock;				/* clock rate */
	emu_timer *timer;        /* VCLK callback timer          */
	INT32 data;               /* next adpcm data              */
	INT32 vclk;               /* vclk signal (external mode)  */
	INT32 reset;              /* reset pin signal             */
	INT32 prescaler;          /* prescaler selector S1 and S2 */
	INT32 bitwidth;           /* bit width selector -3B/4B    */
	INT32 signal;             /* current ADPCM signal         */
	INT32 step;               /* current ADPCM step           */
	int diff_lookup[49*16];
};

INLINE msm5205_state *get_safe_token(running_device *device)
{
	assert(device != NULL);
	assert(device->type() == SOUND_MSM5205);
	return (msm5205_state *)downcast<legacy_device_base *>(device)->token();
}


static void msm5205_playmode(msm5205_state *voice,int select);

/*
 * ADPCM lockup tabe
 */

/* step size index shift table */
static const int index_shift[8] = { -1, -1, -1, -1, 2, 4, 6, 8 };

/*
 *   Compute the difference table
 */

static void ComputeTables (msm5205_state *voice)
{
	/* nibble to bit map */
	static const int nbl2bit[16][4] =
	{
		{ 1, 0, 0, 0}, { 1, 0, 0, 1}, { 1, 0, 1, 0}, { 1, 0, 1, 1},
		{ 1, 1, 0, 0}, { 1, 1, 0, 1}, { 1, 1, 1, 0}, { 1, 1, 1, 1},
		{-1, 0, 0, 0}, {-1, 0, 0, 1}, {-1, 0, 1, 0}, {-1, 0, 1, 1},
		{-1, 1, 0, 0}, {-1, 1, 0, 1}, {-1, 1, 1, 0}, {-1, 1, 1, 1}
	};

	int step, nib;

	/* loop over all possible steps */
	for (step = 0; step <= 48; step++)
	{
		/* compute the step value */
		int stepval = floor (16.0 * pow (11.0 / 10.0, (double)step));

		/* loop over all nibbles and compute the difference */
		for (nib = 0; nib < 16; nib++)
		{
			voice->diff_lookup[step*16 + nib] = nbl2bit[nib][0] *
				(stepval   * nbl2bit[nib][1] +
				 stepval/2 * nbl2bit[nib][2] +
				 stepval/4 * nbl2bit[nib][3] +
				 stepval/8);
		}
	}
}

/* stream update callbacks */
static STREAM_UPDATE( MSM5205_update )
{
	msm5205_state *voice = (msm5205_state *)param;
	stream_sample_t *buffer = outputs[0];

	/* if this voice is active */
	if(voice->signal)
	{
		short val = voice->signal * 16;
		while (samples)
		{
			*buffer++ = val;
			samples--;
		}
	}
	else
		memset (buffer,0,samples*sizeof(*buffer));
}

/* timer callback at VCLK low eddge */
static TIMER_CALLBACK( MSM5205_vclk_callback )
{
	msm5205_state *voice = (msm5205_state *)ptr;
	int val;
	int new_signal;
	/* callback user handler and latch next data */
	if(voice->intf->vclk_callback) (*voice->intf->vclk_callback)(voice->device);

	/* reset check at last hieddge of VCLK */
	if(voice->reset)
	{
		new_signal = 0;
		voice->step = 0;
	}
	else
	{
		/* update signal */
		/* !! MSM5205 has internal 12bit decoding, signal width is 0 to 8191 !! */
		val = voice->data;
		new_signal = voice->signal + voice->diff_lookup[voice->step * 16 + (val & 15)];
		if (new_signal > 2047) new_signal = 2047;
		else if (new_signal < -2048) new_signal = -2048;
		voice->step += index_shift[val & 7];
		if (voice->step > 48) voice->step = 48;
		else if (voice->step < 0) voice->step = 0;
	}
	/* update when signal changed */
	if( voice->signal != new_signal)
	{
		stream_update(voice->stream);
		voice->signal = new_signal;
	}
}

/*
 *    Reset emulation of an MSM5205-compatible chip
 */
static DEVICE_RESET( msm5205 )
{
	msm5205_state *voice = get_safe_token(device);

	/* initialize work */
	voice->data    = 0;
	voice->vclk    = 0;
	voice->reset   = 0;
	voice->signal  = 0;
	voice->step    = 0;
	/* timer and bitwidth set */
	msm5205_playmode(voice,voice->intf->select);
}


/*
 *    Start emulation of an MSM5205-compatible chip
 */

static DEVICE_START( msm5205 )
{
	msm5205_state *voice = get_safe_token(device);

	/* save a global pointer to our interface */
	voice->intf = (const msm5205_interface *)device->baseconfig().static_config();
	voice->device = device;
	voice->clock = device->clock();

	/* compute the difference tables */
	ComputeTables (voice);

	/* stream system initialize */
	voice->stream = stream_create(device,0,1,device->clock(),voice,MSM5205_update);
	voice->timer = timer_alloc(device->machine, MSM5205_vclk_callback, voice);

	/* initialize */
	DEVICE_RESET_CALL(msm5205);

	/* register for save states */
	state_save_register_device_item(device, 0, voice->clock);
	state_save_register_device_item(device, 0, voice->data);
	state_save_register_device_item(device, 0, voice->vclk);
	state_save_register_device_item(device, 0, voice->reset);
	state_save_register_device_item(device, 0, voice->prescaler);
	state_save_register_device_item(device, 0, voice->bitwidth);
	state_save_register_device_item(device, 0, voice->signal);
	state_save_register_device_item(device, 0, voice->step);
}

/*
 *    Handle an update of the vclk status of a chip (1 is reset ON, 0 is reset OFF)
 *    This function can use selector = MSM5205_SEX only
 */
void msm5205_vclk_w (running_device *device, int vclk)
{
	msm5205_state *voice = get_safe_token(device);

	if( voice->prescaler != 0 )
	{
		logerror("error: msm5205_vclk_w() called with chip = '%s', but VCLK selected master mode\n", device->tag());
	}
	else
	{
		if( voice->vclk != vclk)
		{
			voice->vclk = vclk;
			if( !vclk ) MSM5205_vclk_callback(voice->device->machine, voice, 0);
		}
	}
}

/*
 *    Handle an update of the reset status of a chip (1 is reset ON, 0 is reset OFF)
 */

void msm5205_reset_w (running_device *device, int reset)
{
	msm5205_state *voice = get_safe_token(device);
	voice->reset = reset;
}

/*
 *    Handle an update of the data to the chip
 */

void msm5205_data_w (running_device *device, int data)
{
	msm5205_state *voice = get_safe_token(device);
	if( voice->bitwidth == 4)
		voice->data = data & 0x0f;
	else
		voice->data = (data & 0x07)<<1; /* unknown */
}

/*
 *    Handle an change of the selector
 */

void msm5205_playmode_w(running_device *device, int select)
{
	msm5205_state *voice = get_safe_token(device);
	msm5205_playmode(voice,select);
}

static void msm5205_playmode(msm5205_state *voice,int select)
{
	static const int prescaler_table[4] = {96,48,64,0};
	int prescaler = prescaler_table[select & 3];
	int bitwidth = (select & 4) ? 4 : 3;


	if( voice->prescaler != prescaler )
	{
		stream_update(voice->stream);

		voice->prescaler = prescaler;
		/* timer set */
		if( prescaler )
		{
			attotime period = attotime_mul(ATTOTIME_IN_HZ(voice->clock), prescaler);
			timer_adjust_periodic(voice->timer, period, 0, period);
		}
		else
			timer_adjust_oneshot(voice->timer, attotime_never, 0);
	}

	if( voice->bitwidth != bitwidth )
	{
		stream_update(voice->stream);

		voice->bitwidth = bitwidth;
	}
}


void msm5205_set_volume(running_device *device,int volume)
{
	msm5205_state *voice = get_safe_token(device);

	stream_set_output_gain(voice->stream,0,volume / 100.0);
}




/**************************************************************************
 * Generic get_info
 **************************************************************************/

DEVICE_GET_INFO( msm5205 )
{
	switch (state)
	{
		/* --- the following bits of info are returned as 64-bit signed integers --- */
		case DEVINFO_INT_TOKEN_BYTES:					info->i = sizeof(msm5205_state);				break;

		/* --- the following bits of info are returned as pointers to data or functions --- */
		case DEVINFO_FCT_START:							info->start = DEVICE_START_NAME( msm5205 );		break;
		case DEVINFO_FCT_STOP:							/* nothing */									break;
		case DEVINFO_FCT_RESET:							info->reset = DEVICE_RESET_NAME( msm5205 );		break;

		/* --- the following bits of info are returned as NULL-terminated strings --- */
		case DEVINFO_STR_NAME:							strcpy(info->s, "MSM5205");						break;
		case DEVINFO_STR_FAMILY:					strcpy(info->s, "ADPCM");						break;
		case DEVINFO_STR_VERSION:					strcpy(info->s, "1.0");							break;
		case DEVINFO_STR_SOURCE_FILE:						strcpy(info->s, __FILE__);						break;
		case DEVINFO_STR_CREDITS:					strcpy(info->s, "Copyright Nicola Salmoria and the MAME Team"); break;
	}
}