446 lines
12 KiB
C
446 lines
12 KiB
C
/**********************************************************************************************
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*
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* OKI MSM6258 ADPCM
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*
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* TODO:
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* 3-bit ADPCM support
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* Recording?
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*
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**********************************************************************************************/
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//#include "emu.h"
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#include "mamedef.h"
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#ifdef _DEBUG
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#include <stdio.h>
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#endif
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//#include "streams.h"
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#include <math.h>
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#include <stdlib.h>
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#include "okim6258.h"
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#define COMMAND_STOP (1 << 0)
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#define COMMAND_PLAY (1 << 1)
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#define COMMAND_RECORD (1 << 2)
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#define STATUS_PLAYING (1 << 1)
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#define STATUS_RECORDING (1 << 2)
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static const int dividers[4] = { 1024, 768, 512, 512 };
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typedef struct _okim6258_state okim6258_state;
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struct _okim6258_state
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{
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UINT8 status;
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UINT32 master_clock; /* master clock frequency */
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UINT32 divider; /* master clock divider */
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UINT8 adpcm_type; /* 3/4 bit ADPCM select */
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UINT8 data_in; /* ADPCM data-in register */
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UINT8 nibble_shift; /* nibble select */
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//sound_stream *stream; /* which stream are we playing on? */
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UINT8 output_bits;
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INT32 signal;
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INT32 step;
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UINT8 clock_buffer[0x04];
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};
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/* step size index shift table */
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static const int index_shift[8] = { -1, -1, -1, -1, 2, 4, 6, 8 };
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/* lookup table for the precomputed difference */
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static int diff_lookup[49*16];
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/* tables computed? */
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static int tables_computed = 0;
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/*INLINE okim6258_state *get_safe_token(running_device *device)
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{
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assert(device != NULL);
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assert(device->type() == OKIM6258);
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return (okim6258_state *)downcast<legacy_device_base *>(device)->token();
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}*/
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/**********************************************************************************************
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compute_tables -- compute the difference tables
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***********************************************************************************************/
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static void compute_tables(void)
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{
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/* nibble to bit map */
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static const int nbl2bit[16][4] =
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{
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{ 1, 0, 0, 0}, { 1, 0, 0, 1}, { 1, 0, 1, 0}, { 1, 0, 1, 1},
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{ 1, 1, 0, 0}, { 1, 1, 0, 1}, { 1, 1, 1, 0}, { 1, 1, 1, 1},
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{-1, 0, 0, 0}, {-1, 0, 0, 1}, {-1, 0, 1, 0}, {-1, 0, 1, 1},
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{-1, 1, 0, 0}, {-1, 1, 0, 1}, {-1, 1, 1, 0}, {-1, 1, 1, 1}
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};
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int step, nib;
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if (tables_computed)
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return;
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/* loop over all possible steps */
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for (step = 0; step <= 48; step++)
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{
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/* compute the step value */
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int stepval = floor(16.0 * pow(11.0 / 10.0, (double)step));
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/* loop over all nibbles and compute the difference */
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for (nib = 0; nib < 16; nib++)
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{
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diff_lookup[step*16 + nib] = nbl2bit[nib][0] *
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(stepval * nbl2bit[nib][1] +
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stepval/2 * nbl2bit[nib][2] +
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stepval/4 * nbl2bit[nib][3] +
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stepval/8);
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}
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}
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tables_computed = 1;
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}
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static INT16 clock_adpcm(okim6258_state *chip, UINT8 nibble)
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{
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INT32 max = (1 << (chip->output_bits - 1)) - 1;
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INT32 min = -(1 << (chip->output_bits - 1));
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chip->signal += diff_lookup[chip->step * 16 + (nibble & 15)];
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/* clamp to the maximum */
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if (chip->signal > max)
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chip->signal = max;
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else if (chip->signal < min)
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chip->signal = min;
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/* adjust the step size and clamp */
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chip->step += index_shift[nibble & 7];
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if (chip->step > 48)
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chip->step = 48;
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else if (chip->step < 0)
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chip->step = 0;
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/* return the signal scaled up to 32767 */
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return chip->signal << 4;
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}
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/**********************************************************************************************
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okim6258_update -- update the sound chip so that it is in sync with CPU execution
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***********************************************************************************************/
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//static STREAM_UPDATE( okim6258_update )
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void okim6258_update(void *_chip, stream_sample_t **outputs, int samples)
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{
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okim6258_state *chip = (okim6258_state *)_chip;
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//stream_sample_t *buffer = outputs[0];
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stream_sample_t *bufL = outputs[0];
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stream_sample_t *bufR = outputs[1];
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//memset(outputs[0], 0, samples * sizeof(*outputs[0]));
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if (chip->status & STATUS_PLAYING)
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{
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int nibble_shift = chip->nibble_shift;
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while (samples)
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{
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/* Compute the new amplitude and update the current step */
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int nibble = (chip->data_in >> nibble_shift) & 0xf;
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/* Output to the buffer */
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INT16 sample = clock_adpcm(chip, nibble);
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nibble_shift ^= 4;
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//*buffer++ = sample;
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*bufL++ = sample;
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*bufR++ = sample;
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samples--;
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}
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/* Update the parameters */
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chip->nibble_shift = nibble_shift;
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}
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else
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{
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/* Fill with 0 */
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while (samples--)
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{
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//*buffer++ = 0;
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*bufL++ = 0;
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*bufR++ = 0;
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}
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}
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}
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/**********************************************************************************************
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state save support for MAME
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***********************************************************************************************/
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/*static void okim6258_state_save_register(okim6258_state *info, running_device *device)
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{
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state_save_register_device_item(device, 0, info->status);
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state_save_register_device_item(device, 0, info->master_clock);
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state_save_register_device_item(device, 0, info->divider);
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state_save_register_device_item(device, 0, info->data_in);
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state_save_register_device_item(device, 0, info->nibble_shift);
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state_save_register_device_item(device, 0, info->signal);
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state_save_register_device_item(device, 0, info->step);
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}*/
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/**********************************************************************************************
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OKIM6258_start -- start emulation of an OKIM6258-compatible chip
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***********************************************************************************************/
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//static DEVICE_START( okim6258 )
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void * device_start_okim6258(int clock, int divider, int adpcm_type, int output_12bits)
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{
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//const okim6258_interface *intf = (const okim6258_interface *)device->baseconfig().static_config();
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//okim6258_state *info = get_safe_token(device);
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okim6258_state *info;
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info = (okim6258_state *) calloc(1, sizeof(okim6258_state));
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compute_tables();
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//info->master_clock = device->clock();
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info->master_clock = clock;
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info->adpcm_type = /*intf->*/adpcm_type;
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info->clock_buffer[0x00] = (clock & 0x000000FF) >> 0;
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info->clock_buffer[0x01] = (clock & 0x0000FF00) >> 8;
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info->clock_buffer[0x02] = (clock & 0x00FF0000) >> 16;
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info->clock_buffer[0x03] = (clock & 0xFF000000) >> 24;
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/* D/A precision is 10-bits but 12-bit data can be output serially to an external DAC */
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info->output_bits = /*intf->*/output_12bits ? 12 : 10;
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info->divider = dividers[/*intf->*/divider];
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//info->stream = stream_create(device, 0, 1, device->clock()/info->divider, info, okim6258_update);
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info->signal = -2;
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info->step = 0;
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//okim6258_state_save_register(info, device);
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return info; //return info->master_clock / info->divider;
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}
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/**********************************************************************************************
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OKIM6258_stop -- stop emulation of an OKIM6258-compatible chip
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***********************************************************************************************/
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void device_stop_okim6258(void *chip)
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{
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okim6258_state *info = (okim6258_state *) chip;
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free(info);
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}
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//static DEVICE_RESET( okim6258 )
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void device_reset_okim6258(void *chip)
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{
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//okim6258_state *info = get_safe_token(device);
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okim6258_state *info = (okim6258_state *) chip;
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//stream_update(info->stream);
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info->signal = -2;
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info->step = 0;
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info->status = 0;
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}
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/**********************************************************************************************
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okim6258_set_divider -- set the master clock divider
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***********************************************************************************************/
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//void okim6258_set_divider(running_device *device, int val)
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void okim6258_set_divider(void *chip, int val)
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{
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okim6258_state *info = (okim6258_state *) chip;
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info->divider = dividers[val];
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//stream_set_sample_rate(info->stream, info->master_clock / divider);
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}
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/**********************************************************************************************
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okim6258_set_clock -- set the master clock
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***********************************************************************************************/
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//void okim6258_set_clock(running_device *device, int val)
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void okim6258_set_clock(void *chip, int val)
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{
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okim6258_state *info = (okim6258_state *) chip;
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if (val)
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{
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info->master_clock = val;
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}
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else
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{
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info->master_clock = (info->clock_buffer[0x00] << 0) |
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(info->clock_buffer[0x01] << 8) |
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(info->clock_buffer[0x02] << 16) |
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(info->clock_buffer[0x03] << 24);
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}
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}
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/**********************************************************************************************
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okim6258_get_vclk -- get the VCLK/sampling frequency
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***********************************************************************************************/
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//int okim6258_get_vclk(running_device *device)
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int okim6258_get_vclk(void *chip)
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{
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okim6258_state *info = (okim6258_state *) chip;
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return (info->master_clock / info->divider);
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}
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/**********************************************************************************************
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okim6258_status_r -- read the status port of an OKIM6258-compatible chip
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***********************************************************************************************/
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//READ8_DEVICE_HANDLER( okim6258_status_r )
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UINT8 okim6258_status_r(void *chip, offs_t offset)
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{
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//okim6258_state *info = get_safe_token(device);
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okim6258_state *info = (okim6258_state *) chip;
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//stream_update(info->stream);
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return (info->status & STATUS_PLAYING) ? 0x00 : 0x80;
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}
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/**********************************************************************************************
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okim6258_data_w -- write to the control port of an OKIM6258-compatible chip
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***********************************************************************************************/
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//WRITE8_DEVICE_HANDLER( okim6258_data_w )
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void okim6258_data_w(void *chip, offs_t offset, UINT8 data)
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{
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//okim6258_state *info = get_safe_token(device);
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okim6258_state *info = (okim6258_state *) chip;
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/* update the stream */
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//stream_update(info->stream);
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info->data_in = data;
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info->nibble_shift = 0;
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}
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/**********************************************************************************************
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okim6258_ctrl_w -- write to the control port of an OKIM6258-compatible chip
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***********************************************************************************************/
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//WRITE8_DEVICE_HANDLER( okim6258_ctrl_w )
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void okim6258_ctrl_w(void *chip, offs_t offset, UINT8 data)
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{
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//okim6258_state *info = get_safe_token(device);
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okim6258_state *info = (okim6258_state *) chip;
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//stream_update(info->stream);
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if (data & COMMAND_STOP)
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{
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info->status &= ~(STATUS_PLAYING | STATUS_RECORDING);
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return;
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}
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if (data & COMMAND_PLAY)
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{
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if (!(info->status & STATUS_PLAYING))
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{
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info->status |= STATUS_PLAYING;
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/* Also reset the ADPCM parameters */
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info->signal = -2;
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info->step = 0;
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info->nibble_shift = 0;
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}
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}
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else
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{
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info->status &= ~STATUS_PLAYING;
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}
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if (data & COMMAND_RECORD)
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{
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/*logerror("M6258: Record enabled\n");*/
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info->status |= STATUS_RECORDING;
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}
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else
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{
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info->status &= ~STATUS_RECORDING;
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}
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}
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void okim6258_set_clock_byte(void *chip, UINT8 Byte, UINT8 val)
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{
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okim6258_state *info = (okim6258_state *) chip;
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info->clock_buffer[Byte] = val;
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return;
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}
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void okim6258_write(void *chip, UINT8 Port, UINT8 Data)
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{
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switch(Port)
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{
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case 0x00:
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okim6258_ctrl_w(chip, 0x00, Data);
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break;
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case 0x01:
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okim6258_data_w(chip, 0x00, Data);
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break;
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case 0x08:
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case 0x09:
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case 0x0A:
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okim6258_set_clock_byte(chip, Port & 0x03, Data);
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break;
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case 0x0B:
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okim6258_set_clock_byte(chip, Port & 0x03, Data);
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okim6258_set_clock(chip, 0);
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break;
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case 0x0C:
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okim6258_set_divider(chip, Data);
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break;
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}
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}
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