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Merge pull request #1841 from libretro/arcadez2003-patch-5

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Namco rollback 4
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arcadez2003 2024-08-21 21:15:34 +01:00 committed by GitHub
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1 changed files with 39 additions and 102 deletions
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src/sound/namco52.c
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@ -34,146 +34,83 @@ OUT = sound output
GND|21 22|D0
+------+
[1] in polepos, GND; in bosco, 4kHz output from a 555 timer
[1] in polepos, GND; in bosco, output from a 555 timer
[2] in polepos, +5V; in bosco, GND
[3] in polepos, these are true address lines, in bosco they are chip select lines
(each one select one of the four ROM chips). Behaviour related to [2]?
TODO:
- the purpose of the 555 timer in bosco is unknown; maybe modulate the output?
Jan 12, 2005. The 555 is probably an external playback frequency.
***************************************************************************/
#include "driver.h"
#include "filter.h"
#include "namco52.h"
/* macro to convert 4-bit unsigned samples to 8-bit signed samples */
#define SAMPLE_CONV4(a) (0x11*((a&0x0f))-0x80)
static INT8 *samples; /* 4-bit samples will be unpacked to 8-bit here */
static int channel; /* channel assigned by the mixer */
static const struct namco_52xx_interface *intf; /* pointer to our config data */
static UINT8 *rom; /* pointer to sample ROM */
static UINT8 *rom; /* pointer to sample ROM */
static int rom_len;
static int stream; /* the output stream */
static double n52_pb_cycle; /* playback clock time based on machine sample rate */
static double n52_step; /* playback clock step based on machine sample rate */
/* n52_pb_cycle is incremented by n52_step every machine-sample.
* At every integer value of n52_pb_cycle the next 4bit value is used. */
static int n52_start; /* current effect start position in the ROM */
static int n52_end; /* current effect end position in the ROM */
static int n52_length; /* # of 4bit samples in current effect */
static int n52_pos; /* current 4bit sample of effect */
static struct filter2_context n52_hp_filter;
static struct filter2_context n52_lp_filter;
static void namco_52xx_stream_update_one(int num, INT16 *buffer, int length)
{
int i, rom_pos, whole_pb_cycles, buf;
if (n52_start >= n52_end)
{
memset(buffer, 0, length * sizeof(INT16));
return;
}
for (i = 0; i < length; i++)
{
n52_pb_cycle += n52_step;
if (n52_pb_cycle >= 1)
{
whole_pb_cycles = (int)n52_pb_cycle;
n52_pos += whole_pb_cycles;
n52_pb_cycle -= whole_pb_cycles;
}
if (n52_pos > n52_length)
{
/* sample done */
memset(&buffer[i], 0, (length - i) * sizeof(INT16));
i = length;
namco_52xx_sh_reset();
}
else
{
/* filter and fill the buffer */
rom_pos = n52_start + (n52_pos >> 1);
/* get the 4bit sample from rom and shift to +7/-8 value */
n52_hp_filter.x0 = (((n52_pos & 1) ? rom[rom_pos] >> 4 : rom[rom_pos]) & 0x0f) - 0x08;
filter2_step(&n52_hp_filter);
n52_lp_filter.x0 = n52_hp_filter.y0;
filter2_step(&n52_lp_filter);
/* convert 4bit filtered to 16bit allowing room for filter gain */
buf = (int)(n52_lp_filter.y0 * 0x0fff);
if (buf > 32767) buf = 32767;
if (buf < -32768) buf = -32768;
buffer[i] = buf;
}
}
}
void namco_52xx_sh_reset(void)
{
n52_pb_cycle = n52_start = n52_end = n52_length = n52_pos = 0;
filter2_reset(&n52_hp_filter);
filter2_reset(&n52_lp_filter);
}
int namco_52xx_sh_start(const struct MachineSound *msound)
{
int i;
unsigned char bits;
intf = msound->sound_interface;
rom = memory_region(intf->region);
rom_len = memory_region_length(intf->region);
if (Machine->sample_rate == 0)
channel = mixer_allocate_channel(intf->mixing_level);
mixer_set_name(channel,sound_name(msound));
samples = auto_malloc(2*rom_len);
if (!samples)
return 1;
if (intf->play_rate == 0)
/* decode the rom samples */
for (i = 0;i < rom_len;i++)
{
/* If play clock is 0 (grounded) then default to internal clock */
n52_step = (double)(intf->baseclock) / 384 / Machine->sample_rate;
bits = rom[i] & 0x0f;
samples[2*i] = SAMPLE_CONV4(bits);
bits = (rom[i] & 0xf0) >> 4;
samples[2*i + 1] = SAMPLE_CONV4(bits);
}
else
{
n52_step = intf->play_rate / Machine->sample_rate;
}
filter2_setup(FILTER_HIGHPASS, intf->hp_filt_fc, Q_TO_DAMP(intf->hp_filt_q), 1, &n52_hp_filter);
filter2_setup(FILTER_LOWPASS, intf->lp_filt_fc, Q_TO_DAMP(intf->lp_filt_q), intf->filt_gain, &n52_lp_filter);
stream = stream_init(sound_name(msound), intf->mixing_level, Machine->sample_rate, 0, namco_52xx_stream_update_one);
/* handle failure */
if (stream == -1)
osd_die("Namco 52xx - Stream init returned an error\n");
namco_52xx_sh_reset();
return 0;
}
void namco_52xx_sh_stop(void)
{
}
void namcoio_52XX_write(int data)
{
data &= 0x0f;
/*logerror("%04x: custom 52XX write %02x\n",activecpu_get_pc(),data); */
if (Machine->sample_rate == 0)
return;
if (data != 0)
{
stream_update(stream, 0);
int start = rom[data-1] + (rom[data-1+0x10] << 8);
int end = rom[data] + (rom[data+0x10] << 8);
n52_start = rom[data-1] + (rom[data-1+0x10] << 8);
n52_end = rom[data] + (rom[data+0x10] << 8);
if (end >= rom_len)
end = rom_len;
if (n52_end >= rom_len)
n52_end = rom_len;
n52_length = (n52_end - n52_start) * 2;
n52_pos = 0;
n52_pb_cycle= 0;
if (start < end)
mixer_play_sample(channel, samples + start * 2, (end - start) * 2, intf->baseclock/384, 0);
}
}
void namco_52xx_sh_stop(void)
{
}