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-rw-r--r--src/mame/audio/warpwarp.c221
1 files changed, 221 insertions, 0 deletions
diff --git a/src/mame/audio/warpwarp.c b/src/mame/audio/warpwarp.c
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index 00000000000..fc1e4a8c246
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+++ b/src/mame/audio/warpwarp.c
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+/****************************************************************************
+ *
+ * warpwarp.c
+ *
+ * sound driver
+ * juergen buchmueller <pullmoll@t-online.de>, jan 2000
+ *
+ ****************************************************************************/
+
+#include <math.h>
+#include "driver.h"
+#include "streams.h"
+#include "sound/custom.h"
+#include "includes/warpwarp.h"
+
+#define CLOCK_16H (18432000/3/2/16)
+#define CLOCK_1V (18432000/3/2/384)
+
+static INT16 *decay = NULL;
+static sound_stream *channel;
+static int sound_latch = 0;
+static int music1_latch = 0;
+static int music2_latch = 0;
+static int sound_signal = 0;
+static int sound_volume = 0;
+static emu_timer *sound_volume_timer = NULL;
+static int music_signal = 0;
+static int music_volume = 0;
+static emu_timer *music_volume_timer = NULL;
+static int noise = 0;
+
+static TIMER_CALLBACK( sound_volume_decay )
+{
+ if( --sound_volume < 0 )
+ sound_volume = 0;
+}
+
+WRITE8_HANDLER( warpwarp_sound_w )
+{
+ stream_update(channel);
+ sound_latch = data & 0x0f;
+ sound_volume = 0x7fff; /* set sound_volume */
+ noise = 0x0000; /* reset noise shifter */
+
+ /* faster decay enabled? */
+ if( sound_latch & 8 )
+ {
+ /*
+ * R85(?) is 10k, Rb is 0, C92 is 1uF
+ * charge time t1 = 0.693 * (R24 + Rb) * C57 -> 0.22176s
+ * discharge time t2 = 0.693 * (Rb) * C57 -> 0
+ * C90(?) is only charged via D17 (1N914), no discharge!
+ * Decay:
+ * discharge C90(?) (1uF) through R13||R14 (22k||47k)
+ * 0.639 * 15k * 1uF -> 0.9585s
+ */
+ attotime period = attotime_div(attotime_mul(ATTOTIME_IN_HZ(32768), 95850), 100000);
+ timer_adjust(sound_volume_timer, period, 0, period);
+ }
+ else
+ {
+ /*
+ * discharge only after R93 (100k) and through the 10k
+ * potentiometerin the amplifier section.
+ * 0.639 * 110k * 1uF -> 7.0290s
+ * ...but this is not very realistic for the game sound :(
+ * maybe there _is_ a discharge through the diode D17?
+ */
+// attotime period = attotime_div(attotime_mul(ATTOTIME_IN_HZ(32768), 702900), 100000);
+ attotime period = attotime_div(attotime_mul(ATTOTIME_IN_HZ(32768), 191700), 100000);
+ timer_adjust(sound_volume_timer, period, 0, period);
+ }
+}
+
+WRITE8_HANDLER( warpwarp_music1_w )
+{
+ stream_update(channel);
+ music1_latch = data & 0x3f;
+}
+
+static TIMER_CALLBACK( music_volume_decay )
+{
+ if( --music_volume < 0 )
+ music_volume = 0;
+}
+
+WRITE8_HANDLER( warpwarp_music2_w )
+{
+ stream_update(channel);
+ music2_latch = data & 0x3f;
+ music_volume = 0x7fff;
+ /* fast decay enabled? */
+ if( music2_latch & 0x10 )
+ {
+ /*
+ * Ra (R83?) is 10k, Rb is 0, C92 is 1uF
+ * charge time t1 = 0.693 * (Ra + Rb) * C -> 0.22176s
+ * discharge time is (nearly) zero, because Rb is zero
+ * C95(?) is only charged via D17, not discharged!
+ * Decay:
+ * discharge C95(?) (10uF) through R13||R14 (22k||47k)
+ * 0.639 * 15k * 10uF -> 9.585s
+ * ...I'm sure this is off by one number of magnitude :/
+ */
+ attotime period = attotime_div(attotime_mul(ATTOTIME_IN_HZ(32768), 95850), 100000);
+ timer_adjust(music_volume_timer, period, 0, period);
+ }
+ else
+ {
+ /*
+ * discharge through R14 (47k),
+ * discharge C95(?) (10uF) through R14 (47k)
+ * 0.639 * 47k * 10uF -> 30.033s
+ */
+// attotime period = attotime_div(attotime_mul(ATTOTIME_IN_HZ(32768), 3003300), 100000);
+ attotime period = attotime_div(attotime_mul(ATTOTIME_IN_HZ(32768), 300330), 100000);
+ timer_adjust(music_volume_timer, period, 0, period);
+ }
+
+}
+
+static void warpwarp_sound_update(void *param, stream_sample_t **inputs, stream_sample_t **outputs, int length)
+{
+ static int vcarry = 0;
+ static int vcount = 0;
+ static int mcarry = 0;
+ static int mcount = 0;
+ stream_sample_t *buffer = outputs[0];
+
+ while (length--)
+ {
+ *buffer++ = (sound_signal + music_signal) / 2;
+
+ /*
+ * The music signal is selected at a rate of 2H (1.536MHz) from the
+ * four bits of a 4 bit binary counter which is clocked with 16H,
+ * which is 192kHz, and is divided by 4 times (64 - music1_latch).
+ * 0 = 256 steps -> 750 Hz
+ * 1 = 252 steps -> 761.9 Hz
+ * ...
+ * 32 = 128 steps -> 1500 Hz
+ * ...
+ * 48 = 64 steps -> 3000 Hz
+ * ...
+ * 63 = 4 steps -> 48 kHz
+ */
+ mcarry -= CLOCK_16H / (4 * (64 - music1_latch));
+ while( mcarry < 0 )
+ {
+ mcarry += CLOCK_16H;
+ mcount++;
+ music_signal = (mcount & ~music2_latch & 15) ? decay[music_volume] : 0;
+ /* override by noise gate? */
+ if( (music2_latch & 32) && (noise & 0x8000) )
+ music_signal = decay[music_volume];
+ }
+
+ /* clock 1V = 8kHz */
+ vcarry -= CLOCK_1V;
+ while (vcarry < 0)
+ {
+ vcarry += CLOCK_16H;
+ vcount++;
+
+ /* noise is clocked with raising edge of 2V */
+ if ((vcount & 3) == 2)
+ {
+ /* bit0 = bit0 ^ !bit10 */
+ if ((noise & 1) == ((noise >> 10) & 1))
+ noise = (noise << 1) | 1;
+ else
+ noise = noise << 1;
+ }
+
+ switch (sound_latch & 7)
+ {
+ case 0: /* 4V */
+ sound_signal = (vcount & 0x04) ? decay[sound_volume] : 0;
+ break;
+ case 1: /* 8V */
+ sound_signal = (vcount & 0x08) ? decay[sound_volume] : 0;
+ break;
+ case 2: /* 16V */
+ sound_signal = (vcount & 0x10) ? decay[sound_volume] : 0;
+ break;
+ case 3: /* 32V */
+ sound_signal = (vcount & 0x20) ? decay[sound_volume] : 0;
+ break;
+ case 4: /* TONE1 */
+ sound_signal = !(vcount & 0x01) && !(vcount & 0x10) ? decay[sound_volume] : 0;
+ break;
+ case 5: /* TONE2 */
+ sound_signal = !(vcount & 0x02) && !(vcount & 0x20) ? decay[sound_volume] : 0;
+ break;
+ case 6: /* TONE3 */
+ sound_signal = !(vcount & 0x04) && !(vcount & 0x40) ? decay[sound_volume] : 0;
+ break;
+ default: /* NOISE */
+ /* QH of 74164 #4V */
+ sound_signal = (noise & 0x8000) ? decay[sound_volume] : 0;
+ }
+
+ }
+ }
+}
+
+void *warpwarp_sh_start(int clock, const struct CustomSound_interface *config)
+{
+ int i;
+
+ decay = (INT16 *) auto_malloc(32768 * sizeof(INT16));
+
+ for( i = 0; i < 0x8000; i++ )
+ decay[0x7fff-i] = (INT16) (0x7fff/exp(1.0*i/4096));
+
+ channel = stream_create(0, 1, CLOCK_16H, NULL, warpwarp_sound_update);
+
+ sound_volume_timer = timer_alloc(sound_volume_decay);
+ music_volume_timer = timer_alloc(music_volume_decay);
+ return auto_malloc(1);
+}