summaryrefslogtreecommitdiffstatshomepage
path: root/trunk/src/emu/sound/tms3615.c
diff options
context:
space:
mode:
Diffstat (limited to 'trunk/src/emu/sound/tms3615.c')
-rw-r--r--trunk/src/emu/sound/tms3615.c123
1 files changed, 123 insertions, 0 deletions
diff --git a/trunk/src/emu/sound/tms3615.c b/trunk/src/emu/sound/tms3615.c
new file mode 100644
index 00000000000..5c263335fee
--- /dev/null
+++ b/trunk/src/emu/sound/tms3615.c
@@ -0,0 +1,123 @@
+#include "emu.h"
+#include "tms3615.h"
+
+#define VMIN 0x0000
+#define VMAX 0x7fff
+
+#define TONES 13
+
+static const int divisor[TONES] = { 478, 451, 426, 402, 379, 358, 338, 319, 301, 284, 268, 253, 239 };
+
+typedef struct _tms_state tms_state;
+struct _tms_state {
+ sound_stream *channel; /* returned by stream_create() */
+ int samplerate; /* output sample rate */
+ int basefreq; /* chip's base frequency */
+ int counter8[TONES]; /* tone frequency counter for 8' */
+ int counter16[TONES]; /* tone frequency counter for 16'*/
+ int output8; /* output signal bits for 8' */
+ int output16; /* output signal bits for 16' */
+ int enable; /* mask which tones to play */
+};
+
+INLINE tms_state *get_safe_token(device_t *device)
+{
+ assert(device != NULL);
+ assert(device->type() == TMS3615);
+ return (tms_state *)downcast<legacy_device_base *>(device)->token();
+}
+
+
+static STREAM_UPDATE( tms3615_sound_update )
+{
+ tms_state *tms = (tms_state *)param;
+ int samplerate = tms->samplerate;
+ stream_sample_t *buffer8 = outputs[TMS3615_FOOTAGE_8];
+ stream_sample_t *buffer16 = outputs[TMS3615_FOOTAGE_16];
+
+ while( samples-- > 0 )
+ {
+ int sum8 = 0, sum16 = 0, tone = 0;
+
+ for (tone = 0; tone < TONES; tone++)
+ {
+ // 8'
+
+ tms->counter8[tone] -= (tms->basefreq / divisor[tone]);
+
+ while( tms->counter8[tone] <= 0 )
+ {
+ tms->counter8[tone] += samplerate;
+ tms->output8 ^= 1 << tone;
+ }
+
+ if (tms->output8 & tms->enable & (1 << tone))
+ {
+ sum8 += VMAX;
+ }
+
+ // 16'
+
+ tms->counter16[tone] -= (tms->basefreq / divisor[tone] / 2);
+
+ while( tms->counter16[tone] <= 0 )
+ {
+ tms->counter16[tone] += samplerate;
+ tms->output16 ^= 1 << tone;
+ }
+
+ if (tms->output16 & tms->enable & (1 << tone))
+ {
+ sum16 += VMAX;
+ }
+ }
+
+ *buffer8++ = sum8 / TONES;
+ *buffer16++ = sum16 / TONES;
+ }
+
+ tms->enable = 0;
+}
+
+void tms3615_enable_w(device_t *device, int enable)
+{
+ tms_state *tms = get_safe_token(device);
+ tms->enable = enable;
+}
+
+static DEVICE_START( tms3615 )
+{
+ tms_state *tms = get_safe_token(device);
+
+ tms->channel = device->machine().sound().stream_alloc(*device, 0, 2, device->clock()/8, tms, tms3615_sound_update);
+ tms->samplerate = device->clock()/8;
+ tms->basefreq = device->clock();
+}
+
+/**************************************************************************
+ * Generic get_info
+ **************************************************************************/
+
+DEVICE_GET_INFO( tms3615 )
+{
+ switch (state)
+ {
+ /* --- the following bits of info are returned as 64-bit signed integers --- */
+ case DEVINFO_INT_TOKEN_BYTES: info->i = sizeof(tms_state); break;
+
+ /* --- the following bits of info are returned as pointers to data or functions --- */
+ case DEVINFO_FCT_START: info->start = DEVICE_START_NAME( tms3615 ); break;
+ case DEVINFO_FCT_STOP: /* Nothing */ break;
+ case DEVINFO_FCT_RESET: /* Nothing */ break;
+
+ /* --- the following bits of info are returned as NULL-terminated strings --- */
+ case DEVINFO_STR_NAME: strcpy(info->s, "TMS3615"); break;
+ case DEVINFO_STR_FAMILY: strcpy(info->s, "TI PSG"); 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;
+ }
+}
+
+
+DEFINE_LEGACY_SOUND_DEVICE(TMS3615, tms3615);