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Diffstat (limited to 'trunk/src/emu/sound/segapcm.c')
-rw-r--r--trunk/src/emu/sound/segapcm.c179
1 files changed, 179 insertions, 0 deletions
diff --git a/trunk/src/emu/sound/segapcm.c b/trunk/src/emu/sound/segapcm.c
new file mode 100644
index 00000000000..7f6f7054748
--- /dev/null
+++ b/trunk/src/emu/sound/segapcm.c
@@ -0,0 +1,179 @@
+/*********************************************************/
+/* SEGA 16ch 8bit PCM */
+/*********************************************************/
+
+#include "emu.h"
+#include "segapcm.h"
+
+typedef struct _segapcm_state segapcm_state;
+struct _segapcm_state
+{
+ UINT8 *ram;
+ UINT8 low[16];
+ const UINT8 *rom;
+ int bankshift;
+ int bankmask;
+ int rgnmask;
+ sound_stream * stream;
+};
+
+INLINE segapcm_state *get_safe_token(device_t *device)
+{
+ assert(device != NULL);
+ assert(device->type() == SEGAPCM);
+ return (segapcm_state *)downcast<legacy_device_base *>(device)->token();
+}
+
+static STREAM_UPDATE( SEGAPCM_update )
+{
+ segapcm_state *spcm = (segapcm_state *)param;
+ int rgnmask = spcm->rgnmask;
+ int ch;
+
+ /* clear the buffers */
+ memset(outputs[0], 0, samples*sizeof(*outputs[0]));
+ memset(outputs[1], 0, samples*sizeof(*outputs[1]));
+
+ // reg function
+ // ------------------------------------------------
+ // 0x00 ?
+ // 0x01 ?
+ // 0x02 volume left
+ // 0x03 volume right
+ // 0x04 loop address (08-15)
+ // 0x05 loop address (16-23)
+ // 0x06 end address
+ // 0x07 address delta
+ // 0x80 ?
+ // 0x81 ?
+ // 0x82 ?
+ // 0x83 ?
+ // 0x84 current address (08-15), 00-07 is internal?
+ // 0x85 current address (16-23)
+ // 0x86 bit 0: channel disable?
+ // bit 1: loop disable
+ // other bits: bank
+ // 0x87 ?
+
+ /* loop over channels */
+ for (ch = 0; ch < 16; ch++)
+ {
+ UINT8 *regs = spcm->ram+8*ch;
+
+ /* only process active channels */
+ if (!(regs[0x86]&1))
+ {
+ const UINT8 *rom = spcm->rom + ((regs[0x86] & spcm->bankmask) << spcm->bankshift);
+ UINT32 addr = (regs[0x85] << 16) | (regs[0x84] << 8) | spcm->low[ch];
+ UINT32 loop = (regs[0x05] << 16) | (regs[0x04] << 8);
+ UINT8 end = regs[6] + 1;
+ int i;
+
+ /* loop over samples on this channel */
+ for (i = 0; i < samples; i++)
+ {
+ INT8 v = 0;
+
+ /* handle looping if we've hit the end */
+ if ((addr >> 16) == end)
+ {
+ if (regs[0x86] & 2)
+ {
+ regs[0x86] |= 1;
+ break;
+ }
+ else addr = loop;
+ }
+
+ /* fetch the sample */
+ v = rom[(addr >> 8) & rgnmask] - 0x80;
+
+ /* apply panning and advance */
+ outputs[0][i] += v * regs[2];
+ outputs[1][i] += v * regs[3];
+ addr = (addr + regs[7]) & 0xffffff;
+ }
+
+ /* store back the updated address */
+ regs[0x84] = addr >> 8;
+ regs[0x85] = addr >> 16;
+ spcm->low[ch] = regs[0x86] & 1 ? 0 : addr;
+ }
+ }
+}
+
+static DEVICE_START( segapcm )
+{
+ const sega_pcm_interface *intf = (const sega_pcm_interface *)device->static_config();
+ int mask, rom_mask, len;
+ segapcm_state *spcm = get_safe_token(device);
+
+ spcm->rom = *device->region();
+ spcm->ram = auto_alloc_array(device->machine(), UINT8, 0x800);
+
+ memset(spcm->ram, 0xff, 0x800);
+
+ spcm->bankshift = (UINT8)(intf->bank);
+ mask = intf->bank >> 16;
+ if(!mask)
+ mask = BANK_MASK7>>16;
+
+ len = device->region()->bytes();
+ spcm->rgnmask = len - 1;
+
+ for(rom_mask = 1; rom_mask < len; rom_mask *= 2);
+
+ rom_mask--;
+
+ spcm->bankmask = mask & (rom_mask >> spcm->bankshift);
+
+ spcm->stream = device->machine().sound().stream_alloc(*device, 0, 2, device->clock() / 128, spcm, SEGAPCM_update);
+
+ device->save_item(NAME(spcm->low));
+ device->save_pointer(NAME(spcm->ram), 0x800);
+}
+
+
+WRITE8_DEVICE_HANDLER( sega_pcm_w )
+{
+ segapcm_state *spcm = get_safe_token(device);
+ spcm->stream->update();
+ spcm->ram[offset & 0x07ff] = data;
+}
+
+READ8_DEVICE_HANDLER( sega_pcm_r )
+{
+ segapcm_state *spcm = get_safe_token(device);
+ spcm->stream->update();
+ return spcm->ram[offset & 0x07ff];
+}
+
+
+
+/**************************************************************************
+ * Generic get_info
+ **************************************************************************/
+
+DEVICE_GET_INFO( segapcm )
+{
+ switch (state)
+ {
+ /* --- the following bits of info are returned as 64-bit signed integers --- */
+ case DEVINFO_INT_TOKEN_BYTES: info->i = sizeof(segapcm_state); break;
+
+ /* --- the following bits of info are returned as pointers to data or functions --- */
+ case DEVINFO_FCT_START: info->start = DEVICE_START_NAME( segapcm ); 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, "Sega PCM"); break;
+ case DEVINFO_STR_FAMILY: strcpy(info->s, "Sega custom"); 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(SEGAPCM, segapcm);