Some work on the Bochs sound support.

- OPL3: Added support to change the samplerate of the generator.
- SDL sound: convert wave packet to 16 Bit signed stereo format.
- Increased the maximum size of a single wave packet for playbck/recording.

bochs/iodev/sound/opl.cc

@@ -991,7 +991,7 @@ static void OPL_INLINE clipit16(Bit32s ival, Bit16s* outval)
   opl_active = 1;
 #endif
 
-bx_bool adlib_getsample(Bit16s* sndptr, Bits numsamples)
+bx_bool adlib_getsample(Bit16u rate, Bit16s* sndptr, Bits numsamples)
 {
   Bits i, endsamples;
   op_type* cptr;
@@ -1009,6 +1009,10 @@ bx_bool adlib_getsample(Bit16s* sndptr, Bits numsamples)
 
   Bits samples_to_process = numsamples;
 
+  if (rate != (Bit16u)int_samplerate) {
+    adlib_init(rate);
+  }
+
   for (Bits cursmp=0; cursmp<samples_to_process; cursmp+=endsamples) {
     endsamples = samples_to_process-cursmp;
     if (endsamples>BLOCKBUF_SIZE) endsamples = BLOCKBUF_SIZE;

bochs/iodev/sound/opl.h

@@ -204,7 +204,7 @@ static Bit32u generator_add; // should be a chip parameter
 // general functions
 void adlib_init(Bit32u samplerate);
 void adlib_write(Bitu idx, Bit8u val);
-bx_bool adlib_getsample(Bit16s* sndptr, Bits numsamples);
+bx_bool adlib_getsample(Bit16u rate, Bit16s* sndptr, Bits numsamples);
 
 Bitu adlib_reg_read(Bitu port);
 void adlib_write_index(Bitu port, Bit8u val);

bochs/iodev/sound/sb16.cc

@@ -2364,7 +2364,7 @@ void bx_sb16_c::opl_settimermask(int value, int chipid)
 
 Bit32u bx_sb16_c::fmopl_generator(Bit16u rate, Bit8u *buffer, Bit32u len)
 {
-  bx_bool ret = adlib_getsample((Bit16s*)buffer, len / 4);
+  bx_bool ret = adlib_getsample(rate, (Bit16s*)buffer, len / 4);
   return ret ? len : 0;
 }
 

bochs/iodev/sound/soundlow.h

@@ -20,10 +20,9 @@
 
 // Common code for sound lowlevel modules
 
-// this is the size of a sound packet used for sending and receiving
-// it should not be too large to avoid lag, and not too
-// small to avoid unnecessary overhead.
-#define BX_SOUNDLOW_WAVEPACKETSIZE  8192
+// This is the maximum size of a wave data packet.
+// It should be large enough for 0.1 seconds of playback or recording.
+#define BX_SOUNDLOW_WAVEPACKETSIZE  19200
 
 // Definitions for the output functions
 #define BX_SOUNDLOW_OK   0

bochs/iodev/sound/soundsdl.cc

@@ -157,35 +157,83 @@ int bx_sound_sdl_c::waveready()
   return BX_SOUNDLOW_OK;
 }
 
+void bx_sound_sdl_c::convert_wavedata(Bit8u *src, int srcsize, Bit8u *dst, int dstsize, bx_pcm_param_t *param)
+{
+  int i, j;
+  Bit8u xor_val;
+
+  xor_val = (param->format & 1) ? 0x00 : 0x80;
+  if (param->bits == 16) {
+    if ((param->format & 1) && (param->channels == 2)) {
+      memcpy(dst, src, dstsize);
+    } else if (param->channels == 2) {
+      j = 0;
+      for (i = 0; i < srcsize; i+=2) {
+        dst[j++] = src[i];
+        dst[j++] = src[i+1] ^ xor_val;
+      }
+    } else {
+      j = 0;
+      for (i = 0; i < srcsize; i+=2) {
+        dst[j++] = src[i];
+        dst[j++] = src[i+1] ^ xor_val;
+        dst[j++] = src[i];
+        dst[j++] = src[i+1] ^ xor_val;
+      }
+    }
+  } else {
+    if (param->channels == 2) {
+      j = 0;
+      for (i = 0; i < srcsize; i++) {
+        dst[j++] = 0;
+        dst[j++] = src[i] ^ xor_val;
+      }
+    } else {
+      j = 0;
+      for (i = 0; i < srcsize; i++) {
+        dst[j++] = 0;
+        dst[j++] = src[i] ^ xor_val;
+        dst[j++] = 0;
+        dst[j++] = src[i] ^ xor_val;
+      }
+    }
+  }
+}
+
 int bx_sound_sdl_c::sendwavepacket(int length, Bit8u data[], bx_pcm_param_t *param)
 {
   int ret = BX_SOUNDLOW_OK;
   int tmpsize;
-  int size;
+  int bsize, len2, ssize = 1;
 
   if (memcmp(param, &pcm_param, sizeof(bx_pcm_param_t)) != 0) {
-    startwaveplayback(param->samplerate, param->bits, param->channels == 2,
-                      param->format);
+    startwaveplayback(param->samplerate, 16, 1, 1);
     pcm_param = *param;
   }
+  len2 = length;
+  if (param->bits == 8) ssize = 2;
+  if (param->channels == 1) ssize *= 2;
+  len2 = length * ssize;
   SDL_LockAudio();
   if (WaveOpen) {
-    size = audio_buffer.optr - audio_buffer.iptr;
-    if (size <= 0) {
-      size += BX_SOUND_SDL_BUFSIZE;
+    bsize = audio_buffer.optr - audio_buffer.iptr;
+    if (bsize <= 0) {
+      bsize += BX_SOUND_SDL_BUFSIZE;
     }
-    if (size < length) {
-      BX_ERROR(("SDL: audio buffer overflow: l=%d s=%d", length, size));
-      ret = BX_SOUNDLOW_ERR;
-    } else {
-      if ((audio_buffer.iptr + length) > BX_SOUND_SDL_BUFSIZE) {
+    if (bsize < len2) {
+      BX_ERROR(("SDL: audio buffer overflow: l=%d s=%d", len2, bsize));
+      len2 = (bsize > ssize) ? bsize - ssize : 0;
+    }
+    if (len2 > 0) {
+      if ((audio_buffer.iptr + len2) > BX_SOUND_SDL_BUFSIZE) {
         tmpsize = BX_SOUND_SDL_BUFSIZE - audio_buffer.iptr;
-        memcpy(audio_buffer.data+audio_buffer.iptr, data, tmpsize);
-        memcpy(audio_buffer.data, data+tmpsize, length-tmpsize);
-        audio_buffer.iptr = length-tmpsize;
+        len2 -= tmpsize;
+        convert_wavedata(data, tmpsize/ssize, audio_buffer.data+audio_buffer.iptr, tmpsize, param);
+        convert_wavedata(data+tmpsize/ssize, len2/ssize, audio_buffer.data, len2, param);
+        audio_buffer.iptr = len2;
       } else {
-        memcpy(audio_buffer.data+audio_buffer.iptr, data, length);
-        audio_buffer.iptr += length;
+        convert_wavedata(data, length, audio_buffer.data+audio_buffer.iptr, len2, param);
+        audio_buffer.iptr += len2;
       }
     }
   } else {

bochs/iodev/sound/soundsdl.h

@@ -45,6 +45,7 @@ public:
   virtual void unregister_wave_callback(int callback_id);
   void get_wave_data(Bit8u *stream, int len);
 private:
+  void convert_wavedata(Bit8u *src, int srcsize, Bit8u *dst, int dstsize, bx_pcm_param_t *param);
   bx_bool WaveOpen;
   SDL_AudioSpec fmt;
   int cb_count;