bfsoundlib: Avoid uninitialized variables on invallid use

It was possible to make the library use uninitialized variables
by putting the library into invalid state.

While it was unlikely situation, better to not have uninitialized
variables at all.

Author: mefistotelis

bfsoundlib/include/mssal.h

@@ -674,8 +674,15 @@ struct VDI_CALL {
   int16_t AX;
   int16_t BX;
   int16_t CX;
-  int16_t DX;
-  int16_t SI;
+  union {
+    struct {
+      int16_t DX;
+      int16_t SI;
+    };
+    /** Some commands are transferring a pointer over DX:DI.
+     * This definition makes it possible regardless of architecture. */
+    uintptr_t pDXSI;
+  };
   int16_t DI;
 };
 

bfsoundlib/src/ailss.c

@@ -269,6 +269,7 @@ int32_t SS_configure_buffers(DIG_DRIVER *digdrv)
         pref[3] = DIG_F_MONO_16;
         break;
 
+    default:
     case DIG_F_STEREO_16:
         pref[0] = DIG_F_STEREO_16;
         pref[1] = DIG_F_STEREO_8;
@@ -366,6 +367,7 @@ int32_t SS_configure_buffers(DIG_DRIVER *digdrv)
     // Round half-buffer size to nearest binary power between 8 and
     // DIG_DMA_RESERVE / 2; ensure result within driver limits
     delta = LONG_MAX;
+    match = bsmax;
 
     for (n = 8; n <= (AIL_preference[DIG_DMA_RESERVE] / 2); n <<= 1)
     {

bfsoundlib/src/awe32use.c

@@ -72,7 +72,7 @@ int AWEDefMemMap(MDI_DRIVER *mdidrv, short part_cnt, long *memMap, uint16_t memM
     regs.SI = 0;
 #else
     assert(sizeof(VDI_CALL) - offsetof(VDI_CALL, DX) >= sizeof(SF_DATA *));
-    *(SF_DATA **)(&regs.DX) = awe_data;
+    *(SF_DATA **)(&regs.pDXSI) = awe_data;
 #endif
     AIL_call_driver(mdidrv->drvr, MDI_VSE, &regs, &regs);
     return regs.AX;
@@ -102,7 +102,7 @@ SF_INFO *AWEGetSFInfo(MDI_DRIVER *mdidrv, short bank_no, uint8_t *hdr_data, uint
     regs.SI = 0;
 #else
     assert(sizeof(VDI_CALL) - offsetof(VDI_CALL, DX) >= sizeof(SF_DATA *));
-    *(SF_DATA **)(&regs.DX) = awe_data;
+    *(SF_DATA **)(&regs.pDXSI) = awe_data;
 #endif
     AIL_call_driver(mdidrv->drvr, MDI_VSE, &regs, &regs);
 
@@ -111,7 +111,7 @@ SF_INFO *AWEGetSFInfo(MDI_DRIVER *mdidrv, short bank_no, uint8_t *hdr_data, uint
 #if defined(DOS)||defined(GO32)
         ret = MK_FP(CreateSelector(regs.DX), regs.SI);
 #else
-        ret = *(SF_INFO **)(&regs.DX);
+        ret = *(SF_INFO **)(&regs.pDXSI);
 #endif
         return ret;
     }
@@ -142,7 +142,7 @@ int AWEStreamSample(MDI_DRIVER *mdidrv, short bank_no, uint8_t *smpl_data, uint1
     regs.SI = 0;
 #else
     assert(sizeof(VDI_CALL) - offsetof(VDI_CALL, DX) >= sizeof(SF_DATA *));
-    *(SF_DATA **)(&regs.DX) = awe_data;
+    *(SF_DATA **)(&regs.pDXSI) = awe_data;
 #endif
 
     AIL_call_driver(mdidrv->drvr, MDI_VSE, &regs, &regs);
@@ -173,7 +173,7 @@ int AWELoadPreset(MDI_DRIVER *mdidrv, short bank_no, uint8_t *preset_data, uint1
     regs.SI = 0;
 #else
     assert(sizeof(VDI_CALL) - offsetof(VDI_CALL, DX) >= sizeof(SF_DATA *));
-    *(SF_DATA **)(&regs.DX) = awe_data;
+    *(SF_DATA **)(&regs.pDXSI) = awe_data;
 #endif
     AIL_call_driver(mdidrv->drvr, MDI_VSE, &regs, &regs);
     return regs.AX;

bfsoundlib/src/cd.c

@@ -217,6 +217,10 @@ sbyte GetCDVolume(void)
         fvol = ogg_vorbis_stream_get_gain(&sound_music_stream);
         vol = fvol * (127.f / 1.f);
         break;
+    default:
+        vol = 0;
+        SNDLOGFAIL("CDA play", "wrong CDType, cannot get volume");
+        break;
     }
     return vol;
 }
@@ -237,6 +241,9 @@ void SetCDVolume(short vol)
     case CDTYP_OGG:
         ogg_vorbis_stream_set_gain(&sound_music_stream, vol * (1.f / 127.f));
         break;
+    default:
+        SNDLOGFAIL("CDA play", "wrong CDType, cannot set volume");
+        break;
     }
 }