GBA BIOS: Stub out SoundBias

CHANGES

@@ -106,6 +106,7 @@ Misc:
  - VFS: Add sync method to force syncing with backing
  - GBA: Savedata is now synced shortly after data finishes being written
  - GBA Input: Allow axes and buttons to be mapped to the same key
+ - GBA BIOS: Stub out SoundBias
 
 0.2.1: (2015-05-13)
 Bugfixes:

src/gba/bios.c

@@ -300,6 +300,10 @@ void GBASwi16(struct ARMCore* cpu, int immediate) {
 			break;
 		}
 		break;
+	case 0x19:
+		// SoundBias is mostly meaningless here
+		GBALog(gba, GBA_LOG_STUB, "Stub software interrupt: SoundBias (19)");
+		break;
 	case 0x1F:
 		_MidiKey2Freq(gba);
 		break;