Added IBM Cell SDK 2.x software_cache to Bullet/Extras. There is an option to enable it for the BulletMultiThreaded Cell version.

See USE_SOFTWARE_CACHE in Bullet\src\BulletMultiThreaded\SpuNarrowPhaseCollisionTask\SpuGatheringCollisionTask.cpp
It improves the Bullet midphase collision detection (triangle/vertex fetch)
The license is CommonPublicLicense-1.0, see included license docs.

Extras/software_cache/cache/include/api.h

@@ -0,0 +1,31 @@
+/* --------------------------------------------------------------- */
+/* PLEASE DO NOT MODIFY THIS SECTION                               */
+/* This prolog section is automatically generated.                 */
+/*                                                                 */
+/* (C) Copyright 2001,2006,                                        */
+/* International Business Machines Corporation,                    */
+/*                                                                 */
+/* All Rights Reserved.                                            */
+/* --------------------------------------------------------------- */
+/* PROLOG END TAG zYx                                              */
+/* api.h
+ *
+ * Copyright (C) 2005 IBM Corp.
+ *
+ * Simple API for software managed cache on SPEs.
+ * A sophisticated application would not use these,
+ * but rather use the low-level lookup functions.
+ */
+
+#ifndef __SPE_CACHE_API_H__
+#define __SPE_CACHE_API_H__
+
+typedef void *spe_cache_entry_t;
+
+#define spe_cache_rd(ea)		_spe_cache_lookup_xfer_wait_(ea, 0, 1)
+#define spe_cache_tr(ea)		_spe_cache_lookup_xfer_(ea, 0, 1)
+#define spe_cache_lr(ea)		_spe_cache_lookup_(ea, 0)
+
+#define spe_cache_wait(entry)		_spe_cache_wait_(entry)
+
+#endif