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/nway-replace.h

@@ -0,0 +1,38 @@
+/* --------------------------------------------------------------- */
+/* 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                                              */
+/* nway-replace.h
+ *
+ * Copyright (C) 2005 IBM Corp.
+ *
+ * Implement replacement for software
+ * managed cache.
+ */
+
+#ifndef __SPE_CACHE_NWAY_REPLACE_H_
+#define __SPE_CACHE_NWAY_REPLACE_H_
+
+static vec_uint4 spe_cache_replace_cntr[SPE_CACHE_NSETS+1];
+
+static inline vec_uint4 _spe_cache_replace_(int set, int avail)
+{
+    unsigned int mask = ((1 << SPE_CACHE_NWAY) - 1) & avail;
+    unsigned int curr, currbit, next;
+
+    curr = spu_extract(spe_cache_replace_cntr[set], 0) & SPE_CACHE_NWAY_MASK;
+    currbit = (1 << curr);
+    next = (curr + 1) & SPE_CACHE_NWAY_MASK;
+    spe_cache_replace_cntr[set] = (vec_uint4) spu_promote(next, 0);
+    mask = (mask & currbit) ? currbit : mask;
+
+    return (vec_uint4) spu_promote(mask, 0);
+}
+
+#endif