3 files changed, 71 insertions, 1 deletions

diff --git a/include/linux/carta_random32.h b/include/linux/carta_random32.h
new file mode 100644
index 000000000000..f6f3bd9f20b5
--- /dev/null
+++ b/include/linux/carta_random32.h
@@ -0,0 +1,29 @@
+/*
+ * Fast, simple, yet decent quality random number generator based on
+ * a paper by David G. Carta ("Two Fast Implementations of the
+ * `Minimal Standard' Random Number Generator," Communications of the
+ * ACM, January, 1990).
+ *
+ * Copyright (c) 2002-2006 Hewlett-Packard Development Company, L.P.
+ *      Contributed by Stephane Eranian <eranian@hpl.hp.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307 USA
+ */
+#ifndef _LINUX_CARTA_RANDOM32_H_
+#define _LINUX_CARTA_RANDOM32_H_
+
+u64 carta_random32(u64 seed);
+
+#endif /* _LINUX_CARTA_RANDOM32_H_ */
diff --git a/lib/Makefile b/lib/Makefile
index 8e6662bb9c37..59070dbfbeb4 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -5,7 +5,7 @@
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
          bust_spinlocks.o rbtree.o radix-tree.o dump_stack.o \
          idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
-         sha1.o irq_regs.o
+         sha1.o irq_regs.o carta_random32.o
 
 lib-$(CONFIG_MMU) += ioremap.o
 lib-$(CONFIG_SMP) += cpumask.o
diff --git a/lib/carta_random32.c b/lib/carta_random32.c
new file mode 100644
index 000000000000..ca82df70eee4
--- /dev/null
+++ b/lib/carta_random32.c
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2002-2006 Hewlett-Packard Development Company, L.P.
+ *      Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307 USA
+ */
+#include <linux/types.h>
+#include <linux/module.h>
+
+/*
+ * Fast, simple, yet decent quality random number generator based on
+ * a paper by David G. Carta ("Two Fast Implementations of the
+ * `Minimal Standard' Random Number Generator," Communications of the
+ * ACM, January, 1990).
+ */
+u64 carta_random32 (u64 seed)
+{
+#       define A 16807
+#       define M ((u32) 1 << 31)
+        u64 s, prod = A * seed, p, q;
+
+        p = (prod >> 31) & (M - 1);
+        q = (prod >>  0) & (M - 1);
+        s = p + q;
+        if (s >= M)
+                s -= M - 1;
+        return s;
+}
+EXPORT_SYMBOL_GPL(carta_random32);