new ssx and lib files

Change-Id: I2328b1e86d59e3788910687d762fb70ec680058f
Reviewed-on: http://gfw160.aus.stglabs.ibm.com:8080/gerrit/19503
Reviewed-by: William A. Bryan <wilbryan@us.ibm.com>
Tested-by: William A. Bryan <wilbryan@us.ibm.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/src/lib/ppc405lib/lfsr.c b/src/lib/ppc405lib/lfsr.c
new file mode 100644
index 0000000..21ddb93
--- /dev/null
+++ b/src/lib/ppc405lib/lfsr.c
@@ -0,0 +1,50 @@
+/* IBM_PROLOG_BEGIN_TAG                                                   */
+/* This is an automatically generated prolog.                             */
+/*                                                                        */
+/* $Source: src/lib/ppc405lib/lfsr.c $                                    */
+/*                                                                        */
+/* OpenPOWER OnChipController Project                                     */
+/*                                                                        */
+/* Contributors Listed Below - COPYRIGHT 2015                             */
+/* [+] International Business Machines Corp.                              */
+/*                                                                        */
+/*                                                                        */
+/* Licensed under the Apache License, Version 2.0 (the "License");        */
+/* you may not use this file except in compliance with the License.       */
+/* You may obtain a copy of the License at                                */
+/*                                                                        */
+/*     http://www.apache.org/licenses/LICENSE-2.0                         */
+/*                                                                        */
+/* Unless required by applicable law or agreed to in writing, software    */
+/* distributed under the License is distributed on an "AS IS" BASIS,      */
+/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or        */
+/* implied. See the License for the specific language governing           */
+/* permissions and limitations under the License.                         */
+/*                                                                        */
+/* IBM_PROLOG_END_TAG                                                     */
+// $Id$
+
+/// \file lfsr.c
+/// \brief 
+
+#include <stdint.h>
+#include "lfsr.h"
+
+// Parity for 4-bit numbers
+static uint8_t S_parity4[16] = {
+    0, 1, 1, 0,
+    1, 0, 0, 1,
+    1, 0, 0, 1,
+    0, 1, 1, 0
+};
+
+// 64, 63, 61, 60 LFSR.  The routine is coded with the uint8_t casting to help
+// the compiler generate more efficient code.
+
+void
+_lfsr64(uint64_t* io_seed)
+{
+    *io_seed = (*io_seed << 1) |
+        S_parity4[(uint8_t)((*io_seed >> 59) & 0x3) | 
+                  (uint8_t)((*io_seed >> 60) & 0xc)];
+}