PowerPC: strncat optimization for PPC64

The optimization is achieved by following techniques:
1. Doubleword aligned memory access and compares using
   cmpb instruction.
2. Loop unrolling for byte load/store.
3. CPU pre-fetch to avoid cache miss.

1 files changed, 31 insertions, 0 deletions

diff --git a/sysdeps/powerpc/powerpc64/multiarch/strncat.c b/sysdeps/powerpc/powerpc64/multiarch/strncat.c
new file mode 100644
index 0000000000..db98ec1a00
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/multiarch/strncat.c
@@ -0,0 +1,31 @@
+/* Multiple versions of strncat. PowerPC64 version.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef NOT_IN_libc
+# include <string.h>
+# include <shlib-compat.h>
+# include "init-arch.h"
+
+extern __typeof (strncat) __strncat_ppc attribute_hidden;
+extern __typeof (strncat) __strncat_power7 attribute_hidden;
+
+libc_ifunc (strncat,
+            (hwcap & PPC_FEATURE_HAS_VSX)
+            ? __strncat_power7
+            : __strncat_ppc);
+#endif