1 files changed, 38 insertions, 0 deletions

diff --git a/arch/tile/lib/strlen_64.c b/arch/tile/lib/strlen_64.c
new file mode 100644
index 000000000000..1c92d46202a8
--- /dev/null
+++ b/arch/tile/lib/strlen_64.c
@@ -0,0 +1,38 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/module.h>
+
+#undef strlen
+
+size_t strlen(const char *s)
+{
+        /* Get an aligned pointer. */
+        const uintptr_t s_int = (uintptr_t) s;
+        const uint64_t *p = (const uint64_t *)(s_int & -8);
+
+        /* Read the first word, but force bytes before the string to be nonzero.
+         * This expression works because we know shift counts are taken mod 64.
+         */
+        uint64_t v = *p | ((1ULL << (s_int << 3)) - 1);
+
+        uint64_t bits;
+        while ((bits = __insn_v1cmpeqi(v, 0)) == 0)
+                v = *++p;
+
+        return ((const char *)p) + (__insn_ctz(bits) >> 3) - s;
+}
+EXPORT_SYMBOL(strlen);