1 files changed, 71 insertions, 0 deletions

diff --git a/arch/tile/lib/memchr_64.c b/arch/tile/lib/memchr_64.c
new file mode 100644
index 000000000000..84fdc8d8e735
--- /dev/null
+++ b/arch/tile/lib/memchr_64.c
@@ -0,0 +1,71 @@
+/*
+ * 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>
+
+void *memchr(const void *s, int c, size_t n)
+{
+        const uint64_t *last_word_ptr;
+        const uint64_t *p;
+        const char *last_byte_ptr;
+        uintptr_t s_int;
+        uint64_t goal, before_mask, v, bits;
+        char *ret;
+
+        if (__builtin_expect(n == 0, 0)) {
+                /* Don't dereference any memory if the array is empty. */
+                return NULL;
+        }
+
+        /* Get an aligned pointer. */
+        s_int = (uintptr_t) s;
+        p = (const uint64_t *)(s_int & -8);
+
+        /* Create eight copies of the byte for which we are looking. */
+        goal = 0x0101010101010101ULL * (uint8_t) c;
+
+        /* Read the first word, but munge it so that bytes before the array
+         * will not match goal.
+         *
+         * Note that this shift count expression works because we know
+         * shift counts are taken mod 64.
+         */
+        before_mask = (1ULL << (s_int << 3)) - 1;
+        v = (*p | before_mask) ^ (goal & before_mask);
+
+        /* Compute the address of the last byte. */
+        last_byte_ptr = (const char *)s + n - 1;
+
+        /* Compute the address of the word containing the last byte. */
+        last_word_ptr = (const uint64_t *)((uintptr_t) last_byte_ptr & -8);
+
+        while ((bits = __insn_v1cmpeq(v, goal)) == 0) {
+                if (__builtin_expect(p == last_word_ptr, 0)) {
+                        /* We already read the last word in the array,
+                         * so give up.
+                         */
+                        return NULL;
+                }
+                v = *++p;
+        }
+
+        /* We found a match, but it might be in a byte past the end
+         * of the array.
+         */
+        ret = ((char *)p) + (__insn_ctz(bits) >> 3);
+        return (ret <= last_byte_ptr) ? ret : NULL;
+}
+EXPORT_SYMBOL(memchr);