summaryrefslogtreecommitdiff
path: root/sysdeps/tile/strchr.c
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/tile/strchr.c')
-rw-r--r--sysdeps/tile/strchr.c67
1 files changed, 67 insertions, 0 deletions
diff --git a/sysdeps/tile/strchr.c b/sysdeps/tile/strchr.c
new file mode 100644
index 0000000000..1a5eb5c927
--- /dev/null
+++ b/sysdeps/tile/strchr.c
@@ -0,0 +1,67 @@
+/* Copyright (C) 2011-2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
+
+ 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/>. */
+
+#include <string.h>
+#include <stdint.h>
+#include "string-endian.h"
+
+#undef strchr
+
+char *
+strchr (const char *s, int c)
+{
+ int z, g;
+
+ /* Get an aligned pointer. */
+ const uintptr_t s_int = (uintptr_t) s;
+ const uint64_t *p = (const uint64_t *) (s_int & -8);
+
+ /* Create eight copies of the byte for which we are looking. */
+ const uint64_t goal = copy_byte(c);
+
+ /* Read the first aligned word, but force bytes before the string to
+ match neither zero nor goal (we make sure the high bit of each byte
+ is 1, and the low 7 bits are all the opposite of the goal byte). */
+ const uint64_t before_mask = MASK (s_int);
+ uint64_t v = (*p | before_mask) ^ (goal & v1shrui (before_mask, 1));
+
+ uint64_t zero_matches, goal_matches;
+ while (1)
+ {
+ /* Look for a terminating '\0'. */
+ zero_matches = v1cmpeqi (v, 0);
+
+ /* Look for the goal byte. */
+ goal_matches = v1cmpeq (v, goal);
+
+ if (__builtin_expect ((zero_matches | goal_matches) != 0, 0))
+ break;
+
+ v = *++p;
+ }
+
+ z = CFZ (zero_matches);
+ g = CFZ (goal_matches);
+
+ /* If we found c before '\0' we got a match. Note that if c == '\0'
+ then g == z, and we correctly return the address of the '\0'
+ rather than NULL. */
+ return (g <= z) ? ((char *) p) + (g >> 3) : NULL;
+}
+weak_alias (strchr, index)
+libc_hidden_builtin_def (strchr)