1 files changed, 73 insertions, 0 deletions
diff --git a/ports/sysdeps/tile/tilepro/strrchr.c b/ports/sysdeps/tile/tilepro/strrchr.c
new file mode 100644
index 0000000000..a41f9dad92
--- /dev/null
+++ b/ports/sysdeps/tile/tilepro/strrchr.c
@@ -0,0 +1,73 @@
+/* Copyright (C) 2011 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>
+
+char *
+strrchr (const char *s, int c)
+{
+  /* Get an aligned pointer. */
+  const uintptr_t s_int = (uintptr_t) s;
+  const uint32_t *p = (const uint32_t *) (s_int & -4);
+
+  /* Create four copies of the byte for which we are looking. */
+  const uint32_t goal = 0x01010101 * (uint8_t) 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).  Note that this shift count expression works because we
+     know shift counts are taken mod 32.  */
+  const uint32_t before_mask = (1 << (s_int << 3)) - 1;
+  uint32_t v = (*p | before_mask) ^ (goal & __insn_shrib (before_mask, 1));
+  const char *found = NULL;
+  uint32_t zero_matches, goal_matches;
+  while (1)
+    {
+      /* Look for a terminating '\0'. */
+      zero_matches = __insn_seqb (v, 0);
+
+      /* Look for the goal byte. */
+      goal_matches = __insn_seqb (v, goal);
+
+      /* If we found the goal, record the last offset. */
+      if (__builtin_expect (goal_matches != 0, 0))
+        {
+          if (__builtin_expect (zero_matches != 0, 0))
+            {
+              /* Clear any goal after the first zero. */
+              int first_nul = __insn_ctz (zero_matches);
+              /* The number of top bits we need to clear is
+                 32 - (first_nul + 8).  */
+              int shift_amt = (24 - first_nul);
+              goal_matches <<= shift_amt;
+              goal_matches >>= shift_amt;
+            }
+          if (__builtin_expect (goal_matches != 0, 1))
+            found = ((char *) p) + 3 - (__insn_clz (goal_matches) >> 3);
+        }
+
+      if (__builtin_expect (zero_matches != 0, 0))
+        return (char *) found;
+
+      v = *++p;
+    }
+}
+weak_alias (strrchr, rindex)
+libc_hidden_builtin_def (strrchr)