Add a simple rawmemchr implementation. Use strlen for rawmemchr(s, '\0') as it

is the fastest way to search for '\0'.  Otherwise use memchr with an infinite
size.  This is 3x faster on benchtests for large sizes.  Passes GLIBC tests.

	* sysdeps/aarch64/rawmemchr.S (__rawmemchr): New file.
	* sysdeps/aarch64/strlen.S (__strlen): Change to __strlen to avoid PLT.

diff --git a/ChangeLog b/ChangeLog
index a9cedf0..4ed597b 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2016-06-20  Wilco Dijkstra  <wdijkstr@arm.com>
 
+       * sysdeps/aarch64/rawmemchr.S (__rawmemchr): New file.
+       * sysdeps/aarch64/strlen.S (__strlen): Change to __strlen to avoid PLT.
+
+2016-06-20  Wilco Dijkstra  <wdijkstr@arm.com>
+
        * sysdeps/aarch64/memcpy.S (memcpy):
        Rewrite of optimized memcpy and memmove.
        * sysdeps/aarch64/memmove.S (memmove): Remove

diff --git a/sysdeps/aarch64/rawmemchr.S b/sysdeps/aarch64/rawmemchr.S
new file mode 100644 (file)
index 0000000..ec958e8
--- /dev/null
+++ b/sysdeps/aarch64/rawmemchr.S
@@ -0,0 +1,42 @@
+/* rawmemchr - find a character in a memory zone
+
+   Copyright (C) 2015 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/>.  */
+
+#include <sysdep.h>
+
+/* Special case rawmemchr (s, 0) as strlen, otherwise tailcall memchr.
+   Call strlen without setting up a full frame - it preserves x14/x15.
+*/
+
+ENTRY (__rawmemchr)
+       cbz     w1, L(do_strlen)
+       mov     x2, -1
+       b       __memchr
+
+L(do_strlen):
+       mov     x15, x30
+       cfi_return_column (x15)
+       mov     x14, x0
+       bl      __strlen
+       add     x0, x14, x0
+       ret     x15
+
+END (__rawmemchr)
+weak_alias (__rawmemchr, rawmemchr)
+libc_hidden_builtin_def (__rawmemchr)

diff --git a/sysdeps/aarch64/strlen.S b/sysdeps/aarch64/strlen.S
index 9b4d1da..a07834b 100644 (file)
--- a/sysdeps/aarch64/strlen.S
+++ b/sysdeps/aarch64/strlen.S
@@ -84,7 +84,7 @@
           whether the first fetch, which may be misaligned, crosses a page
           boundary.  */
 
-ENTRY_ALIGN (strlen, 6)
+ENTRY_ALIGN (__strlen, 6)
        and     tmp1, srcin, MIN_PAGE_SIZE - 1
        mov     zeroones, REP8_01
        cmp     tmp1, MIN_PAGE_SIZE - 16
@@ -213,5 +213,6 @@ L(page_cross):
        csel    data1, data1, tmp4, eq
        csel    data2, data2, tmp2, eq
        b       L(page_cross_entry)
-END (strlen)
+END (__strlen)
+weak_alias (__strlen, strlen)
 libc_hidden_builtin_def (strlen)