source: trunk/libs/newlib/src/newlib/libc/machine/aarch64/rawmemchr.S @ 444

Last change on this file since 444 was 444, checked in by satin@…, 6 years ago

add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc

File size: 2.2 KB
Line 
1/* Copyright (c) 2015-2016, ARM Limited
2   All rights reserved.
3
4   Redistribution and use in source and binary forms, with or without
5   modification, are permitted provided that the following conditions are met:
6       * Redistributions of source code must retain the above copyright
7         notice, this list of conditions and the following disclaimer.
8       * Redistributions in binary form must reproduce the above copyright
9         notice, this list of conditions and the following disclaimer in the
10         documentation and/or other materials provided with the distribution.
11       * Neither the name of the company nor the names of its contributors
12         may be used to endorse or promote products derived from this
13         software without specific prior written permission.
14
15   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  */
26
27/* Assumptions:
28 *
29 * ARMv8-a, AArch64, unaligned accesses
30 *
31 */
32
33#if (defined (__OPTIMIZE_SIZE__) || defined (PREFER_SIZE_OVER_SPEED))
34/* See rawmemchr-stub.c.  */
35#else
36
37#define L(l) .L ## l
38
39        .macro def_fn f p2align=0
40        .text
41        .p2align \p2align
42        .global \f
43        .type \f, %function
44\f:
45        .endm
46
47/* Special case rawmemchr (s, 0) as strlen, otherwise tailcall memchr.
48   Call strlen without setting up a full frame - it preserves x14/x15.
49*/
50
51def_fn rawmemchr p2align=5
52        .cfi_startproc
53        cbz     w1, L(do_strlen)
54        mov     x2, -1
55        b       memchr
56
57L(do_strlen):
58        mov     x15, x30
59        .cfi_return_column x15
60        mov     x14, x0
61        bl      strlen
62        add     x0, x14, x0
63        ret     x15
64        .cfi_endproc
65
66        .size   rawmemchr, . - rawmemchr
67#endif
68
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