1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
/*
* ========================
* ===== ===============
* ====== ================
* ====== ================
* ====== ==== ==== ==
* ====== === == = =
* ====== === = == =
* = === === = == ====
* = === === = == = =
* == ===== ==== ==
* ========================
*
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2020 Joe
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the organization nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOE ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL JOE BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* bsdsetsid: src/u_strncmp.S
* 2020-11-21 14:02
* Joe
*
* General error handling happen here.
*/
.text
.globl u_strncmp
u_strncmp:
xor %rcx, %rcx
dec %rdx
.u.loop:
xor %r8, %r8
xor %r9, %r9
movb (%rdi, %rcx), %r8b
movb (%rsi, %rcx), %r9b
cmpb %r8b, %r9b
jne .u.retdiff
cmp %rdx, %rcx
jge .u.retdiff
cmpb $0x0, (%rdi, %rcx)
jne .u.inc
cmpb $0x0, (%rsi, %rcx)
je .u.retzer
.u.inc:
inc %rcx
jmp .u.loop
.u.retdiff:
xor %r8, %r8
xor %r9, %r9
movb (%rdi, %rcx), %r8b
movb (%rsi, %rcx), %r9b
sub %r9, %r8
xor %rax, %rax
movl %r8d, %eax
ret
.u.retzer:
xor %rax, %rax
ret
|
