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1 | /* Optimized version of the standard strncmp() function. |
2 | This file is part of the GNU C Library. | |
04277e02 | 3 | Copyright (C) 2000-2019 Free Software Foundation, Inc. |
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4 | Contributed by Dan Pop <Dan.Pop@cern.ch>. |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Lesser General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public | |
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17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
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19 | |
20 | /* Return: the result of the comparison | |
21 | ||
22 | Inputs: | |
23 | in0: s1 | |
24 | in1: s2 | |
c70a4b1d | 25 | in2: n |
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26 | |
27 | Unlike memcmp(), this function is optimized for mismatches within the | |
28 | first few characters. */ | |
29 | ||
30 | #include <sysdep.h> | |
31 | #undef ret | |
32 | ||
33 | #define s1 in0 | |
34 | #define s2 in1 | |
35 | #define n in2 | |
36 | ||
37 | #define val1 r15 | |
38 | #define val2 r16 | |
39 | ||
40 | ||
41 | ENTRY(strncmp) | |
42 | alloc r2 = ar.pfs, 3, 0, 0, 0 | |
43 | mov ret0 = r0 | |
44 | cmp.eq p6, p0 = r0, r0 // set p6 | |
45 | cmp.eq p7, p0 = n, r0 // return immediately if n == 0 | |
46 | (p7) br.cond.spnt .restore_and_exit ;; | |
47 | .loop: | |
48 | ld1 val1 = [s1], 1 | |
49 | ld1 val2 = [s2], 1 | |
50 | adds n = -1, n // n-- | |
51 | ;; | |
52 | cmp.ne.and p6, p0 = val1, r0 | |
53 | cmp.ne.and p6, p0 = val2, r0 | |
54 | cmp.ne.and p6, p0 = n, r0 | |
55 | cmp.eq.and p6, p0 = val1, val2 | |
56 | (p6) br.cond.sptk .loop | |
57 | sub ret0 = val1, val2 | |
58 | .restore_and_exit: | |
59 | br.ret.sptk.many b0 | |
0347518d | 60 | END(strncmp) |
d5efd131 | 61 | libc_hidden_builtin_def (strncmp) |