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06e51c8f | 1 | /* strspn with SSE4.2 intrinsics |
688903eb | 2 | Copyright (C) 2009-2018 Free Software Foundation, Inc. |
06e51c8f L |
3 | Contributed by Intel Corporation. |
4 | This file is part of the GNU C Library. | |
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 | |
59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
06e51c8f L |
19 | |
20 | #include <nmmintrin.h> | |
21 | #include <string.h> | |
73f27d5e | 22 | #include "varshift.h" |
06e51c8f L |
23 | |
24 | /* We use 0x12: | |
25 | _SIDD_SBYTE_OPS | |
26 | | _SIDD_CMP_EQUAL_ANY | |
27 | | _SIDD_NEGATIVE_POLARITY | |
28 | | _SIDD_LEAST_SIGNIFICANT | |
29 | on pcmpistri to compare xmm/mem128 | |
30 | ||
31 | 0 1 2 3 4 5 6 7 8 9 A B C D E F | |
32 | X X X X X X X X X X X X X X X X | |
33 | ||
34 | against xmm | |
35 | ||
36 | 0 1 2 3 4 5 6 7 8 9 A B C D E F | |
37 | A A A A A A A A A A A A A A A A | |
38 | ||
39 | to find out if the first 16byte data element has any non-A byte and | |
40 | the offset of the first byte. There are 2 cases: | |
41 | ||
42 | 1. The first 16byte data element has the non-A byte, including | |
43 | EOS, at the offset X. | |
44 | 2. The first 16byte data element is valid and doesn't have the non-A | |
45 | byte. | |
46 | ||
47 | Here is the table of ECX, CFlag, ZFlag and SFlag for 2 cases: | |
48 | ||
49 | case ECX CFlag ZFlag SFlag | |
50 | 1 X 1 0/1 0 | |
51 | 2 16 0 0 0 | |
52 | ||
53 | We exit from the loop for case 1. */ | |
54 | ||
7550717e | 55 | extern size_t __strspn_sse2 (const char *, const char *) attribute_hidden; |
06e51c8f | 56 | |
cea43295 | 57 | |
06e51c8f L |
58 | size_t |
59 | __attribute__ ((section (".text.sse4.2"))) | |
60 | __strspn_sse42 (const char *s, const char *a) | |
61 | { | |
06e51c8f L |
62 | if (*a == 0) |
63 | return 0; | |
64 | ||
cea43295 UD |
65 | const char *aligned; |
66 | __m128i mask; | |
67 | int offset = (int) ((size_t) a & 15); | |
06e51c8f L |
68 | if (offset != 0) |
69 | { | |
70 | /* Load masks. */ | |
02cea471 | 71 | aligned = (const char *) ((size_t) a & -16L); |
cea43295 | 72 | __m128i mask0 = _mm_load_si128 ((__m128i *) aligned); |
06e51c8f | 73 | |
73f27d5e | 74 | mask = __m128i_shift_right (mask0, offset); |
06e51c8f L |
75 | |
76 | /* Find where the NULL terminator is. */ | |
cea43295 | 77 | int length = _mm_cmpistri (mask, mask, 0x3a); |
06e51c8f L |
78 | if (length == 16 - offset) |
79 | { | |
80 | /* There is no NULL terminator. */ | |
cea43295 UD |
81 | __m128i mask1 = _mm_load_si128 ((__m128i *) (aligned + 16)); |
82 | int index = _mm_cmpistri (mask1, mask1, 0x3a); | |
06e51c8f L |
83 | length += index; |
84 | ||
85 | /* Don't use SSE4.2 if the length of A > 16. */ | |
86 | if (length > 16) | |
87 | return __strspn_sse2 (s, a); | |
88 | ||
89 | if (index != 0) | |
90 | { | |
73f27d5e RH |
91 | /* Combine mask0 and mask1. We could play games with |
92 | palignr, but frankly this data should be in L1 now | |
93 | so do the merge via an unaligned load. */ | |
94 | mask = _mm_loadu_si128 ((__m128i *) a); | |
06e51c8f L |
95 | } |
96 | } | |
97 | } | |
98 | else | |
99 | { | |
100 | /* A is aligned. */ | |
101 | mask = _mm_load_si128 ((__m128i *) a); | |
102 | ||
103 | /* Find where the NULL terminator is. */ | |
cea43295 | 104 | int length = _mm_cmpistri (mask, mask, 0x3a); |
06e51c8f L |
105 | if (length == 16) |
106 | { | |
107 | /* There is no NULL terminator. Don't use SSE4.2 if the length | |
108 | of A > 16. */ | |
109 | if (a[16] != 0) | |
110 | return __strspn_sse2 (s, a); | |
111 | } | |
112 | } | |
113 | ||
114 | offset = (int) ((size_t) s & 15); | |
115 | if (offset != 0) | |
116 | { | |
117 | /* Check partial string. */ | |
02cea471 | 118 | aligned = (const char *) ((size_t) s & -16L); |
cea43295 | 119 | __m128i value = _mm_load_si128 ((__m128i *) aligned); |
06e51c8f | 120 | |
73f27d5e | 121 | value = __m128i_shift_right (value, offset); |
06e51c8f | 122 | |
cea43295 | 123 | int length = _mm_cmpistri (mask, value, 0x12); |
06e51c8f L |
124 | /* No need to check CFlag since it is always 1. */ |
125 | if (length < 16 - offset) | |
126 | return length; | |
127 | /* Find where the NULL terminator is. */ | |
cea43295 | 128 | int index = _mm_cmpistri (value, value, 0x3a); |
06e51c8f L |
129 | if (index < 16 - offset) |
130 | return length; | |
131 | aligned += 16; | |
132 | } | |
133 | else | |
134 | aligned = s; | |
135 | ||
cea43295 UD |
136 | while (1) |
137 | { | |
138 | __m128i value = _mm_load_si128 ((__m128i *) aligned); | |
139 | int index = _mm_cmpistri (mask, value, 0x12); | |
140 | int cflag = _mm_cmpistrc (mask, value, 0x12); | |
141 | if (cflag) | |
142 | return (size_t) (aligned + index - s); | |
143 | aligned += 16; | |
144 | } | |
06e51c8f | 145 | } |