-
Notifications
You must be signed in to change notification settings - Fork 29
/
Copy pathsse4-strstr-unrolled.cpp
337 lines (228 loc) · 9.84 KB
/
sse4-strstr-unrolled.cpp
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
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
// Note: it appears that these specialized functions do not help.
// But I decided to left them, just in case.
// use functions/templates dealing with certain substring length
//#define ENABLE_SSE4_LENGTH_SPECIALIZATIONS
// When defined use sse4_strstr_unrolled_memcmp template,
// otherwise use just sse4_strstr_unrolled_max20 and sse4_strstr_unrolled_max36
//#define ENABLE_SSE4_MEMCMP_TEMPLATES
size_t sse4_strstr_unrolled_anysize(const char* s, size_t n, const char* needle, size_t needle_size) {
assert(needle_size > 4);
assert(n > 0);
const __m128i prefix = _mm_loadu_si128(reinterpret_cast<const __m128i*>(needle));
const __m128i zeros = _mm_setzero_si128();
__m128i prev = _mm_loadu_si128(reinterpret_cast<const __m128i*>(s));
__m128i curr;
for (size_t i = 0; i < n; i += 16) {
curr = _mm_loadu_si128(reinterpret_cast<const __m128i*>(s + i + 16));
const __m128i data0 = prev;
const __m128i data1 = _mm_alignr_epi8(curr, prev, 8);
const __m128i result0 = _mm_mpsadbw_epu8(data0, prefix, 0);
const __m128i result1 = _mm_mpsadbw_epu8(data1, prefix, 0);
prev = curr;
const __m128i result = _mm_packus_epi16(result0, result1);
const __m128i cmp = _mm_cmpeq_epi8(result, zeros);
unsigned mask = _mm_movemask_epi8(cmp);
while (mask != 0) {
const auto bitpos = bits::get_first_bit_set(mask);
if (memcmp(s + i + bitpos + 4, needle + 4, needle_size - 4) == 0) {
return i + bitpos;
}
mask = bits::clear_leftmost_set(mask);
}
}
return std::string::npos;
}
// ------------------------------------------------------------------------
template <size_t k, typename MEMCMP>
size_t sse4_strstr_unrolled_memcmp(const char* s, size_t n, const char* needle, MEMCMP memcmp_fun) {
assert(k > 4);
assert(n > 0);
const __m128i prefix = _mm_loadu_si128(reinterpret_cast<const __m128i*>(needle));
const __m128i zeros = _mm_setzero_si128();
__m128i prev = _mm_loadu_si128(reinterpret_cast<const __m128i*>(s));
__m128i curr;
for (size_t i = 0; i < n; i += 16) {
curr = _mm_loadu_si128(reinterpret_cast<const __m128i*>(s + i + 16));
const __m128i data0 = prev;
const __m128i data1 = _mm_alignr_epi8(curr, prev, 8);
const __m128i result0 = _mm_mpsadbw_epu8(data0, prefix, 0);
const __m128i result1 = _mm_mpsadbw_epu8(data1, prefix, 0);
prev = curr;
const __m128i result = _mm_packus_epi16(result0, result1);
const __m128i cmp = _mm_cmpeq_epi8(result, zeros);
unsigned mask = _mm_movemask_epi8(cmp);
while (mask != 0) {
const auto bitpos = bits::get_first_bit_set(mask);
if (memcmp_fun(s + i + bitpos + 4, needle + 4)) {
return i + bitpos;
}
mask = bits::clear_leftmost_set(mask);
}
}
return std::string::npos;
}
// ------------------------------------------------------------------------
size_t sse4_strstr_unrolled_max20(const char* s, size_t n, const char* needle, size_t needle_size) {
const __m128i zeros = _mm_setzero_si128();
const __m128i prefix = sse::load(needle);
const __m128i suffix = sse::load(needle + 4);
const __m128i suff_mask = sse::mask_lower_bytes(needle_size - 4);
for (size_t i = 0; i < n; i += 8) {
const __m128i data = sse::load(s + i);
const __m128i result = _mm_mpsadbw_epu8(data, prefix, 0);
const __m128i cmp = _mm_cmpeq_epi16(result, zeros);
unsigned mask = _mm_movemask_epi8(cmp) & 0x5555;
while (mask != 0) {
const auto bitpos = bits::get_first_bit_set(mask)/2;
const __m128i str = sse::load(s + i + bitpos + 4);
const __m128i cmp = _mm_cmpeq_epi8(str, suffix);
if (_mm_testc_si128(cmp, suff_mask)) {
return i + bitpos;
}
mask = bits::clear_leftmost_set(mask);
}
}
return std::string::npos;
}
// ------------------------------------------------------------------------
size_t sse4_strstr_unrolled_max36(const char* s, size_t n, const char* needle, size_t needle_size) {
const __m128i zeros = _mm_setzero_si128();
const __m128i prefix = sse::load(needle);
const __m128i suffix1 = sse::load(needle + 4);
const __m128i suffix2 = sse::load(needle + 16 + 4);
const __m128i suff_mask = sse::mask_higher_bytes(needle_size - (16 + 4));
for (size_t i = 0; i < n; i += 8) {
const __m128i data = sse::load(s + i);
const __m128i result = _mm_mpsadbw_epu8(data, prefix, 0);
const __m128i cmp = _mm_cmpeq_epi16(result, zeros);
unsigned mask = _mm_movemask_epi8(cmp) & 0x5555;
while (mask != 0) {
const auto bitpos = bits::get_first_bit_set(mask)/2;
const __m128i c1 = _mm_cmpeq_epi8(sse::load(s + i + bitpos + 4), suffix1);
const __m128i c2 = _mm_cmpeq_epi8(sse::load(s + i + bitpos + 16 + 4), suffix2);
const __m128i c3 = _mm_or_si128(c2, suff_mask);
const __m128i tmp = _mm_and_si128(c1, c3);
if (_mm_movemask_epi8(tmp) == 0xffff) {
return i + bitpos;
}
mask = bits::clear_leftmost_set(mask);
}
}
return std::string::npos;
}
// ------------------------------------------------------------------------
size_t sse4_strstr_unrolled_len3(const char* s, size_t n, const char* needle) {
const __m128i prefix = _mm_loadu_si128(reinterpret_cast<const __m128i*>(needle));
const __m128i zeros = _mm_setzero_si128();
for (size_t i = 0; i < n; i += 8) {
const __m128i data = _mm_loadu_si128(reinterpret_cast<const __m128i*>(s + i));
const __m128i lastbyte = _mm_cvtepu8_epi16(_mm_srli_si128(data, 3));
const __m128i result = _mm_mpsadbw_epu8(data, prefix, 0);
const __m128i cmp = _mm_cmpeq_epi16(_mm_sub_epi16(result, lastbyte), zeros);
unsigned mask = _mm_movemask_epi8(cmp) & 0x5555;
if (mask != 0) {
return i + bits::get_first_bit_set(mask)/2;
}
}
return std::string::npos;
}
// ------------------------------------------------------------------------
size_t sse4_strstr_unrolled_len4(const char* s, size_t n, const char* needle) {
const __m128i prefix = _mm_loadu_si128(reinterpret_cast<const __m128i*>(needle));
const __m128i zeros = _mm_setzero_si128();
for (size_t i = 0; i < n; i += 8) {
const __m128i data = _mm_loadu_si128(reinterpret_cast<const __m128i*>(s + i));
const __m128i result = _mm_mpsadbw_epu8(data, prefix, 0);
const __m128i cmp = _mm_cmpeq_epi16(result, zeros);
unsigned mask = _mm_movemask_epi8(cmp);
if (mask != 0) {
return i + bits::get_first_bit_set(mask)/2;
}
}
return std::string::npos;
}
// ------------------------------------------------------------------------
size_t sse4_strstr_unrolled(const char* s, size_t n, const char* needle, size_t needle_size) {
size_t result = std::string::npos;
if (n < needle_size) {
return result;
}
switch (needle_size) {
case 0:
return 0;
case 1: {
const char* res = reinterpret_cast<const char*>(strchr(s, needle[0]));
return (res != nullptr) ? res - s : std::string::npos;
}
case 2: {
const char* res = reinterpret_cast<const char*>(strstr(s, needle));
return (res != nullptr) ? res - s : std::string::npos;
}
case 3:
result = sse4_strstr_unrolled_len3(s, n, needle);
break;
case 4:
result = sse4_strstr_unrolled_len4(s, n, needle);
break;
#ifdef ENABLE_SSE4_LENGTH_SPECIALIZATIONS
#ifdef ENABLE_SSE4_MEMCMP_TEMPLATES
case 5:
result = sse4_strstr_unrolled_memcmp<5>(s, n, needle, memcmp1);
break;
case 6:
result = sse4_strstr_unrolled_memcmp<6>(s, n, needle, memcmp2);
break;
case 7:
result = sse4_strstr_unrolled_memcmp<7>(s, n, needle, memcmp3);
break;
case 8:
result = sse4_strstr_unrolled_memcmp<8>(s, n, needle, memcmp4);
break;
case 9:
result = sse4_strstr_unrolled_memcmp<9>(s, n, needle, memcmp5);
break;
case 10:
result = sse4_strstr_unrolled_memcmp<10>(s, n, needle, memcmp6);
break;
case 11:
result = sse4_strstr_unrolled_memcmp<11>(s, n, needle, memcmp7);
break;
case 12:
result = sse4_strstr_unrolled_memcmp<12>(s, n, needle, memcmp8);
break;
case 13:
result = sse4_strstr_unrolled_memcmp<13>(s, n, needle, memcmp9);
break;
case 14:
result = sse4_strstr_unrolled_memcmp<14>(s, n, needle, memcmp10);
break;
#else
case 5: case 6: case 7: case 8:
case 9: case 10: case 11: case 12:
case 13: case 14: /* 5 .. 14 */
#endif // ENABLE_SSE4_MEMCMP_TEMPLATES
case 15: case 16: case 17: case 18: case 19:
case 20: /* 15..20 */
result = sse4_strstr_unrolled_max20(s, n, needle, needle_size);
break;
case 21: case 22: case 23: case 24: case 25:
case 26: case 27: case 28: case 29: case 30:
case 31: case 32: case 33: case 34: case 35:
case 36: /* 21..36 */
result = sse4_strstr_unrolled_max36(s, n, needle, needle_size);
break;
#endif // ENABLE_SSE4_LENGTH_SPECIALIZATIONS
default:
result = sse4_strstr_unrolled_anysize(s, n, needle, needle_size);
break;
}
if (result <= n - needle_size) {
return result;
} else {
return std::string::npos;
}
}
// --------------------------------------------------
size_t sse4_strstr_unrolled(const std::string& s, const std::string& needle) {
return sse4_strstr_unrolled(s.data(), s.size(), needle.data(), needle.size());
}