/
adler32_simd.c
370 lines (307 loc) · 10.5 KB
/
adler32_simd.c
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
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
/* adler32_simd.c
*
* Copyright 2017 The Chromium Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the Chromium source repository LICENSE file.
*
* Per http://en.wikipedia.org/wiki/Adler-32 the adler32 A value (aka s1) is
* the sum of N input data bytes D1 ... DN,
*
* A = A0 + D1 + D2 + ... + DN
*
* where A0 is the initial value.
*
* SSE2 _mm_sad_epu8() can be used for byte sums (see http://bit.ly/2wpUOeD,
* for example) and accumulating the byte sums can use SSE shuffle-adds (see
* the "Integer" section of http://bit.ly/2erPT8t for details). Arm NEON has
* similar instructions.
*
* The adler32 B value (aka s2) sums the A values from each step:
*
* B0 + (A0 + D1) + (A0 + D1 + D2) + ... + (A0 + D1 + D2 + ... + DN) or
*
* B0 + N.A0 + N.D1 + (N-1).D2 + (N-2).D3 + ... + (N-(N-1)).DN
*
* B0 being the initial value. For 32 bytes (ideal for garden-variety SIMD):
*
* B = B0 + 32.A0 + [D1 D2 D3 ... D32] x [32 31 30 ... 1].
*
* Adjacent blocks of 32 input bytes can be iterated with the expressions to
* compute the adler32 s1 s2 of M >> 32 input bytes [1].
*
* As M grows, the s1 s2 sums grow. If left unchecked, they would eventually
* overflow the precision of their integer representation (bad). However, s1
* and s2 also need to be computed modulo the adler BASE value (reduced). If
* at most NMAX bytes are processed before a reduce, s1 s2 _cannot_ overflow
* a uint32_t type (the NMAX constraint) [2].
*
* [1] the iterative equations for s2 contain constant factors; these can be
* hoisted from the n-blocks do loop of the SIMD code.
*
* [2] zlib adler32_z() uses this fact to implement NMAX-block-based updates
* of the adler s1 s2 of uint32_t type (see adler32.c).
*/
#include "adler32_simd.h"
/* Definitions from adler32.c: largest prime smaller than 65536 */
#define BASE 65521U
/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
#define NMAX 5552
#if defined(ADLER32_SIMD_SSSE3)
#ifndef __GNUC__
#define __attribute__()
#endif
#include <tmmintrin.h>
__attribute__((target("ssse3")))
uint32_t ZLIB_INTERNAL adler32_simd_( /* SSSE3 */
uint32_t adler,
const unsigned char *buf,
z_size_t len)
{
/*
* Split Adler-32 into component sums.
*/
uint32_t s1 = adler & 0xffff;
uint32_t s2 = adler >> 16;
/*
* Process the data in blocks.
*/
const unsigned BLOCK_SIZE = 1 << 5;
z_size_t blocks = len / BLOCK_SIZE;
len -= blocks * BLOCK_SIZE;
while (blocks)
{
unsigned n = NMAX / BLOCK_SIZE; /* The NMAX constraint. */
if (n > blocks)
n = (unsigned) blocks;
blocks -= n;
const __m128i tap1 =
_mm_setr_epi8(32,31,30,29,28,27,26,25,24,23,22,21,20,19,18,17);
const __m128i tap2 =
_mm_setr_epi8(16,15,14,13,12,11,10, 9, 8, 7, 6, 5, 4, 3, 2, 1);
const __m128i zero =
_mm_setr_epi8( 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
const __m128i ones =
_mm_set_epi16( 1, 1, 1, 1, 1, 1, 1, 1);
/*
* Process n blocks of data. At most NMAX data bytes can be
* processed before s2 must be reduced modulo BASE.
*/
__m128i v_ps = _mm_set_epi32(0, 0, 0, s1 * n);
__m128i v_s2 = _mm_set_epi32(0, 0, 0, s2);
__m128i v_s1 = _mm_set_epi32(0, 0, 0, 0);
do {
/*
* Load 32 input bytes.
*/
const __m128i bytes1 = _mm_loadu_si128((__m128i*)(buf));
const __m128i bytes2 = _mm_loadu_si128((__m128i*)(buf + 16));
/*
* Add previous block byte sum to v_ps.
*/
v_ps = _mm_add_epi32(v_ps, v_s1);
/*
* Horizontally add the bytes for s1, multiply-adds the
* bytes by [ 32, 31, 30, ... ] for s2.
*/
v_s1 = _mm_add_epi32(v_s1, _mm_sad_epu8(bytes1, zero));
const __m128i mad1 = _mm_maddubs_epi16(bytes1, tap1);
v_s2 = _mm_add_epi32(v_s2, _mm_madd_epi16(mad1, ones));
v_s1 = _mm_add_epi32(v_s1, _mm_sad_epu8(bytes2, zero));
const __m128i mad2 = _mm_maddubs_epi16(bytes2, tap2);
v_s2 = _mm_add_epi32(v_s2, _mm_madd_epi16(mad2, ones));
buf += BLOCK_SIZE;
} while (--n);
v_s2 = _mm_add_epi32(v_s2, _mm_slli_epi32(v_ps, 5));
/*
* Sum epi32 ints v_s1(s2) and accumulate in s1(s2).
*/
#define S23O1 _MM_SHUFFLE(2,3,0,1) /* A B C D -> B A D C */
#define S1O32 _MM_SHUFFLE(1,0,3,2) /* A B C D -> C D A B */
v_s1 = _mm_add_epi32(v_s1, _mm_shuffle_epi32(v_s1, S23O1));
v_s1 = _mm_add_epi32(v_s1, _mm_shuffle_epi32(v_s1, S1O32));
s1 += _mm_cvtsi128_si32(v_s1);
v_s2 = _mm_add_epi32(v_s2, _mm_shuffle_epi32(v_s2, S23O1));
v_s2 = _mm_add_epi32(v_s2, _mm_shuffle_epi32(v_s2, S1O32));
s2 = _mm_cvtsi128_si32(v_s2);
#undef S23O1
#undef S1O32
/*
* Reduce.
*/
s1 %= BASE;
s2 %= BASE;
}
/*
* Handle leftover data.
*/
if (len) {
if (len >= 16) {
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
len -= 16;
}
while (len--) {
s2 += (s1 += *buf++);
}
if (s1 >= BASE)
s1 -= BASE;
s2 %= BASE;
}
/*
* Return the recombined sums.
*/
return s1 | (s2 << 16);
}
#elif defined(ADLER32_SIMD_NEON)
#include <arm_neon.h>
uint32_t ZLIB_INTERNAL adler32_simd_( /* NEON */
uint32_t adler,
const unsigned char *buf,
z_size_t len)
{
/*
* Split Adler-32 into component sums.
*/
uint32_t s1 = adler & 0xffff;
uint32_t s2 = adler >> 16;
/*
* Serially compute s1 & s2, until the data is 16-byte aligned.
*/
if ((uintptr_t)buf & 15) {
while ((uintptr_t)buf & 15) {
s2 += (s1 += *buf++);
--len;
}
if (s1 >= BASE)
s1 -= BASE;
s2 %= BASE;
}
/*
* Process the data in blocks.
*/
const unsigned BLOCK_SIZE = 1 << 5;
z_size_t blocks = len / BLOCK_SIZE;
len -= blocks * BLOCK_SIZE;
while (blocks)
{
unsigned n = NMAX / BLOCK_SIZE; /* The NMAX constraint. */
if (n > blocks)
n = (unsigned) blocks;
blocks -= n;
/*
* Process n blocks of data. At most NMAX data bytes can be
* processed before s2 must be reduced modulo BASE.
*/
uint32x4_t v_s2 = (uint32x4_t) { 0, 0, 0, s1 * n };
uint32x4_t v_s1 = (uint32x4_t) { 0, 0, 0, 0 };
uint16x8_t v_column_sum_1 = vdupq_n_u16(0);
uint16x8_t v_column_sum_2 = vdupq_n_u16(0);
uint16x8_t v_column_sum_3 = vdupq_n_u16(0);
uint16x8_t v_column_sum_4 = vdupq_n_u16(0);
do {
/*
* Load 32 input bytes.
*/
const uint8x16_t bytes1 = vld1q_u8((uint8_t*)(buf));
const uint8x16_t bytes2 = vld1q_u8((uint8_t*)(buf + 16));
/*
* Add previous block byte sum to v_s2.
*/
v_s2 = vaddq_u32(v_s2, v_s1);
/*
* Horizontally add the bytes for s1.
*/
v_s1 = vpadalq_u16(v_s1, vpadalq_u8(vpaddlq_u8(bytes1), bytes2));
/*
* Vertically add the bytes for s2.
*/
v_column_sum_1 = vaddw_u8(v_column_sum_1, vget_low_u8 (bytes1));
v_column_sum_2 = vaddw_u8(v_column_sum_2, vget_high_u8(bytes1));
v_column_sum_3 = vaddw_u8(v_column_sum_3, vget_low_u8 (bytes2));
v_column_sum_4 = vaddw_u8(v_column_sum_4, vget_high_u8(bytes2));
buf += BLOCK_SIZE;
} while (--n);
v_s2 = vshlq_n_u32(v_s2, 5);
/*
* Multiply-add bytes by [ 32, 31, 30, ... ] for s2.
*/
v_s2 = vmlal_u16(v_s2, vget_low_u16 (v_column_sum_1),
(uint16x4_t) { 32, 31, 30, 29 });
v_s2 = vmlal_u16(v_s2, vget_high_u16(v_column_sum_1),
(uint16x4_t) { 28, 27, 26, 25 });
v_s2 = vmlal_u16(v_s2, vget_low_u16 (v_column_sum_2),
(uint16x4_t) { 24, 23, 22, 21 });
v_s2 = vmlal_u16(v_s2, vget_high_u16(v_column_sum_2),
(uint16x4_t) { 20, 19, 18, 17 });
v_s2 = vmlal_u16(v_s2, vget_low_u16 (v_column_sum_3),
(uint16x4_t) { 16, 15, 14, 13 });
v_s2 = vmlal_u16(v_s2, vget_high_u16(v_column_sum_3),
(uint16x4_t) { 12, 11, 10, 9 });
v_s2 = vmlal_u16(v_s2, vget_low_u16 (v_column_sum_4),
(uint16x4_t) { 8, 7, 6, 5 });
v_s2 = vmlal_u16(v_s2, vget_high_u16(v_column_sum_4),
(uint16x4_t) { 4, 3, 2, 1 });
/*
* Sum epi32 ints v_s1(s2) and accumulate in s1(s2).
*/
uint32x2_t sum1 = vpadd_u32(vget_low_u32(v_s1), vget_high_u32(v_s1));
uint32x2_t sum2 = vpadd_u32(vget_low_u32(v_s2), vget_high_u32(v_s2));
uint32x2_t s1s2 = vpadd_u32(sum1, sum2);
s1 += vget_lane_u32(s1s2, 0);
s2 += vget_lane_u32(s1s2, 1);
/*
* Reduce.
*/
s1 %= BASE;
s2 %= BASE;
}
/*
* Handle leftover data.
*/
if (len) {
if (len >= 16) {
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
s2 += (s1 += *buf++);
len -= 16;
}
while (len--) {
s2 += (s1 += *buf++);
}
if (s1 >= BASE)
s1 -= BASE;
s2 %= BASE;
}
/*
* Return the recombined sums.
*/
return s1 | (s2 << 16);
}
#endif /* ADLER32_SIMD_SSSE3 */