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/* Copyright (C) 1995-2011, 2016 Mark Adler
* Copyright (C) 2017 ARM Holdings Inc.
* Authors:
* Adenilson Cavalcanti <adenilson.cavalcanti@arm.com>
* Adam Stylinski <kungfujesus06@gmail.com>
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#ifdef ARM_NEON
#include "neon_intrins.h"
#include "zbuild.h"
#include "adler32_p.h"
static void NEON_accum32(uint32_t *s, const uint8_t *buf, size_t len) {
static const uint16_t ALIGNED_(16) taps[64] = {
64, 63, 62, 61, 60, 59, 58, 57,
56, 55, 54, 53, 52, 51, 50, 49,
48, 47, 46, 45, 44, 43, 42, 41,
40, 39, 38, 37, 36, 35, 34, 33,
32, 31, 30, 29, 28, 27, 26, 25,
24, 23, 22, 21, 20, 19, 18, 17,
16, 15, 14, 13, 12, 11, 10, 9,
8, 7, 6, 5, 4, 3, 2, 1 };
uint32x4_t adacc = vdupq_n_u32(0);
uint32x4_t s2acc = vdupq_n_u32(0);
uint32x4_t s2acc_0 = vdupq_n_u32(0);
uint32x4_t s2acc_1 = vdupq_n_u32(0);
uint32x4_t s2acc_2 = vdupq_n_u32(0);
adacc = vsetq_lane_u32(s[0], adacc, 0);
s2acc = vsetq_lane_u32(s[1], s2acc, 0);
uint32x4_t s3acc = vdupq_n_u32(0);
uint32x4_t adacc_prev = adacc;
uint16x8_t s2_0, s2_1, s2_2, s2_3;
s2_0 = s2_1 = s2_2 = s2_3 = vdupq_n_u16(0);
uint16x8_t s2_4, s2_5, s2_6, s2_7;
s2_4 = s2_5 = s2_6 = s2_7 = vdupq_n_u16(0);
size_t num_iter = len >> 2;
int rem = len & 3;
for (size_t i = 0; i < num_iter; ++i) {
uint8x16x4_t d0_d3 = vld1q_u8_x4(buf);
/* Unfortunately it doesn't look like there's a direct sum 8 bit to 32
* bit instruction, we'll have to make due summing to 16 bits first */
uint16x8x2_t hsum, hsum_fold;
hsum.val[0] = vpaddlq_u8(d0_d3.val[0]);
hsum.val[1] = vpaddlq_u8(d0_d3.val[1]);
hsum_fold.val[0] = vpadalq_u8(hsum.val[0], d0_d3.val[2]);
hsum_fold.val[1] = vpadalq_u8(hsum.val[1], d0_d3.val[3]);
adacc = vpadalq_u16(adacc, hsum_fold.val[0]);
s3acc = vaddq_u32(s3acc, adacc_prev);
adacc = vpadalq_u16(adacc, hsum_fold.val[1]);
/* If we do straight widening additions to the 16 bit values, we don't incur
* the usual penalties of a pairwise add. We can defer the multiplications
* until the very end. These will not overflow because we are incurring at
* most 408 loop iterations (NMAX / 64), and a given lane is only going to be
* summed into once. This means for the maximum input size, the largest value
* we will see is 255 * 102 = 26010, safely under uint16 max */
s2_0 = vaddw_u8(s2_0, vget_low_u8(d0_d3.val[0]));
s2_1 = vaddw_high_u8(s2_1, d0_d3.val[0]);
s2_2 = vaddw_u8(s2_2, vget_low_u8(d0_d3.val[1]));
s2_3 = vaddw_high_u8(s2_3, d0_d3.val[1]);
s2_4 = vaddw_u8(s2_4, vget_low_u8(d0_d3.val[2]));
s2_5 = vaddw_high_u8(s2_5, d0_d3.val[2]);
s2_6 = vaddw_u8(s2_6, vget_low_u8(d0_d3.val[3]));
s2_7 = vaddw_high_u8(s2_7, d0_d3.val[3]);
adacc_prev = adacc;
buf += 64;
}
s3acc = vshlq_n_u32(s3acc, 6);
if (rem) {
uint32x4_t s3acc_0 = vdupq_n_u32(0);
while (rem--) {
uint8x16_t d0 = vld1q_u8(buf);
uint16x8_t adler;
adler = vpaddlq_u8(d0);
s2_6 = vaddw_u8(s2_6, vget_low_u8(d0));
s2_7 = vaddw_high_u8(s2_7, d0);
adacc = vpadalq_u16(adacc, adler);
s3acc_0 = vaddq_u32(s3acc_0, adacc_prev);
adacc_prev = adacc;
buf += 16;
}
s3acc_0 = vshlq_n_u32(s3acc_0, 4);
s3acc = vaddq_u32(s3acc_0, s3acc);
}
uint16x8x4_t t0_t3 = vld1q_u16_x4(taps);
uint16x8x4_t t4_t7 = vld1q_u16_x4(taps + 32);
s2acc = vmlal_high_u16(s2acc, t0_t3.val[0], s2_0);
s2acc_0 = vmlal_u16(s2acc_0, vget_low_u16(t0_t3.val[0]), vget_low_u16(s2_0));
s2acc_1 = vmlal_high_u16(s2acc_1, t0_t3.val[1], s2_1);
s2acc_2 = vmlal_u16(s2acc_2, vget_low_u16(t0_t3.val[1]), vget_low_u16(s2_1));
s2acc = vmlal_high_u16(s2acc, t0_t3.val[2], s2_2);
s2acc_0 = vmlal_u16(s2acc_0, vget_low_u16(t0_t3.val[2]), vget_low_u16(s2_2));
s2acc_1 = vmlal_high_u16(s2acc_1, t0_t3.val[3], s2_3);
s2acc_2 = vmlal_u16(s2acc_2, vget_low_u16(t0_t3.val[3]), vget_low_u16(s2_3));
s2acc = vmlal_high_u16(s2acc, t4_t7.val[0], s2_4);
s2acc_0 = vmlal_u16(s2acc_0, vget_low_u16(t4_t7.val[0]), vget_low_u16(s2_4));
s2acc_1 = vmlal_high_u16(s2acc_1, t4_t7.val[1], s2_5);
s2acc_2 = vmlal_u16(s2acc_2, vget_low_u16(t4_t7.val[1]), vget_low_u16(s2_5));
s2acc = vmlal_high_u16(s2acc, t4_t7.val[2], s2_6);
s2acc_0 = vmlal_u16(s2acc_0, vget_low_u16(t4_t7.val[2]), vget_low_u16(s2_6));
s2acc_1 = vmlal_high_u16(s2acc_1, t4_t7.val[3], s2_7);
s2acc_2 = vmlal_u16(s2acc_2, vget_low_u16(t4_t7.val[3]), vget_low_u16(s2_7));
s2acc = vaddq_u32(s2acc_0, s2acc);
s2acc_2 = vaddq_u32(s2acc_1, s2acc_2);
s2acc = vaddq_u32(s2acc, s2acc_2);
uint32x2_t adacc2, s2acc2, as;
s2acc = vaddq_u32(s2acc, s3acc);
adacc2 = vpadd_u32(vget_low_u32(adacc), vget_high_u32(adacc));
s2acc2 = vpadd_u32(vget_low_u32(s2acc), vget_high_u32(s2acc));
as = vpadd_u32(adacc2, s2acc2);
s[0] = vget_lane_u32(as, 0);
s[1] = vget_lane_u32(as, 1);
}
static void NEON_handle_tail(uint32_t *pair, const uint8_t *buf, size_t len) {
unsigned int i;
for (i = 0; i < len; ++i) {
pair[0] += buf[i];
pair[1] += pair[0];
}
}
Z_INTERNAL uint32_t adler32_neon(uint32_t adler, const uint8_t *buf, size_t len) {
/* split Adler-32 into component sums */
uint32_t sum2 = (adler >> 16) & 0xffff;
adler &= 0xffff;
/* in case user likes doing a byte at a time, keep it fast */
if (len == 1)
return adler32_len_1(adler, buf, sum2);
/* initial Adler-32 value (deferred check for len == 1 speed) */
if (buf == NULL)
return 1L;
/* in case short lengths are provided, keep it somewhat fast */
if (len < 16)
return adler32_len_16(adler, buf, len, sum2);
uint32_t pair[2];
int n = NMAX;
unsigned int done = 0;
/* Split Adler-32 into component sums, it can be supplied by
* the caller sites (e.g. in a PNG file).
*/
pair[0] = adler;
pair[1] = sum2;
/* If memory is not SIMD aligned, do scalar sums to an aligned
* offset, provided that doing so doesn't completely eliminate
* SIMD operation. Aligned loads are still faster on ARM, even
* though there's no explicit aligned load instruction */
unsigned int align_offset = ((uintptr_t)buf & 15);
unsigned int align_adj = (align_offset) ? 16 - align_offset : 0;
if (align_offset && len >= (16 + align_adj)) {
NEON_handle_tail(pair, buf, align_adj);
n -= align_adj;
done += align_adj;
} else {
/* If here, we failed the len criteria test, it wouldn't be
* worthwhile to do scalar aligning sums */
align_adj = 0;
}
while (done < len) {
int remaining = (int)(len - done);
n = MIN(remaining, (done == align_adj) ? n : NMAX);
if (n < 16)
break;
NEON_accum32(pair, buf + done, n >> 4);
pair[0] %= BASE;
pair[1] %= BASE;
int actual_nsums = (n >> 4) << 4;
done += actual_nsums;
}
/* Handle the tail elements. */
if (done < len) {
NEON_handle_tail(pair, (buf + done), len - done);
pair[0] %= BASE;
pair[1] %= BASE;
}
/* D = B * 65536 + A, see: https://en.wikipedia.org/wiki/Adler-32. */
return (pair[1] << 16) | pair[0];
}
#endif
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