/* adler32_vmx.c -- compute the Adler-32 checksum of a data stream * Copyright (C) 1995-2011 Mark Adler * Copyright (C) 2017-2023 Mika T. Lindqvist * Copyright (C) 2021 Adam Stylinski * For conditions of distribution and use, see copyright notice in zlib.h */ #ifdef PPC_VMX #include #include "zbuild.h" #include "zendian.h" #include "adler32_p.h" #define vmx_zero() (vec_splat_u32(0)) static inline void vmx_handle_head_or_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]; } } static void vmx_accum32(uint32_t *s, const uint8_t *buf, size_t len) { /* Different taps for the separable components of sums */ const vector unsigned char t0 = {64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49}; const vector unsigned char t1 = {48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33}; const vector unsigned char t2 = {32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17}; const vector unsigned char t3 = {16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1}; /* As silly and inefficient as it seems, creating 1 permutation vector to permute * a 2 element vector from a single load + a subsequent shift is just barely faster * than doing 2 indexed insertions into zero initialized vectors from unaligned memory. */ const vector unsigned char s0_perm = {0, 1, 2, 3, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8}; const vector unsigned char shift_vec = vec_sl(vec_splat_u8(8), vec_splat_u8(2)); vector unsigned int adacc, s2acc; vector unsigned int pair_vec = vec_ld(0, s); adacc = vec_perm(pair_vec, pair_vec, s0_perm); #if BYTE_ORDER == LITTLE_ENDIAN s2acc = vec_sro(pair_vec, shift_vec); #else s2acc = vec_slo(pair_vec, shift_vec); #endif vector unsigned int zero = vmx_zero(); vector unsigned int s3acc = zero; vector unsigned int s3acc_0 = zero; vector unsigned int adacc_prev = adacc; vector unsigned int adacc_prev_0 = zero; vector unsigned int s2acc_0 = zero; vector unsigned int s2acc_1 = zero; vector unsigned int s2acc_2 = zero; /* Maintain a running sum of a second half, this might help use break yet another * data dependency bubble in the sum */ vector unsigned int adacc_0 = zero; int num_iter = len / 4; int rem = len & 3; for (int i = 0; i < num_iter; ++i) { vector unsigned char d0 = vec_ld(0, buf); vector unsigned char d1 = vec_ld(16, buf); vector unsigned char d2 = vec_ld(32, buf); vector unsigned char d3 = vec_ld(48, buf); /* The core operation of the loop, basically * what is being unrolled below */ adacc = vec_sum4s(d0, adacc); s3acc = vec_add(s3acc, adacc_prev); s3acc_0 = vec_add(s3acc_0, adacc_prev_0); s2acc = vec_msum(t0, d0, s2acc); /* interleave dependent sums in here */ adacc_0 = vec_sum4s(d1, adacc_0); s2acc_0 = vec_msum(t1, d1, s2acc_0); adacc = vec_sum4s(d2, adacc); s2acc_1 = vec_msum(t2, d2, s2acc_1); s2acc_2 = vec_msum(t3, d3, s2acc_2); adacc_0 = vec_sum4s(d3, adacc_0); adacc_prev = adacc; adacc_prev_0 = adacc_0; buf += 64; } adacc = vec_add(adacc, adacc_0); s3acc = vec_add(s3acc, s3acc_0); s3acc = vec_sl(s3acc, vec_splat_u32(6)); if (rem) { adacc_prev = vec_add(adacc_prev_0, adacc_prev); adacc_prev = vec_sl(adacc_prev, vec_splat_u32(4)); while (rem--) { vector unsigned char d0 = vec_ld(0, buf); adacc = vec_sum4s(d0, adacc); s3acc = vec_add(s3acc, adacc_prev); s2acc = vec_msum(t3, d0, s2acc); adacc_prev = vec_sl(adacc, vec_splat_u32(4)); buf += 16; } } /* Sum up independent second sums */ s2acc = vec_add(s2acc, s2acc_0); s2acc_2 = vec_add(s2acc_1, s2acc_2); s2acc = vec_add(s2acc, s2acc_2); s2acc = vec_add(s2acc, s3acc); adacc = vec_add(adacc, vec_sld(adacc, adacc, 8)); s2acc = vec_add(s2acc, vec_sld(s2acc, s2acc, 8)); adacc = vec_add(adacc, vec_sld(adacc, adacc, 4)); s2acc = vec_add(s2acc, vec_sld(s2acc, s2acc, 4)); vec_ste(adacc, 0, s); vec_ste(s2acc, 0, s+1); } Z_INTERNAL uint32_t adler32_vmx(uint32_t adler, const uint8_t *buf, size_t len) { uint32_t sum2; uint32_t pair[16] ALIGNED_(16); memset(&pair[2], 0, 14); int n = NMAX; unsigned int done = 0, i; /* Split Adler-32 into component sums, it can be supplied by * the caller sites (e.g. in a PNG file). */ sum2 = (adler >> 16) & 0xffff; adler &= 0xffff; pair[0] = adler; pair[1] = sum2; /* in case user likes doing a byte at a time, keep it fast */ if (UNLIKELY(len == 1)) return adler32_len_1(adler, buf, sum2); /* initial Adler-32 value (deferred check for len == 1 speed) */ if (UNLIKELY(buf == NULL)) return 1L; /* in case short lengths are provided, keep it somewhat fast */ if (UNLIKELY(len < 16)) return adler32_len_16(adler, buf, len, sum2); // Align buffer unsigned int al = 0; if ((uintptr_t)buf & 0xf) { al = 16-((uintptr_t)buf & 0xf); if (al > len) { al=len; } vmx_handle_head_or_tail(pair, buf, al); done += al; /* Rather than rebasing, we can reduce the max sums for the * first round only */ n -= al; } for (i = al; i < len; i += n) { int remaining = (int)(len-i); n = MIN(remaining, (i == al) ? n : NMAX); if (n < 16) break; vmx_accum32(pair, buf + i, n / 16); pair[0] %= BASE; pair[1] %= BASE; done += (n / 16) * 16; } /* Handle the tail elements. */ if (done < len) { vmx_handle_head_or_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