7f3194932d
This is the Fletcher4 algorithm implemented in pure C, but using multiple counters using algorithms identical to those used for SSE/NEON and AVX2. This allows for faster execution on core with strong superscalar capabilities but weak SIMD capabilities. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Romain Dolbeau <romain.dolbeau@atos.net> Closes #5317
229 lines
6.8 KiB
C
229 lines
6.8 KiB
C
/*
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* Implement fast Fletcher4 using superscalar pipelines.
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*
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* Use regular C code to compute
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* Fletcher4 in four incremental 64-bit parallel accumulator streams,
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* and then combine the streams to form the final four checksum words.
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* This implementation is a derivative of the AVX SIMD implementation by
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* James Guilford and Jinshan Xiong from Intel (see zfs_fletcher_intel.c).
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*
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* Copyright (C) 2016 Romain Dolbeau.
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*
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* Authors:
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* Romain Dolbeau <romain.dolbeau@atos.net>
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*
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* This software is available to you under a choice of one of two
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* licenses. You may choose to be licensed under the terms of the GNU
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* General Public License (GPL) Version 2, available from the file
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* COPYING in the main directory of this source tree, or the
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* OpenIB.org BSD license below:
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* - Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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*
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* - Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include <sys/byteorder.h>
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#include <sys/spa_checksum.h>
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#include <zfs_fletcher.h>
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#include <strings.h>
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static void
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fletcher_4_superscalar4_init(fletcher_4_ctx_t *ctx)
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{
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bzero(ctx->superscalar, 4 * sizeof (zfs_fletcher_superscalar_t));
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}
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static void
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fletcher_4_superscalar4_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp)
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{
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uint64_t A, B, C, D;
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A = ctx->superscalar[0].v[0] + ctx->superscalar[0].v[1] +
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ctx->superscalar[0].v[2] + ctx->superscalar[0].v[3];
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B = 0 - ctx->superscalar[0].v[1] - 2 * ctx->superscalar[0].v[2] -
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3 * ctx->superscalar[0].v[3] + 4 * ctx->superscalar[1].v[0] +
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4 * ctx->superscalar[1].v[1] + 4 * ctx->superscalar[1].v[2] +
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4 * ctx->superscalar[1].v[3];
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C = ctx->superscalar[0].v[2] + 3 * ctx->superscalar[0].v[3] -
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6 * ctx->superscalar[1].v[0] - 10 * ctx->superscalar[1].v[1] -
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14 * ctx->superscalar[1].v[2] - 18 * ctx->superscalar[1].v[3] +
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16 * ctx->superscalar[2].v[0] + 16 * ctx->superscalar[2].v[1] +
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16 * ctx->superscalar[2].v[2] + 16 * ctx->superscalar[2].v[3];
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D = 0 - ctx->superscalar[0].v[3] + 4 * ctx->superscalar[1].v[0] +
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10 * ctx->superscalar[1].v[1] + 20 * ctx->superscalar[1].v[2] +
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34 * ctx->superscalar[1].v[3] - 48 * ctx->superscalar[2].v[0] -
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64 * ctx->superscalar[2].v[1] - 80 * ctx->superscalar[2].v[2] -
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96 * ctx->superscalar[2].v[3] + 64 * ctx->superscalar[3].v[0] +
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64 * ctx->superscalar[3].v[1] + 64 * ctx->superscalar[3].v[2] +
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64 * ctx->superscalar[3].v[3];
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ZIO_SET_CHECKSUM(zcp, A, B, C, D);
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}
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static void
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fletcher_4_superscalar4_native(fletcher_4_ctx_t *ctx,
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const void *buf, uint64_t size)
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{
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const uint32_t *ip = buf;
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const uint32_t *ipend = ip + (size / sizeof (uint32_t));
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uint64_t a, b, c, d;
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uint64_t a2, b2, c2, d2;
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uint64_t a3, b3, c3, d3;
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uint64_t a4, b4, c4, d4;
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a = ctx->superscalar[0].v[0];
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b = ctx->superscalar[1].v[0];
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c = ctx->superscalar[2].v[0];
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d = ctx->superscalar[3].v[0];
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a2 = ctx->superscalar[0].v[1];
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b2 = ctx->superscalar[1].v[1];
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c2 = ctx->superscalar[2].v[1];
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d2 = ctx->superscalar[3].v[1];
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a3 = ctx->superscalar[0].v[2];
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b3 = ctx->superscalar[1].v[2];
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c3 = ctx->superscalar[2].v[2];
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d3 = ctx->superscalar[3].v[2];
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a4 = ctx->superscalar[0].v[3];
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b4 = ctx->superscalar[1].v[3];
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c4 = ctx->superscalar[2].v[3];
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d4 = ctx->superscalar[3].v[3];
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for (; ip < ipend; ip += 4) {
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a += ip[0];
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a2 += ip[1];
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a3 += ip[2];
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a4 += ip[3];
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b += a;
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b2 += a2;
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b3 += a3;
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b4 += a4;
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c += b;
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c2 += b2;
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c3 += b3;
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c4 += b4;
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d += c;
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d2 += c2;
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d3 += c3;
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d4 += c4;
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}
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ctx->superscalar[0].v[0] = a;
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ctx->superscalar[1].v[0] = b;
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ctx->superscalar[2].v[0] = c;
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ctx->superscalar[3].v[0] = d;
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ctx->superscalar[0].v[1] = a2;
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ctx->superscalar[1].v[1] = b2;
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ctx->superscalar[2].v[1] = c2;
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ctx->superscalar[3].v[1] = d2;
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ctx->superscalar[0].v[2] = a3;
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ctx->superscalar[1].v[2] = b3;
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ctx->superscalar[2].v[2] = c3;
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ctx->superscalar[3].v[2] = d3;
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ctx->superscalar[0].v[3] = a4;
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ctx->superscalar[1].v[3] = b4;
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ctx->superscalar[2].v[3] = c4;
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ctx->superscalar[3].v[3] = d4;
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}
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static void
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fletcher_4_superscalar4_byteswap(fletcher_4_ctx_t *ctx,
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const void *buf, uint64_t size)
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{
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const uint32_t *ip = buf;
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const uint32_t *ipend = ip + (size / sizeof (uint32_t));
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uint64_t a, b, c, d;
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uint64_t a2, b2, c2, d2;
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uint64_t a3, b3, c3, d3;
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uint64_t a4, b4, c4, d4;
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a = ctx->superscalar[0].v[0];
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b = ctx->superscalar[1].v[0];
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c = ctx->superscalar[2].v[0];
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d = ctx->superscalar[3].v[0];
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a2 = ctx->superscalar[0].v[1];
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b2 = ctx->superscalar[1].v[1];
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c2 = ctx->superscalar[2].v[1];
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d2 = ctx->superscalar[3].v[1];
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a3 = ctx->superscalar[0].v[2];
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b3 = ctx->superscalar[1].v[2];
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c3 = ctx->superscalar[2].v[2];
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d3 = ctx->superscalar[3].v[2];
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a4 = ctx->superscalar[0].v[3];
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b4 = ctx->superscalar[1].v[3];
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c4 = ctx->superscalar[2].v[3];
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d4 = ctx->superscalar[3].v[3];
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for (; ip < ipend; ip += 4) {
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a += BSWAP_32(ip[0]);
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a2 += BSWAP_32(ip[1]);
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a3 += BSWAP_32(ip[2]);
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a4 += BSWAP_32(ip[3]);
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b += a;
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b2 += a2;
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b3 += a3;
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b4 += a4;
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c += b;
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c2 += b2;
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c3 += b3;
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c4 += b4;
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d += c;
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d2 += c2;
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d3 += c3;
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d4 += c4;
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}
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ctx->superscalar[0].v[0] = a;
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ctx->superscalar[1].v[0] = b;
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ctx->superscalar[2].v[0] = c;
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ctx->superscalar[3].v[0] = d;
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ctx->superscalar[0].v[1] = a2;
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ctx->superscalar[1].v[1] = b2;
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ctx->superscalar[2].v[1] = c2;
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ctx->superscalar[3].v[1] = d2;
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ctx->superscalar[0].v[2] = a3;
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ctx->superscalar[1].v[2] = b3;
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ctx->superscalar[2].v[2] = c3;
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ctx->superscalar[3].v[2] = d3;
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ctx->superscalar[0].v[3] = a4;
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ctx->superscalar[1].v[3] = b4;
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ctx->superscalar[2].v[3] = c4;
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ctx->superscalar[3].v[3] = d4;
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}
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static boolean_t fletcher_4_superscalar4_valid(void)
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{
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return (B_TRUE);
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}
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const fletcher_4_ops_t fletcher_4_superscalar4_ops = {
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.init_native = fletcher_4_superscalar4_init,
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.compute_native = fletcher_4_superscalar4_native,
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.fini_native = fletcher_4_superscalar4_fini,
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.init_byteswap = fletcher_4_superscalar4_init,
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.compute_byteswap = fletcher_4_superscalar4_byteswap,
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.fini_byteswap = fletcher_4_superscalar4_fini,
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.valid = fletcher_4_superscalar4_valid,
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.name = "superscalar4"
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};
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