sam-t2/sam/cpus/vonk/bl/lib/ecc/src/BL_Hsiao_30_7_Synd.cc

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// OpenSPARC T2 Processor File: BL_Hsiao_30_7_Synd.cc
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**  Copyright (C) 2006, Sun Microsystems, Inc.
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#include <stdlib.h>
#include "BL_Types.h"
#include "BL_Hsiao_30_7_Synd.h"


BL_EccBits BL_Hsiao_30_7_Synd::Patterns::syndromes[30];

BL_Hsiao_30_7_Synd::Patterns BL_Hsiao_30_7_Synd::hsiao_30_7_patterns;

BL_Hsiao_30_7_Synd::Patterns::Patterns()
{
  // These syndromes are defined in PRM 1.3 Section 16.14.2
  // Note they are written in base 2 so we use strtoul() to convert them.
  syndromes[0]     = strtoul("1110000", NULL, 2);
  syndromes[1]     = strtoul("0001110", NULL, 2);
  syndromes[2]     = strtoul("1100001", NULL, 2);
  syndromes[3]     = strtoul("0011010", NULL, 2);
  syndromes[4]     = strtoul("1000101", NULL, 2);
  syndromes[5]     = strtoul("0110010", NULL, 2);
  syndromes[6]     = strtoul("0001101", NULL, 2);
  syndromes[7]     = strtoul("1101000", NULL, 2);
  syndromes[8]     = strtoul("0000111", NULL, 2);
  syndromes[9]     = strtoul("1010010", NULL, 2);
  syndromes[10]    = strtoul("0101001", NULL, 2);
  syndromes[11]    = strtoul("1010100", NULL, 2);
  syndromes[12]    = strtoul("0101010", NULL, 2);
  syndromes[13]    = strtoul("0010101", NULL, 2);
  syndromes[14]    = strtoul("1100010", NULL, 2);
  syndromes[15]    = strtoul("0011001", NULL, 2);
  syndromes[16]    = strtoul("1000110", NULL, 2);
  syndromes[17]    = strtoul("0100101", NULL, 2);
  syndromes[18]    = strtoul("0111000", NULL, 2);
  syndromes[19]    = strtoul("1001010", NULL, 2);
  syndromes[20]    = strtoul("0010110", NULL, 2);
  syndromes[21]    = strtoul("1010001", NULL, 2);
  syndromes[22]    = strtoul("0101100", NULL, 2);
  syndromes[23]    = strtoul("1001001", NULL, 2);
  syndromes[24]    = strtoul("0010011", NULL, 2);
  syndromes[25]    = strtoul("0100110", NULL, 2);
  syndromes[26]    = strtoul("1011000", NULL, 2);
  syndromes[27]    = strtoul("0110001", NULL, 2);
  syndromes[28]    = strtoul("1100100", NULL, 2);
  syndromes[29]    = strtoul("0001011", NULL, 2);

  // Convert the syndromes for each single bit error into the H matrix.
  // Each pattern (there are 10) is multiplied by the data (a
  // BL_Uint256) to generate one bit of ECC.
  for (uint_t pattern_ndx = 0; pattern_ndx < 7; ++pattern_ndx)
    patterns[6 - pattern_ndx] = calc_pattern(pattern_ndx);

  // self check
  // For Hsiao ECC, the check bits and the syndrome are calculated
  // using the same algorithm.
  // Check that inverting one data bit and calculating the resulting
  // ECC matching the bit's syndrome.
  for (uint_t syndrome_ndx = 0; syndrome_ndx < 30; ++syndrome_ndx)
  {
    uint32_t data = 1 << syndrome_ndx;

    if (calc_checks(7, patterns, data).get() != syndromes[syndrome_ndx].get())
    {
      fprintf(stderr,
              "syndrome mismatch: ndx %d calc_check 0x%x syndrome 0x%x\n",
              syndrome_ndx,
              calc_checks(7, patterns, data).get(),
              syndromes[syndrome_ndx].get());
      exit(-1);
    }
  }
}

uint64_t BL_Hsiao_30_7_Synd::Patterns::calc_pattern(uint_t pattern_ndx)
{
  uint64_t pattern = 0;

  for (uint_t ndx = 0; ndx < 30; ++ndx)
  {
    if (syndromes[ndx].get() == 0)
    {
      fprintf(stderr, "bad zero syndrome: %d\n", ndx);
      exit(-1);
    }

    pattern |= ((syndromes[ndx].get() >> pattern_ndx) & 0x1ULL)
                                                    << ndx;
  }

  return pattern;
}