value-representation.cpp

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/*
 * Copyright 2014 Helge Bahmann <hcb@chaoticmind.net>
 * Copyright 2015 Nico Reißmann <nico.reissmann@gmail.com>
 * See COPYING for terms of redistribution.
 */
 
#include <jlm/rvsdg/bitstring/value-representation.hpp>
 
#include <stdexcept>
 
namespace jlm::rvsdg
{
 
uint64_t
BitValueRepresentation::to_uint() const
{
  size_t limit = std::min(nbits(), size_t(64));
  /* bits beyond 64 must be zero, else value is not representable as uint64_t */
  for (size_t n = limit; n < nbits(); ++n)
  {
    if (data_[n] != '0')
      throw std::range_error("Bit constant value exceeds uint64 range");
  }
 
  uint64_t result = 0;
  uint64_t pos_value = 1;
  for (size_t n = 0; n < limit; ++n)
  {
    switch (data_[n])
    {
    case '0':
    {
      break;
    }
    case '1':
    {
      result |= pos_value;
      break;
    }
    default:
    {
      throw std::range_error("Undetermined bit constant");
    }
    }
    pos_value = pos_value << 1;
  }
  return result;
}
 
int64_t
BitValueRepresentation::to_int() const
{
  /* all bits from 63 on must be identical, else value is not representable as int64_t */
  char sign_bit = data_[nbits() - 1];
  size_t limit = std::min(nbits(), size_t(63));
  for (size_t n = limit; n < nbits(); ++n)
  {
    if (data_[n] != sign_bit)
      throw std::range_error("Bit constant value exceeds int64 range");
  }
 
  int64_t result = 0;
  uint64_t pos_value = 1;
  for (size_t n = 0; n < 64; ++n)
  {
    switch (n < nbits() ? data_[n] : sign_bit)
    {
    case '0':
    {
      break;
    }
    case '1':
    {
      result |= pos_value;
      break;
    }
    default:
    {
      throw std::range_error("Undetermined bit constant");
    }
    }
    pos_value = pos_value << 1;
  }
  return result;
}
 
}