addr_range.hh

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#ifndef __BASE_ADDR_RANGE_HH__
#define __BASE_ADDR_RANGE_HH__
 
#include <algorithm>
#include <list>
#include <vector>
 
#include "base/bitfield.hh"
#include "base/cprintf.hh"
#include "base/logging.hh"
#include "base/types.hh"
 
namespace gem5
{
 
class AddrRange
{
 
  private:
 
    Addr _start;
    Addr _end;
 
    std::vector<Addr> masks;
 
    uint8_t intlvMatch;
 
  public:
 
    AddrRange()
        : _start(1), _end(0), intlvMatch(0)
    {}
 
    AddrRange(Addr _start, Addr _end, const std::vector<Addr> &_masks,
              uint8_t _intlv_match)
        : _start(_start), _end(_end), masks(_masks),
          intlvMatch(_intlv_match)
    {
        // sanity checks
        fatal_if(!masks.empty() && _intlv_match >= 1ULL << masks.size(),
                 "Match value %d does not fit in %d interleaving bits\n",
                 _intlv_match, masks.size());
    }
 
    AddrRange(Addr _start, Addr _end, uint8_t _intlv_high_bit,
              uint8_t _xor_high_bit, uint8_t _intlv_bits,
              uint8_t _intlv_match)
        : _start(_start), _end(_end), masks(_intlv_bits),
          intlvMatch(_intlv_match)
    {
        // sanity checks
        fatal_if(_intlv_bits && _intlv_match >= 1ULL << _intlv_bits,
                 "Match value %d does not fit in %d interleaving bits\n",
                 _intlv_match, _intlv_bits);
 
        // ignore the XOR bits if not interleaving
        if (_intlv_bits && _xor_high_bit) {
            if (_xor_high_bit == _intlv_high_bit) {
                fatal("XOR and interleave high bit must be different\n");
            }  else if (_xor_high_bit > _intlv_high_bit) {
                if ((_xor_high_bit - _intlv_high_bit) < _intlv_bits)
                    fatal("XOR and interleave high bit must be at least "
                          "%d bits apart\n", _intlv_bits);
            } else {
                if ((_intlv_high_bit - _xor_high_bit) < _intlv_bits) {
                    fatal("Interleave and XOR high bit must be at least "
                          "%d bits apart\n", _intlv_bits);
                }
            }
        }
 
        for (auto i = 0; i < _intlv_bits; i++) {
            uint8_t bit1 = _intlv_high_bit - i;
            Addr mask = (1ULL << bit1);
            if (_xor_high_bit) {
                uint8_t bit2 = _xor_high_bit - i;
                mask |= (1ULL << bit2);
            }
            masks[_intlv_bits - i - 1] = mask;
        }
    }
 
    AddrRange(Addr _start, Addr _end)
        : _start(_start), _end(_end), intlvMatch(0)
    {}
 
    AddrRange(const std::vector<AddrRange>& ranges)
        : _start(1), _end(0), intlvMatch(0)
    {
        if (!ranges.empty()) {
            // get the values from the first one and check the others
            _start = ranges.front()._start;
            _end = ranges.front()._end;
            masks = ranges.front().masks;
            intlvMatch = ranges.front().intlvMatch;
        }
        // either merge if got all ranges or keep this equal to the single
        // interleaved range
        if (ranges.size() > 1) {
 
            if (ranges.size() != (1ULL << masks.size()))
                fatal("Got %d ranges spanning %d interleaving bits\n",
                      ranges.size(), masks.size());
 
            uint8_t match = 0;
            for (const auto& r : ranges) {
                if (!mergesWith(r))
                    fatal("Can only merge ranges with the same start, end "
                          "and interleaving bits, %s %s\n", to_string(),
                          r.to_string());
 
                if (r.intlvMatch != match)
                    fatal("Expected interleave match %d but got %d when "
                          "merging\n", match, r.intlvMatch);
                ++match;
            }
            masks.clear();
            intlvMatch = 0;
        }
    }
 
    bool interleaved() const { return masks.size() > 0; }
 
    uint64_t granularity() const
    {
        if (interleaved()) {
            auto combined_mask = 0;
            for (auto mask: masks) {
                combined_mask |= mask;
            }
            const uint8_t lowest_bit = ctz64(combined_mask);
            return 1ULL << lowest_bit;
        } else {
            return size();
        }
    }
 
    uint32_t stripes() const { return 1ULL << masks.size(); }
 
    Addr size() const
    {
        return (_end - _start) >> masks.size();
    }
 
    bool valid() const { return _start <= _end; }
 
    Addr start() const { return _start; }
 
    Addr end() const { return _end; }
 
    std::string to_string() const
    {
        if (interleaved()) {
            std::string str;
            for (int i = 0; i < masks.size(); i++) {
                str += " ";
                Addr mask = masks[i];
                while (mask) {
                    auto bit = ctz64(mask);
                    mask &= ~(1ULL << bit);
                    str += csprintf("a[%d]^", bit);
                }
                str += csprintf("\b=%d", bits(intlvMatch, i));
            }
            return csprintf("[%#llx:%#llx]%s", _start, _end, str);
        } else {
            return csprintf("[%#llx:%#llx]", _start, _end);
        }
    }
 
    bool mergesWith(const AddrRange& r) const
    {
        return r._start == _start && r._end == _end &&
            r.masks == masks;
    }
 
    bool intersects(const AddrRange& r) const
    {
        if (_start >= r._end || _end <= r._start)
            // start with the simple case of no overlap at all,
            // applicable even if we have interleaved ranges
            return false;
        else if (!interleaved() && !r.interleaved())
            // if neither range is interleaved, we are done
            return true;
 
        // now it gets complicated, focus on the cases we care about
        if (r.size() == 1)
            // keep it simple and check if the address is within
            // this range
            return contains(r.start());
        else if (mergesWith(r))
            // restrict the check to ranges that belong to the
            // same chunk
            return intlvMatch == r.intlvMatch;
        else
            panic("Cannot test intersection of %s and %s\n",
                  to_string(), r.to_string());
    }
 
    bool isSubset(const AddrRange& r) const
    {
        if (interleaved())
            panic("Cannot test subset of interleaved range %s\n", to_string());
 
        // This address range is not interleaved and therefore it
        // suffices to check the upper bound, the lower bound and
        // whether it would fit in a continuous segment of the input
        // addr range.
        if (r.interleaved()) {
            return r.contains(_start) && r.contains(_end - 1) &&
                size() <= r.granularity();
        } else {
            return _start >= r._start && _end <= r._end;
        }
    }
 
    bool contains(const Addr& a) const
    {
        // check if the address is in the range and if there is either
        // no interleaving, or with interleaving also if the selected
        // bits from the address match the interleaving value
        bool in_range = a >= _start && a < _end;
        if (in_range) {
            auto sel = 0;
            for (int i = 0; i < masks.size(); i++) {
                Addr masked = a & masks[i];
                // The result of an xor operation is 1 if the number
                // of bits set is odd or 0 othersize, thefore it
                // suffices to count the number of bits set to
                // determine the i-th bit of sel.
                sel |= (popCount(masked) % 2) << i;
            }
            return sel == intlvMatch;
        }
        return false;
    }
 
    inline Addr removeIntlvBits(Addr a) const
    {
        // Directly return the address if the range is not interleaved
        // to prevent undefined behavior.
        if (!interleaved()) {
            return a;
        }
 
        // Get the LSB set from each mask
        int masks_lsb[masks.size()];
        for (int i = 0; i < masks.size(); i++) {
            masks_lsb[i] = ctz64(masks[i]);
        }
 
        // we need to sort the list of bits we will discard as we
        // discard them one by one starting.
        std::sort(masks_lsb, masks_lsb + masks.size());
 
        for (int i = 0; i < masks.size(); i++) {
            const int intlv_bit = masks_lsb[i];
            if (intlv_bit > 0) {
                // on every iteration we remove one bit from the input
                // address, and therefore the lowest invtl_bit has
                // also shifted to the right by i positions.
                a = insertBits(a >> 1, intlv_bit - i - 1, 0, a);
            } else {
                a >>= 1;
            }
        }
        return a;
    }
 
    inline Addr addIntlvBits(Addr a) const
    {
        // Directly return the address if the range is not interleaved
        // to prevent undefined behavior.
        if (!interleaved()) {
            return a;
        }
 
        // Get the LSB set from each mask
        int masks_lsb[masks.size()];
        for (int i = 0; i < masks.size(); i++) {
            masks_lsb[i] = ctz64(masks[i]);
        }
 
        // Add bits one-by-one from the LSB side.
        std::sort(masks_lsb, masks_lsb + masks.size());
        for (int i = 0; i < masks.size(); i++) {
            const int intlv_bit = masks_lsb[i];
            if (intlv_bit > 0) {
                // on every iteration we add one bit from the input
                // address, but the lowest invtl_bit in the iteration is
                // always in the right position because they are sorted
                // increasingly from the LSB
                a = insertBits(a << 1, intlv_bit - 1, 0, a);
            } else {
                a <<= 1;
            }
        }
 
        for (int i = 0; i < masks.size(); i++) {
            const int lsb = ctz64(masks[i]);
            const Addr intlv_bit = bits(intlvMatch, i);
            // Calculate the mask ignoring the LSB
            const Addr masked = a & masks[i] & ~(1 << lsb);
            // Set the LSB of the mask to whatever satisfies the selector bit
            a = insertBits(a, lsb, intlv_bit ^ popCount(masked));
        }
 
        return a;
    }
 
    Addr getOffset(const Addr& a) const
    {
        bool in_range = a >= _start && a < _end;
        if (!in_range) {
            return MaxAddr;
        }
        if (interleaved()) {
            return removeIntlvBits(a) - removeIntlvBits(_start);
        } else {
            return a - _start;
        }
    }
 
    bool operator<(const AddrRange& r) const
    {
        if (_start != r._start) {
            return _start < r._start;
        } else {
            // For now assume that the end is also the same.
            // If both regions are interleaved, assume same interleaving,
            // and compare intlvMatch values.
            // Otherwise, return true if this address range is interleaved.
            if (interleaved() && r.interleaved()) {
                return intlvMatch < r.intlvMatch;
            } else {
                return interleaved();
            }
        }
    }
 
    bool operator==(const AddrRange& r) const
    {
        if (_start != r._start)    return false;
        if (_end != r._end)      return false;
        if (masks != r.masks)         return false;
        if (intlvMatch != r.intlvMatch)   return false;
 
        return true;
    }
 
    bool operator!=(const AddrRange& r) const
    {
        return !(*this == r);
    }
};
 
typedef std::list<AddrRange> AddrRangeList;
 
inline AddrRange
RangeEx(Addr start, Addr end)
{ return AddrRange(start, end); }
 
inline AddrRange
RangeIn(Addr start, Addr end)
{ return AddrRange(start, end + 1); }
 
inline AddrRange
RangeSize(Addr start, Addr size)
{ return AddrRange(start, start + size); }
 
} // namespace gem5
 
#endif // __BASE_ADDR_RANGE_HH__