// ----------------------------------------------------------------------------
|
// ----------------------------------------------------------------------------
|
|
|
// Debug Unit SPR cache: implementation
|
// Debug Unit SPR cache: implementation
|
|
|
// Copyright (C) 2008 Embecosm Limited <info@embecosm.com>
|
// Copyright (C) 2008 Embecosm Limited <info@embecosm.com>
|
|
|
// Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>
|
// Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>
|
|
|
// This file is part of the GDB interface to the cycle accurate model of the
|
// This file is part of the GDB interface to the cycle accurate model of the
|
// OpenRISC 1000 based system-on-chip, ORPSoC, built using Verilator.
|
// OpenRISC 1000 based system-on-chip, ORPSoC, built using Verilator.
|
|
|
// This program is free software: you can redistribute it and/or modify it
|
// This program is free software: you can redistribute it and/or modify it
|
// under the terms of the GNU Lesser General Public License as published by
|
// under the terms of the GNU Lesser General Public License as published by
|
// the Free Software Foundation, either version 3 of the License, or (at your
|
// the Free Software Foundation, either version 3 of the License, or (at your
|
// option) any later version.
|
// option) any later version.
|
|
|
// This program is distributed in the hope that it will be useful, but WITHOUT
|
// This program is distributed in the hope that it will be useful, but WITHOUT
|
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
|
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
|
// License for more details.
|
// License for more details.
|
|
|
// You should have received a copy of the GNU Lesser General Public License
|
// You should have received a copy of the GNU Lesser General Public License
|
// along with this program. If not, see <http://www.gnu.org/licenses/>.
|
// along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
// ----------------------------------------------------------------------------
|
// ----------------------------------------------------------------------------
|
|
|
// $Id: SprCache.cpp 331 2009-03-12 17:01:48Z jeremy $
|
// $Id: SprCache.cpp 331 2009-03-12 17:01:48Z jeremy $
|
|
|
#include <iostream>
|
#include <iostream>
|
#include <cstring>
|
#include <cstring>
|
|
|
#include "SprCache.h"
|
#include "SprCache.h"
|
|
|
|
|
//-----------------------------------------------------------------------------
|
//-----------------------------------------------------------------------------
|
//! Constructor
|
//! Constructor
|
|
|
//! Allocate tables and clear the cache
|
//! Allocate tables and clear the cache
|
|
|
//! @param[in] _tableSize The desire hash table size. A prime number is
|
//! @param[in] _tableSize The desire hash table size. A prime number is
|
//! recommended.
|
//! recommended.
|
//-----------------------------------------------------------------------------
|
//-----------------------------------------------------------------------------
|
SprCache::SprCache (int _tableSize) :
|
SprCache::SprCache(int _tableSize):
|
tableSize (_tableSize)
|
tableSize(_tableSize)
|
{
|
{
|
sprIsValid = new bool [tableSize];
|
sprIsValid = new bool[tableSize];
|
sprKeyNum = new uint16_t [tableSize];
|
sprKeyNum = new uint16_t[tableSize];
|
sprValue = new uint32_t [tableSize];
|
sprValue = new uint32_t[tableSize];
|
|
|
clear ();
|
clear();
|
|
|
} // SprCache ()
|
} // SprCache ()
|
|
|
|
|
//-----------------------------------------------------------------------------
|
//-----------------------------------------------------------------------------
|
//! Destructor
|
//! Destructor
|
|
|
//! Free up the tables
|
//! Free up the tables
|
//-----------------------------------------------------------------------------
|
//-----------------------------------------------------------------------------
|
SprCache::~SprCache ()
|
SprCache::~SprCache()
|
{
|
{
|
delete [] sprValue;
|
delete[]sprValue;
|
delete [] sprKeyNum;
|
delete[]sprKeyNum;
|
delete [] sprIsValid;
|
delete[]sprIsValid;
|
|
|
} // ~SprCache ()
|
} // ~SprCache ()
|
|
|
|
|
//! Empty the hash table
|
//! Empty the hash table
|
|
|
//! Only need to worry about the validity field
|
//! Only need to worry about the validity field
|
void
|
void
|
SprCache::clear ()
|
SprCache::clear()
|
{
|
{
|
memset (sprIsValid, false, tableSize);
|
memset(sprIsValid, false, tableSize);
|
|
|
// No more than 70% full
|
// No more than 70% full
|
maxToUse = tableSize * 7 / 10;
|
maxToUse = tableSize * 7 / 10;
|
|
|
} // clear ()
|
} // clear ()
|
|
|
|
|
//-----------------------------------------------------------------------------
|
//-----------------------------------------------------------------------------
|
//! Write a new value into the cache
|
//! Write a new value into the cache
|
|
|
//! If the hash table is full silently does nothing, unless the force
|
//! If the hash table is full silently does nothing, unless the force
|
//! parameter is set to TRUE. Under this circumstance the value WILL be
|
//! parameter is set to TRUE. Under this circumstance the value WILL be
|
//! written into the hash table. This is safe, because the table is never more
|
//! written into the hash table. This is safe, because the table is never more
|
//! than 70% full, and force is used only for NPC.
|
//! than 70% full, and force is used only for NPC.
|
|
|
//! @param[in] spr The SPR being written to
|
//! @param[in] spr The SPR being written to
|
//! @param[in] value The value to write
|
//! @param[in] value The value to write
|
//! @param[in] force If TRUE the value will be written to the hash table,
|
//! @param[in] force If TRUE the value will be written to the hash table,
|
//! even if it is too full.
|
//! even if it is too full.
|
//-----------------------------------------------------------------------------
|
//-----------------------------------------------------------------------------
|
void
|
void SprCache::write(uint16_t sprNum, uint32_t value, bool force)
|
SprCache::write (uint16_t sprNum,
|
|
uint32_t value,
|
|
bool force)
|
|
{
|
|
if (maxToUse <= 0)
|
|
{
|
{
|
|
if (maxToUse <= 0) {
|
return; // Table is full
|
return; // Table is full
|
}
|
}
|
|
|
int hv = sprNum % tableSize;
|
int hv = sprNum % tableSize;
|
|
|
// We can use the slot if either it is empty, or it is full and the key
|
// We can use the slot if either it is empty, or it is full and the key
|
// number matches.
|
// number matches.
|
while (sprIsValid[hv] && (sprKeyNum[hv] != sprNum))
|
while (sprIsValid[hv] && (sprKeyNum[hv] != sprNum)) {
|
{
|
|
hv = (hv + 1) % tableSize;
|
hv = (hv + 1) % tableSize;
|
}
|
}
|
|
|
sprIsValid[hv] = true;
|
sprIsValid[hv] = true;
|
sprKeyNum[hv] = sprNum;
|
sprKeyNum[hv] = sprNum;
|
sprValue[hv] = value;
|
sprValue[hv] = value;
|
maxToUse--;
|
maxToUse--;
|
|
|
} // write ()
|
} // write ()
|
|
|
|
|
//-----------------------------------------------------------------------------
|
//-----------------------------------------------------------------------------
|
//! Try to read a value from the cache
|
//! Try to read a value from the cache
|
|
|
//! The entry must be valid.
|
//! The entry must be valid.
|
|
|
//! @param[in] sprNum The SPR being read from
|
//! @param[in] sprNum The SPR being read from
|
//! @param[out] value The value read. Will be written, even if the value is
|
//! @param[out] value The value read. Will be written, even if the value is
|
//! not valid.
|
//! not valid.
|
|
|
//! @return True if the value was found in the hash table
|
//! @return True if the value was found in the hash table
|
//-----------------------------------------------------------------------------
|
//-----------------------------------------------------------------------------
|
bool
|
bool SprCache::read(uint16_t sprNum, uint32_t & value)
|
SprCache::read (uint16_t sprNum,
|
|
uint32_t &value)
|
|
{
|
{
|
int hv = sprNum % tableSize;
|
int hv = sprNum % tableSize;
|
|
|
// Look for either an empty slot (we are not there) or a matching key (we
|
// Look for either an empty slot (we are not there) or a matching key (we
|
// are there)
|
// are there)
|
while (sprIsValid[hv] && (sprKeyNum[hv] != sprNum))
|
while (sprIsValid[hv] && (sprKeyNum[hv] != sprNum)) {
|
{
|
|
hv = (hv + 1) % tableSize;
|
hv = (hv + 1) % tableSize;
|
}
|
}
|
|
|
value = sprValue[hv];
|
value = sprValue[hv];
|
return sprIsValid[hv];
|
return sprIsValid[hv];
|
|
|
} // read ()
|
} // read ()
|
|
|