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/* icache-model.c -- instruction cache simulation

   Copyright (C) 1999 Damjan Lampret, lampret@opencores.org

   Copyright (C) 2008 Embecosm Limited

   Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>

   This file is part of OpenRISC 1000 Architectural Simulator.

   This program is free software; you can redistribute it and/or modify it

   under the terms of the GNU General Public License as published by the Free

   Software Foundation; either version 3 of the License, or (at your option)

   any later version.

   This program is distributed in the hope that it will be useful, but WITHOUT

   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

   more details.

   You should have received a copy of the GNU General Public License along

   with this program.  If not, see <http://www.gnu.org/licenses/>. */

/* This program is commented throughout in a fashion suitable for processing

   with Doxygen. */

/* Cache functions.

   At the moment this functions only simulate functionality of instruction

   caches and do not influence on fetche/decode/execute stages and timings.

   They are here only to verify performance of various cache configurations.

 */

/* Autoconf and/or portability configuration */

#include "config.h"

#include "port.h"

/* System includes */

#include <stdlib.h>

/* Package includes */

#include "icache-model.h"

#include "execute.h"

#include "spr-defs.h"

#include "abstract.h"

#include "misc.h"

#include "stats.h"

#include "sim-cmd.h"

#define MAX_IC_SETS        1024

#define MAX_IC_WAYS          32

#define MIN_IC_BLOCK_SIZE    16

#define MAX_IC_BLOCK_SIZE    32

struct ic *ic_state = NULL;

static void

ic_info (void *dat)

{

  struct ic *ic = dat;

  if (!(cpu_state.sprs[SPR_UPR] & SPR_UPR_ICP))

    {

      PRINTF ("ICache not implemented. Set UPR[ICP].\n");

      return;

    }

  PRINTF ("Instruction cache %dKB: ",

          ic->nsets * ic->blocksize * ic->nways / 1024);

  PRINTF ("%d ways, %d sets, block size %d bytes\n", ic->nways, ic->nsets,

          ic->blocksize);

}

/* First check if instruction is already in the cache and if it is:

    - increment IC read hit stats,

    - set 'lru' at this way to ic->ustates - 1 and

      decrement 'lru' of other ways unless they have reached 0,

    - read insn from the cache line

   and if not:

    - increment IC read miss stats

    - find lru way and entry and replace old tag with tag of the 'fetchaddr'

    - set 'lru' with ic->ustates - 1 and decrement 'lru' of other

      ways unless they have reached 0

    - refill cache line

*/

uint32_t

ic_simulate_fetch (oraddr_t fetchaddr, oraddr_t virt_addr)

{

  oraddr_t set;

  oraddr_t way;

  oraddr_t lru_way;

  oraddr_t tagaddr;

  uint32_t tmp;

  oraddr_t reload_addr;

  oraddr_t reload_end;

  unsigned int minlru;

  struct ic *ic = ic_state;

  /* ICache simulation enabled/disabled. */

  if (!(cpu_state.sprs[SPR_UPR] & SPR_UPR_ICP) ||

      !(cpu_state.sprs[SPR_SR] & SPR_SR_ICE) || insn_ci)

    {

      tmp = evalsim_mem32 (fetchaddr, virt_addr);

      if (cur_area && cur_area->log)

        fprintf (cur_area->log, "[%" PRIxADDR "] -> read %08" PRIx32 "\n",

                 fetchaddr, tmp);

      return tmp;

    }

  /* Which set to check out? */

  set = (fetchaddr & ic->set_mask) >> ic->blocksize_log2;

  tagaddr = fetchaddr & ic->tagaddr_mask;

  /* Scan all ways and try to find a matching way. */

  for (way = set; way < ic->last_way; way += ic->nsets)

    {

      if (ic->tags[way] == tagaddr)

        {

          ic_stats.readhit++;

          for (lru_way = set; lru_way < ic->last_way; lru_way += ic->nsets)

            if (ic->lrus[lru_way] > ic->lrus[way])

              ic->lrus[lru_way]--;

          ic->lrus[way] = ic->ustates_reload;

          runtime.sim.mem_cycles += ic->hitdelay;

          way <<= ic->blocksize_log2;

          return *(uint32_t *) & ic->

            mem[way | (fetchaddr & ic->block_offset_mask)];

        }

    }

  minlru = ic->ustates_reload;

  way = set;

  ic_stats.readmiss++;

  for (lru_way = set; lru_way < ic->last_way; lru_way += ic->nsets)

    {

      if (ic->lrus[lru_way] < minlru)

        {

          way = lru_way;

          minlru = ic->lrus[lru_way];

        }

    }

  ic->tags[way] = tagaddr;

  for (lru_way = set; lru_way < ic->last_way; lru_way += ic->nsets)

    if (ic->lrus[lru_way])

      ic->lrus[lru_way]--;

  ic->lrus[way] = ic->ustates_reload;

  reload_addr = fetchaddr & ic->block_offset_mask;

  reload_end = reload_addr + ic->blocksize;

  fetchaddr &= ic->block_mask;

  way <<= ic->blocksize_log2;

  for (; reload_addr < reload_end; reload_addr += 4)

    {

      tmp =

        *(uint32_t *) & ic->mem[way | (reload_addr & ic->block_offset_mask)] =

        /* FIXME: What is the virtual address meant to be? (ie. What happens if

         * we read out of memory while refilling a cache line?) */

        evalsim_mem32 (fetchaddr | (reload_addr & ic->block_offset_mask), 0);

      if (!cur_area)

        {

          ic->tags[way >> ic->blocksize_log2] = -1;

          ic->lrus[way >> ic->blocksize_log2] = 0;

          return 0;

        }

      else if (cur_area->log)

        fprintf (cur_area->log, "[%" PRIxADDR "] -> read %08" PRIx32 "\n",

                 fetchaddr, tmp);

    }

  runtime.sim.mem_cycles += ic->missdelay;

  return *(uint32_t *) & ic->mem[way | (reload_addr & ic->block_offset_mask)];

}

/* First check if data is already in the cache and if it is:

    - invalidate block if way isn't locked

   otherwise don't do anything.

*/

void

ic_inv (oraddr_t dataaddr)

{

  oraddr_t set;

  oraddr_t way;

  oraddr_t tagaddr;

  struct ic *ic = ic_state;

  if (!(cpu_state.sprs[SPR_UPR] & SPR_UPR_ICP))

    return;

  /* Which set to check out? */

  set = (dataaddr & ic->set_mask) >> ic->blocksize_log2;

  if (!(cpu_state.sprs[SPR_SR] & SPR_SR_ICE))

    {

      for (way = set; way < ic->last_way; way += ic->nsets)

        {

          ic->tags[way] = -1;

          ic->lrus[way] = 0;

        }

      return;

    }

  tagaddr = dataaddr & ic->tagaddr_mask;

  /* Scan all ways and try to find a matching way. */

  for (way = set; way < ic->last_way; way += ic->nsets)

    {

      if (ic->tags[way] == tagaddr)

        {

          ic->tags[way] = -1;

          ic->lrus[way] = 0;

        }

    }

}

/*-----------------------------------------------------[ IC configuration ]---*/

/*---------------------------------------------------------------------------*/

/*!Enable or disable the instruction cache

   Set the corresponding fields in the UPR

   @param[in] val  The value to use

   @param[in] dat  The config data structure                                 */

/*---------------------------------------------------------------------------*/

static void

ic_enabled (union param_val  val,

            void            *dat)

{

  struct ic *ic = dat;

  ic->enabled = val.int_val;

  if (val.int_val)

    {

      cpu_state.sprs[SPR_UPR] |= SPR_UPR_ICP;

    }

  else

    {

      cpu_state.sprs[SPR_UPR] &= ~SPR_UPR_ICP;

    }

}       /* ic_enabled() */

/*---------------------------------------------------------------------------*/

/*!Set the number of instruction cache sets

   Set the corresponding field in the UPR

   @param[in] val  The value to use

   @param[in] dat  The config data structure                                 */

/*---------------------------------------------------------------------------*/

static void

ic_nsets (union param_val  val,

          void            *dat)

{

  struct ic *ic = dat;

  if (is_power2 (val.int_val) && (val.int_val <= MAX_IC_SETS))

    {

      int  set_bits = log2_int (val.int_val);

      ic->nsets = val.int_val;

      cpu_state.sprs[SPR_ICCFGR] &= ~SPR_ICCFGR_NCS;

      cpu_state.sprs[SPR_ICCFGR] |= set_bits << SPR_ICCFGR_NCS_OFF;

    }

  else

    {

      fprintf (stderr, "Warning: instruction cache nsets not a power of "

               "2 <= %d: ignored\n", MAX_IC_SETS);

    }

}       /* ic_nsets() */

/*---------------------------------------------------------------------------*/

/*!Set the number of instruction cache ways

   Set the corresponding field in the UPR

   @param[in] val  The value to use

   @param[in] dat  The config data structure                                 */

/*---------------------------------------------------------------------------*/

static void

ic_nways (union param_val  val,

            void            *dat)

{

  struct ic *ic = dat;

  if (is_power2 (val.int_val) && (val.int_val <= MAX_IC_WAYS))

    {

      int  way_bits = log2_int (val.int_val);

      ic->nways = val.int_val;

      cpu_state.sprs[SPR_ICCFGR] &= ~SPR_ICCFGR_NCW;

      cpu_state.sprs[SPR_ICCFGR] |= way_bits << SPR_ICCFGR_NCW_OFF;

    }

  else

    {

      fprintf (stderr, "Warning: instruction cache nways not a power of "

               "2 <= %d: ignored\n", MAX_IC_WAYS);

    }

}       /* ic_nways() */

/*---------------------------------------------------------------------------*/

/*!Set the instruction cache block size

   Value must be either MIN_IC_BLOCK_SIZE or MAX_IC_BLOCK_SIZE. If not issue a

   warning and ignore. Set the relevant field in the data cache config register

   @param[in] val  The value to use

   @param[in] dat  The config data structure                                 */

/*---------------------------------------------------------------------------*/

static void

ic_blocksize (union param_val  val,

              void            *dat)

{

  struct ic *ic = dat;

  switch (val.int_val)

    {

    case MIN_IC_BLOCK_SIZE:

      ic->blocksize               = val.int_val;

      cpu_state.sprs[SPR_ICCFGR] &= ~SPR_ICCFGR_CBS;

      break;

    case MAX_IC_BLOCK_SIZE:

      ic->blocksize               = val.int_val;

      cpu_state.sprs[SPR_ICCFGR] |= SPR_ICCFGR_CBS;

      break;

    default:

      fprintf (stderr, "Warning: instruction cache block size not %d or %d: "

               "ignored\n", MIN_IC_BLOCK_SIZE, MAX_IC_BLOCK_SIZE);

      break;

    }

}       /* ic_blocksize() */

/*---------------------------------------------------------------------------*/

/*!Set the number of instruction cache usage states

   Value must be 2, 3 or 4. If not issue a warning and ignore.

   @param[in] val  The value to use

   @param[in] dat  The config data structure                                 */

/*---------------------------------------------------------------------------*/

static void

ic_ustates (union param_val  val,

            void            *dat)

{

  struct ic *ic = dat;

  if ((val.int_val >= 2) && (val.int_val <= 4))

    {

      ic->ustates = val.int_val;

    }

  else

    {

      fprintf (stderr, "Warning number of instruction cache usage states "

               "must be 2, 3 or 4: ignored\n");

    }

}       /* ic_ustates() */

static void

ic_hitdelay (union param_val  val,

             void            *dat)

{

  struct ic *ic = dat;

  ic->hitdelay = val.int_val;

}

static void

ic_missdelay (union param_val  val,

              void            *dat)

{

  struct ic *ic = dat;

  ic->missdelay = val.int_val;

}

/*---------------------------------------------------------------------------*/

/*!Initialize a new instruction cache configuration

   ALL parameters are set explicitly to default values. Corresponding SPR

   flags are set as appropriate.

   @return  The new memory configuration data structure                      */

/*---------------------------------------------------------------------------*/

static void *

ic_start_sec ()

{

  struct ic *ic;

  int        set_bits;

  int        way_bits;

  if (NULL == (ic = malloc (sizeof (struct ic))))

    {

      fprintf (stderr, "OOM\n");

      exit (1);

    }

  ic->enabled   = 0;

  ic->nsets     = 1;

  ic->nways     = 1;

  ic->blocksize = MIN_IC_BLOCK_SIZE;

  ic->ustates   = 2;

  ic->hitdelay  = 1;

  ic->missdelay = 1;

  ic->mem       = NULL;         /* Internal configuration */

  ic->lrus      = NULL;

  ic->tags      = NULL;

  /* Set SPRs as appropriate */

  if (ic->enabled)

    {

      cpu_state.sprs[SPR_UPR] |= SPR_UPR_ICP;

    }

  else

    {

      cpu_state.sprs[SPR_UPR] &= ~SPR_UPR_ICP;

    }

  set_bits = log2_int (ic->nsets);

  cpu_state.sprs[SPR_ICCFGR] &= ~SPR_ICCFGR_NCS;

  cpu_state.sprs[SPR_ICCFGR] |= set_bits << SPR_ICCFGR_NCS_OFF;

  way_bits = log2_int (ic->nways);

  cpu_state.sprs[SPR_ICCFGR] &= ~SPR_ICCFGR_NCW;

  cpu_state.sprs[SPR_ICCFGR] |= way_bits << SPR_ICCFGR_NCW_OFF;

  if (MIN_IC_BLOCK_SIZE == ic->blocksize)

    {

      cpu_state.sprs[SPR_ICCFGR] &= ~SPR_ICCFGR_CBS;

    }

  else

    {

      cpu_state.sprs[SPR_ICCFGR] |= SPR_ICCFGR_CBS;

    }

  ic_state = ic;

  return ic;

}       /* ic_start_sec() */

static void

ic_end_sec (void *dat)

{

  struct ic *ic = dat;

  unsigned int size = ic->nways * ic->nsets * ic->blocksize;

  if (size)

    {

      if (!(ic->mem = malloc (size)))

        {

          fprintf (stderr, "OOM\n");

          exit (1);

        }

      if (!

          (ic->lrus = malloc (ic->nsets * ic->nways * sizeof (unsigned int))))

        {

          fprintf (stderr, "OOM\n");

          exit (1);

        }

      if (!(ic->tags = malloc (ic->nsets * ic->nways * sizeof (oraddr_t))))

        {

          fprintf (stderr, "OOM\n");

          exit (1);

        }

      /* Clear the cache data. John Alfredo's fix for using 0 (which is a

         valid tag), so we now use -1 */

      memset (ic->mem,  0, size);

      memset (ic->lrus, 0, ic->nsets * ic->nways * sizeof (unsigned int));

      memset (ic->tags, -1, ic->nsets * ic->nways * sizeof (oraddr_t));

    }

  else

    {

      ic->enabled = 0;

    }

  ic->blocksize_log2    = log2_int (ic->blocksize);

  ic->set_mask          = (ic->nsets - 1) << ic->blocksize_log2;

  ic->tagaddr_mask      = ~((ic->nsets * ic->blocksize) - 1);

  ic->last_way          = ic->nsets * ic->nways;

  ic->block_offset_mask = ic->blocksize - 1;

  ic->block_mask        = ~ic->block_offset_mask;

  ic->ustates_reload    = ic->ustates - 1;

  if (ic->enabled)

    reg_sim_stat (ic_info, dat);

}

void

reg_ic_sec (void)

{

  struct config_section *sec =

    reg_config_sec ("ic", ic_start_sec, ic_end_sec);

  reg_config_param (sec, "enabled",   PARAMT_INT, ic_enabled);

  reg_config_param (sec, "nsets",     PARAMT_INT, ic_nsets);

  reg_config_param (sec, "nways",     PARAMT_INT, ic_nways);

  reg_config_param (sec, "blocksize", PARAMT_INT, ic_blocksize);

  reg_config_param (sec, "ustates",   PARAMT_INT, ic_ustates);

  reg_config_param (sec, "missdelay", PARAMT_INT, ic_missdelay);

  reg_config_param (sec, "hitdelay" , PARAMT_INT, ic_hitdelay);

}