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/* Main simulator loop for CGEN-based simulators.

   Copyright (C) 1998, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.

   Contributed by Cygnus Solutions.

This file is part of GDB, the GNU debugger.

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/>.  */

/* ??? These are old notes, kept around for now.

   Collecting profile data and tracing slow us down so we don't do them in

   "fast mode".

   There are 6 possibilities on 2 axes:

   - no-scaching, insn-scaching, basic-block-scaching

   - run with full features or run fast

   Supporting all six possibilities in one executable is a bit much but

   supporting full/fast seems reasonable.

   If the scache is configured in it is always used.

   If pbb-scaching is configured in it is always used.

   ??? Sometimes supporting more than one set of semantic functions will make

   the simulator too large - this should be configurable.  Blah blah blah.

   ??? Supporting full/fast can be more modular, blah blah blah.

   When the framework is more modular, this can be.

*/

#include "sim-main.h"

#include "sim-assert.h"

#ifndef SIM_ENGINE_PREFIX_HOOK

#define SIM_ENGINE_PREFIX_HOOK(sd)

#endif

#ifndef SIM_ENGINE_POSTFIX_HOOK

#define SIM_ENGINE_POSTFIX_HOOK(sd)

#endif

static sim_event_handler has_stepped;

static void prime_cpu (SIM_CPU *, int);

static void engine_run_1 (SIM_DESC, int, int);

static void engine_run_n (SIM_DESC, int, int, int, int);

/* sim_resume for cgen */

void

sim_resume (SIM_DESC sd, int step, int siggnal)

{

  sim_engine *engine = STATE_ENGINE (sd);

  jmp_buf buf;

  int jmpval;

  ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);

  /* we only want to be single stepping the simulator once */

  if (engine->stepper != NULL)

    {

      sim_events_deschedule (sd, engine->stepper);

      engine->stepper = NULL;

    }

  if (step)

    engine->stepper = sim_events_schedule (sd, 1, has_stepped, sd);

  sim_module_resume (sd);

#if WITH_SCACHE

  if (USING_SCACHE_P (sd))

    scache_flush (sd);

#endif

  /* run/resume the simulator */

  sim_engine_set_run_state (sd, sim_running, 0);

  engine->jmpbuf = &buf;

  jmpval = setjmp (buf);

  if (jmpval == sim_engine_start_jmpval

      || jmpval == sim_engine_restart_jmpval)

    {

      int last_cpu_nr = sim_engine_last_cpu_nr (sd);

      int next_cpu_nr = sim_engine_next_cpu_nr (sd);

      int nr_cpus = sim_engine_nr_cpus (sd);

      /* ??? Setting max_insns to 0 allows pbb/jit code to run wild and is

         useful if all one wants to do is run a benchmark.  Need some better

         way to identify this case.  */

      int max_insns = (step

                       ? 1

                       : (nr_cpus == 1

                          /*&& wip:no-events*/

                          /* Don't do this if running under gdb, need to

                             poll ui for events.  */

                          && STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE)

                       ? 0

                       : 8); /*FIXME: magic number*/

      int fast_p = STATE_RUN_FAST_P (sd);

      sim_events_preprocess (sd, last_cpu_nr >= nr_cpus, next_cpu_nr >= nr_cpus);

      if (next_cpu_nr >= nr_cpus)

        next_cpu_nr = 0;

      if (nr_cpus == 1)

        engine_run_1 (sd, max_insns, fast_p);

      else

        engine_run_n (sd, next_cpu_nr, nr_cpus, max_insns, fast_p);

    }

#if 1 /*wip*/

  else

    {

      /* Account for the last insn executed.  */

      SIM_CPU *cpu = STATE_CPU (sd, sim_engine_last_cpu_nr (sd));

      ++ CPU_INSN_COUNT (cpu);

      TRACE_INSN_FINI (cpu, NULL, 1);

    }

#endif

  engine->jmpbuf = NULL;

  {

    int i;

    int nr_cpus = sim_engine_nr_cpus (sd);

#if 0 /*wip,ignore*/

    /* If the loop exits, either we single-stepped or @cpu@_engine_stop

       was called.  */

    if (step)

      sim_engine_set_run_state (sd, sim_stopped, SIM_SIGTRAP);

    else

      sim_engine_set_run_state (sd, pending_reason, pending_sigrc);

#endif

    for (i = 0; i < nr_cpus; ++i)

      {

        SIM_CPU *cpu = STATE_CPU (sd, i);

        PROFILE_TOTAL_INSN_COUNT (CPU_PROFILE_DATA (cpu)) += CPU_INSN_COUNT (cpu);

      }

  }

  sim_module_suspend (sd);

}

/* Halt the simulator after just one instruction.  */

static void

has_stepped (SIM_DESC sd, void *data)

{

  ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);

  sim_engine_halt (sd, NULL, NULL, NULL_CIA, sim_stopped, SIM_SIGTRAP);

}

/* Prepare a cpu for running.

   MAX_INSNS is the number of insns to execute per time slice.

   If 0 it means the cpu can run as long as it wants (e.g. until the

   program completes).

   ??? Perhaps this should be an argument to the engine_fn.  */

static void

prime_cpu (SIM_CPU *cpu, int max_insns)

{

  CPU_MAX_SLICE_INSNS (cpu) = max_insns;

  CPU_INSN_COUNT (cpu) = 0;

  /* Initialize the insn descriptor table.

     This has to be done after all initialization so we just defer it to

     here.  */

  if (MACH_PREPARE_RUN (CPU_MACH (cpu)))

    (* MACH_PREPARE_RUN (CPU_MACH (cpu))) (cpu);

}

/* Main loop, for 1 cpu.  */

static void

engine_run_1 (SIM_DESC sd, int max_insns, int fast_p)

{

  sim_cpu *cpu = STATE_CPU (sd, 0);

  ENGINE_FN *fn = fast_p ? CPU_FAST_ENGINE_FN (cpu) : CPU_FULL_ENGINE_FN (cpu);

  prime_cpu (cpu, max_insns);

  while (1)

    {

      SIM_ENGINE_PREFIX_HOOK (sd);

      (*fn) (cpu);

      SIM_ENGINE_POSTFIX_HOOK (sd);

      /* process any events */

      if (sim_events_tick (sd))

        sim_events_process (sd);

    }

}

/* Main loop, for multiple cpus.  */

static void

engine_run_n (SIM_DESC sd, int next_cpu_nr, int nr_cpus, int max_insns, int fast_p)

{

  int i;

  ENGINE_FN *engine_fns[MAX_NR_PROCESSORS];

  for (i = 0; i < nr_cpus; ++i)

    {

      SIM_CPU *cpu = STATE_CPU (sd, i);

      engine_fns[i] = fast_p ? CPU_FAST_ENGINE_FN (cpu) : CPU_FULL_ENGINE_FN (cpu);

      prime_cpu (cpu, max_insns);

    }

  while (1)

    {

      SIM_ENGINE_PREFIX_HOOK (sd);

      /* FIXME: proper cycling of all of them, blah blah blah.  */

      while (next_cpu_nr != nr_cpus)

        {

          SIM_CPU *cpu = STATE_CPU (sd, next_cpu_nr);

          (* engine_fns[next_cpu_nr]) (cpu);

          ++next_cpu_nr;

        }

      SIM_ENGINE_POSTFIX_HOOK (sd);

      /* process any events */

      if (sim_events_tick (sd))

        sim_events_process (sd);

    }

}