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/* Main simulator loop for CGEN-based simulators.

   Copyright (C) 1998, 2007, 2008 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);

    }

}