/* gdb.c --- sim interface to GDB.

Copyright (C) 2005, 2007, 2008 Free Software Foundation, Inc.
Contributed by Red Hat, Inc.

This file is part of the GNU simulators.

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/>.  */


#include <stdio.h>
#include <assert.h>
#include <signal.h>
#include <string.h>
#include <ctype.h>

#include "ansidecl.h"
#include "gdb/callback.h"
#include "gdb/remote-sim.h"
#include "gdb/signals.h"
#include "gdb/sim-m32c.h"

#include "cpu.h"
#include "mem.h"
#include "load.h"
#include "syscalls.h"

/* I don't want to wrap up all the minisim's data structures in an
   object and pass that around.  That'd be a big change, and neither
   GDB nor run needs that ability.

   So we just have one instance, that lives in global variables, and
   each time we open it, we re-initialize it.  */
struct sim_state
{
  const char *message;
};

static struct sim_state the_minisim = {
  "This is the sole m32c minisim instance.  See libsim.a's global variables."
};

static int open;

SIM_DESC
sim_open (SIM_OPEN_KIND kind,
	  struct host_callback_struct *callback,
	  struct bfd *abfd, char **argv)
{
  if (open)
    fprintf (stderr, "m32c minisim: re-opened sim\n");

  /* The 'run' interface doesn't use this function, so we don't care
     about KIND; it's always SIM_OPEN_DEBUG.  */
  if (kind != SIM_OPEN_DEBUG)
    fprintf (stderr, "m32c minisim: sim_open KIND != SIM_OPEN_DEBUG: %d\n",
	     kind);

  if (abfd)
    m32c_set_mach (bfd_get_mach (abfd));

  /* We can use ABFD, if non-NULL to select the appropriate
     architecture.  But we only support the r8c right now.  */

  set_callbacks (callback);

  /* We don't expect any command-line arguments.  */

  init_mem ();
  init_regs ();

  open = 1;
  return &the_minisim;
}

static void
check_desc (SIM_DESC sd)
{
  if (sd != &the_minisim)
    fprintf (stderr, "m32c minisim: desc != &the_minisim\n");
}

void
sim_close (SIM_DESC sd, int quitting)
{
  check_desc (sd);

  /* Not much to do.  At least free up our memory.  */
  init_mem ();

  open = 0;
}

static bfd *
open_objfile (const char *filename)
{
  bfd *prog = bfd_openr (filename, 0);

  if (!prog)
    {
      fprintf (stderr, "Can't read %s\n", filename);
      return 0;
    }

  if (!bfd_check_format (prog, bfd_object))
    {
      fprintf (stderr, "%s not a m32c program\n", filename);
      return 0;
    }

  return prog;
}


SIM_RC
sim_load (SIM_DESC sd, char *prog, struct bfd *abfd, int from_tty)
{
  check_desc (sd);

  if (!abfd)
    abfd = open_objfile (prog);
  if (!abfd)
    return SIM_RC_FAIL;

  m32c_load (abfd);

  return SIM_RC_OK;
}

SIM_RC
sim_create_inferior (SIM_DESC sd, struct bfd *abfd, char **argv, char **env)
{
  check_desc (sd);

  if (abfd)
    m32c_load (abfd);

  return SIM_RC_OK;
}

int
sim_read (SIM_DESC sd, SIM_ADDR mem, unsigned char *buf, int length)
{
  check_desc (sd);

  if (mem == 0)
    return 0;

  mem_get_blk ((int) mem, buf, length);

  return length;
}

int
sim_write (SIM_DESC sd, SIM_ADDR mem, unsigned char *buf, int length)
{
  check_desc (sd);

  mem_put_blk ((int) mem, buf, length);

  return length;
}


/* Read the LENGTH bytes at BUF as an little-endian value.  */
static DI
get_le (unsigned char *buf, int length)
{
  DI acc = 0;
  while (--length >= 0)
    acc = (acc << 8) + buf[length];

  return acc;
}

/* Store VAL as a little-endian value in the LENGTH bytes at BUF.  */
static void
put_le (unsigned char *buf, int length, DI val)
{
  int i;

  for (i = 0; i < length; i++)
    {
      buf[i] = val & 0xff;
      val >>= 8;
    }
}

static int
check_regno (enum m32c_sim_reg regno)
{
  return 0 <= regno && regno < m32c_sim_reg_num_regs;
}

static size_t
mask_size (int addr_mask)
{
  switch (addr_mask)
    {
    case 0xffff:
      return 2;
    case 0xfffff:
    case 0xffffff:
      return 3;
    default:
      fprintf (stderr,
	       "m32c minisim: addr_mask_size: unexpected mask 0x%x\n",
	       addr_mask);
      return sizeof (addr_mask);
    }
}

static size_t
reg_size (enum m32c_sim_reg regno)
{
  switch (regno)
    {
    case m32c_sim_reg_r0_bank0:
    case m32c_sim_reg_r1_bank0:
    case m32c_sim_reg_r2_bank0:
    case m32c_sim_reg_r3_bank0:
    case m32c_sim_reg_r0_bank1:
    case m32c_sim_reg_r1_bank1:
    case m32c_sim_reg_r2_bank1:
    case m32c_sim_reg_r3_bank1:
    case m32c_sim_reg_flg:
    case m32c_sim_reg_svf:
      return 2;

    case m32c_sim_reg_a0_bank0:
    case m32c_sim_reg_a1_bank0:
    case m32c_sim_reg_fb_bank0:
    case m32c_sim_reg_sb_bank0:
    case m32c_sim_reg_a0_bank1:
    case m32c_sim_reg_a1_bank1:
    case m32c_sim_reg_fb_bank1:
    case m32c_sim_reg_sb_bank1:
    case m32c_sim_reg_usp:
    case m32c_sim_reg_isp:
      return mask_size (addr_mask);

    case m32c_sim_reg_pc:
    case m32c_sim_reg_intb:
    case m32c_sim_reg_svp:
    case m32c_sim_reg_vct:
      return mask_size (membus_mask);

    case m32c_sim_reg_dmd0:
    case m32c_sim_reg_dmd1:
      return 1;

    case m32c_sim_reg_dct0:
    case m32c_sim_reg_dct1:
    case m32c_sim_reg_drc0:
    case m32c_sim_reg_drc1:
      return 2;

    case m32c_sim_reg_dma0:
    case m32c_sim_reg_dma1:
    case m32c_sim_reg_dsa0:
    case m32c_sim_reg_dsa1:
    case m32c_sim_reg_dra0:
    case m32c_sim_reg_dra1:
      return 3;

    default:
      fprintf (stderr, "m32c minisim: unrecognized register number: %d\n",
	       regno);
      return -1;
    }
}

int
sim_fetch_register (SIM_DESC sd, int regno, unsigned char *buf, int length)
{
  size_t size;

  check_desc (sd);

  if (!check_regno (regno))
    return 0;

  size = reg_size (regno);
  if (length == size)
    {
      DI val;

      switch (regno)
	{
	case m32c_sim_reg_r0_bank0:
	  val = regs.r[0].r_r0;
	  break;
	case m32c_sim_reg_r1_bank0:
	  val = regs.r[0].r_r1;
	  break;
	case m32c_sim_reg_r2_bank0:
	  val = regs.r[0].r_r2;
	  break;
	case m32c_sim_reg_r3_bank0:
	  val = regs.r[0].r_r3;
	  break;
	case m32c_sim_reg_a0_bank0:
	  val = regs.r[0].r_a0;
	  break;
	case m32c_sim_reg_a1_bank0:
	  val = regs.r[0].r_a1;
	  break;
	case m32c_sim_reg_fb_bank0:
	  val = regs.r[0].r_fb;
	  break;
	case m32c_sim_reg_sb_bank0:
	  val = regs.r[0].r_sb;
	  break;
	case m32c_sim_reg_r0_bank1:
	  val = regs.r[1].r_r0;
	  break;
	case m32c_sim_reg_r1_bank1:
	  val = regs.r[1].r_r1;
	  break;
	case m32c_sim_reg_r2_bank1:
	  val = regs.r[1].r_r2;
	  break;
	case m32c_sim_reg_r3_bank1:
	  val = regs.r[1].r_r3;
	  break;
	case m32c_sim_reg_a0_bank1:
	  val = regs.r[1].r_a0;
	  break;
	case m32c_sim_reg_a1_bank1:
	  val = regs.r[1].r_a1;
	  break;
	case m32c_sim_reg_fb_bank1:
	  val = regs.r[1].r_fb;
	  break;
	case m32c_sim_reg_sb_bank1:
	  val = regs.r[1].r_sb;
	  break;

	case m32c_sim_reg_usp:
	  val = regs.r_usp;
	  break;
	case m32c_sim_reg_isp:
	  val = regs.r_isp;
	  break;
	case m32c_sim_reg_pc:
	  val = regs.r_pc;
	  break;
	case m32c_sim_reg_intb:
	  val = regs.r_intbl * 65536 + regs.r_intbl;
	  break;
	case m32c_sim_reg_flg:
	  val = regs.r_flags;
	  break;

	  /* These registers aren't implemented by the minisim.  */
	case m32c_sim_reg_svf:
	case m32c_sim_reg_svp:
	case m32c_sim_reg_vct:
	case m32c_sim_reg_dmd0:
	case m32c_sim_reg_dmd1:
	case m32c_sim_reg_dct0:
	case m32c_sim_reg_dct1:
	case m32c_sim_reg_drc0:
	case m32c_sim_reg_drc1:
	case m32c_sim_reg_dma0:
	case m32c_sim_reg_dma1:
	case m32c_sim_reg_dsa0:
	case m32c_sim_reg_dsa1:
	case m32c_sim_reg_dra0:
	case m32c_sim_reg_dra1:
	  return 0;

	default:
	  fprintf (stderr, "m32c minisim: unrecognized register number: %d\n",
		   regno);
	  return -1;
	}

      put_le (buf, length, val);
    }

  return size;
}

int
sim_store_register (SIM_DESC sd, int regno, unsigned char *buf, int length)
{
  size_t size;

  check_desc (sd);

  if (!check_regno (regno))
    return 0;

  size = reg_size (regno);

  if (length == size)
    {
      DI val = get_le (buf, length);

      switch (regno)
	{
	case m32c_sim_reg_r0_bank0:
	  regs.r[0].r_r0 = val & 0xffff;
	  break;
	case m32c_sim_reg_r1_bank0:
	  regs.r[0].r_r1 = val & 0xffff;
	  break;
	case m32c_sim_reg_r2_bank0:
	  regs.r[0].r_r2 = val & 0xffff;
	  break;
	case m32c_sim_reg_r3_bank0:
	  regs.r[0].r_r3 = val & 0xffff;
	  break;
	case m32c_sim_reg_a0_bank0:
	  regs.r[0].r_a0 = val & addr_mask;
	  break;
	case m32c_sim_reg_a1_bank0:
	  regs.r[0].r_a1 = val & addr_mask;
	  break;
	case m32c_sim_reg_fb_bank0:
	  regs.r[0].r_fb = val & addr_mask;
	  break;
	case m32c_sim_reg_sb_bank0:
	  regs.r[0].r_sb = val & addr_mask;
	  break;
	case m32c_sim_reg_r0_bank1:
	  regs.r[1].r_r0 = val & 0xffff;
	  break;
	case m32c_sim_reg_r1_bank1:
	  regs.r[1].r_r1 = val & 0xffff;
	  break;
	case m32c_sim_reg_r2_bank1:
	  regs.r[1].r_r2 = val & 0xffff;
	  break;
	case m32c_sim_reg_r3_bank1:
	  regs.r[1].r_r3 = val & 0xffff;
	  break;
	case m32c_sim_reg_a0_bank1:
	  regs.r[1].r_a0 = val & addr_mask;
	  break;
	case m32c_sim_reg_a1_bank1:
	  regs.r[1].r_a1 = val & addr_mask;
	  break;
	case m32c_sim_reg_fb_bank1:
	  regs.r[1].r_fb = val & addr_mask;
	  break;
	case m32c_sim_reg_sb_bank1:
	  regs.r[1].r_sb = val & addr_mask;
	  break;

	case m32c_sim_reg_usp:
	  regs.r_usp = val & addr_mask;
	  break;
	case m32c_sim_reg_isp:
	  regs.r_isp = val & addr_mask;
	  break;
	case m32c_sim_reg_pc:
	  regs.r_pc = val & membus_mask;
	  break;
	case m32c_sim_reg_intb:
	  regs.r_intbl = (val & membus_mask) & 0xffff;
	  regs.r_intbh = (val & membus_mask) >> 16;
	  break;
	case m32c_sim_reg_flg:
	  regs.r_flags = val & 0xffff;
	  break;

	  /* These registers aren't implemented by the minisim.  */
	case m32c_sim_reg_svf:
	case m32c_sim_reg_svp:
	case m32c_sim_reg_vct:
	case m32c_sim_reg_dmd0:
	case m32c_sim_reg_dmd1:
	case m32c_sim_reg_dct0:
	case m32c_sim_reg_dct1:
	case m32c_sim_reg_drc0:
	case m32c_sim_reg_drc1:
	case m32c_sim_reg_dma0:
	case m32c_sim_reg_dma1:
	case m32c_sim_reg_dsa0:
	case m32c_sim_reg_dsa1:
	case m32c_sim_reg_dra0:
	case m32c_sim_reg_dra1:
	  return 0;

	default:
	  fprintf (stderr, "m32c minisim: unrecognized register number: %d\n",
		   regno);
	  return -1;
	}
    }

  return size;
}

void
sim_info (SIM_DESC sd, int verbose)
{
  check_desc (sd);

  printf ("The m32c minisim doesn't collect any statistics.\n");
}

static volatile int stop;
static enum sim_stop reason;
int siggnal;


/* Given a signal number used by the M32C bsp (that is, newlib),
   return a host signal number.  (Oddly, the gdb/sim interface uses
   host signal numbers...)  */
int
m32c_signal_to_host (int m32c)
{
  switch (m32c)
    {
    case 4:
#ifdef SIGILL
      return SIGILL;
#else
      return SIGSEGV;
#endif

    case 5:
      return SIGTRAP;

    case 10:
#ifdef SIGBUS
      return SIGBUS;
#else
      return SIGSEGV;
#endif

    case 11:
      return SIGSEGV;

    case 24:
#ifdef SIGXCPU
      return SIGXCPU;
#else
      break;
#endif

    case 2:
      return SIGINT;

    case 8:
#ifdef SIGFPE
      return SIGFPE;
#else
      break;
#endif

    case 6:
      return SIGABRT;
    }

  return 0;
}


/* Take a step return code RC and set up the variables consulted by
   sim_stop_reason appropriately.  */
void
handle_step (int rc)
{
  if (M32C_STEPPED (rc) || M32C_HIT_BREAK (rc))
    {
      reason = sim_stopped;
      siggnal = TARGET_SIGNAL_TRAP;
    }
  else if (M32C_STOPPED (rc))
    {
      reason = sim_stopped;
      siggnal = m32c_signal_to_host (M32C_STOP_SIG (rc));
    }
  else
    {
      assert (M32C_EXITED (rc));
      reason = sim_exited;
      siggnal = M32C_EXIT_STATUS (rc);
    }
}


void
sim_resume (SIM_DESC sd, int step, int sig_to_deliver)
{
  check_desc (sd);

  if (sig_to_deliver != 0)
    {
      fprintf (stderr,
	       "Warning: the m32c minisim does not implement "
	       "signal delivery yet.\n" "Resuming with no signal.\n");
    }

  if (step)
    handle_step (decode_opcode ());
  else
    {
      /* We don't clear 'stop' here, because then we would miss
         interrupts that arrived on the way here.  Instead, we clear
         the flag in sim_stop_reason, after GDB has disabled the
         interrupt signal handler.  */
      for (;;)
	{
	  if (stop)
	    {
	      stop = 0;
	      reason = sim_stopped;
	      siggnal = TARGET_SIGNAL_INT;
	      break;
	    }

	  int rc = decode_opcode ();

	  if (!M32C_STEPPED (rc))
	    {
	      handle_step (rc);
	      break;
	    }
	}
    }
}

int
sim_stop (SIM_DESC sd)
{
  stop = 1;

  return 1;
}

void
sim_stop_reason (SIM_DESC sd, enum sim_stop *reason_p, int *sigrc_p)
{
  check_desc (sd);

  *reason_p = reason;
  *sigrc_p = siggnal;
}

void
sim_do_command (SIM_DESC sd, char *cmd)
{
  check_desc (sd);

  char *p = cmd;

  /* Skip leading whitespace.  */
  while (isspace (*p))
    p++;

  /* Find the extent of the command word.  */
  for (p = cmd; *p; p++)
    if (isspace (*p))
      break;

  /* Null-terminate the command word, and record the start of any
     further arguments.  */
  char *args;
  if (*p)
    {
      *p = '\0';
      args = p + 1;
      while (isspace (*args))
	args++;
    }
  else
    args = p;

  if (strcmp (cmd, "trace") == 0)
    {
      if (strcmp (args, "on") == 0)
	trace = 1;
      else if (strcmp (args, "off") == 0)
	trace = 0;
      else
	printf ("The 'sim trace' command expects 'on' or 'off' "
		"as an argument.\n");
    }
  else if (strcmp (cmd, "verbose") == 0)
    {
      if (strcmp (args, "on") == 0)
	verbose = 1;
      else if (strcmp (args, "off") == 0)
	verbose = 0;
      else
	printf ("The 'sim verbose' command expects 'on' or 'off'"
		" as an argument.\n");
    }
  else
    printf ("The 'sim' command expects either 'trace' or 'verbose'"
	    " as a subcommand.\n");
}
