sim: avr/mcore/moxie: fill out sim-cpu pc fetch/store helpers

[thirdparty/binutils-gdb.git] / sim / mcore / interp.c

/* Simulator for Motorola's MCore processor
   Copyright (C) 1999-2015 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/>.  */

#include "config.h"
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/times.h>
#include <sys/param.h>
#include <unistd.h>
#include "bfd.h"
#include "gdb/callback.h"
#include "libiberty.h"
#include "gdb/remote-sim.h"

#include "sim-main.h"
#include "sim-base.h"
#include "sim-options.h"

#ifndef NUM_ELEM
#define NUM_ELEM(A) (sizeof (A) / sizeof (A)[0])
#endif

#define target_big_endian (CURRENT_TARGET_BYTE_ORDER == BIG_ENDIAN)


static unsigned long
mcore_extract_unsigned_integer (unsigned char *addr, int len)
{
  unsigned long retval;
  unsigned char * p;
  unsigned char * startaddr = (unsigned char *)addr;
  unsigned char * endaddr = startaddr + len;

  if (len > (int) sizeof (unsigned long))
    printf ("That operation is not available on integers of more than %zu bytes.",
            sizeof (unsigned long));

  /* Start at the most significant end of the integer, and work towards
     the least significant.  */
  retval = 0;

  if (! target_big_endian)
    {
      for (p = endaddr; p > startaddr;)
        retval = (retval << 8) | * -- p;
    }
  else
    {
      for (p = startaddr; p < endaddr;)
        retval = (retval << 8) | * p ++;
    }

  return retval;
}

static void
mcore_store_unsigned_integer (unsigned char *addr, int len, unsigned long val)
{
  unsigned char * p;
  unsigned char * startaddr = (unsigned char *)addr;
  unsigned char * endaddr = startaddr + len;

  if (! target_big_endian)
    {
      for (p = startaddr; p < endaddr;)
        {
          * p ++ = val & 0xff;
          val >>= 8;
        }
    }
  else
    {
      for (p = endaddr; p > startaddr;)
        {
          * -- p = val & 0xff;
          val >>= 8;
        }
    }
}

/* The machine state.
   This state is maintained in host byte order.  The
   fetch/store register functions must translate between host
   byte order and the target processor byte order.
   Keeping this data in target byte order simplifies the register
   read/write functions.  Keeping this data in native order improves
   the performance of the simulator.  Simulation speed is deemed more
   important.  */
/* TODO: Should be moved to sim-main.h:sim_cpu.  */

/* The ordering of the mcore_regset structure is matched in the
   gdb/config/mcore/tm-mcore.h file in the REGISTER_NAMES macro.  */
struct mcore_regset
{
  word            gregs [16];           /* primary registers */
  word            alt_gregs [16];       /* alt register file */
  word            cregs [32];           /* control registers */
  int             ticks;
  int             stalls;
  int             cycles;
  int             insts;
  int             exception;
  unsigned long   msize;
  unsigned char * memory;
  word *          active_gregs;
};

union
{
  struct mcore_regset asregs;
  word asints [1];              /* but accessed larger... */
} cpu;

#define LAST_VALID_CREG 32              /* only 0..12 implemented */
#define NUM_MCORE_REGS  (16 + 16 + LAST_VALID_CREG + 1)

static int memcycles = 1;

static int issue_messages = 0;

#define gr      asregs.active_gregs
#define cr      asregs.cregs
#define sr      asregs.cregs[0]
#define vbr     asregs.cregs[1]
#define esr     asregs.cregs[2]
#define fsr     asregs.cregs[3]
#define epc     asregs.cregs[4]
#define fpc     asregs.cregs[5]
#define ss0     asregs.cregs[6]
#define ss1     asregs.cregs[7]
#define ss2     asregs.cregs[8]
#define ss3     asregs.cregs[9]
#define ss4     asregs.cregs[10]
#define gcr     asregs.cregs[11]
#define gsr     asregs.cregs[12]
#define mem     asregs.memory

/* maniuplate the carry bit */
#define C_ON()   (cpu.sr & 1)
#define C_VALUE() (cpu.sr & 1)
#define C_OFF()  ((cpu.sr & 1) == 0)
#define SET_C()  {cpu.sr |= 1;}
#define CLR_C()  {cpu.sr &= 0xfffffffe;}
#define NEW_C(v) {CLR_C(); cpu.sr |= ((v) & 1);}

#define SR_AF() ((cpu.sr >> 1) & 1)

#define TRAPCODE        1       /* r1 holds which function we want */
#define PARM1   2               /* first parameter  */
#define PARM2   3
#define PARM3   4
#define PARM4   5
#define RET1    2               /* register for return values. */

static void
wbat (word x, word v)
{
  if (((uword)x) >= cpu.asregs.msize)
    {
      if (issue_messages)
        fprintf (stderr, "byte write to 0x%x outside memory range\n", x);

      cpu.asregs.exception = SIGSEGV;
    }
  else
    {
      unsigned char *p = cpu.mem + x;
      p[0] = v;
    }
}

static void
wlat (word x, word v)
{
  if (((uword)x) >= cpu.asregs.msize)
    {
      if (issue_messages)
        fprintf (stderr, "word write to 0x%x outside memory range\n", x);

      cpu.asregs.exception = SIGSEGV;
    }
  else
    {
      if ((x & 3) != 0)
        {
          if (issue_messages)
            fprintf (stderr, "word write to unaligned memory address: 0x%x\n", x);

          cpu.asregs.exception = SIGBUS;
        }
      else if (! target_big_endian)
        {
          unsigned char * p = cpu.mem + x;
          p[3] = v >> 24;
          p[2] = v >> 16;
          p[1] = v >> 8;
          p[0] = v;
        }
      else
        {
          unsigned char * p = cpu.mem + x;
          p[0] = v >> 24;
          p[1] = v >> 16;
          p[2] = v >> 8;
          p[3] = v;
        }
    }
}

static void
what (word x, word v)
{
  if (((uword)x) >= cpu.asregs.msize)
    {
      if (issue_messages)
        fprintf (stderr, "short write to 0x%x outside memory range\n", x);

      cpu.asregs.exception = SIGSEGV;
    }
  else
    {
      if ((x & 1) != 0)
        {
          if (issue_messages)
            fprintf (stderr, "short write to unaligned memory address: 0x%x\n",
                     x);

          cpu.asregs.exception = SIGBUS;
        }
      else if (! target_big_endian)
        {
          unsigned char * p = cpu.mem + x;
          p[1] = v >> 8;
          p[0] = v;
        }
      else
        {
          unsigned char * p = cpu.mem + x;
          p[0] = v >> 8;
          p[1] = v;
        }
    }
}

/* Read functions.  */
static int
rbat (word x)
{
  if (((uword)x) >= cpu.asregs.msize)
    {
      if (issue_messages)
        fprintf (stderr, "byte read from 0x%x outside memory range\n", x);

      cpu.asregs.exception = SIGSEGV;
      return 0;
    }
  else
    {
      unsigned char * p = cpu.mem + x;
      return p[0];
    }
}

static int
rlat (word x)
{
  if (((uword) x) >= cpu.asregs.msize)
    {
      if (issue_messages)
        fprintf (stderr, "word read from 0x%x outside memory range\n", x);

      cpu.asregs.exception = SIGSEGV;
      return 0;
    }
  else
    {
      if ((x & 3) != 0)
        {
          if (issue_messages)
            fprintf (stderr, "word read from unaligned address: 0x%x\n", x);

          cpu.asregs.exception = SIGBUS;
          return 0;
        }
      else if (! target_big_endian)
        {
          unsigned char * p = cpu.mem + x;
          return (p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[0];
        }
      else
        {
          unsigned char * p = cpu.mem + x;
          return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
        }
    }
}

static int
rhat (word x)
{
  if (((uword)x) >= cpu.asregs.msize)
    {
      if (issue_messages)
        fprintf (stderr, "short read from 0x%x outside memory range\n", x);

      cpu.asregs.exception = SIGSEGV;
      return 0;
    }
  else
    {
      if ((x & 1) != 0)
        {
          if (issue_messages)
            fprintf (stderr, "short read from unaligned address: 0x%x\n", x);

          cpu.asregs.exception = SIGBUS;
          return 0;
        }
      else if (! target_big_endian)
        {
          unsigned char * p = cpu.mem + x;
          return (p[1] << 8) | p[0];
        }
      else
        {
          unsigned char * p = cpu.mem + x;
          return (p[0] << 8) | p[1];
        }
    }
}


/* Default to a 8 Mbyte (== 2^23) memory space.  */
/* TODO: Delete all this custom memory logic and move to common sim helpers.  */
static int sim_memory_size = 23;

#define MEM_SIZE_FLOOR  64
static void
sim_size (int power)
{
  sim_memory_size = power;
  cpu.asregs.msize = 1 << sim_memory_size;

  if (cpu.mem)
    free (cpu.mem);

  /* Watch out for the '0 count' problem. There's probably a better
     way.. e.g., why do we use 64 here?  */
  if (cpu.asregs.msize < 64)    /* Ensure a boundary.  */
    cpu.mem = (unsigned char *) calloc (64, (64 + cpu.asregs.msize) / 64);
  else
    cpu.mem = (unsigned char *) calloc (64, cpu.asregs.msize / 64);

  if (!cpu.mem)
    {
      if (issue_messages)
        fprintf (stderr,
                 "Not enough VM for simulation of %lu bytes of RAM\n",
                 cpu.asregs.msize);

      cpu.asregs.msize = 1;
      cpu.mem = (unsigned char *) calloc (1, 1);
    }
}

static void
init_pointers (void)
{
  if (cpu.asregs.msize != (1 << sim_memory_size))
    sim_size (sim_memory_size);
}

static void
set_initial_gprs (SIM_CPU *scpu)
{
  int i;
  long space;
  unsigned long memsize;

  init_pointers ();

  /* Set up machine just out of reset.  */
  CIA_SET (scpu, 0);
  cpu.sr = 0;

  memsize = cpu.asregs.msize / (1024 * 1024);

  if (issue_messages > 1)
    fprintf (stderr, "Simulated memory of %lu Mbytes (0x0 .. 0x%08lx)\n",
             memsize, cpu.asregs.msize - 1);

  /* Clean out the GPRs and alternate GPRs.  */
  for (i = 0; i < 16; i++)
    {
      cpu.asregs.gregs[i] = 0;
      cpu.asregs.alt_gregs[i] = 0;
    }

  /* Make our register set point to the right place.  */
  if (SR_AF())
    cpu.asregs.active_gregs = &cpu.asregs.alt_gregs[0];
  else
    cpu.asregs.active_gregs = &cpu.asregs.gregs[0];

  /* ABI specifies initial values for these registers.  */
  cpu.gr[0] = cpu.asregs.msize - 4;

  /* dac fix, the stack address must be 8-byte aligned! */
  cpu.gr[0] = cpu.gr[0] - cpu.gr[0] % 8;
  cpu.gr[PARM1] = 0;
  cpu.gr[PARM2] = 0;
  cpu.gr[PARM3] = 0;
  cpu.gr[PARM4] = cpu.gr[0];
}

/* Functions so that trapped open/close don't interfere with the
   parent's functions.  We say that we can't close the descriptors
   that we didn't open.  exit() and cleanup() get in trouble here,
   to some extent.  That's the price of emulation.  */

unsigned char opened[100];

static void
log_open (int fd)
{
  if (fd < 0 || fd > NUM_ELEM (opened))
    return;

  opened[fd] = 1;
}

static void
log_close (int fd)
{
  if (fd < 0 || fd > NUM_ELEM (opened))
    return;

  opened[fd] = 0;
}

static int
is_opened (int fd)
{
  if (fd < 0 || fd > NUM_ELEM (opened))
    return 0;

  return opened[fd];
}

static void
handle_trap1 (SIM_DESC sd)
{
  unsigned long a[3];
  host_callback *callback = STATE_CALLBACK (sd);

  switch ((unsigned long) (cpu.gr [TRAPCODE]))
    {
    case 3:
      a[0] = (unsigned long) (cpu.gr[PARM1]);
      a[1] = (unsigned long) (cpu.mem + cpu.gr[PARM2]);
      a[2] = (unsigned long) (cpu.gr[PARM3]);
      cpu.gr[RET1] = callback->read (callback, a[0], (char *) a[1], a[2]);
      break;

    case 4:
      a[0] = (unsigned long) (cpu.gr[PARM1]);
      a[1] = (unsigned long) (cpu.mem + cpu.gr[PARM2]);
      a[2] = (unsigned long) (cpu.gr[PARM3]);
      cpu.gr[RET1] = (int)callback->write (callback, a[0], (char *) a[1], a[2]);
      break;

    case 5:
      a[0] = (unsigned long) (cpu.mem + cpu.gr[PARM1]);
      a[1] = (unsigned long) (cpu.gr[PARM2]);
      /* a[2] = (unsigned long) (cpu.gr[PARM3]); */
      cpu.gr[RET1] = callback->open (callback, (char *) a[0], a[1]);
      log_open (cpu.gr[RET1]);
      break;

    case 6:
      a[0] = (unsigned long) (cpu.gr[PARM1]);
      /* Watch out for debugger's files. */
      if (is_opened (a[0]))
        {
          log_close (a[0]);
          cpu.gr[RET1] = callback->close (callback, a[0]);
        }
      else
        {
          /* Don't let him close it.  */
          cpu.gr[RET1] = (-1);
        }
      break;

    case 9:
      a[0] = (unsigned long) (cpu.mem + cpu.gr[PARM1]);
      a[1] = (unsigned long) (cpu.mem + cpu.gr[PARM2]);
      cpu.gr[RET1] = link ((char *) a[0], (char *) a[1]);
      break;

    case 10:
      a[0] = (unsigned long) (cpu.mem + cpu.gr[PARM1]);
      cpu.gr[RET1] = callback->unlink (callback, (char *) a[0]);
      break;

    case 13:
      /* handle time(0) vs time(&var) */
      a[0] = (unsigned long) (cpu.gr[PARM1]);
      if (a[0])
        a[0] += (unsigned long) cpu.mem;
      cpu.gr[RET1] = callback->time (callback, (time_t *) a[0]);
      break;

    case 19:
      a[0] = (unsigned long) (cpu.gr[PARM1]);
      a[1] = (unsigned long) (cpu.gr[PARM2]);
      a[2] = (unsigned long) (cpu.gr[PARM3]);
      cpu.gr[RET1] = callback->lseek (callback, a[0], a[1], a[2]);
      break;

    case 33:
      a[0] = (unsigned long) (cpu.mem + cpu.gr[PARM1]);
      a[1] = (unsigned long) (cpu.gr[PARM2]);
      cpu.gr[RET1] = access ((char *) a[0], a[1]);
      break;

    case 43:
      a[0] = (unsigned long) (cpu.mem + cpu.gr[PARM1]);
#if 0
      cpu.gr[RET1] = times ((char *)a[0]);
#else
      {
        /* Give him simulated cycles for utime
           and an instruction count for stime. */
        struct tms
        {
          time_t tms_utime;
          time_t tms_stime;
          time_t tms_cutime;
          time_t tms_cstime;
        } t;

        t.tms_utime = cpu.asregs.cycles;
        t.tms_stime = cpu.asregs.insts;
        t.tms_cutime = t.tms_utime;
        t.tms_cstime = t.tms_stime;

        memcpy ((struct tms *)(a[0]), &t, sizeof (t));

        cpu.gr[RET1] = cpu.asregs.cycles;
      }
#endif
      break;

    case 69:
      /* Historically this was sbrk(), but no one used it, and the
        implementation didn't actually work, so it's a stub now.  */
      a[0] = (unsigned long) (cpu.gr[PARM1]);
      cpu.gr[RET1] = -1;
      break;

    default:
      if (issue_messages)
        fprintf (stderr, "WARNING: sys call %d unimplemented\n",
                 cpu.gr[TRAPCODE]);
      break;
    }
}

static void
process_stub (SIM_DESC sd, int what)
{
  /* These values should match those in libgloss/mcore/syscalls.s.  */
  switch (what)
    {
    case 3:  /* _read */
    case 4:  /* _write */
    case 5:  /* _open */
    case 6:  /* _close */
    case 10: /* _unlink */
    case 19: /* _lseek */
    case 43: /* _times */
      cpu.gr [TRAPCODE] = what;
      handle_trap1 (sd);
      break;

    default:
      if (issue_messages)
        fprintf (stderr, "Unhandled stub opcode: %d\n", what);
      break;
    }
}

static void
util (SIM_DESC sd, unsigned what)
{
  switch (what)
    {
    case 0:     /* exit */
      cpu.asregs.exception = SIGQUIT;
      break;

    case 1:     /* printf */
      {
        unsigned long a[6];
        unsigned char *s;
        int i;

        a[0] = (unsigned long)(cpu.mem + cpu.gr[PARM1]);

        for (s = (unsigned char *)a[0], i = 1 ; *s && i < 6 ; s++)
          {
            if (*s == '%')
              {
                if (*++s == 's')
                  a[i] = (unsigned long)(cpu.mem + cpu.gr[PARM1+i]);
                else
                  a[i] = cpu.gr[i+PARM1];
                i++;
              }
          }

        cpu.gr[RET1] = printf ((char *)a[0], a[1], a[2], a[3], a[4], a[5]);
      }
      break;

    case 2:     /* scanf */
      if (issue_messages)
        fprintf (stderr, "WARNING: scanf unimplemented\n");
      break;

    case 3:     /* utime */
      cpu.gr[RET1] = cpu.asregs.insts;
      break;

    case 0xFF:
      process_stub (sd, cpu.gr[1]);
      break;

    default:
      if (issue_messages)
        fprintf (stderr, "Unhandled util code: %x\n", what);
      break;
    }
}

/* For figuring out whether we carried; addc/subc use this. */
static int
iu_carry (unsigned long a, unsigned long b, int cin)
{
  unsigned long x;

  x = (a & 0xffff) + (b & 0xffff) + cin;
  x = (x >> 16) + (a >> 16) + (b >> 16);
  x >>= 16;

  return (x != 0);
}

#define WATCHFUNCTIONS 1
#ifdef WATCHFUNCTIONS

#define MAXWL 80
word WL[MAXWL];
char * WLstr[MAXWL];

int ENDWL=0;
int WLincyc;
int WLcyc[MAXWL];
int WLcnts[MAXWL];
int WLmax[MAXWL];
int WLmin[MAXWL];
word WLendpc;
int WLbcyc;
int WLW;
#endif

#define RD      (inst        & 0xF)
#define RS      ((inst >> 4) & 0xF)
#define RX      ((inst >> 8) & 0xF)
#define IMM5    ((inst >> 4) & 0x1F)
#define IMM4    ((inst) & 0xF)

static int tracing = 0;

void
sim_resume (SIM_DESC sd, int step, int siggnal)
{
  SIM_CPU *scpu = STATE_CPU (sd, 0);
  int needfetch;
  word ibuf;
  word pc;
  unsigned short inst;
  int memops;
  int bonus_cycles;
  int insts;
  int w;
  int cycs;
  word WLhash;

  cpu.asregs.exception = step ? SIGTRAP: 0;
  pc = CIA_GET (scpu);

  /* Fetch the initial instructions that we'll decode. */
  ibuf = rlat (pc & 0xFFFFFFFC);
  needfetch = 0;

  memops = 0;
  bonus_cycles = 0;
  insts = 0;

  /* make our register set point to the right place */
  if (SR_AF ())
    cpu.asregs.active_gregs = & cpu.asregs.alt_gregs[0];
  else
    cpu.asregs.active_gregs = & cpu.asregs.gregs[0];

  /* make a hash to speed exec loop, hope it's nonzero */
  WLhash = 0xFFFFFFFF;

  for (w = 1; w <= ENDWL; w++)
    WLhash = WLhash & WL[w];

  do
    {
      word oldpc;

      insts ++;

      if (pc & 02)
        {
          if (! target_big_endian)
            inst = ibuf >> 16;
          else
            inst = ibuf & 0xFFFF;
          needfetch = 1;
        }
      else
        {
          if (! target_big_endian)
            inst = ibuf & 0xFFFF;
          else
            inst = ibuf >> 16;
        }

#ifdef WATCHFUNCTIONS
      /* now scan list of watch addresses, if match, count it and
         note return address and count cycles until pc=return address */

      if ((WLincyc == 1) && (pc == WLendpc))
        {
          cycs = (cpu.asregs.cycles + (insts + bonus_cycles +
                                       (memops * memcycles)) - WLbcyc);

          if (WLcnts[WLW] == 1)
            {
              WLmax[WLW] = cycs;
              WLmin[WLW] = cycs;
              WLcyc[WLW] = 0;
            }

          if (cycs > WLmax[WLW])
            {
              WLmax[WLW] = cycs;
            }

          if (cycs < WLmin[WLW])
            {
              WLmin[WLW] = cycs;
            }

          WLcyc[WLW] += cycs;
          WLincyc = 0;
          WLendpc = 0;
        }

      /* Optimize with a hash to speed loop.  */
      if (WLincyc == 0)
        {
          if ((WLhash == 0) || ((WLhash & pc) != 0))
            {
              for (w=1; w <= ENDWL; w++)
                {
                  if (pc == WL[w])
                    {
                      WLcnts[w]++;
                      WLbcyc = cpu.asregs.cycles + insts
                        + bonus_cycles + (memops * memcycles);
                      WLendpc = cpu.gr[15];
                      WLincyc = 1;
                      WLW = w;
                      break;
                    }
                }
            }
        }
#endif

      if (tracing)
        fprintf (stderr, "%.4x: inst = %.4x ", pc, inst);

      oldpc = pc;

      pc += 2;

      switch (inst >> 8)
        {
        case 0x00:
          switch RS
            {
            case 0x0:
              switch RD
                {
                case 0x0:                               /* bkpt */
                  cpu.asregs.exception = SIGTRAP;
                  pc -= 2;
                  break;

                case 0x1:                               /* sync */
                  break;

                case 0x2:                               /* rte */
                  pc = cpu.epc;
                  cpu.sr = cpu.esr;
                  needfetch = 1;

                  if (SR_AF ())
                    cpu.asregs.active_gregs = & cpu.asregs.alt_gregs[0];
                  else
                    cpu.asregs.active_gregs = & cpu.asregs.gregs[0];
                  break;

                case 0x3:                               /* rfi */
                  pc = cpu.fpc;
                  cpu.sr = cpu.fsr;
                  needfetch = 1;

                  if (SR_AF ())
                    cpu.asregs.active_gregs = &cpu.asregs.alt_gregs[0];
                  else
                    cpu.asregs.active_gregs = &cpu.asregs.gregs[0];
                  break;

                case 0x4:                               /* stop */
                  if (issue_messages)
                    fprintf (stderr, "WARNING: stop unimplemented\n");
                  break;

                case 0x5:                               /* wait */
                  if (issue_messages)
                    fprintf (stderr, "WARNING: wait unimplemented\n");
                  break;

                case 0x6:                               /* doze */
                  if (issue_messages)
                    fprintf (stderr, "WARNING: doze unimplemented\n");
                  break;

                case 0x7:
                  cpu.asregs.exception = SIGILL;        /* illegal */
                  break;

                case 0x8:                               /* trap 0 */
                case 0xA:                               /* trap 2 */
                case 0xB:                               /* trap 3 */
                  cpu.asregs.exception = SIGTRAP;
                  break;

                case 0xC:                               /* trap 4 */
                case 0xD:                               /* trap 5 */
                case 0xE:                               /* trap 6 */
                  cpu.asregs.exception = SIGILL;        /* illegal */
                  break;

                case 0xF:                               /* trap 7 */
                  cpu.asregs.exception = SIGTRAP;       /* integer div-by-0 */
                  break;

                case 0x9:                               /* trap 1 */
                  handle_trap1 (sd);
                  break;
                }
              break;

            case 0x1:
              cpu.asregs.exception = SIGILL;            /* illegal */
              break;

            case 0x2:                                   /* mvc */
              cpu.gr[RD] = C_VALUE();
              break;
            case 0x3:                                   /* mvcv */
              cpu.gr[RD] = C_OFF();
              break;
            case 0x4:                                   /* ldq */
              {
                word addr = cpu.gr[RD];
                int regno = 4;                  /* always r4-r7 */

                bonus_cycles++;
                memops += 4;
                do
                  {
                    cpu.gr[regno] = rlat(addr);
                    addr += 4;
                    regno++;
                  }
                while ((regno&0x3) != 0);
              }
              break;
            case 0x5:                                   /* stq */
              {
                word addr = cpu.gr[RD];
                int regno = 4;                  /* always r4-r7 */

                memops += 4;
                bonus_cycles++;
                do
                  {
                    wlat(addr, cpu.gr[regno]);
                    addr += 4;
                    regno++;
                  }
                while ((regno & 0x3) != 0);
              }
              break;
            case 0x6:                                   /* ldm */
              {
                word addr = cpu.gr[0];
                int regno = RD;

                /* bonus cycle is really only needed if
                   the next insn shifts the last reg loaded.

                   bonus_cycles++;
                */
                memops += 16-regno;
                while (regno <= 0xF)
                  {
                    cpu.gr[regno] = rlat(addr);
                    addr += 4;
                    regno++;
                  }
              }
              break;
            case 0x7:                                   /* stm */
              {
                word addr = cpu.gr[0];
                int regno = RD;

                /* this should be removed! */
                /*  bonus_cycles ++; */

                memops += 16 - regno;
                while (regno <= 0xF)
                  {
                    wlat(addr, cpu.gr[regno]);
                    addr += 4;
                    regno++;
                  }
              }
              break;

            case 0x8:                                   /* dect */
              cpu.gr[RD] -= C_VALUE();
              break;
            case 0x9:                                   /* decf */
              cpu.gr[RD] -= C_OFF();
              break;
            case 0xA:                                   /* inct */
              cpu.gr[RD] += C_VALUE();
              break;
            case 0xB:                                   /* incf */
              cpu.gr[RD] += C_OFF();
              break;
            case 0xC:                                   /* jmp */
              pc = cpu.gr[RD];
              if (tracing && RD == 15)
                fprintf (stderr, "Func return, r2 = %x, r3 = %x\n",
                         cpu.gr[2], cpu.gr[3]);
              bonus_cycles++;
              needfetch = 1;
              break;
            case 0xD:                                   /* jsr */
              cpu.gr[15] = pc;
              pc = cpu.gr[RD];
              bonus_cycles++;
              needfetch = 1;
              break;
            case 0xE:                                   /* ff1 */
              {
                word tmp, i;
                tmp = cpu.gr[RD];
                for (i = 0; !(tmp & 0x80000000) && i < 32; i++)
                  tmp <<= 1;
                cpu.gr[RD] = i;
              }
              break;
            case 0xF:                                   /* brev */
              {
                word tmp;
                tmp = cpu.gr[RD];
                tmp = ((tmp & 0xaaaaaaaa) >>  1) | ((tmp & 0x55555555) <<  1);
                tmp = ((tmp & 0xcccccccc) >>  2) | ((tmp & 0x33333333) <<  2);
                tmp = ((tmp & 0xf0f0f0f0) >>  4) | ((tmp & 0x0f0f0f0f) <<  4);
                tmp = ((tmp & 0xff00ff00) >>  8) | ((tmp & 0x00ff00ff) <<  8);
                cpu.gr[RD] = ((tmp & 0xffff0000) >> 16) | ((tmp & 0x0000ffff) << 16);
              }
              break;
            }
          break;
        case 0x01:
          switch RS
            {
            case 0x0:                                   /* xtrb3 */
              cpu.gr[1] = (cpu.gr[RD]) & 0xFF;
              NEW_C (cpu.gr[RD] != 0);
              break;
            case 0x1:                                   /* xtrb2 */
              cpu.gr[1] = (cpu.gr[RD]>>8) & 0xFF;
              NEW_C (cpu.gr[RD] != 0);
              break;
            case 0x2:                                   /* xtrb1 */
              cpu.gr[1] = (cpu.gr[RD]>>16) & 0xFF;
              NEW_C (cpu.gr[RD] != 0);
              break;
            case 0x3:                                   /* xtrb0 */
              cpu.gr[1] = (cpu.gr[RD]>>24) & 0xFF;
              NEW_C (cpu.gr[RD] != 0);
              break;
            case 0x4:                                   /* zextb */
              cpu.gr[RD] &= 0x000000FF;
              break;
            case 0x5:                                   /* sextb */
              {
                long tmp;
                tmp = cpu.gr[RD];
                tmp <<= 24;
                tmp >>= 24;
                cpu.gr[RD] = tmp;
              }
              break;
            case 0x6:                                   /* zexth */
              cpu.gr[RD] &= 0x0000FFFF;
              break;
            case 0x7:                                   /* sexth */
              {
                long tmp;
                tmp = cpu.gr[RD];
                tmp <<= 16;
                tmp >>= 16;
                cpu.gr[RD] = tmp;
              }
              break;
            case 0x8:                                   /* declt */
              --cpu.gr[RD];
              NEW_C ((long)cpu.gr[RD] < 0);
              break;
            case 0x9:                                   /* tstnbz */
              {
                word tmp = cpu.gr[RD];
                NEW_C ((tmp & 0xFF000000) != 0 &&
                       (tmp & 0x00FF0000) != 0 && (tmp & 0x0000FF00) != 0 &&
                       (tmp & 0x000000FF) != 0);
              }
              break;
            case 0xA:                                   /* decgt */
              --cpu.gr[RD];
              NEW_C ((long)cpu.gr[RD] > 0);
              break;
            case 0xB:                                   /* decne */
              --cpu.gr[RD];
              NEW_C ((long)cpu.gr[RD] != 0);
              break;
            case 0xC:                                   /* clrt */
              if (C_ON())
                cpu.gr[RD] = 0;
              break;
            case 0xD:                                   /* clrf */
              if (C_OFF())
                cpu.gr[RD] = 0;
              break;
            case 0xE:                                   /* abs */
              if (cpu.gr[RD] & 0x80000000)
                cpu.gr[RD] = ~cpu.gr[RD] + 1;
              break;
            case 0xF:                                   /* not */
              cpu.gr[RD] = ~cpu.gr[RD];
              break;
            }
          break;
        case 0x02:                                      /* movt */
          if (C_ON())
            cpu.gr[RD] = cpu.gr[RS];
          break;
        case 0x03:                                      /* mult */
          /* consume 2 bits per cycle from rs, until rs is 0 */
          {
            unsigned int t = cpu.gr[RS];
            int ticks;
            for (ticks = 0; t != 0 ; t >>= 2)
              ticks++;
            bonus_cycles += ticks;
          }
          bonus_cycles += 2;  /* min. is 3, so add 2, plus ticks above */
          if (tracing)
            fprintf (stderr, "  mult %x by %x to give %x",
                     cpu.gr[RD], cpu.gr[RS], cpu.gr[RD] * cpu.gr[RS]);
          cpu.gr[RD] = cpu.gr[RD] * cpu.gr[RS];
          break;
        case 0x04:                                      /* loopt */
          if (C_ON())
            {
              pc += (IMM4 << 1) - 32;
              bonus_cycles ++;
              needfetch = 1;
            }
          --cpu.gr[RS];                         /* not RD! */
          NEW_C (((long)cpu.gr[RS]) > 0);
          break;
        case 0x05:                                      /* subu */
          cpu.gr[RD] -= cpu.gr[RS];
          break;
        case 0x06:                                      /* addc */
          {
            unsigned long tmp, a, b;
            a = cpu.gr[RD];
            b = cpu.gr[RS];
            cpu.gr[RD] = a + b + C_VALUE ();
            tmp = iu_carry (a, b, C_VALUE ());
            NEW_C (tmp);
          }
          break;
        case 0x07:                                      /* subc */
          {
            unsigned long tmp, a, b;
            a = cpu.gr[RD];
            b = cpu.gr[RS];
            cpu.gr[RD] = a - b + C_VALUE () - 1;
            tmp = iu_carry (a,~b, C_VALUE ());
            NEW_C (tmp);
          }
          break;
        case 0x08:                                      /* illegal */
        case 0x09:                                      /* illegal*/
          cpu.asregs.exception = SIGILL;
          break;
        case 0x0A:                                      /* movf */
          if (C_OFF())
            cpu.gr[RD] = cpu.gr[RS];
          break;
        case 0x0B:                                      /* lsr */
          {
            unsigned long dst, src;
            dst = cpu.gr[RD];
            src = cpu.gr[RS];
            /* We must not rely solely upon the native shift operations, since they
               may not match the M*Core's behaviour on boundary conditions.  */
            dst = src > 31 ? 0 : dst >> src;
            cpu.gr[RD] = dst;
          }
          break;
        case 0x0C:                                      /* cmphs */
          NEW_C ((unsigned long )cpu.gr[RD] >=
                 (unsigned long)cpu.gr[RS]);
          break;
        case 0x0D:                                      /* cmplt */
          NEW_C ((long)cpu.gr[RD] < (long)cpu.gr[RS]);
          break;
        case 0x0E:                                      /* tst */
          NEW_C ((cpu.gr[RD] & cpu.gr[RS]) != 0);
          break;
        case 0x0F:                                      /* cmpne */
          NEW_C (cpu.gr[RD] != cpu.gr[RS]);
          break;
        case 0x10: case 0x11:                           /* mfcr */
          {
            unsigned r;
            r = IMM5;
            if (r <= LAST_VALID_CREG)
              cpu.gr[RD] = cpu.cr[r];
            else
              cpu.asregs.exception = SIGILL;
          }
          break;

        case 0x12:                                      /* mov */
          cpu.gr[RD] = cpu.gr[RS];
          if (tracing)
            fprintf (stderr, "MOV %x into reg %d", cpu.gr[RD], RD);
          break;

        case 0x13:                                      /* bgenr */
          if (cpu.gr[RS] & 0x20)
            cpu.gr[RD] = 0;
          else
            cpu.gr[RD] = 1 << (cpu.gr[RS] & 0x1F);
          break;

        case 0x14:                                      /* rsub */
          cpu.gr[RD] = cpu.gr[RS] - cpu.gr[RD];
          break;

        case 0x15:                                      /* ixw */
          cpu.gr[RD] += cpu.gr[RS]<<2;
          break;

        case 0x16:                                      /* and */
          cpu.gr[RD] &= cpu.gr[RS];
          break;

        case 0x17:                                      /* xor */
          cpu.gr[RD] ^= cpu.gr[RS];
          break;

        case 0x18: case 0x19:                           /* mtcr */
          {
            unsigned r;
            r = IMM5;
            if (r <= LAST_VALID_CREG)
              cpu.cr[r] = cpu.gr[RD];
            else
              cpu.asregs.exception = SIGILL;

            /* we might have changed register sets... */
            if (SR_AF ())
              cpu.asregs.active_gregs = & cpu.asregs.alt_gregs[0];
            else
              cpu.asregs.active_gregs = & cpu.asregs.gregs[0];
          }
          break;

        case 0x1A:                                      /* asr */
          /* We must not rely solely upon the native shift operations, since they
             may not match the M*Core's behaviour on boundary conditions.  */
          if (cpu.gr[RS] > 30)
            cpu.gr[RD] = ((long) cpu.gr[RD]) < 0 ? -1 : 0;
          else
            cpu.gr[RD] = (long) cpu.gr[RD] >> cpu.gr[RS];
          break;

        case 0x1B:                                      /* lsl */
          /* We must not rely solely upon the native shift operations, since they
             may not match the M*Core's behaviour on boundary conditions.  */
          cpu.gr[RD] = cpu.gr[RS] > 31 ? 0 : cpu.gr[RD] << cpu.gr[RS];
          break;

        case 0x1C:                                      /* addu */
          cpu.gr[RD] += cpu.gr[RS];
          break;

        case 0x1D:                                      /* ixh */
          cpu.gr[RD] += cpu.gr[RS] << 1;
          break;

        case 0x1E:                                      /* or */
          cpu.gr[RD] |= cpu.gr[RS];
          break;

        case 0x1F:                                      /* andn */
          cpu.gr[RD] &= ~cpu.gr[RS];
          break;
        case 0x20: case 0x21:                           /* addi */
          cpu.gr[RD] =
            cpu.gr[RD] + (IMM5 + 1);
          break;
        case 0x22: case 0x23:                           /* cmplti */
          {
            int tmp = (IMM5 + 1);
            if (cpu.gr[RD] < tmp)
              {
                SET_C();
              }
            else
              {
                CLR_C();
              }
          }
          break;
        case 0x24: case 0x25:                           /* subi */
          cpu.gr[RD] =
            cpu.gr[RD] - (IMM5 + 1);
          break;
        case 0x26: case 0x27:                           /* illegal */
          cpu.asregs.exception = SIGILL;
          break;
        case 0x28: case 0x29:                           /* rsubi */
          cpu.gr[RD] =
            IMM5 - cpu.gr[RD];
          break;
        case 0x2A: case 0x2B:                           /* cmpnei */
          if (cpu.gr[RD] != IMM5)
            {
              SET_C();
            }
          else
            {
              CLR_C();
            }
          break;

        case 0x2C: case 0x2D:                           /* bmaski, divu */
          {
            unsigned imm = IMM5;

            if (imm == 1)
              {
                int exe;
                int rxnlz, r1nlz;
                unsigned int rx, r1;

                rx = cpu.gr[RD];
                r1 = cpu.gr[1];
                exe = 0;

                /* unsigned divide */
                cpu.gr[RD] = (word) ((unsigned int) cpu.gr[RD] / (unsigned int)cpu.gr[1] );

                /* compute bonus_cycles for divu */
                for (r1nlz = 0; ((r1 & 0x80000000) == 0) && (r1nlz < 32); r1nlz ++)
                  r1 = r1 << 1;

                for (rxnlz = 0; ((rx & 0x80000000) == 0) && (rxnlz < 32); rxnlz ++)
                  rx = rx << 1;

                if (r1nlz < rxnlz)
                  exe += 4;
                else
                  exe += 5 + r1nlz - rxnlz;

                if (exe >= (2 * memcycles - 1))
                  {
                    bonus_cycles += exe - (2 * memcycles) + 1;
                  }
              }
            else if (imm == 0 || imm >= 8)
              {
                /* bmaski */
                if (imm == 0)
                  cpu.gr[RD] = -1;
                else
                  cpu.gr[RD] = (1 << imm) - 1;
              }
            else
              {
                /* illegal */
                cpu.asregs.exception = SIGILL;
              }
          }
          break;
        case 0x2E: case 0x2F:                           /* andi */
          cpu.gr[RD] = cpu.gr[RD] & IMM5;
          break;
        case 0x30: case 0x31:                           /* bclri */
          cpu.gr[RD] = cpu.gr[RD] & ~(1<<IMM5);
          break;
        case 0x32: case 0x33:                           /* bgeni, divs */
          {
            unsigned imm = IMM5;
            if (imm == 1)
              {
                int exe,sc;
                int rxnlz, r1nlz;
                signed int rx, r1;

                /* compute bonus_cycles for divu */
                rx = cpu.gr[RD];
                r1 = cpu.gr[1];
                exe = 0;

                if (((rx < 0) && (r1 > 0)) || ((rx >= 0) && (r1 < 0)))
                  sc = 1;
                else
                  sc = 0;

                rx = abs (rx);
                r1 = abs (r1);

                /* signed divide, general registers are of type int, so / op is OK */
                cpu.gr[RD] = cpu.gr[RD] / cpu.gr[1];

                for (r1nlz = 0; ((r1 & 0x80000000) == 0) && (r1nlz < 32) ; r1nlz ++ )
                  r1 = r1 << 1;

                for (rxnlz = 0; ((rx & 0x80000000) == 0) && (rxnlz < 32) ; rxnlz ++ )
                  rx = rx << 1;

                if (r1nlz < rxnlz)
                  exe += 5;
                else
                  exe += 6 + r1nlz - rxnlz + sc;

                if (exe >= (2 * memcycles - 1))
                  {
                    bonus_cycles += exe - (2 * memcycles) + 1;
                  }
              }
            else if (imm >= 7)
              {
                /* bgeni */
                cpu.gr[RD] = (1 << IMM5);
              }
            else
              {
                /* illegal */
                cpu.asregs.exception = SIGILL;
              }
            break;
          }
        case 0x34: case 0x35:                           /* bseti */
          cpu.gr[RD] = cpu.gr[RD] | (1 << IMM5);
          break;
        case 0x36: case 0x37:                           /* btsti */
          NEW_C (cpu.gr[RD] >> IMM5);
          break;
        case 0x38: case 0x39:                           /* xsr, rotli */
          {
            unsigned imm = IMM5;
            unsigned long tmp = cpu.gr[RD];
            if (imm == 0)
              {
                word cbit;
                cbit = C_VALUE();
                NEW_C (tmp);
                cpu.gr[RD] = (cbit << 31) | (tmp >> 1);
              }
            else
              cpu.gr[RD] = (tmp << imm) | (tmp >> (32 - imm));
          }
          break;
        case 0x3A: case 0x3B:                           /* asrc, asri */
          {
            unsigned imm = IMM5;
            long tmp = cpu.gr[RD];
            if (imm == 0)
              {
                NEW_C (tmp);
                cpu.gr[RD] = tmp >> 1;
              }
            else
              cpu.gr[RD] = tmp >> imm;
          }
          break;
        case 0x3C: case 0x3D:                           /* lslc, lsli */
          {
            unsigned imm = IMM5;
            unsigned long tmp = cpu.gr[RD];
            if (imm == 0)
              {
                NEW_C (tmp >> 31);
                cpu.gr[RD] = tmp << 1;
              }
            else
              cpu.gr[RD] = tmp << imm;
          }
          break;
        case 0x3E: case 0x3F:                           /* lsrc, lsri */
          {
            unsigned imm = IMM5;
            unsigned long tmp = cpu.gr[RD];
            if (imm == 0)
              {
                NEW_C (tmp);
                cpu.gr[RD] = tmp >> 1;
              }
            else
              cpu.gr[RD] = tmp >> imm;
          }
          break;
        case 0x40: case 0x41: case 0x42: case 0x43:
        case 0x44: case 0x45: case 0x46: case 0x47:
        case 0x48: case 0x49: case 0x4A: case 0x4B:
        case 0x4C: case 0x4D: case 0x4E: case 0x4F:
          cpu.asregs.exception = SIGILL;
          break;
        case 0x50:
          util (sd, inst & 0xFF);
          break;
        case 0x51: case 0x52: case 0x53:
        case 0x54: case 0x55: case 0x56: case 0x57:
        case 0x58: case 0x59: case 0x5A: case 0x5B:
        case 0x5C: case 0x5D: case 0x5E: case 0x5F:
          cpu.asregs.exception = SIGILL;
          break;
        case 0x60: case 0x61: case 0x62: case 0x63:     /* movi  */
        case 0x64: case 0x65: case 0x66: case 0x67:
          cpu.gr[RD] = (inst >> 4) & 0x7F;
          break;
        case 0x68: case 0x69: case 0x6A: case 0x6B:
        case 0x6C: case 0x6D: case 0x6E: case 0x6F:     /* illegal */
          cpu.asregs.exception = SIGILL;
          break;
        case 0x71: case 0x72: case 0x73:
        case 0x74: case 0x75: case 0x76: case 0x77:
        case 0x78: case 0x79: case 0x7A: case 0x7B:
        case 0x7C: case 0x7D: case 0x7E:                /* lrw */
          cpu.gr[RX] =  rlat ((pc + ((inst & 0xFF) << 2)) & 0xFFFFFFFC);
          if (tracing)
            fprintf (stderr, "LRW of 0x%x from 0x%x to reg %d",
                     rlat ((pc + ((inst & 0xFF) << 2)) & 0xFFFFFFFC),
                     (pc + ((inst & 0xFF) << 2)) & 0xFFFFFFFC, RX);
          memops++;
          break;
        case 0x7F:                                      /* jsri */
          cpu.gr[15] = pc;
          if (tracing)
            fprintf (stderr, "func call: r2 = %x r3 = %x r4 = %x r5 = %x r6 = %x r7 = %x\n",
                     cpu.gr[2], cpu.gr[3], cpu.gr[4], cpu.gr[5], cpu.gr[6], cpu.gr[7]);
        case 0x70:                                      /* jmpi */
          pc = rlat ((pc + ((inst & 0xFF) << 2)) & 0xFFFFFFFC);
          memops++;
          bonus_cycles++;
          needfetch = 1;
          break;

        case 0x80: case 0x81: case 0x82: case 0x83:
        case 0x84: case 0x85: case 0x86: case 0x87:
        case 0x88: case 0x89: case 0x8A: case 0x8B:
        case 0x8C: case 0x8D: case 0x8E: case 0x8F:     /* ld */
          cpu.gr[RX] = rlat (cpu.gr[RD] + ((inst >> 2) & 0x003C));
          if (tracing)
            fprintf (stderr, "load reg %d from 0x%x with 0x%x",
                     RX,
                     cpu.gr[RD] + ((inst >> 2) & 0x003C), cpu.gr[RX]);
          memops++;
          break;
        case 0x90: case 0x91: case 0x92: case 0x93:
        case 0x94: case 0x95: case 0x96: case 0x97:
        case 0x98: case 0x99: case 0x9A: case 0x9B:
        case 0x9C: case 0x9D: case 0x9E: case 0x9F:     /* st */
          wlat (cpu.gr[RD] + ((inst >> 2) & 0x003C), cpu.gr[RX]);
          if (tracing)
            fprintf (stderr, "store reg %d (containing 0x%x) to 0x%x",
                     RX, cpu.gr[RX],
                     cpu.gr[RD] + ((inst >> 2) & 0x003C));
          memops++;
          break;
        case 0xA0: case 0xA1: case 0xA2: case 0xA3:
        case 0xA4: case 0xA5: case 0xA6: case 0xA7:
        case 0xA8: case 0xA9: case 0xAA: case 0xAB:
        case 0xAC: case 0xAD: case 0xAE: case 0xAF:     /* ld.b */
          cpu.gr[RX] = rbat (cpu.gr[RD] + RS);
          memops++;
          break;
        case 0xB0: case 0xB1: case 0xB2: case 0xB3:
        case 0xB4: case 0xB5: case 0xB6: case 0xB7:
        case 0xB8: case 0xB9: case 0xBA: case 0xBB:
        case 0xBC: case 0xBD: case 0xBE: case 0xBF:     /* st.b */
          wbat (cpu.gr[RD] + RS, cpu.gr[RX]);
          memops++;
          break;
        case 0xC0: case 0xC1: case 0xC2: case 0xC3:
        case 0xC4: case 0xC5: case 0xC6: case 0xC7:
        case 0xC8: case 0xC9: case 0xCA: case 0xCB:
        case 0xCC: case 0xCD: case 0xCE: case 0xCF:     /* ld.h */
          cpu.gr[RX] = rhat (cpu.gr[RD] + ((inst >> 3) & 0x001E));
          memops++;
          break;
        case 0xD0: case 0xD1: case 0xD2: case 0xD3:
        case 0xD4: case 0xD5: case 0xD6: case 0xD7:
        case 0xD8: case 0xD9: case 0xDA: case 0xDB:
        case 0xDC: case 0xDD: case 0xDE: case 0xDF:     /* st.h */
          what (cpu.gr[RD] + ((inst >> 3) & 0x001E), cpu.gr[RX]);
          memops++;
          break;
        case 0xE8: case 0xE9: case 0xEA: case 0xEB:
        case 0xEC: case 0xED: case 0xEE: case 0xEF:     /* bf */
          if (C_OFF())
            {
              int disp;
              disp = inst & 0x03FF;
              if (inst & 0x0400)
                disp |= 0xFFFFFC00;
              pc += disp<<1;
              bonus_cycles++;
              needfetch = 1;
            }
          break;
        case 0xE0: case 0xE1: case 0xE2: case 0xE3:
        case 0xE4: case 0xE5: case 0xE6: case 0xE7:     /* bt */
          if (C_ON())
            {
              int disp;
              disp = inst & 0x03FF;
              if (inst & 0x0400)
                disp |= 0xFFFFFC00;
              pc += disp<<1;
              bonus_cycles++;
              needfetch = 1;
            }
          break;

        case 0xF8: case 0xF9: case 0xFA: case 0xFB:
        case 0xFC: case 0xFD: case 0xFE: case 0xFF:     /* bsr */
          cpu.gr[15] = pc;
        case 0xF0: case 0xF1: case 0xF2: case 0xF3:
        case 0xF4: case 0xF5: case 0xF6: case 0xF7:     /* br */
          {
            int disp;
            disp = inst & 0x03FF;
            if (inst & 0x0400)
              disp |= 0xFFFFFC00;
            pc += disp<<1;
            bonus_cycles++;
            needfetch = 1;
          }
          break;

        }

      if (tracing)
        fprintf (stderr, "\n");

      if (needfetch)
        {
          /* Do not let him fetch from a bad address! */
          if (((uword)pc) >= cpu.asregs.msize)
            {
              if (issue_messages)
                fprintf (stderr, "PC loaded at 0x%x is outside of available memory! (0x%x)\n", oldpc, pc);

              cpu.asregs.exception = SIGSEGV;
            }
          else
            {
              ibuf = rlat (pc & 0xFFFFFFFC);
              needfetch = 0;
            }
        }
    }
  while (!cpu.asregs.exception);

  /* Hide away the things we've cached while executing.  */
  CIA_SET (scpu, pc);
  cpu.asregs.insts += insts;            /* instructions done ... */
  cpu.asregs.cycles += insts;           /* and each takes a cycle */
  cpu.asregs.cycles += bonus_cycles;    /* and extra cycles for branches */
  cpu.asregs.cycles += memops * memcycles;      /* and memop cycle delays */
}


int
sim_write (SIM_DESC sd, SIM_ADDR addr, const unsigned char *buffer, int size)
{
  int i;
  init_pointers ();

  memcpy (& cpu.mem[addr], buffer, size);

  return size;
}

int
sim_read (SIM_DESC sd, SIM_ADDR addr, unsigned char *buffer, int size)
{
  int i;
  init_pointers ();

  memcpy (buffer, & cpu.mem[addr], size);

  return size;
}


int
sim_store_register (SIM_DESC sd, int rn, unsigned char *memory, int length)
{
  init_pointers ();

  if (rn < NUM_MCORE_REGS && rn >= 0)
    {
      if (length == 4)
        {
          long ival;

          /* misalignment safe */
          ival = mcore_extract_unsigned_integer (memory, 4);
          cpu.asints[rn] = ival;
        }

      return 4;
    }
  else
    return 0;
}

int
sim_fetch_register (SIM_DESC sd, int rn, unsigned char *memory, int length)
{
  init_pointers ();

  if (rn < NUM_MCORE_REGS && rn >= 0)
    {
      if (length == 4)
        {
          long ival = cpu.asints[rn];

          /* misalignment-safe */
          mcore_store_unsigned_integer (memory, 4, ival);
        }

      return 4;
    }
  else
    return 0;
}

void
sim_stop_reason (SIM_DESC sd, enum sim_stop *reason, int *sigrc)
{
  if (cpu.asregs.exception == SIGQUIT)
    {
      * reason = sim_exited;
      * sigrc = cpu.gr[PARM1];
    }
  else
    {
      * reason = sim_stopped;
      * sigrc = cpu.asregs.exception;
    }
}

void
sim_info (SIM_DESC sd, int verbose)
{
#ifdef WATCHFUNCTIONS
  int w, wcyc;
#endif
  double virttime = cpu.asregs.cycles / 36.0e6;
  host_callback *callback = STATE_CALLBACK (sd);

  callback->printf_filtered (callback, "\n\n# instructions executed  %10d\n",
                             cpu.asregs.insts);
  callback->printf_filtered (callback, "# cycles                 %10d\n",
                             cpu.asregs.cycles);
  callback->printf_filtered (callback, "# pipeline stalls        %10d\n",
                             cpu.asregs.stalls);
  callback->printf_filtered (callback, "# virtual time taken     %10.4f\n",
                             virttime);

#ifdef WATCHFUNCTIONS
  callback->printf_filtered (callback, "\nNumber of watched functions: %d\n",
                             ENDWL);

  wcyc = 0;

  for (w = 1; w <= ENDWL; w++)
    {
      callback->printf_filtered (callback, "WL = %s %8x\n",WLstr[w],WL[w]);
      callback->printf_filtered (callback, "  calls = %d, cycles = %d\n",
                                 WLcnts[w],WLcyc[w]);

      if (WLcnts[w] != 0)
        callback->printf_filtered (callback,
                                   "  maxcpc = %d, mincpc = %d, avecpc = %d\n",
                                   WLmax[w],WLmin[w],WLcyc[w]/WLcnts[w]);
      wcyc += WLcyc[w];
    }

  callback->printf_filtered (callback,
                             "Total cycles for watched functions: %d\n",wcyc);
#endif
}

static sim_cia
mcore_pc_get (sim_cpu *cpu)
{
  return cpu->pc;
}

static void
mcore_pc_set (sim_cpu *cpu, sim_cia pc)
{
  cpu->pc = pc;
}

static void
free_state (SIM_DESC sd)
{
  if (STATE_MODULES (sd) != NULL)
    sim_module_uninstall (sd);
  sim_cpu_free_all (sd);
  sim_state_free (sd);
}

SIM_DESC
sim_open (SIM_OPEN_KIND kind, host_callback *cb, struct bfd *abfd, char **argv)
{
  SIM_DESC sd = sim_state_alloc (kind, cb);
  int i, osize;
  SIM_ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);

  /* The cpu data is kept in a separately allocated chunk of memory.  */
  if (sim_cpu_alloc_all (sd, 1, /*cgen_cpu_max_extra_bytes ()*/0) != SIM_RC_OK)
    {
      free_state (sd);
      return 0;
    }

  if (sim_pre_argv_init (sd, argv[0]) != SIM_RC_OK)
    {
      free_state (sd);
      return 0;
    }

  /* getopt will print the error message so we just have to exit if this fails.
     FIXME: Hmmm...  in the case of gdb we need getopt to call
     print_filtered.  */
  if (sim_parse_args (sd, argv) != SIM_RC_OK)
    {
      free_state (sd);
      return 0;
    }

  /* Check for/establish the a reference program image.  */
  if (sim_analyze_program (sd,
                           (STATE_PROG_ARGV (sd) != NULL
                            ? *STATE_PROG_ARGV (sd)
                            : NULL), abfd) != SIM_RC_OK)
    {
      free_state (sd);
      return 0;
    }

  /* Configure/verify the target byte order and other runtime
     configuration options.  */
  if (sim_config (sd) != SIM_RC_OK)
    {
      sim_module_uninstall (sd);
      return 0;
    }

  if (sim_post_argv_init (sd) != SIM_RC_OK)
    {
      /* Uninstall the modules to avoid memory leaks,
         file descriptor leaks, etc.  */
      sim_module_uninstall (sd);
      return 0;
    }

  osize = sim_memory_size;

  if (kind == SIM_OPEN_STANDALONE)
    issue_messages = 1;

  /* Discard and reacquire memory -- start with a clean slate.  */
  sim_size (1);         /* small */
  sim_size (osize);     /* and back again */

  /* CPU specific initialization.  */
  for (i = 0; i < MAX_NR_PROCESSORS; ++i)
    {
      SIM_CPU *cpu = STATE_CPU (sd, i);

      CPU_PC_FETCH (cpu) = mcore_pc_get;
      CPU_PC_STORE (cpu) = mcore_pc_set;

      set_initial_gprs (cpu);   /* Reset the GPR registers.  */
    }

  return sd;
}

void
sim_close (SIM_DESC sd, int quitting)
{
  /* nothing to do */
}

SIM_RC
sim_create_inferior (SIM_DESC sd, struct bfd *prog_bfd, char **argv, char **env)
{
  SIM_CPU *scpu = STATE_CPU (sd, 0);
  char ** avp;
  int nargs = 0;
  int nenv = 0;
  int s_length;
  int l;
  unsigned long strings;
  unsigned long pointers;
  unsigned long hi_stack;


  /* Set the initial register set.  */
  l = issue_messages;
  issue_messages = 0;
  set_initial_gprs (scpu);
  issue_messages = l;

  hi_stack = cpu.asregs.msize - 4;
  CIA_SET (scpu, bfd_get_start_address (prog_bfd));

  /* Calculate the argument and environment strings.  */
  s_length = 0;
  nargs = 0;
  avp = argv;
  while (avp && *avp)
    {
      l = strlen (*avp) + 1;    /* include the null */
      s_length += (l + 3) & ~3; /* make it a 4 byte boundary */
      nargs++; avp++;
    }

  nenv = 0;
  avp = env;
  while (avp && *avp)
    {
      l = strlen (*avp) + 1;    /* include the null */
      s_length += (l + 3) & ~ 3;/* make it a 4 byte boundary */
      nenv++; avp++;
    }

  /* Claim some memory for the pointers and strings. */
  pointers = hi_stack - sizeof(word) * (nenv+1+nargs+1);
  pointers &= ~3;               /* must be 4-byte aligned */
  cpu.gr[0] = pointers;

  strings = cpu.gr[0] - s_length;
  strings &= ~3;                /* want to make it 4-byte aligned */
  cpu.gr[0] = strings;
  /* dac fix, the stack address must be 8-byte aligned! */
  cpu.gr[0] = cpu.gr[0] - cpu.gr[0] % 8;

  /* Loop through the arguments and fill them in.  */
  cpu.gr[PARM1] = nargs;
  if (nargs == 0)
    {
      /* No strings to fill in.  */
      cpu.gr[PARM2] = 0;
    }
  else
    {
      cpu.gr[PARM2] = pointers;
      avp = argv;
      while (avp && *avp)
        {
          /* Save where we're putting it.  */
          wlat (pointers, strings);

          /* Copy the string.  */
          l = strlen (* avp) + 1;
          strcpy ((char *)(cpu.mem + strings), *avp);

          /* Bump the pointers.  */
          avp++;
          pointers += 4;
          strings += l+1;
        }

      /* A null to finish the list.  */
      wlat (pointers, 0);
      pointers += 4;
    }

  /* Now do the environment pointers.  */
  if (nenv == 0)
    {
      /* No strings to fill in.  */
      cpu.gr[PARM3] = 0;
    }
  else
    {
      cpu.gr[PARM3] = pointers;
      avp = env;

      while (avp && *avp)
        {
          /* Save where we're putting it.  */
          wlat (pointers, strings);

          /* Copy the string.  */
          l = strlen (* avp) + 1;
          strcpy ((char *)(cpu.mem + strings), *avp);

          /* Bump the pointers.  */
          avp++;
          pointers += 4;
          strings += l+1;
        }

      /* A null to finish the list.  */
      wlat (pointers, 0);
      pointers += 4;
    }

  return SIM_RC_OK;
}

void
sim_do_command (SIM_DESC sd, const char *cmd)
{
  /* Nothing there yet; it's all an error.  */

  if (cmd != NULL)
    {
      char ** simargv = buildargv (cmd);

      if (strcmp (simargv[0], "watch") == 0)
        {
          if ((simargv[1] == NULL) || (simargv[2] == NULL))
            {
              fprintf (stderr, "Error: missing argument to watch cmd.\n");
              freeargv (simargv);
              return;
            }

          ENDWL++;

          WL[ENDWL] = strtol (simargv[2], NULL, 0);
          WLstr[ENDWL] = strdup (simargv[1]);
          fprintf (stderr, "Added %s (%x) to watchlist, #%d\n",WLstr[ENDWL],
                   WL[ENDWL], ENDWL);

        }
      else if (strcmp (simargv[0], "dumpmem") == 0)
        {
          unsigned char * p;
          FILE * dumpfile;

          if (simargv[1] == NULL)
            fprintf (stderr, "Error: missing argument to dumpmem cmd.\n");

          fprintf (stderr, "Writing dumpfile %s...",simargv[1]);

          dumpfile = fopen (simargv[1], "w");
          p = cpu.mem;
          fwrite (p, cpu.asregs.msize-1, 1, dumpfile);
          fclose (dumpfile);

          fprintf (stderr, "done.\n");
        }
      else if (strcmp (simargv[0], "clearstats") == 0)
        {
          cpu.asregs.cycles = 0;
          cpu.asregs.insts = 0;
          cpu.asregs.stalls = 0;
          ENDWL = 0;
        }
      else if (strcmp (simargv[0], "verbose") == 0)
        {
          issue_messages = 2;
        }
      else
        {
          fprintf (stderr,"Error: \"%s\" is not a valid M.CORE simulator command.\n",
                   cmd);
        }

      freeargv (simargv);
    }
  else
    {
      fprintf (stderr, "M.CORE sim commands: \n");
      fprintf (stderr, "  watch <funcname> <addr>\n");
      fprintf (stderr, "  dumpmem <filename>\n");
      fprintf (stderr, "  clearstats\n");
      fprintf (stderr, "  verbose\n");
    }
}