[deliverable/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"

#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;
  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;

#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]

/* 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. */

/* Default to a 8 Mbyte (== 2^23) memory space.  */
#define DEFAULT_MEMORY_SIZE 0x800000

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

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

  /* 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] = DEFAULT_MEMORY_SIZE - 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];
}

/* Read/write functions for system call interface.  */

static int
syscall_read_mem (host_callback *cb, struct cb_syscall *sc,
                  unsigned long taddr, char *buf, int bytes)
{
  SIM_DESC sd = (SIM_DESC) sc->p1;
  SIM_CPU *cpu = (SIM_CPU *) sc->p2;

  return sim_core_read_buffer (sd, cpu, read_map, buf, taddr, bytes);
}

static int
syscall_write_mem (host_callback *cb, struct cb_syscall *sc,
                  unsigned long taddr, const char *buf, int bytes)
{
  SIM_DESC sd = (SIM_DESC) sc->p1;
  SIM_CPU *cpu = (SIM_CPU *) sc->p2;

  return sim_core_write_buffer (sd, cpu, write_map, buf, taddr, bytes);
}

/* Simulate a monitor trap.  */

static void
handle_trap1 (SIM_DESC sd)
{
  host_callback *cb = STATE_CALLBACK (sd);
  CB_SYSCALL sc;

  CB_SYSCALL_INIT (&sc);

  sc.func = cpu.gr[TRAPCODE];
  sc.arg1 = cpu.gr[PARM1];
  sc.arg2 = cpu.gr[PARM2];
  sc.arg3 = cpu.gr[PARM3];
  sc.arg4 = cpu.gr[PARM4];

  sc.p1 = (PTR) sd;
  sc.p2 = (PTR) STATE_CPU (sd, 0);
  sc.read_mem = syscall_read_mem;
  sc.write_mem = syscall_write_mem;

  cb_syscall (cb, &sc);

  /* XXX: We don't pass back the actual errno value.  */
  cpu.gr[RET1] = sc.result;
}

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 (STATE_VERBOSE_P (sd))
        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 */
      if (STATE_VERBOSE_P (sd))
        fprintf (stderr, "WARNING: printf unimplemented\n");
      break;

    case 2:     /* scanf */
      if (STATE_VERBOSE_P (sd))
        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 (STATE_VERBOSE_P (sd))
        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);
}

/* TODO: Convert to common watchpoints.  */
#undef WATCHFUNCTIONS
#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)

#define rbat(X) sim_core_read_1 (scpu, 0, read_map, X)
#define rhat(X) sim_core_read_2 (scpu, 0, read_map, X)
#define rlat(X) sim_core_read_4 (scpu, 0, read_map, X)
#define wbat(X, D) sim_core_write_1 (scpu, 0, write_map, X, D)
#define what(X, D) sim_core_write_2 (scpu, 0, write_map, X, D)
#define wlat(X, D) sim_core_write_4 (scpu, 0, write_map, X, D)

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;
#ifdef WATCHFUNCTIONS
  word WLhash;
#endif

  cpu.asregs.exception = step ? SIGTRAP: 0;
  pc = CPU_PC_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];

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

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

  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, "%.4lx: 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 (STATE_VERBOSE_P (sd))
                    fprintf (stderr, "WARNING: stop unimplemented\n");
                  break;

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

                case 0x6:                               /* doze */
                  if (STATE_VERBOSE_P (sd))
                    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 = %lxx, r3 = %lx\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 %lx by %lx to give %lx",
                     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 %lx 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%lx 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 = %lx r3 = %lx r4 = %lx r5 = %lx r6 = %lx r7 = %lx\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%lx with 0x%lx",
                     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%lx) to 0x%lx",
                     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)
        {
          ibuf = rlat (pc & 0xFFFFFFFC);
          needfetch = 0;
        }
    }
  while (!cpu.asregs.exception);

  /* Hide away the things we've cached while executing.  */
  CPU_PC_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_store_register (SIM_DESC sd, int rn, unsigned char *memory, int length)
{
  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)
{
  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)
{
  int i;
  SIM_DESC sd = sim_state_alloc (kind, cb);
  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;
    }

  /* 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.  */
    }

  /* Default to a 8 Mbyte (== 2^23) memory space.  */
  sim_do_commandf (sd, "memory-size %#x", DEFAULT_MEMORY_SIZE);

  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.  */
  set_initial_gprs (scpu);

  hi_stack = DEFAULT_MEMORY_SIZE - 4;
  CPU_PC_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;
          sim_core_write_buffer (sd, scpu, write_map, *avp, strings, l);

          /* 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;
          sim_core_write_buffer (sd, scpu, write_map, *avp, strings, l);

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

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

  return SIM_RC_OK;
}