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/* Print VAX instructions.

   Copyright (C) 1995, 1998 Free Software Foundation, Inc.

   Contributed by Pauline Middelink <middelin@polyware.iaf.nl>

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 2 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, write to the Free Software

Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#include "opcode/vax.h"

#include "dis-asm.h"

/* Local function prototypes */

static int

print_insn_arg PARAMS ((const char *, unsigned char *, bfd_vma,

                        disassemble_info *));

static int

print_insn_mode PARAMS ((int, unsigned char *, bfd_vma, disassemble_info *));

static char *reg_names[] =

{

  "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",

  "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc"

};

/* Sign-extend an (unsigned char). */

#if __STDC__ == 1

#define COERCE_SIGNED_CHAR(ch) ((signed char)(ch))

#else

#define COERCE_SIGNED_CHAR(ch) ((int)(((ch) ^ 0x80) & 0xFF) - 128)

#endif

/* Get a 1 byte signed integer.  */

#define NEXTBYTE(p)  \

  (p += 1, FETCH_DATA (info, p), \

  COERCE_SIGNED_CHAR(p[-1]))

/* Get a 2 byte signed integer.  */

#define COERCE16(x) ((int) (((x) ^ 0x8000) - 0x8000))

#define NEXTWORD(p)  \

  (p += 2, FETCH_DATA (info, p), \

   COERCE16 ((p[-1] << 8) + p[-2]))

/* Get a 4 byte signed integer.  */

#define COERCE32(x) ((int) (((x) ^ 0x80000000) - 0x80000000))

#define NEXTLONG(p)  \

  (p += 4, FETCH_DATA (info, p), \

   (COERCE32 ((((((p[-1] << 8) + p[-2]) << 8) + p[-3]) << 8) + p[-4])))

/* Maximum length of an instruction.  */

#define MAXLEN 25

#include <setjmp.h>

struct private

{

  /* Points to first byte not fetched.  */

  bfd_byte *max_fetched;

  bfd_byte the_buffer[MAXLEN];

  bfd_vma insn_start;

  jmp_buf bailout;

};

/* Make sure that bytes from INFO->PRIVATE_DATA->BUFFER (inclusive)

   to ADDR (exclusive) are valid.  Returns 1 for success, longjmps

   on error.  */

#define FETCH_DATA(info, addr) \

  ((addr) <= ((struct private *)(info->private_data))->max_fetched \

   ? 1 : fetch_data ((info), (addr)))

static int

fetch_data (info, addr)

     struct disassemble_info *info;

     bfd_byte *addr;

{

  int status;

  struct private *priv = (struct private *) info->private_data;

  bfd_vma start = priv->insn_start + (priv->max_fetched - priv->the_buffer);

  status = (*info->read_memory_func) (start,

                                      priv->max_fetched,

                                      addr - priv->max_fetched,

                                      info);

  if (status != 0)

    {

      (*info->memory_error_func) (status, start, info);

      longjmp (priv->bailout, 1);

    }

  else

    priv->max_fetched = addr;

  return 1;

}

/* Print the vax instruction at address MEMADDR in debugged memory,

   on INFO->STREAM.  Returns length of the instruction, in bytes.  */

int

print_insn_vax (memaddr, info)

     bfd_vma memaddr;

     disassemble_info *info;

{

  const struct vot *votp;

  const char *argp = NULL;

  unsigned char *arg;

  struct private priv;

  bfd_byte *buffer = priv.the_buffer;

  info->private_data = (PTR) &priv;

  priv.max_fetched = priv.the_buffer;

  priv.insn_start = memaddr;

  if (setjmp (priv.bailout) != 0)

    {

      /* Error return.  */

      return -1;

    }

  FETCH_DATA (info, buffer + 2);

  for (votp = &votstrs[0]; votp->name[0]; votp++)

    {

      register vax_opcodeT opcode = votp->detail.code;

      /* 2 byte codes match 2 buffer pos. */

      if ((bfd_byte) opcode == buffer[0]

          && (opcode >> 8 == 0 || opcode >> 8 == buffer[1]))

        {

          argp = votp->detail.args;

          break;

        }

    }

  if (argp == NULL)

    {

      /* Handle undefined instructions. */

      (*info->fprintf_func) (info->stream, ".word 0x%x",

                             (buffer[0] << 8) + buffer[1]);

      return 2;

    }

  /* Point at first byte of argument data, and at descriptor for first

     argument.  */

  arg = buffer + ((votp->detail.code >> 8) ? 2 : 1);

  /* Make sure we have it in mem */

  FETCH_DATA (info, arg);

  (*info->fprintf_func) (info->stream, "%s", votp->name);

  if (*argp)

    (*info->fprintf_func) (info->stream, " ");

  while (*argp)

    {

      arg += print_insn_arg (argp, arg, memaddr + arg - buffer, info);

      argp += 2;

      if (*argp)

        (*info->fprintf_func) (info->stream, ",");

    }

  return arg - buffer;

}

/* Returns number of bytes "eaten" by the operand, or return -1 if an

   invalid operand was found, or -2 if an opcode tabel error was

   found. */

static int

print_insn_arg (d, p0, addr, info)

     const char *d;

     unsigned char *p0;

     bfd_vma addr;              /* PC for this arg to be relative to */

     disassemble_info *info;

{

  int arg_len;

  /* check validity of addressing length */

  switch (d[1])

    {

    case 'b' : arg_len = 1;     break;

    case 'd' : arg_len = 8;     break;

    case 'f' : arg_len = 4;     break;

    case 'g' : arg_len = 8;     break;

    case 'h' : arg_len = 16;    break;

    case 'l' : arg_len = 4;     break;

    case 'o' : arg_len = 16;    break;

    case 'w' : arg_len = 2;     break;

    case 'q' : arg_len = 8;     break;

    default  : abort();

    }

  /* branches have no mode byte */

  if (d[0] == 'b')

    {

      unsigned char *p = p0;

      if (arg_len == 1)

        (*info->print_address_func) (addr + 1 + NEXTBYTE (p), info);

      else

        (*info->print_address_func) (addr + 2 + NEXTWORD (p), info);

      return p - p0;

    }

  return print_insn_mode (arg_len, p0, addr, info);

}

static int

print_insn_mode (size, p0, addr, info)

     int size;

     unsigned char *p0;

     bfd_vma addr;              /* PC for this arg to be relative to */

     disassemble_info *info;

{

  unsigned char *p = p0;

  unsigned char mode, reg;

  /* fetch and interpret mode byte */

  mode = (unsigned char) NEXTBYTE (p);

  reg = mode & 0xF;

  switch (mode & 0xF0)

    {

    case 0x00:

    case 0x10:

    case 0x20:

    case 0x30: /* literal mode                  $number */

      (*info->fprintf_func) (info->stream, "$0x%x", mode);

      break;

    case 0x40: /* index:                        base-addr[Rn] */

      p += print_insn_mode (size, p0 + 1, addr + 1, info);

      (*info->fprintf_func) (info->stream, "[%s]", reg_names[reg]);

      break;

    case 0x50: /* register:                     Rn */

      (*info->fprintf_func) (info->stream, "%s", reg_names[reg]);

      break;

    case 0x60: /* register deferred:            (Rn) */

      (*info->fprintf_func) (info->stream, "(%s)", reg_names[reg]);

      break;

    case 0x70: /* autodecrement:                -(Rn) */

      (*info->fprintf_func) (info->stream, "-(%s)", reg_names[reg]);

      break;

    case 0x80: /* autoincrement:                (Rn)+ */

      if (reg == 0xF)

        {       /* immediate? */

          int i;

          FETCH_DATA (info, p + size);

          (*info->fprintf_func) (info->stream, "$0x");

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

            (*info->fprintf_func) (info->stream, "%02x", p[size - i - 1]);

          p += size;

        }

      else

        (*info->fprintf_func) (info->stream, "(%s)+", reg_names[reg]);

      break;

    case 0x90: /* autoincrement deferred:       @(Rn)+ */

      if (reg == 0xF)

        (*info->fprintf_func) (info->stream, "*0x%x", NEXTLONG (p));

      else

        (*info->fprintf_func) (info->stream, "@(%s)+", reg_names[reg]);

      break;

    case 0xB0: /* displacement byte deferred:   *displ(Rn) */

      (*info->fprintf_func) (info->stream, "*");

    case 0xA0: /* displacement byte:            displ(Rn) */

      if (reg == 0xF)

        (*info->print_address_func) (addr + 2 + NEXTBYTE (p), info);

      else

        (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTBYTE (p),

                               reg_names[reg]);

      break;

    case 0xD0: /* displacement word deferred:   *displ(Rn) */

      (*info->fprintf_func) (info->stream, "*");

    case 0xC0: /* displacement word:            displ(Rn) */

      if (reg == 0xF)

        (*info->print_address_func) (addr + 3 + NEXTWORD (p), info);

      else

        (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTWORD (p),

                               reg_names[reg]);

      break;

    case 0xF0: /* displacement long deferred:   *displ(Rn) */

      (*info->fprintf_func) (info->stream, "*");

    case 0xE0: /* displacement long:            displ(Rn) */

      if (reg == 0xF)

        (*info->print_address_func) (addr + 5 + NEXTLONG (p), info);

      else

        (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTLONG (p),

                               reg_names[reg]);

      break;

    }

  return p - p0;

}