Again: Disassembly with variable instruction size

[Ronald Hecht <ronald.hecht@uni-rostock.de>]

Hello,

the problem seems to be in <arch>-dis.c. The generated function 
my_print_instruction looks wrong. It looks like this*

#undef  CGEN_PRINT_INSN
#define CGEN_PRINT_INSN my_print_insn

static int
my_print_insn (CGEN_CPU_DESC cd,
           bfd_vma pc,
           disassemble_info *info)
{
  bfd_byte buffer[CGEN_MAX_INSN_SIZE];
  bfd_byte *buf = buffer;
  int status;
  int buflen = (pc & 3) == 0 ? 4 : 2;
  int big_p = CGEN_CPU_INSN_ENDIAN (cd) == CGEN_ENDIAN_BIG;
  bfd_byte *x;

  /* Read the base part of the insn.  */

  status = (*info->read_memory_func) (pc - ((!big_p && (pc & 3) != 0) ? 
2 : 0),
                                      buf, buflen, info);
  if (status != 0)
    {
      (*info->memory_error_func) (status, pc, info);
      return -1;
    }

  /* 32 bit insn?  */
  x = (big_p ? &buf[0] : &buf[3]);
  if ((pc & 3) == 0 && (*x & 0x80) != 0)
    return print_insn (cd, pc, info, buf, buflen);

  /* Print the first insn.  */
  if ((pc & 3) == 0)
    {
      buf += (big_p ? 0 : 2);
      if (print_insn (cd, pc, info, buf, 2) == 0)
    (*info->fprintf_func) (info->stream, UNKNOWN_INSN_MSG);
      buf += (big_p ? 2 : -2);
    }

  x = (big_p ? &buf[0] : &buf[1]);
  if (*x & 0x80)
    {
      /* Parallel.  */
      (*info->fprintf_func) (info->stream, " || ");
      *x &= 0x7f;
    }
  else
    (*info->fprintf_func) (info->stream, " -> ");

  /* The "& 3" is to pass a consistent address.
     Parallel insns arguably both begin on the word boundary.
     Also, branch insns are calculated relative to the word boundary.  */
  if (print_insn (cd, pc & ~ (bfd_vma) 3, info, buf, 2) == 0)
    (*info->fprintf_func) (info->stream, UNKNOWN_INSN_MSG);

  return (pc & 3) ? 2 : 4;
}

I replaced it with the stuff from fr30-dis.c :

/* Default value for CGEN_PRINT_INSN.
   The result is the size of the insn in bytes or zero for an unknown insn
   or -1 if an error occured fetching bytes.  */

#ifndef CGEN_PRINT_INSN
#define CGEN_PRINT_INSN default_print_insn
#endif

static int
default_print_insn (CGEN_CPU_DESC cd, bfd_vma pc, disassemble_info *info)
{
  bfd_byte buf[CGEN_MAX_INSN_SIZE];
  int buflen;
  int status;

  /* Attempt to read the base part of the insn.  */
  buflen = cd->base_insn_bitsize / 8;
  status = (*info->read_memory_func) (pc, buf, buflen, info);

  /* Try again with the minimum part, if min < base.  */
  if (status != 0 && (cd->min_insn_bitsize < cd->base_insn_bitsize))
    {
      buflen = cd->min_insn_bitsize / 8;
      status = (*info->read_memory_func) (pc, buf, buflen, info);
    }

  if (status != 0)
    {
      (*info->memory_error_func) (status, pc, info);
      return -1;
    }

  return print_insn (cd, pc, info, buf, buflen);
}

This works for me. So the bug seems to be in the generation of <arch>-dis.c

Best Regards
Ronald
*