binutils-gdb/opcodes/arc-dis.c

/* Instruction printing code for the ARC.
   Copyright (C) 1994, 1995, 1997, 1998 Free Software Foundation, Inc. 
   Contributed by Doug Evans (dje@cygnus.com).

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 "sysdep.h"
#include "dis-asm.h"
#include "opcode/arc.h"
#include "elf-bfd.h"
#include "elf/arc.h"
#include "opintl.h"

static int print_insn_arc_base_little PARAMS ((bfd_vma, disassemble_info *));
static int print_insn_arc_base_big PARAMS ((bfd_vma, disassemble_info *));

static int print_insn PARAMS ((bfd_vma, disassemble_info *, int, int));

/* Print one instruction from PC on INFO->STREAM.
   Return the size of the instruction (4 or 8 for the ARC). */

static int
print_insn (pc, info, mach, big_p)
     bfd_vma pc;
     disassemble_info *info;
     int mach;
     int big_p;
{
  const struct arc_opcode *opcode;
  bfd_byte buffer[4];
  void *stream = info->stream;
  fprintf_ftype func = info->fprintf_func;
  int status;
  /* First element is insn, second element is limm (if present).  */
  arc_insn insn[2];
  int got_limm_p = 0;
  static int initialized = 0;
  static int current_mach = 0;

  if (!initialized || mach != current_mach)
    {
      initialized = 1;
      current_mach = arc_get_opcode_mach (mach, big_p);
      arc_opcode_init_tables (current_mach);
    }

  status = (*info->read_memory_func) (pc, buffer, 4, info);
  if (status != 0)
    {
      (*info->memory_error_func) (status, pc, info);
      return -1;
    }
  if (big_p)
    insn[0] = bfd_getb32 (buffer);
  else
    insn[0] = bfd_getl32 (buffer);

  (*func) (stream, "%08lx\t", insn[0]);

  /* The instructions are stored in lists hashed by the insn code
     (though we needn't care how they're hashed).  */

  opcode = arc_opcode_lookup_dis (insn[0]);
  for ( ; opcode != NULL; opcode = ARC_OPCODE_NEXT_DIS (opcode))
    {
      char *syn;
      int mods,invalid;
      long value;
      const struct arc_operand *operand;
      const struct arc_operand_value *opval;

      /* Basic bit mask must be correct.  */
      if ((insn[0] & opcode->mask) != opcode->value)
	continue;

      /* Supported by this cpu?  */
      if (! arc_opcode_supported (opcode))
	continue;

      /* Make two passes over the operands.  First see if any of them
	 have extraction functions, and, if they do, make sure the
	 instruction is valid.  */

      arc_opcode_init_extract ();
      invalid = 0;

      /* ??? Granted, this is slower than the `ppc' way.  Maybe when this is
	 done it'll be clear what the right way to do this is.  */
      /* Instructions like "add.f r0,r1,1" are tricky because the ".f" gets
	 printed first, but we don't know how to print it until we've processed
	 the regs.  Since we're scanning all the args before printing the insn
	 anyways, it's actually quite easy.  */

      for (syn = opcode->syntax; *syn; ++syn)
	{
	  int c;

	  if (*syn != '%' || *++syn == '%')
	    continue;
	  mods = 0;
	  c = *syn;
	  while (ARC_MOD_P (arc_operands[arc_operand_map[c]].flags))
	    {
	      mods |= arc_operands[arc_operand_map[c]].flags & ARC_MOD_BITS;
	      ++syn;
	      c = *syn;
	    }
	  operand = arc_operands + arc_operand_map[c];
	  if (operand->extract)
	    (*operand->extract) (insn, operand, mods,
				 (const struct arc_operand_value **) NULL,
				 &invalid);
	}
      if (invalid)
	continue;

      /* The instruction is valid.  */

      /* If we have an insn with a limm, fetch it now.  Scanning the insns
	 twice lets us do this.  */
      if (arc_opcode_limm_p (NULL))
	{
	  status = (*info->read_memory_func) (pc + 4, buffer, 4, info);
	  if (status != 0)
	    {
	      (*info->memory_error_func) (status, pc, info);
	      return -1;
	    }
	  if (big_p)
	    insn[1] = bfd_getb32 (buffer);
	  else
	    insn[1] = bfd_getl32 (buffer);
	  got_limm_p = 1;
	}

      for (syn = opcode->syntax; *syn; ++syn)
	{
	  int c;

	  if (*syn != '%' || *++syn == '%')
	    {
	      (*func) (stream, "%c", *syn);
	      continue;
	    }

	  /* We have an operand.  Fetch any special modifiers.  */
	  mods = 0;
	  c = *syn;
	  while (ARC_MOD_P (arc_operands[arc_operand_map[c]].flags))
	    {
	      mods |= arc_operands[arc_operand_map[c]].flags & ARC_MOD_BITS;
	      ++syn;
	      c = *syn;
	    }
	  operand = arc_operands + arc_operand_map[c];

	  /* Extract the value from the instruction.  */
	  opval = NULL;
	  if (operand->extract)
	    {
	      value = (*operand->extract) (insn, operand, mods,
					   &opval, (int *) NULL);
	    }
	  else
	    {
	      value = (insn[0] >> operand->shift) & ((1 << operand->bits) - 1);
	      if ((operand->flags & ARC_OPERAND_SIGNED)
		  && (value & (1 << (operand->bits - 1))))
		value -= 1 << operand->bits;

	      /* If this is a suffix operand, set `opval'.  */
	      if (operand->flags & ARC_OPERAND_SUFFIX)
		opval = arc_opcode_lookup_suffix (operand, value);
	    }

	  /* Print the operand as directed by the flags.  */
	  if (operand->flags & ARC_OPERAND_FAKE)
	    ; /* nothing to do (??? at least not yet) */
	  else if (operand->flags & ARC_OPERAND_SUFFIX)
	    {
	      /* Default suffixes aren't printed.  Fortunately, they all have
		 zero values.  Also, zero values for boolean suffixes are
		 represented by the absence of text.  */

	      if (value != 0)
		{
		  /* ??? OPVAL should have a value.  If it doesn't just cope
		     as we want disassembly to be reasonably robust.
		     Also remember that several condition code values (16-31)
		     aren't defined yet.  For these cases just print the
		     number suitably decorated.  */
		  if (opval)
		    (*func) (stream, "%s%s",
			     mods & ARC_MOD_DOT ? "." : "",
			     opval->name);
		  else
		    (*func) (stream, "%s%c%d",
			     mods & ARC_MOD_DOT ? "." : "",
			     operand->fmt, value);
		}
	    }
	  else if (operand->flags & ARC_OPERAND_RELATIVE_BRANCH)
	    (*info->print_address_func) (pc + 4 + value, info);
	  /* ??? Not all cases of this are currently caught.  */
	  else if (operand->flags & ARC_OPERAND_ABSOLUTE_BRANCH)
	    (*info->print_address_func) ((bfd_vma) value & 0xffffffff, info);
	  else if (operand->flags & ARC_OPERAND_ADDRESS)
	    (*info->print_address_func) ((bfd_vma) value & 0xffffffff, info);
	  else if (opval)
	    /* Note that this case catches both normal and auxiliary regs.  */
	    (*func) (stream, "%s", opval->name);
	  else
	    (*func) (stream, "%ld", value);
	}

      /* We have found and printed an instruction; return.  */
      return got_limm_p ? 8 : 4;
    }

  (*func) (stream, _("*unknown*"));
  return 4;
}

/* Given MACH, one of bfd_mach_arc_xxx, return the print_insn function to use.
   This does things a non-standard way (the "standard" way would be to copy
   this code into disassemble.c).  Since there are more than a couple of
   variants, hiding all this crud here seems cleaner.  */

disassembler_ftype
arc_get_disassembler (mach, big_p)
     int mach;
     int big_p;
{
  switch (mach)
    {
    case bfd_mach_arc_base:
      return big_p ? print_insn_arc_base_big : print_insn_arc_base_little;
    }
  return print_insn_arc_base_little;
}

static int
print_insn_arc_base_little (pc, info)
     bfd_vma pc;
     disassemble_info *info;
{
  return print_insn (pc, info, bfd_mach_arc_base, 0);
}

static int
print_insn_arc_base_big (pc, info)
     bfd_vma pc;
     disassemble_info *info;
{
  return print_insn (pc, info, bfd_mach_arc_base, 1);
}