opcodes/tic80-dis.c

/* Print TI TMS320C80 (MVP) instructions
   Copyright (C) 1996-2016 Free Software Foundation, Inc.

   This file is part of the GNU opcodes library.

   This library 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, or (at your option)
   any later version.

   It 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., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */

#include "sysdep.h"
#include <stdio.h>
#include "opcode/tic80.h"
#include "dis-asm.h"

static int length;

/* Print an integer operand.  Try to be somewhat smart about the
   format by assuming that small positive or negative integers are
   probably loop increment values, structure offsets, or similar
   values that are more meaningful printed as signed decimal values.
   Larger numbers are probably better printed as hex values.  */

static void
print_operand_integer (struct disassemble_info *info, long value)
{
  if ((value > 9999 || value < -9999))
    (*info->fprintf_func) (info->stream, "%#lx", value);
  else
    (*info->fprintf_func) (info->stream, "%ld", value);
}

/* FIXME: depends upon sizeof (long) == sizeof (float) and
   also upon host floating point format matching target
   floating point format.  */

static void
print_operand_float (struct disassemble_info *info, long value)
{
  union { float f; long l; } fval;

  fval.l = value;
  (*info->fprintf_func) (info->stream, "%g", fval.f);
}

static void
print_operand_control_register (struct disassemble_info *info, long value)
{
  const char *tmp;

  tmp = tic80_value_to_symbol (value, TIC80_OPERAND_CR);
  if (tmp != NULL)
    (*info->fprintf_func) (info->stream, "%s", tmp);
  else
    (*info->fprintf_func) (info->stream, "%#lx", value);
}

static void
print_operand_condition_code (struct disassemble_info *info, long value)
{
  const char *tmp;

  tmp = tic80_value_to_symbol (value, TIC80_OPERAND_CC);
  if (tmp != NULL)
    (*info->fprintf_func) (info->stream, "%s", tmp);
  else
    (*info->fprintf_func) (info->stream, "%ld", value);
}

static void
print_operand_bitnum (struct disassemble_info *info, long value)
{
  int bitnum;
  const char *tmp;

  bitnum = ~value & 0x1F;
  tmp = tic80_value_to_symbol (bitnum, TIC80_OPERAND_BITNUM);
  if (tmp != NULL)
    (*info->fprintf_func) (info->stream, "%s", tmp);
  else
    (*info->fprintf_func) (info->stream, "%d", bitnum);
}

/* Print the operand as directed by the flags.  */

#define M_SI(insn,op) ((((op)->flags & TIC80_OPERAND_M_SI) != 0) && ((insn) & (1 << 17)))
#define M_LI(insn,op) ((((op)->flags & TIC80_OPERAND_M_LI) != 0) && ((insn) & (1 << 15)))
#define R_SCALED(insn,op) ((((op)->flags & TIC80_OPERAND_SCALED) != 0) && ((insn) & (1 << 11)))

static void
print_operand (struct disassemble_info *info,
	       long value,
	       unsigned long insn,
	       const struct tic80_operand *operand,
	       bfd_vma memaddr)
{
  if ((operand->flags & TIC80_OPERAND_GPR) != 0)
    {
      (*info->fprintf_func) (info->stream, "r%ld", value);
      if (M_SI (insn, operand) || M_LI (insn, operand))
	{
	  (*info->fprintf_func) (info->stream, ":m");
	}
    }
  else if ((operand->flags & TIC80_OPERAND_FPA) != 0)
    (*info->fprintf_func) (info->stream, "a%ld", value);

  else if ((operand->flags & TIC80_OPERAND_PCREL) != 0)
    (*info->print_address_func) (memaddr + 4 * value, info);

  else if ((operand->flags & TIC80_OPERAND_BASEREL) != 0)
    (*info->print_address_func) (value, info);

  else if ((operand->flags & TIC80_OPERAND_BITNUM) != 0)
    print_operand_bitnum (info, value);

  else if ((operand->flags & TIC80_OPERAND_CC) != 0)
    print_operand_condition_code (info, value);

  else if ((operand->flags & TIC80_OPERAND_CR) != 0)
    print_operand_control_register (info, value);

  else if ((operand->flags & TIC80_OPERAND_FLOAT) != 0)
    print_operand_float (info, value);

  else if ((operand->flags & TIC80_OPERAND_BITFIELD))
    (*info->fprintf_func) (info->stream, "%#lx", value);

  else
    print_operand_integer (info, value);

  /* If this is a scaled operand, then print the modifier.  */
  if (R_SCALED (insn, operand))
    (*info->fprintf_func) (info->stream, ":s");
}

/* Get the next 32 bit word from the instruction stream and convert it
   into internal format in the unsigned long INSN, for which we are
   passed the address.  Return 0 on success, -1 on error.  */

static int
fill_instruction (struct disassemble_info *info,
		  bfd_vma memaddr,
		  unsigned long *insnp)
{
  bfd_byte buffer[4];
  int status;

  /* Get the bits for the next 32 bit word and put in buffer.  */
  status = (*info->read_memory_func) (memaddr + length, buffer, 4, info);
  if (status != 0)
    {
      (*info->memory_error_func) (status, memaddr, info);
      return -1;
    }

  /* Read was successful, so increment count of bytes read and convert
     the bits into internal format.  */

  length += 4;
  if (info->endian == BFD_ENDIAN_LITTLE)
    *insnp = bfd_getl32 (buffer);

  else if (info->endian == BFD_ENDIAN_BIG)
    *insnp = bfd_getb32 (buffer);

  else
    /* FIXME: Should probably just default to one or the other.  */
    abort ();

  return 0;
}

/* We have chosen an opcode table entry.  */

static int
print_one_instruction (struct disassemble_info *info,
		       bfd_vma memaddr,
		       unsigned long insn,
		       const struct tic80_opcode *opcode)
{
  const struct tic80_operand *operand;
  long value;
  int status;
  const unsigned char *opindex;
  int close_paren;

  (*info->fprintf_func) (info->stream, "%-10s", opcode->name);

  for (opindex = opcode->operands; *opindex != 0; opindex++)
    {
      operand = tic80_operands + *opindex;

      /* Extract the value from the instruction.  */
      if (operand->extract)
	value = (*operand->extract) (insn, NULL);

      else if (operand->bits == 32)
	{
	  status = fill_instruction (info, memaddr, (unsigned long *) &value);
	  if (status == -1)
	    return status;
	}
      else
	{
	  value = (insn >> operand->shift) & ((1 << operand->bits) - 1);

	  if ((operand->flags & TIC80_OPERAND_SIGNED) != 0
	      && (value & (1 << (operand->bits - 1))) != 0)
	    value -= 1 << operand->bits;
	}

      /* If this operand is enclosed in parenthesis, then print
	 the open paren, otherwise just print the regular comma
	 separator, except for the first operand.  */
      if ((operand->flags & TIC80_OPERAND_PARENS) == 0)
	{
	  close_paren = 0;
	  if (opindex != opcode->operands)
	    (*info->fprintf_func) (info->stream, ",");
	}
      else
	{
	  close_paren = 1;
	  (*info->fprintf_func) (info->stream, "(");
	}

      print_operand (info, value, insn, operand, memaddr);

      /* If we printed an open paren before printing this operand, close
	 it now. The flag gets reset on each loop.  */
      if (close_paren)
	(*info->fprintf_func) (info->stream, ")");
    }

  return length;
}

/* There are no specific bits that tell us for certain whether a vector
   instruction opcode contains one or two instructions.  However since
   a destination register of r0 is illegal, we can check for nonzero
   values in both destination register fields.  Only opcodes that have
   two valid instructions will have non-zero in both.  */

#define TWO_INSN(insn) ((((insn) & (0x1F << 27)) != 0) && (((insn) & (0x1F << 22)) != 0))

static int
print_instruction (struct disassemble_info *info,
		   bfd_vma memaddr,
		   unsigned long insn,
		   const struct tic80_opcode *vec_opcode)
{
  const struct tic80_opcode *opcode;
  const struct tic80_opcode *opcode_end;

  /* Find the first opcode match in the opcodes table.  For vector
     opcodes (vec_opcode != NULL) find the first match that is not the
     previously found match.  FIXME: there should be faster ways to
     search (hash table or binary search), but don't worry too much
     about it until other TIc80 support is finished.  */

  opcode_end = tic80_opcodes + tic80_num_opcodes;
  for (opcode = tic80_opcodes; opcode < opcode_end; opcode++)
    {
      if ((insn & opcode->mask) == opcode->opcode &&
	  opcode != vec_opcode)
	break;
    }

  if (opcode == opcode_end)
    {
      /* No match found, just print the bits as a .word directive.  */
      (*info->fprintf_func) (info->stream, ".word %#08lx", insn);
    }
  else
    {
      /* Match found, decode the instruction.  */
      length = print_one_instruction (info, memaddr, insn, opcode);
      if (opcode->flags & TIC80_VECTOR && vec_opcode == NULL && TWO_INSN (insn))
	{
	  /* There is another instruction to print from the same opcode.
	     Print the separator and then find and print the other
	     instruction.  */
	  (*info->fprintf_func) (info->stream, "   ||   ");
	  length = print_instruction (info, memaddr, insn, opcode);
	}
    }

  return length;
}

int
print_insn_tic80 (bfd_vma memaddr, struct disassemble_info *info)
{
  unsigned long insn;
  int status;

  length = 0;
  info->bytes_per_line = 8;
  status = fill_instruction (info, memaddr, &insn);
  if (status != -1)
    status = print_instruction (info, memaddr, insn, NULL);

  return status;
}