dist/opcodes/xgate-dis.c

/* xgate-dis.c -- Freescale XGATE disassembly
   Copyright 2009, 2010, 2011, 2012
   Free Software Foundation, Inc.
   Written by Sean Keys (skeys (at) ipdatasys.com)

   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 <assert.h>
#include "dis-asm.h"
#include "opintl.h"
#include "libiberty.h"
#include "ansidecl.h"
#include "opcode/xgate.h"

#define XGATE_TWO_BYTES      0x02
#define XGATE_NINE_BITS      0x1FF
#define XGATE_TEN_BITS       0x3FF
#define XGATE_NINE_SIGNBIT   0x100
#define XGATE_TEN_SIGNBIT    0x200

/* Structures.  */
struct decodeInfo
{
  unsigned int operMask;
  unsigned int operMasksRegisterBits;
  struct xgate_opcode *opcodePTR;
};

/* Prototypes for local functions.  */
static int print_insn (bfd_vma, struct disassemble_info *);
static int read_memory (bfd_vma, bfd_byte*, int, struct disassemble_info *);
static int ripBits (unsigned int *, int,
		    struct xgate_opcode *, unsigned int);
static int macro_search (char *, char *);
static struct decodeInfo * find_match (unsigned int);

/* Statics.  */
static struct decodeInfo *decodeTable;
static int initialized;
static char previousOpName[10];
static unsigned int perviousBin;

/* Disassemble one instruction at address 'memaddr'.  Returns the number
   of bytes used by that instruction.  */

static int
print_insn (bfd_vma memaddr, struct disassemble_info* info)
{
  int status;
  unsigned int raw_code;
  char *s = 0;
  long bytesRead = 0;
  int i = 0;
  struct xgate_opcode *opcodePTR = (struct xgate_opcode*) xgate_opcodes;
  struct decodeInfo *decodeTablePTR = 0;
  struct decodeInfo *decodePTR = 0;
  unsigned int operandRegisterBits = 0;
  signed int relAddr = 0;
  signed int operandOne = 0;
  signed int operandTwo = 0;
  bfd_byte buffer[4];
  bfd_vma absAddress;

  unsigned int operMaskReg = 0;
  /* Initialize our array of opcode masks and check them against our constant
     table.  */
  if (!initialized)
    {
      decodeTable = xmalloc (sizeof (struct decodeInfo) * xgate_num_opcodes);
      for (i = 0, decodeTablePTR = decodeTable; i < xgate_num_opcodes;
          i++, decodeTablePTR++, opcodePTR++)
        {
          unsigned int bin = 0;
          unsigned int mask = 0;
          for (s = opcodePTR->format; *s; s++)
            {
              bin <<= 1;
              mask <<= 1;
              operandRegisterBits <<= 1;
              bin |= (*s == '1');
              mask |= (*s == '0' || *s == '1');
              operandRegisterBits |= (*s == 'r');
            }
          /* Asserting will uncover inconsistencies in our table.  */
          assert ((s - opcodePTR->format) == 16 || (s - opcodePTR->format) == 32);
          assert (opcodePTR->bin_opcode == bin);

          decodeTablePTR->operMask = mask;
          decodeTablePTR->operMasksRegisterBits = operandRegisterBits;
          decodeTablePTR->opcodePTR = opcodePTR;
        }
      initialized = 1;
    }

  /* Read 16 bits.  */
  bytesRead += XGATE_TWO_BYTES;
  status = read_memory (memaddr, buffer, XGATE_TWO_BYTES, info);
  if (status == 0)
    {
      raw_code = buffer[0];
      raw_code <<= 8;
      raw_code += buffer[1];

      decodePTR = find_match (raw_code);
      if (decodePTR)
        {
          operMaskReg = decodePTR->operMasksRegisterBits;
          (*info->fprintf_func)(info->stream, "%s", decodePTR->opcodePTR->name);

          /* First we compare the shorthand format of the constraints. If we
	     still are unable to pinpoint the operands
	     we analyze the opcodes constraint string.  */
          switch (decodePTR->opcodePTR->sh_format)
          {
          case XG_R_C:
            (*info->fprintf_func)(info->stream, " R%x, CCR",
                (raw_code >> 8) & 0x7);
            break;
          case XG_C_R:
            (*info->fprintf_func)(info->stream, " CCR, R%x",
                (raw_code >> 8) & 0x7);
            break;
          case XG_R_P:
            (*info->fprintf_func)(info->stream, " R%x, PC",
                (raw_code >> 8) & 0x7);
            break;
          case XG_INH:
            break;
          case XG_R_R_R:
            if (!strcmp (decodePTR->opcodePTR->constraints, XGATE_OP_TRI))
              {
                (*info->fprintf_func)(info->stream, " R%x, R%x, R%x",
                    (raw_code >> 8) & 0x7, (raw_code >> 5) & 0x7,
                    (raw_code >> 2) & 0x7);
              }
            else if (!strcmp (decodePTR->opcodePTR->constraints, XGATE_OP_IDR))
              {
                if (raw_code & 0x01)
                  {
                    (*info->fprintf_func)(info->stream, " R%x, (R%x, R%x+)",
                        (raw_code >> 8) & 0x7, (raw_code >> 5) & 0x7,
                        (raw_code >> 2) & 0x7);
                  }
                else if (raw_code & 0x02)
                  {
                    (*info->fprintf_func)(info->stream, " R%x, (R%x, -R%x)",
                        (raw_code >> 8) & 0x7, (raw_code >> 5) & 0x7,
                        (raw_code >> 2) & 0x7);
                  }
                else
                  {
                    (*info->fprintf_func)(info->stream, " R%x, (R%x, R%x)",
                        (raw_code >> 8) & 0x7, (raw_code >> 5) & 0x7,
                        (raw_code >> 2) & 0x7);
                  }
              }
            else
              {
                (*info->fprintf_func)(info->stream, " unhandled mode %s",
                    decodePTR->opcodePTR->constraints);
              }
            break;
          case XG_R_R:
            if (!strcmp (decodePTR->opcodePTR->constraints, XGATE_OP_DYA))
              {
                operandOne = ripBits (&operMaskReg, 3, opcodePTR, raw_code);
                operandTwo = ripBits (&operMaskReg, 3, opcodePTR, raw_code);
                (*info->fprintf_func)(info->stream, " R%x, R%x", operandOne,
                    operandTwo);
              }
            else
              {
                (*info->fprintf_func)(info->stream, " unhandled mode %s",
                    opcodePTR->constraints);
              }
            break;
          case XG_R_R_I:
            (*info->fprintf_func)(info->stream, " R%x, (R%x, #0x%x)",
                (raw_code >> 8) & 0x7, (raw_code >> 5) & 0x7, raw_code & 0x1f);
            break;
          case XG_R:
            operandOne = ripBits (&operMaskReg, 3, decodePTR->opcodePTR,
                raw_code);
            (*info->fprintf_func)(info->stream, " R%x", operandOne);
            break;
          case XG_I | XG_PCREL:
          if (!strcmp (decodePTR->opcodePTR->constraints, XGATE_OP_REL9))
            {
              /* If address is negative handle it accordingly.  */
              if (raw_code & XGATE_NINE_SIGNBIT)
                {
                  relAddr = XGATE_NINE_BITS >> 1; /* Clip sign bit.  */
                  relAddr = ~relAddr; /* Make signed.  */
                  relAddr |= (raw_code & 0xFF) + 1; /* Apply our value.  */
                  relAddr <<= 1; /* Multiply by two as per processor docs.  */
                }
              else
                {
                  relAddr = raw_code & 0xff;
                  relAddr = (relAddr << 1) + 2;
                }
              (*info->fprintf_func)(info->stream, " *%d", relAddr);
              (*info->fprintf_func)(info->stream, "  Abs* 0x");
              (*info->print_address_func)(memaddr + relAddr, info);
            }
          else if (!strcmp (decodePTR->opcodePTR->constraints, XGATE_OP_REL10))
            {
              /* If address is negative handle it accordingly.  */
              if (raw_code & XGATE_TEN_SIGNBIT)
                {
                  relAddr = XGATE_TEN_BITS >> 1; /* Clip sign bit.  */
                  relAddr = ~relAddr; /* Make signed.  */
                  relAddr |= (raw_code & 0x1FF) + 1; /* Apply our value.  */
                  relAddr <<= 1; /* Multiply by two as per processor docs.  */
                }
              else
                {
                  relAddr = raw_code & 0x1FF;
                  relAddr = (relAddr << 1) + 2;
                }
              (*info->fprintf_func)(info->stream, " *%d", relAddr);
              (*info->fprintf_func)(info->stream, "  Abs* 0x");
              (*info->print_address_func)(memaddr + relAddr, info);
            }
          else
            {
              (*info->fprintf_func)(info->stream,
                  " Can't disassemble for mode) %s",
                  decodePTR->opcodePTR->constraints);
            }
          break;
          case XG_R_I:
            if (!strcmp (decodePTR->opcodePTR->constraints, XGATE_OP_IMM4))
              {
                (*info->fprintf_func)(info->stream, " R%x, #0x%02x",
                    (raw_code >> 8) & 0x7, (raw_code >> 4) & 0xF);
              }
            else if (!strcmp (decodePTR->opcodePTR->constraints, XGATE_OP_IMM8))
              {
                if (macro_search (decodePTR->opcodePTR->name, previousOpName) &&
                    previousOpName[0])
                  {
                    absAddress = (0xFF & raw_code) << 8;
                    absAddress |= perviousBin & 0xFF;
                    (*info->fprintf_func)(info->stream, " R%x, #0x%02x Abs* 0x",
                        (raw_code >> 8) & 0x7, raw_code & 0xff);
                    (*info->print_address_func)(absAddress, info);
                    previousOpName[0] = 0;
                  }
                else
                  {
                    strcpy (previousOpName, decodePTR->opcodePTR->name);
                    (*info->fprintf_func)(info->stream, " R%x, #0x%02x",
                        (raw_code >> 8) & 0x7, raw_code & 0xff);
                  }
              }
            else
              {
                (*info->fprintf_func)(info->stream,
                    " Can't disassemble for mode %s",
                    decodePTR->opcodePTR->constraints);
              }
            break;
          case XG_I:
            (*info->fprintf_func)(info->stream, " #0x%x",
                (raw_code >> 8) & 0x7);
            break;
          default:
            (*info->fprintf_func)(info->stream, "address mode not found\t %x",
                opcodePTR->bin_opcode);
            break;
          }
          perviousBin = raw_code;
        }
      else
        {
          (*info->fprintf_func)(info->stream,
				" unable to find opcode match #0%x", raw_code);
        }
    }
  return bytesRead;
}

int
print_insn_xgate (bfd_vma memaddr, struct disassemble_info* info)
{
  return print_insn (memaddr, info);
}

static int
read_memory (bfd_vma memaddr, bfd_byte* buffer, int size,
    struct disassemble_info* info)
{
  int status;
  status = (*info->read_memory_func) (memaddr, buffer, size, info);
  if (status != 0)
    {
      (*info->memory_error_func) (status, memaddr, info);
      return -1;
    }
  return 0;
}

static int
ripBits (unsigned int *operandBitsRemaining,
	 int numBitsRequested,
	 struct xgate_opcode *opcodePTR,
	 unsigned int memory)
{
  unsigned int currentBit;
  int operand;
  int numBitsFound;

  for (operand = 0, numBitsFound = 0, currentBit = 1
	 << ((opcodePTR->size * 8) - 1);
       (numBitsFound < numBitsRequested) && currentBit; currentBit >>= 1)
    {
      if (currentBit & *operandBitsRemaining)
	{
	  *operandBitsRemaining &= ~(currentBit); /* Consume the current bit.  */
	  operand <<= 1; /* Make room for our next bit.  */
	  numBitsFound++;
	  operand |= (currentBit & memory) > 0;
	}
    }
  return operand;
}

static int
macro_search (char *currentName, char *lastName)
{
  int i;
  int length = 0;
  char *where;

  for (i = 0; i < xgate_num_opcodes; i++)
    {
      where = strstr (xgate_opcodes[i].constraints, lastName);

      if (where)
        {
          length = strlen (where);
        }
      if (length)
        {
          where = strstr (xgate_opcodes[i].constraints, currentName);
          if (where)
            {
              length = strlen (where);
              return 1;
            }
        }
    }
  return 0;
}

static struct decodeInfo *
find_match (unsigned int raw_code)
{
  struct decodeInfo *decodeTablePTR = 0;
  int i;

  for (i = 0, decodeTablePTR = decodeTable; i < xgate_num_opcodes;
      i++, decodeTablePTR++)
    {
      if ((raw_code & decodeTablePTR->operMask)
          == decodeTablePTR->opcodePTR->bin_opcode)
        {
          /* Make sure we didn't run into a macro or alias.  */
          if (decodeTablePTR->opcodePTR->cycles_min != 0)
            {
              return decodeTablePTR;
              break;
            }
          else
	    continue;
        }
    }
  return 0;
}