/* Print instructions for Tahoe target machines, for GDB.
   Copyright 1986, 1989, 1991, 1992 Free Software Foundation, Inc.
   Contributed by the State University of New York at Buffalo, by the
   Distributed Computer Systems Lab, Department of Computer Science, 1991.

This file is part of GDB.

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., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "defs.h"
#include "symtab.h"
#include "opcode/tahoe.h"

/* Tahoe instructions are never longer than this.  */
#define MAXLEN 62

/* Number of elements in the opcode table.  */
#define NOPCODES (sizeof votstrs / sizeof votstrs[0])

static unsigned char *print_insn_arg ();

/* Print the Tahoe instruction at address MEMADDR in debugged memory,
   on STREAM.  Returns length of the instruction, in bytes.  */

int
print_insn (memaddr, stream)
     CORE_ADDR memaddr;
     GDB_FILE *stream;
{
  unsigned char buffer[MAXLEN];
  register int i;
  register unsigned char *p;
  register char *d;

  read_memory (memaddr, buffer, MAXLEN);

  for (i = 0; i < NOPCODES; i++)
    if (votstrs[i].detail.code == buffer[0]
	|| votstrs[i].detail.code == *(unsigned short *)buffer)
      break;

  /* Handle undefined instructions.  */
  if (i == NOPCODES)
    {
      fprintf_unfiltered (stream, "0%o", buffer[0]);
      return 1;
    }

  fprintf_unfiltered (stream, "%s", votstrs[i].name);

  /* Point at first byte of argument data,
     and at descriptor for first argument.  */
  p = buffer + 1 + (votstrs[i].detail.code >= 0x100);
  d = votstrs[i].detail.args;

  if (*d)
    fputc_unfiltered ('\t', stream);

  while (*d)
    {
      p = print_insn_arg (d, p, memaddr + (p - buffer), stream);
      d += 2;
      if (*d)
	fprintf_unfiltered (stream, ",");
    }
  return p - buffer;
}
/*******************************************************************/
static unsigned char *
print_insn_arg (d, p, addr, stream)
     char *d;
     register char *p;
     CORE_ADDR addr;
     GDB_FILE *stream;
{
  int temp1 = 0;
  register int regnum = *p & 0xf;
  float floatlitbuf;

  if (*d == 'b')
    {
      if (d[1] == 'b')
	fprintf_unfiltered (stream, "0x%x", addr + *p++ + 1);
      else
	{

	  temp1 = *p;
	  temp1 <<= 8;
	  temp1 |= *(p + 1);
	  fprintf_unfiltered (stream, "0x%x", addr + temp1 + 2);
	  p += 2;
	}
    }
  else
    switch ((*p++ >> 4) & 0xf)
      {
      case 0:
      case 1:
      case 2:
      case 3:			/* Literal (short immediate byte) mode */
	if (d[1] == 'd' || d[1] == 'f' || d[1] == 'g' || d[1] == 'h')
	  {
	    *(int *)&floatlitbuf = 0x4000 + ((p[-1] & 0x3f) << 4);
	    fprintf_unfiltered (stream, "$%f", floatlitbuf);
	  }
	else
	  fprintf_unfiltered (stream, "$%d", p[-1] & 0x3f);
	break;

      case 4:			/* Indexed */
	p = (char *) print_insn_arg (d, p, addr + 1, stream);
	fprintf_unfiltered (stream, "[%s]", reg_names[regnum]);
	break;

      case 5:			/* Register */
	fprintf_unfiltered (stream, reg_names[regnum]);
	break;

      case 7:			/* Autodecrement */
	fputc_unfiltered ('-', stream);
      case 6:			/* Register deferred */
	fprintf_unfiltered (stream, "(%s)", reg_names[regnum]);
	break;

      case 9:	                /* Absolute Address & Autoincrement deferred */
	fputc_unfiltered ('*', stream);
	if (regnum == PC_REGNUM)
	  {
	    temp1 = *p;
	    temp1 <<= 8;
	    temp1 |= *(p +1);

	    fputc_unfiltered ('$', stream);
	    print_address (temp1, stream);
	    p += 4;
	    break;
	  }
      case 8:			/*Immediate & Autoincrement SP */
        if (regnum == 8)         /*88 is Immediate Byte Mode*/
	  fprintf_unfiltered (stream, "$%d", *p++);

	else if (regnum == 9)        /*89 is Immediate Word Mode*/
	  {
	    temp1 = *p;
	    temp1 <<= 8; 
	    temp1 |= *(p +1);
	    fprintf_unfiltered (stream, "$%d", temp1);
	    p += 2;
	  }  

	else if (regnum == PC_REGNUM)    /*8F is Immediate Long Mode*/
	  {
	    temp1 = *p;
	    temp1 <<=8;
	    temp1 |= *(p +1);
	    temp1 <<=8;
	    temp1 |= *(p +2);
	    temp1 <<= 8;
	    temp1 |= *(p +3);
	    fprintf_unfiltered (stream, "$%d", temp1);
	    p += 4;
	  }

	else                            /*8E is Autoincrement SP Mode*/
	      fprintf_unfiltered (stream, "(%s)+", reg_names[regnum]);
	break;

      case 11:			/* Register + Byte Displacement Deferred Mode*/
	fputc_unfiltered ('*', stream);
      case 10:			/* Register + Byte Displacement Mode*/
	if (regnum == PC_REGNUM)
	  print_address (addr + *p + 2, stream);
	else
	  fprintf_unfiltered (stream, "%d(%s)", *p, reg_names[regnum]);
	p += 1;
	break;

      case 13:			/* Register + Word Displacement Deferred Mode*/
	fputc_unfiltered ('*', stream);
      case 12:			/* Register + Word Displacement Mode*/
	temp1 = *p;
	temp1 <<= 8;
	temp1 |= *(p +1);
	if (regnum == PC_REGNUM)
	  print_address (addr + temp1 + 3, stream);
	else
	  fprintf_unfiltered (stream, "%d(%s)", temp1, reg_names[regnum]);
	p += 2;
	break;

      case 15:			/* Register + Long Displacement Deferred Mode*/
	fputc_unfiltered ('*', stream);
      case 14:			/* Register + Long Displacement Mode*/
	temp1 = *p;
	temp1 <<= 8;
	temp1 |= *(p +1);
	temp1 <<= 8;
	temp1 |= *(p +2);
	temp1 <<= 8;
	temp1 |= *(p +3);
	if (regnum == PC_REGNUM)
	  print_address (addr + temp1 + 5, stream);
	else
	  fprintf_unfiltered (stream, "%d(%s)", temp1, reg_names[regnum]);
	p += 4;
      }

  return (unsigned char *) p;
}













