Initial revision

[binutils.git] / gas / config / tc-d10v.c

/* tc-d10v.c -- Assembler code for the Mitsubishi D10V

   Copyright (C) 1996, 1997, 1998 Free Software Foundation.

   This file is part of GAS, the GNU Assembler.

   GAS 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, or (at your option)
   any later version.

   GAS 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 GAS; see the file COPYING.  If not, write to
   the Free Software Foundation, 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <stdio.h>
#include <ctype.h>
#include "as.h"
#include "subsegs.h"     
#include "opcode/d10v.h"
#include "elf/ppc.h"

const char comment_chars[] = ";";
const char line_comment_chars[] = "#";
const char line_separator_chars[] = "";
const char *md_shortopts = "O";
const char EXP_CHARS[] = "eE";
const char FLT_CHARS[] = "dD";

int Optimizing = 0;

#define AT_WORD_P(X) ((X)->X_op == O_right_shift \
                      && (X)->X_op_symbol != NULL \
                      && (X)->X_op_symbol->sy_value.X_op == O_constant \
                      && (X)->X_op_symbol->sy_value.X_add_number == AT_WORD_RIGHT_SHIFT)
#define AT_WORD_RIGHT_SHIFT 2


/* fixups */
#define MAX_INSN_FIXUPS (5)
struct d10v_fixup
{
  expressionS exp;
  int operand;
  int pcrel;
  int size;
  bfd_reloc_code_real_type reloc;
};

typedef struct _fixups
{
  int fc;
  struct d10v_fixup fix[MAX_INSN_FIXUPS];
  struct _fixups *next;
} Fixups;

static Fixups FixUps[2];
static Fixups *fixups;

/* True if instruction swapping warnings should be inhibited.  */
static unsigned char flag_warn_suppress_instructionswap; /* --nowarnswap */

/* local functions */
static int reg_name_search PARAMS ((char *name));
static int register_name PARAMS ((expressionS *expressionP));
static int check_range PARAMS ((unsigned long num, int bits, int flags));
static int postfix PARAMS ((char *p));
static bfd_reloc_code_real_type get_reloc PARAMS ((struct d10v_operand *op));
static int get_operands PARAMS ((expressionS exp[]));
static struct d10v_opcode *find_opcode PARAMS ((struct d10v_opcode *opcode, expressionS ops[]));
static unsigned long build_insn PARAMS ((struct d10v_opcode *opcode, expressionS *opers, unsigned long insn));
static void write_long PARAMS ((struct d10v_opcode *opcode, unsigned long insn, Fixups *fx));
static void write_1_short PARAMS ((struct d10v_opcode *opcode, unsigned long insn, Fixups *fx));
static int write_2_short PARAMS ((struct d10v_opcode *opcode1, unsigned long insn1, 
                                  struct d10v_opcode *opcode2, unsigned long insn2, int exec_type, Fixups *fx));
static unsigned long do_assemble PARAMS ((char *str, struct d10v_opcode **opcode));
static unsigned long d10v_insert_operand PARAMS (( unsigned long insn, int op_type,
                                                   offsetT value, int left, fixS *fix));
static int parallel_ok PARAMS ((struct d10v_opcode *opcode1, unsigned long insn1, 
                                struct d10v_opcode *opcode2, unsigned long insn2,
                                int exec_type));
static symbolS * find_symbol_matching_register PARAMS ((expressionS *));

struct option md_longopts[] =
{
#define OPTION_NOWARNSWAP (OPTION_MD_BASE)
  {"nowarnswap", no_argument, NULL, OPTION_NOWARNSWAP},
  {NULL, no_argument, NULL, 0}
};
size_t md_longopts_size = sizeof(md_longopts);       

static void d10v_dot_word PARAMS ((int));

/* The target specific pseudo-ops which we support.  */
const pseudo_typeS md_pseudo_table[] =
{
  { "word",     d10v_dot_word,  2 },
  { NULL,       NULL,           0 }
};

/* Opcode hash table.  */
static struct hash_control *d10v_hash;

/* reg_name_search does a binary search of the d10v_predefined_registers
   array to see if "name" is a valid regiter name.  Returns the register
   number from the array on success, or -1 on failure. */

static int
reg_name_search (name)
     char *name;
{
  int middle, low, high;
  int cmp;

  low = 0;
  high = d10v_reg_name_cnt() - 1;

  do
    {
      middle = (low + high) / 2;
      cmp = strcasecmp (name, d10v_predefined_registers[middle].name);
      if (cmp < 0)
        high = middle - 1;
      else if (cmp > 0)
        low = middle + 1;
      else 
          return d10v_predefined_registers[middle].value;
    }
  while (low <= high);
  return -1;
}

/* register_name() checks the string at input_line_pointer
   to see if it is a valid register name */

static int
register_name (expressionP)
     expressionS *expressionP;
{
  int reg_number;
  char c, *p = input_line_pointer;
  
  while (*p && *p!='\n' && *p!='\r' && *p !=',' && *p!=' ' && *p!=')')
    p++;

  c = *p;
  if (c)
    *p++ = 0;

  /* look to see if it's in the register table */
  reg_number = reg_name_search (input_line_pointer);
  if (reg_number >= 0) 
    {
      expressionP->X_op = O_register;
      /* temporarily store a pointer to the string here */
      expressionP->X_op_symbol = (struct symbol *)input_line_pointer;
      expressionP->X_add_number = reg_number;
      input_line_pointer = p;
      return 1;
    }
  if (c)
    *(p-1) = c;
  return 0;
}


static int
check_range (num, bits, flags)
     unsigned long num;
     int bits;
     int flags;
{
  long min, max, bit1;
  int retval=0;

  /* don't bother checking 16-bit values */
  if (bits == 16)
    return 0;

  if (flags & OPERAND_SHIFT)
    {
      /* all special shift operands are unsigned */
      /* and <= 16.  We allow 0 for now. */
      if (num>16)
        return 1;
      else
        return 0;
    }

  if (flags & OPERAND_SIGNED)
    {
      max = (1 << (bits - 1))-1; 
      min = - (1 << (bits - 1));  
      if (((long)num > max) || ((long)num < min))
        retval = 1;
    }
  else
    {
      max = (1 << bits) - 1;
      min = 0;
      if ((num > max) || (num < min))
        retval = 1;
    }
  return retval;
}


void
md_show_usage (stream)
  FILE *stream;
{
  fprintf(stream, _("D10V options:\n\
-O                      optimize.  Will do some operations in parallel.\n"));
} 

int
md_parse_option (c, arg)
     int c;
     char *arg;
{
  switch (c)
    {
    case 'O':
      /* Optimize. Will attempt to parallelize operations */
      Optimizing = 1;
      break;
    case OPTION_NOWARNSWAP:
      flag_warn_suppress_instructionswap = 1;
      break;
    default:
      return 0;
    }
  return 1;
}

symbolS *
md_undefined_symbol (name)
  char *name;
{
  return 0;
}

/* Turn a string in input_line_pointer into a floating point constant of type
   type, and store the appropriate bytes in *litP.  The number of LITTLENUMS
   emitted is stored in *sizeP .  An error message is returned, or NULL on OK.
 */
char *
md_atof (type, litP, sizeP)
     int type;
     char *litP;
     int *sizeP;
{
  int prec;
  LITTLENUM_TYPE words[4];
  char *t;
  int i;
  
  switch (type)
    {
    case 'f':
      prec = 2;
      break;
    case 'd':
      prec = 4;
      break;
    default:
      *sizeP = 0;
      return _("bad call to md_atof");
    }

  t = atof_ieee (input_line_pointer, type, words);
  if (t)
    input_line_pointer = t;
  
  *sizeP = prec * 2;
  
  for (i = 0; i < prec; i++)
    {
      md_number_to_chars (litP, (valueT) words[i], 2);
          litP += 2;
    }
  return NULL;
}

void
md_convert_frag (abfd, sec, fragP)
  bfd *abfd;
  asection *sec;
  fragS *fragP;
{
  abort ();
}

valueT
md_section_align (seg, addr)
     asection *seg;
     valueT addr;
{
  int align = bfd_get_section_alignment (stdoutput, seg);
  return ((addr + (1 << align) - 1) & (-1 << align));
}


void
md_begin ()
{
  char *prev_name = "";
  struct d10v_opcode *opcode;
  d10v_hash = hash_new();

  /* Insert unique names into hash table.  The D10v instruction set
     has many identical opcode names that have different opcodes based
     on the operands.  This hash table then provides a quick index to
     the first opcode with a particular name in the opcode table.  */

  for (opcode = (struct d10v_opcode *)d10v_opcodes; opcode->name; opcode++)
    {
      if (strcmp (prev_name, opcode->name))
        {
          prev_name = (char *)opcode->name;
          hash_insert (d10v_hash, opcode->name, (char *) opcode);
        }
    }

  fixups = &FixUps[0];
  FixUps[0].next = &FixUps[1];
  FixUps[1].next = &FixUps[0];
}


/* this function removes the postincrement or postdecrement
   operator ( '+' or '-' ) from an expression */

static int postfix (p) 
     char *p;
{
  while (*p != '-' && *p != '+') 
    {
      if (*p==0 || *p=='\n' || *p=='\r') 
        break;
      p++;
    }

  if (*p == '-') 
    {
      *p = ' ';
      return (-1);
    }
  if (*p == '+') 
    {
      *p = ' ';
      return (1);
    }

  return (0);
}


static bfd_reloc_code_real_type 
get_reloc (op) 
     struct d10v_operand *op;
{
  int bits = op->bits;

  if (bits <= 4) 
    return (0);
      
  if (op->flags & OPERAND_ADDR) 
    {
      if (bits == 8)
        return (BFD_RELOC_D10V_10_PCREL_R);
      else
        return (BFD_RELOC_D10V_18_PCREL);
    }

  return (BFD_RELOC_16);
}


/* get_operands parses a string of operands and returns
   an array of expressions */

static int
get_operands (exp) 
     expressionS exp[];
{
  char *p = input_line_pointer;
  int numops = 0;
  int post = 0;

  while (*p)  
    {
      while (*p == ' ' || *p == '\t' || *p == ',') 
        p++;
      if (*p==0 || *p=='\n' || *p=='\r') 
        break;
      
      if (*p == '@') 
        {
          p++;
          exp[numops].X_op = O_absent;
          if (*p == '(') 
            {
              p++;
              exp[numops].X_add_number = OPERAND_ATPAR;
            }
          else if (*p == '-') 
            {
              p++;
              exp[numops].X_add_number = OPERAND_ATMINUS;
            }
          else
            {
              exp[numops].X_add_number = OPERAND_ATSIGN;
              post = postfix (p);
            }
          numops++;
          continue;
        }

      if (*p == ')') 
        {
          /* just skip the trailing paren */
          p++;
          continue;
        }

      input_line_pointer = p;

      /* check to see if it might be a register name */
      if (!register_name (&exp[numops]))
        {
          /* parse as an expression */
          expression (&exp[numops]);
        }

      if (strncasecmp (input_line_pointer, "@word", 5) == 0)
        {
          input_line_pointer += 5;
          if (exp[numops].X_op == O_register)
            {
              /* if it looked like a register name but was followed by
                 "@word" then it was really a symbol, so change it to
                 one */
              exp[numops].X_op = O_symbol;
              exp[numops].X_add_symbol = symbol_find_or_make ((char *)exp[numops].X_op_symbol);
            }

          /* check for identifier@word+constant */
          if (*input_line_pointer == '-' || *input_line_pointer == '+')
          {
            char *orig_line = input_line_pointer;
            expressionS new_exp;
            expression (&new_exp);
            exp[numops].X_add_number = new_exp.X_add_number;
          }

          /* convert expr into a right shift by AT_WORD_RIGHT_SHIFT */
          {
            expressionS new_exp;
            memset (&new_exp, 0, sizeof new_exp);
            new_exp.X_add_number = AT_WORD_RIGHT_SHIFT;
            new_exp.X_op = O_constant;
            new_exp.X_unsigned = 1;
            exp[numops].X_op_symbol = make_expr_symbol (&new_exp);
            exp[numops].X_op = O_right_shift;
          }

          know (AT_WORD_P (&exp[numops]));
        }
      
      if (exp[numops].X_op == O_illegal) 
        as_bad (_("illegal operand"));
      else if (exp[numops].X_op == O_absent) 
        as_bad (_("missing operand"));

      numops++;
      p = input_line_pointer;
    }

  switch (post) 
    {
    case -1:    /* postdecrement mode */
      exp[numops].X_op = O_absent;
      exp[numops++].X_add_number = OPERAND_MINUS;
      break;
    case 1:     /* postincrement mode */
      exp[numops].X_op = O_absent;
      exp[numops++].X_add_number = OPERAND_PLUS;
      break;
    }

  exp[numops].X_op = 0;
  return (numops);
}

static unsigned long
d10v_insert_operand (insn, op_type, value, left, fix) 
     unsigned long insn;
     int op_type;
     offsetT value;
     int left;
     fixS *fix;
{
  int shift, bits;

  shift = d10v_operands[op_type].shift;
  if (left)
    shift += 15;

  bits = d10v_operands[op_type].bits;

  /* truncate to the proper number of bits */
  if (check_range (value, bits, d10v_operands[op_type].flags))
    as_bad_where (fix->fx_file, fix->fx_line, _("operand out of range: %d"), value);

  value &= 0x7FFFFFFF >> (31 - bits);
  insn |= (value << shift);

  return insn;
}


/* build_insn takes a pointer to the opcode entry in the opcode table
   and the array of operand expressions and returns the instruction */

static unsigned long
build_insn (opcode, opers, insn) 
     struct d10v_opcode *opcode;
     expressionS *opers;
     unsigned long insn;
{
  int i, bits, shift, flags, format;
  unsigned long number;
  
  /* the insn argument is only used for the DIVS kludge */
  if (insn)
    format = LONG_R;
  else
    {
      insn = opcode->opcode;
      format = opcode->format;
    }
  
  for (i=0;opcode->operands[i];i++) 
    {
      flags = d10v_operands[opcode->operands[i]].flags;
      bits = d10v_operands[opcode->operands[i]].bits;
      shift = d10v_operands[opcode->operands[i]].shift;
      number = opers[i].X_add_number;

      if (flags & OPERAND_REG) 
        {
          number &= REGISTER_MASK;
          if (format == LONG_L)
            shift += 15;
        }

      if (opers[i].X_op != O_register && opers[i].X_op != O_constant) 
        {
          /* now create a fixup */

          if (fixups->fc >= MAX_INSN_FIXUPS)
            as_fatal (_("too many fixups"));

          if (AT_WORD_P (&opers[i]))
            {
              /* Reconize XXX>>1+N aka XXX@word+N as special (AT_WORD) */
              fixups->fix[fixups->fc].reloc = BFD_RELOC_D10V_18;
              opers[i].X_op = O_symbol;
              opers[i].X_op_symbol = NULL; /* Should free it */
              /* number is left shifted by AT_WORD_RIGHT_SHIFT so
                 that, it is aligned with the symbol's value.  Later,
                 BFD_RELOC_D10V_18 will right shift (symbol_value +
                 X_add_number). */
              number <<= AT_WORD_RIGHT_SHIFT;
              opers[i].X_add_number = number;
            }
          else
            fixups->fix[fixups->fc].reloc = 
              get_reloc((struct d10v_operand *)&d10v_operands[opcode->operands[i]]);

          if (fixups->fix[fixups->fc].reloc == BFD_RELOC_16 || 
              fixups->fix[fixups->fc].reloc == BFD_RELOC_D10V_18)
            fixups->fix[fixups->fc].size = 2;       
          else
            fixups->fix[fixups->fc].size = 4;
            
          fixups->fix[fixups->fc].exp = opers[i];
          fixups->fix[fixups->fc].operand = opcode->operands[i];
          fixups->fix[fixups->fc].pcrel = (flags & OPERAND_ADDR) ? true : false;
          (fixups->fc)++;
        }

      /* truncate to the proper number of bits */
      if ((opers[i].X_op == O_constant) && check_range (number, bits, flags))
        as_bad (_("operand out of range: %d"),number);
      number &= 0x7FFFFFFF >> (31 - bits);
      insn = insn | (number << shift);
    }

  /* kludge: for DIVS, we need to put the operands in twice */
  /* on the second pass, format is changed to LONG_R to force */
  /* the second set of operands to not be shifted over 15 */
  if ((opcode->opcode == OPCODE_DIVS) && (format==LONG_L))
    insn = build_insn (opcode, opers, insn);
      
  return insn;
}

/* write out a long form instruction */
static void
write_long (opcode, insn, fx) 
     struct d10v_opcode *opcode;
     unsigned long insn;
     Fixups *fx;
{
  int i, where;
  char *f = frag_more(4);

  insn |= FM11;
  number_to_chars_bigendian (f, insn, 4);

  for (i=0; i < fx->fc; i++) 
    {
      if (fx->fix[i].reloc)
        { 
          where = f - frag_now->fr_literal; 
          if (fx->fix[i].size == 2)
            where += 2;

          if (fx->fix[i].reloc == BFD_RELOC_D10V_18)
            fx->fix[i].operand |= 4096;   

          fix_new_exp (frag_now,
                       where,
                       fx->fix[i].size,
                       &(fx->fix[i].exp),
                       fx->fix[i].pcrel,
                       fx->fix[i].operand|2048);
        }
    }
  fx->fc = 0;
}


/* write out a short form instruction by itself */
static void
write_1_short (opcode, insn, fx) 
     struct d10v_opcode *opcode;
     unsigned long insn;
     Fixups *fx;
{
  char *f = frag_more(4);
  int i, where;

  if (opcode->exec_type & PARONLY)
    as_fatal (_("Instruction must be executed in parallel with another instruction."));

  /* the other container needs to be NOP */
  /* according to 4.3.1: for FM=00, sub-instructions performed only
     by IU cannot be encoded in L-container. */
  if (opcode->unit == IU)
    insn |= FM00 | (NOP << 15);         /* right container */
  else
    insn = FM00 | (insn << 15) | NOP;   /* left container */

  number_to_chars_bigendian (f, insn, 4);
  for (i=0; i < fx->fc; i++) 
    {
      if (fx->fix[i].reloc)
        { 
          where = f - frag_now->fr_literal; 
          if (fx->fix[i].size == 2)
            where += 2;

          if (fx->fix[i].reloc == BFD_RELOC_D10V_18)
            fx->fix[i].operand |= 4096;   

          /* if it's an R reloc, we may have to switch it to L */
          if ( (fx->fix[i].reloc == BFD_RELOC_D10V_10_PCREL_R) && (opcode->unit != IU) )
            fx->fix[i].operand |= 1024;

          fix_new_exp (frag_now,
                       where, 
                       fx->fix[i].size,
                       &(fx->fix[i].exp),
                       fx->fix[i].pcrel,
                       fx->fix[i].operand|2048);
        }
    }
  fx->fc = 0;
}

/* write out a short form instruction if possible */
/* return number of instructions not written out */
static int
write_2_short (opcode1, insn1, opcode2, insn2, exec_type, fx) 
     struct d10v_opcode *opcode1, *opcode2;
     unsigned long insn1, insn2;
     int exec_type;
     Fixups *fx;
{
  unsigned long insn;
  char *f;
  int i,j, where;

  if ( (exec_type != 1) && ((opcode1->exec_type & PARONLY)
                        || (opcode2->exec_type & PARONLY)))
    as_fatal (_("Instruction must be executed in parallel"));
  
  if ( (opcode1->format & LONG_OPCODE) || (opcode2->format & LONG_OPCODE))
    as_fatal (_("Long instructions may not be combined."));

  if(opcode1->exec_type & BRANCH_LINK && exec_type == 0)
    {
      /* Instructions paired with a subroutine call are executed before the
         subroutine, so don't do these pairings unless explicitly requested.  */
      write_1_short (opcode1, insn1, fx->next);
      return (1);
    }

  switch (exec_type) 
    {
    case 0:     /* order not specified */
      if ( Optimizing && parallel_ok (opcode1, insn1, opcode2, insn2, exec_type))
        {
          /* parallel */
          if (opcode1->unit == IU)
            insn = FM00 | (insn2 << 15) | insn1;
          else if (opcode2->unit == MU)
            insn = FM00 | (insn2 << 15) | insn1;
          else
            {
              insn = FM00 | (insn1 << 15) | insn2;  
              fx = fx->next;
            }
        }
      else if (opcode1->unit == IU) 
        {
          /* reverse sequential */
          insn = FM10 | (insn2 << 15) | insn1;
        }
      else
        {
          /* sequential */
          insn = FM01 | (insn1 << 15) | insn2;
          fx = fx->next;  
        }
      break;
    case 1:     /* parallel */
      if (opcode1->exec_type & SEQ || opcode2->exec_type & SEQ)
        as_fatal (_("One of these instructions may not be executed in parallel."));

      if (opcode1->unit == IU)
        {
          if (opcode2->unit == IU)
            as_fatal (_("Two IU instructions may not be executed in parallel"));
          if (!flag_warn_suppress_instructionswap)
            as_warn (_("Swapping instruction order"));
          insn = FM00 | (insn2 << 15) | insn1;
        }
      else if (opcode2->unit == MU)
        {
          if (opcode1->unit == MU)
            as_fatal (_("Two MU instructions may not be executed in parallel"));
          if (!flag_warn_suppress_instructionswap)
            as_warn (_("Swapping instruction order"));
          insn = FM00 | (insn2 << 15) | insn1;
        }
      else
        {
          insn = FM00 | (insn1 << 15) | insn2;  
          fx = fx->next;
        }
      break;
    case 2:     /* sequential */
      if (opcode1->unit != IU)
        insn = FM01 | (insn1 << 15) | insn2;  
      else if (opcode2->unit == MU || opcode2->unit == EITHER)
        {
          if (!flag_warn_suppress_instructionswap)
            as_warn (_("Swapping instruction order"));
          insn = FM10 | (insn2 << 15) | insn1;  
        }
      else
        as_fatal (_("IU instruction may not be in the left container"));
      fx = fx->next;
      break;
    case 3:     /* reverse sequential */
      if (opcode2->unit != MU)
        insn = FM10 | (insn1 << 15) | insn2;
      else if (opcode1->unit == IU || opcode1->unit == EITHER)
        {
          if (!flag_warn_suppress_instructionswap)
            as_warn (_("Swapping instruction order"));
          insn = FM01 | (insn2 << 15) | insn1;  
        }
      else
        as_fatal (_("MU instruction may not be in the right container"));
      fx = fx->next;
      break;
    default:
      as_fatal (_("unknown execution type passed to write_2_short()"));
    }

  f = frag_more(4);
  number_to_chars_bigendian (f, insn, 4);

  for (j=0; j<2; j++) 
    {
      for (i=0; i < fx->fc; i++) 
        {
          if (fx->fix[i].reloc)
            {
              where = f - frag_now->fr_literal; 
              if (fx->fix[i].size == 2)
                where += 2;
              
              if ( (fx->fix[i].reloc == BFD_RELOC_D10V_10_PCREL_R) && (j == 0) )
                fx->fix[i].operand |= 1024;
              
              if (fx->fix[i].reloc == BFD_RELOC_D10V_18)
                fx->fix[i].operand |= 4096;       

              fix_new_exp (frag_now,
                           where, 
                           fx->fix[i].size,
                           &(fx->fix[i].exp),
                           fx->fix[i].pcrel,
                           fx->fix[i].operand|2048);
            }
        }
      fx->fc = 0;
      fx = fx->next;
    }
  return (0);
}


/* Check 2 instructions and determine if they can be safely */
/* executed in parallel.  Returns 1 if they can be.         */
static int
parallel_ok (op1, insn1, op2, insn2, exec_type)
     struct d10v_opcode *op1, *op2;
     unsigned long insn1, insn2;
     int exec_type;
{
  int i, j, flags, mask, shift, regno;
  unsigned long ins, mod[2], used[2];
  struct d10v_opcode *op;

  if ((op1->exec_type & SEQ) != 0 || (op2->exec_type & SEQ) != 0
      || (op1->exec_type & PAR) == 0 || (op2->exec_type & PAR) == 0
      || (op1->unit == BOTH) || (op2->unit == BOTH)
      || (op1->unit == IU && op2->unit == IU)
      || (op1->unit == MU && op2->unit == MU))
    return 0;

  /* If the first instruction is a branch and this is auto parallazation,
     don't combine with any second instruction.  */
  if (exec_type == 0 && (op1->exec_type & BRANCH) != 0)
    return 0;

  /* The idea here is to create two sets of bitmasks (mod and used)
     which indicate which registers are modified or used by each
     instruction.  The operation can only be done in parallel if
     instruction 1 and instruction 2 modify different registers, and
     the first instruction does not modify registers that the second
     is using (The second instruction can modify registers that the
     first is using as they are only written back after the first
     instruction has completed).  Accesses to control registers, PSW,
     and memory are treated as accesses to a single register.  So if
     both instructions write memory or if the first instruction writes
     memory and the second reads, then they cannot be done in
     parallel.  Likewise, if the first instruction mucks with the psw
     and the second reads the PSW (which includes C, F0, and F1), then
     they cannot operate safely in parallel. */

  /* the bitmasks (mod and used) look like this (bit 31 = MSB) */
  /* r0-r15       0-15  */
  /* a0-a1        16-17 */
  /* cr (not psw) 18    */
  /* psw          19    */
  /* mem          20    */

  for (j=0;j<2;j++)
    {
      if (j == 0)
        {
          op = op1;
          ins = insn1;
        }
      else
        {
          op = op2;
          ins = insn2;
        }
      mod[j] = used[j] = 0;
      if (op->exec_type & BRANCH_LINK)
        mod[j] |= 1 << 13;

      for (i = 0; op->operands[i]; i++)
        {
          flags = d10v_operands[op->operands[i]].flags;
          shift = d10v_operands[op->operands[i]].shift;
          mask = 0x7FFFFFFF >> (31 - d10v_operands[op->operands[i]].bits);
          if (flags & OPERAND_REG)
            {
              regno = (ins >> shift) & mask;
              if (flags & (OPERAND_ACC0|OPERAND_ACC1))
                regno += 16;
              else if (flags & OPERAND_CONTROL) /* mvtc or mvfc */
                { 
                  if (regno == 0)
                    regno = 19;
                  else
                    regno = 18; 
                }
              else if (flags & (OPERAND_FFLAG|OPERAND_CFLAG))
                regno = 19;
              
              if ( flags & OPERAND_DEST )
                {
                  mod[j] |= 1 << regno;
                  if (flags & OPERAND_EVEN)
                    mod[j] |= 1 << (regno + 1);
                }
              else
                {
                  used[j] |= 1 << regno ;
                  if (flags & OPERAND_EVEN)
                    used[j] |= 1 << (regno + 1);

                  /* Auto inc/dec also modifies the register.  */
                  if (op->operands[i+1] != 0
                      && (d10v_operands[op->operands[i+1]].flags
                          & (OPERAND_PLUS | OPERAND_MINUS)) != 0)
                    mod[j] |= 1 << regno;
                }
            }
          else if (flags & OPERAND_ATMINUS)
            {
              /* SP implicitly used/modified */
              mod[j] |= 1 << 15;
              used[j] |= 1 << 15;
            }
        }
      if (op->exec_type & RMEM)
        used[j] |= 1 << 20;
      else if (op->exec_type & WMEM)
        mod[j] |= 1 << 20;
      else if (op->exec_type & RF0)
        used[j] |= 1 << 19;
      else if (op->exec_type & WF0)
        mod[j] |= 1 << 19;
      else if (op->exec_type & WCAR)
        mod[j] |= 1 << 19;
    }
  if ((mod[0] & mod[1]) == 0 && (mod[0] & used[1]) == 0)
    return 1;
  return 0;
}


/* This is the main entry point for the machine-dependent assembler.  str points to a
   machine-dependent instruction.  This function is supposed to emit the frags/bytes 
   it assembles to.  For the D10V, it mostly handles the special VLIW parsing and packing
   and leaves the difficult stuff to do_assemble().
 */

static unsigned long prev_insn;
static struct d10v_opcode *prev_opcode = 0;
static subsegT prev_subseg;
static segT prev_seg = 0;;
static int etype = 0;           /* saved extype.  used for multiline instructions */

void
md_assemble (str)
     char *str;
{
  struct d10v_opcode * opcode;
  unsigned long insn;
  int extype = 0;               /* execution type; parallel, etc */
  char * str2;

  if (etype == 0)
    {
      /* look for the special multiple instruction separators */
      str2 = strstr (str, "||");
      if (str2) 
        extype = 1;
      else
        {
          str2 = strstr (str, "->");
          if (str2) 
            extype = 2;
          else
            {
              str2 = strstr (str, "<-");
              if (str2) 
                extype = 3;
            }
        }
      /* str2 points to the separator, if one */
      if (str2) 
        {
          *str2 = 0;
          
          /* if two instructions are present and we already have one saved
             then first write it out */
          d10v_cleanup ();
          
          /* assemble first instruction and save it */
          prev_insn = do_assemble (str, &prev_opcode);
          if (prev_insn == -1)
            as_fatal (_("can't find opcode "));
          fixups = fixups->next;
          str = str2 + 2;
        }
    }

  insn = do_assemble (str, &opcode);
  if (insn == -1)
    {
      if (extype)
        {
          etype = extype;
          return;
        }
      as_fatal (_("can't find opcode "));
    }

  if (etype)
    {
      extype = etype;
      etype = 0;
    }

  /* if this is a long instruction, write it and any previous short instruction */
  if (opcode->format & LONG_OPCODE) 
    {
      if (extype) 
        as_fatal (_("Unable to mix instructions as specified"));
      d10v_cleanup ();
      write_long (opcode, insn, fixups);
      prev_opcode = NULL;
      return;
    }
  
  if (prev_opcode && prev_seg && ((prev_seg != now_seg) || (prev_subseg != now_subseg)))
    d10v_cleanup();
  
  if (prev_opcode && (write_2_short (prev_opcode, prev_insn, opcode, insn, extype, fixups) == 0)) 
    {
      /* no instructions saved */
      prev_opcode = NULL;
    }
  else
    {
      if (extype) 
        as_fatal (_("Unable to mix instructions as specified"));
      /* save off last instruction so it may be packed on next pass */
      prev_opcode = opcode;
      prev_insn = insn;
      prev_seg = now_seg;
      prev_subseg = now_subseg;
      fixups = fixups->next;
    }
}


/* do_assemble assembles a single instruction and returns an opcode */
/* it returns -1 (an invalid opcode) on error */

static unsigned long
do_assemble (str, opcode) 
     char *str;
     struct d10v_opcode **opcode;
{
  unsigned char *op_start, *save;
  unsigned char *op_end;
  char name[20];
  int nlen = 0;
  expressionS myops[6];
  unsigned long insn;

  /* Drop leading whitespace.  */
  while (*str == ' ')
    str++;

  /* Find the opcode end.  */
  for (op_start = op_end = (unsigned char *) (str);
       *op_end
       && nlen < 20
       && !is_end_of_line[*op_end] && *op_end != ' ';
       op_end++)
    {
      name[nlen] = tolower (op_start[nlen]);
      nlen++;
    }
  name[nlen] = 0;

  if (nlen == 0)
    return -1;
  
  /* Find the first opcode with the proper name.  */
  *opcode = (struct d10v_opcode *)hash_find (d10v_hash, name);
  if (*opcode == NULL)
      as_fatal (_("unknown opcode: %s"),name);

  save = input_line_pointer;
  input_line_pointer = op_end;
  *opcode = find_opcode (*opcode, myops);
  if (*opcode == 0)
    return -1;
  input_line_pointer = save;

  insn = build_insn ((*opcode), myops, 0); 
  return (insn);
}

/* Find the symbol which has the same name as the register in the given expression.  */
static symbolS *
find_symbol_matching_register (exp)
     expressionS * exp;
{
  int i;
  
  if (exp->X_op != O_register)
    return NULL;
  
  /* Find the name of the register.  */
  for (i = d10v_reg_name_cnt (); i--;)
    if (d10v_predefined_registers [i].value == exp->X_add_number)
      break;

  if (i < 0)
    abort ();

  /* Now see if a symbol has been defined with the same name.  */
  return symbol_find (d10v_predefined_registers [i].name);
}


/* find_opcode() gets a pointer to an entry in the opcode table.       */
/* It must look at all opcodes with the same name and use the operands */
/* to choose the correct opcode. */

static struct d10v_opcode *
find_opcode (opcode, myops)
     struct d10v_opcode *opcode;
     expressionS myops[];
{
  int i, match, done;
  struct d10v_opcode *next_opcode;

  /* get all the operands and save them as expressions */
  get_operands (myops);

  /* now see if the operand is a fake.  If so, find the correct size */
  /* instruction, if possible */
  if (opcode->format == OPCODE_FAKE)
    {
      int opnum = opcode->operands[0];
      int flags;
                         
      if (myops[opnum].X_op == O_register)
        {
          myops[opnum].X_op = O_symbol;
          myops[opnum].X_add_symbol = symbol_find_or_make ((char *)myops[opnum].X_op_symbol);
          myops[opnum].X_add_number = 0;
          myops[opnum].X_op_symbol = NULL;
        }

      next_opcode=opcode+1;

      /* If the first operand is supposed to be a register, make sure
         we got a valid one.  */
      flags = d10v_operands[next_opcode->operands[0]].flags;
      if (flags & OPERAND_REG)
        {
          int X_op = myops[0].X_op;
          int num = myops[0].X_add_number;

          if (X_op != O_register
              || (num & ~flags
                  & (OPERAND_GPR | OPERAND_ACC0 | OPERAND_ACC1
                     | OPERAND_FFLAG | OPERAND_CFLAG | OPERAND_CONTROL)))
            {
              as_bad (_("bad opcode or operands"));
              return 0;
            }
        }

      if (myops[opnum].X_op == O_constant || (myops[opnum].X_op == O_symbol &&
          S_IS_DEFINED(myops[opnum].X_add_symbol) &&
          (S_GET_SEGMENT(myops[opnum].X_add_symbol) == now_seg)))
        {
          for (i=0; opcode->operands[i+1]; i++)
            {
              int bits = d10v_operands[next_opcode->operands[opnum]].bits;
              int flags = d10v_operands[next_opcode->operands[opnum]].flags;
              if (flags & OPERAND_ADDR)
                bits += 2;
              if (myops[opnum].X_op == O_constant)
                {
                  if (!check_range (myops[opnum].X_add_number, bits, flags))
                    return next_opcode;
                }
              else
                {
                  fragS *f;
                  long value;
                  /* calculate the current address by running through the previous frags */
                  /* and adding our current offset */
                  for (value = 0, f = frchain_now->frch_root; f; f = f->fr_next)
                    value += f->fr_fix + f->fr_offset;

                  if (flags & OPERAND_ADDR)
                    value = S_GET_VALUE(myops[opnum].X_add_symbol) - value -
                      (obstack_next_free(&frchain_now->frch_obstack) - frag_now->fr_literal);
                  else
                    value = S_GET_VALUE(myops[opnum].X_add_symbol);

                  if (AT_WORD_P (&myops[opnum]))
                    {
                      if (bits > 4)
                        {
                          bits += 2;
                          if (!check_range (value, bits, flags))
                            return next_opcode;
                        }
                    }
                  else if (!check_range (value, bits, flags))
                    return next_opcode;
                }
              next_opcode++;
            }
          as_fatal (_("value out of range"));
        }
      else
        {
          /* not a constant, so use a long instruction */    
          return opcode+2;
        }
    }
  else
    {
      match = 0;
      /* now search the opcode table table for one with operands */
      /* that matches what we've got */
      while (!match)
        {
          match = 1;
          for (i = 0; opcode->operands[i]; i++) 
            {
              int flags = d10v_operands[opcode->operands[i]].flags;
              int X_op = myops[i].X_op;
              int num = myops[i].X_add_number;

              if (X_op == 0)
                {
                  match = 0;
                  break;
                }
              
              if (flags & OPERAND_REG)
                {
                  if ((X_op != O_register)
                      || (num & ~flags
                          & (OPERAND_GPR | OPERAND_ACC0 | OPERAND_ACC1
                             | OPERAND_FFLAG | OPERAND_CFLAG
                             | OPERAND_CONTROL)))
                    {
                      match = 0;
                      break;
                    }
                }
              
              if (((flags & OPERAND_MINUS)   && ((X_op != O_absent) || (num != OPERAND_MINUS))) ||
                  ((flags & OPERAND_PLUS)    && ((X_op != O_absent) || (num != OPERAND_PLUS))) ||
                  ((flags & OPERAND_ATMINUS) && ((X_op != O_absent) || (num != OPERAND_ATMINUS))) ||
                  ((flags & OPERAND_ATPAR)   && ((X_op != O_absent) || (num != OPERAND_ATPAR))) ||
                  ((flags & OPERAND_ATSIGN)  && ((X_op != O_absent) || (num != OPERAND_ATSIGN))))
                {
                  match = 0;
                  break;
                }
              
              /* Unfortunatly, for the indirect operand in instructions such as
                 ``ldb r1, @(c,r14)'' this function can be passed X_op == O_register
                 (because 'c' is a valid register name).  However we cannot just
                 ignore the case when X_op == O_register but flags & OPERAND_REG is
                 null, so we check to see if a symbol of the same name as the register
                 exists.  If the symbol does exist, then the parser was unable to
                 distinguish the two cases and we fix things here.  (Ref: PR14826) */
              
              if (!(flags & OPERAND_REG) && (X_op == O_register))
                {
                  symbolS * sym;
                  
                  sym = find_symbol_matching_register (& myops[i]);
                  
                  if (sym != NULL)
                    {
                      myops [i].X_op == X_op == O_symbol;
                      myops [i].X_add_symbol = sym;
                    }
                  else
                    as_bad
                      (_("illegal operand - register name found where none expected"));
                }
            }
          
          /* We're only done if the operands matched so far AND there
             are no more to check.  */
          if (match && myops[i].X_op == 0) 
            break;
          else
            match = 0;

          next_opcode = opcode + 1;
          
          if (next_opcode->opcode == 0) 
            break;
          
          if (strcmp (next_opcode->name, opcode->name))
            break;
          
          opcode = next_opcode;
        }
    }

  if (!match)  
    {
      as_bad (_("bad opcode or operands"));
      return (0);
    }

  /* Check that all registers that are required to be even are. */
  /* Also, if any operands were marked as registers, but were really symbols */
  /* fix that here. */
  for (i=0; opcode->operands[i]; i++) 
    {
      if ((d10v_operands[opcode->operands[i]].flags & OPERAND_EVEN) &&
          (myops[i].X_add_number & 1)) 
        as_fatal (_("Register number must be EVEN"));
      if (myops[i].X_op == O_register)
        {
          if (!(d10v_operands[opcode->operands[i]].flags & OPERAND_REG)) 
            {
              myops[i].X_op = O_symbol;
              myops[i].X_add_symbol = symbol_find_or_make ((char *)myops[i].X_op_symbol);
              myops[i].X_add_number = 0;
              myops[i].X_op_symbol = NULL;
            }
        }
    }
  return opcode;
}

/* if while processing a fixup, a reloc really needs to be created */
/* then it is done here */
                 
arelent *
tc_gen_reloc (seg, fixp)
     asection *seg;
     fixS *fixp;
{
  arelent *reloc;
  reloc = (arelent *) xmalloc (sizeof (arelent));
  reloc->sym_ptr_ptr = &fixp->fx_addsy->bsym;
  reloc->address = fixp->fx_frag->fr_address + fixp->fx_where;
  reloc->howto = bfd_reloc_type_lookup (stdoutput, fixp->fx_r_type);
  if (reloc->howto == (reloc_howto_type *) NULL)
    {
      as_bad_where (fixp->fx_file, fixp->fx_line,
                    _("reloc %d not supported by object file format"), (int)fixp->fx_r_type);
      return NULL;
    }

  if (fixp->fx_r_type == BFD_RELOC_VTABLE_INHERIT
      || fixp->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
    reloc->address = fixp->fx_offset;

  reloc->addend = fixp->fx_addnumber;

  return reloc;
}

int
md_estimate_size_before_relax (fragp, seg)
     fragS *fragp;
     asection *seg;
{
  abort ();
  return 0;
} 

long
md_pcrel_from_section (fixp, sec)
     fixS *fixp;
     segT sec;
{
  if (fixp->fx_addsy != (symbolS *)NULL && (!S_IS_DEFINED (fixp->fx_addsy) ||
      (S_GET_SEGMENT (fixp->fx_addsy) != sec)))
    return 0;
  return fixp->fx_frag->fr_address + fixp->fx_where;
}

int
md_apply_fix3 (fixp, valuep, seg)
     fixS *fixp;
     valueT *valuep;
     segT seg;
{
  char *where;
  unsigned long insn;
  long value;
  int op_type;
  int left=0;

  if (fixp->fx_addsy == (symbolS *) NULL)
    {
      value = *valuep;
      fixp->fx_done = 1;
    }
  else if (fixp->fx_pcrel)
    value = *valuep;
  else
    {
      value = fixp->fx_offset;
      if (fixp->fx_subsy != (symbolS *) NULL)
        {
          if (S_GET_SEGMENT (fixp->fx_subsy) == absolute_section)
            value -= S_GET_VALUE (fixp->fx_subsy);
          else
            {
              /* We don't actually support subtracting a symbol.  */
              as_bad_where (fixp->fx_file, fixp->fx_line,
                            _("expression too complex"));
            }
        }
    }

  op_type = fixp->fx_r_type;
  if (op_type & 2048)
    {
      op_type -= 2048;
      if (op_type & 1024)
        {
          op_type -= 1024;
          fixp->fx_r_type = BFD_RELOC_D10V_10_PCREL_L;
          left = 1;
        }
      else if (op_type & 4096)
        {
          op_type -= 4096;
          fixp->fx_r_type = BFD_RELOC_D10V_18;
        }
      else
        fixp->fx_r_type = get_reloc((struct d10v_operand *)&d10v_operands[op_type]); 
    }

  /* Fetch the instruction, insert the fully resolved operand
     value, and stuff the instruction back again.  */
  where = fixp->fx_frag->fr_literal + fixp->fx_where;
  insn = bfd_getb32 ((unsigned char *) where);

  switch (fixp->fx_r_type)
    {
    case BFD_RELOC_D10V_10_PCREL_L:
    case BFD_RELOC_D10V_10_PCREL_R:
    case BFD_RELOC_D10V_18_PCREL:
    case BFD_RELOC_D10V_18:
      /* instruction addresses are always right-shifted by 2 */
      value >>= AT_WORD_RIGHT_SHIFT;
      if (fixp->fx_size == 2)
        bfd_putb16 ((bfd_vma) value, (unsigned char *) where);
      else
        {
          struct d10v_opcode *rep, *repi;

          rep = (struct d10v_opcode *) hash_find (d10v_hash, "rep");
          repi = (struct d10v_opcode *) hash_find (d10v_hash, "repi");
          if ((insn & FM11) == FM11
              && (repi != NULL && (insn & repi->mask) == repi->opcode
                  || rep != NULL && (insn & rep->mask) == rep->opcode)
              && value < 4)
            as_fatal
              (_("line %d: rep or repi must include at least 4 instructions"),
               fixp->fx_line);
          insn = d10v_insert_operand (insn, op_type, (offsetT)value, left, fixp);
          bfd_putb32 ((bfd_vma) insn, (unsigned char *) where);  
        }
      break;
    case BFD_RELOC_32:
      bfd_putb32 ((bfd_vma) value, (unsigned char *) where);
      break;
    case BFD_RELOC_16:
      bfd_putb16 ((bfd_vma) value, (unsigned char *) where);
      break;

    case BFD_RELOC_VTABLE_INHERIT:
    case BFD_RELOC_VTABLE_ENTRY:
      fixp->fx_done = 0;
      return 1;

    default:
      as_fatal (_("line %d: unknown relocation type: 0x%x"),fixp->fx_line,fixp->fx_r_type);
    }
  return 0;
}

/* d10v_cleanup() is called after the assembler has finished parsing the input 
   file or after a label is defined.  Because the D10V assembler sometimes saves short 
   instructions to see if it can package them with the next instruction, there may
   be a short instruction that still needs written.  */
int
d10v_cleanup ()
{
  segT seg;
  subsegT subseg;

  if (prev_opcode && etype == 0)
    {
      seg = now_seg;
      subseg = now_subseg;
      if (prev_seg)
        subseg_set (prev_seg, prev_subseg);
      write_1_short (prev_opcode, prev_insn, fixups->next);
      subseg_set (seg, subseg);
      prev_opcode = NULL;
    }
  return 1;
}

/* Like normal .word, except support @word */
/* clobbers input_line_pointer, checks end-of-line. */
static void
d10v_dot_word (nbytes)
     register int nbytes;       /* 1=.byte, 2=.word, 4=.long */
{
  expressionS exp;
  bfd_reloc_code_real_type reloc;
  char *p;
  int offset;

  if (is_it_end_of_statement ())
    {
      demand_empty_rest_of_line ();
      return;
    }

  do
    {
      expression (&exp);
      if (!strncasecmp (input_line_pointer, "@word", 5))
        {
          exp.X_add_number = 0;
          input_line_pointer += 5;
        
          p = frag_more (2);
          fix_new_exp (frag_now, p - frag_now->fr_literal, 2, 
                       &exp, 0, BFD_RELOC_D10V_18);
        }
      else
        emit_expr (&exp, 2);
    }
  while (*input_line_pointer++ == ',');

  input_line_pointer--;         /* Put terminator back into stream. */
  demand_empty_rest_of_line ();
}


/* Mitsubishi asked that we support some old syntax that apparently */
/* had immediate operands starting with '#'.  This is in some of their */
/* sample code but is not documented (although it appears in some  */
/* examples in their assembler manual). For now, we'll solve this */
/* compatibility problem by simply ignoring any '#' at the beginning */
/* of an operand. */

/* operands that begin with '#' should fall through to here */
/* from expr.c */

void 
md_operand (expressionP)
     expressionS *expressionP;
{
  if (*input_line_pointer == '#')
    {
      input_line_pointer++;
      expression (expressionP);
    }
}

boolean
d10v_fix_adjustable (fixP)
   fixS *fixP;
{

  if (fixP->fx_addsy == NULL)
    return 1;
  
  /* Prevent all adjustments to global symbols. */
  if (S_IS_EXTERN (fixP->fx_addsy))
    return 0;
  if (S_IS_WEAK (fixP->fx_addsy))
    return 0;

  /* We need the symbol name for the VTABLE entries */
  if (fixP->fx_r_type == BFD_RELOC_VTABLE_INHERIT
      || fixP->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
    return 0;

  return 1;
}

int
d10v_force_relocation (fixp)
      struct fix *fixp;
{
  if (fixp->fx_r_type == BFD_RELOC_VTABLE_INHERIT
      || fixp->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
    return 1;

  return 0;
}