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

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

   Copyright (C) 1996 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 (-1)

/* 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;

/* 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));


struct option md_longopts[] = {
  {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 pre_defined_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 = reg_name_cnt() - 1;

  do
    {
      middle = (low + high) / 2;
      cmp = strcasecmp (name, pre_defined_registers[middle].name);
      if (cmp < 0)
        high = middle - 1;
      else if (cmp > 0)
        low = middle + 1;
      else 
          return pre_defined_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;
    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;
{
  printf ("call to md_convert_frag \n");
  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;

  /*  printf("get_reloc:  bits=%d  address=%d\n",bits,op->flags & OPERAND_ADDR);   */
  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))
        {
          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);
              exp[numops].X_op_symbol = NULL;
            }
          exp[numops].X_add_number = AT_WORD;
          input_line_pointer += 5;
        }
      
      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 int 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 */

          /*
          printf("need a fixup: ");
          print_expr_1(stdout,&opers[i]);
          printf("\n");
          */

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

          if (opers[i].X_op == O_symbol && number == AT_WORD)
            {
              number = opers[i].X_add_number = 0;
              fixups->fix[fixups->fc].reloc = BFD_RELOC_D10V_18;
            } 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;
  /* printf("INSN: %08x\n",insn); */
  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;
          /*
          printf("fix_new_exp: where:%x size:%d\n    ",where,fx->fix[i].size);
          print_expr_1(stdout,&(fx->fix[i].exp));
          printf("\n");
          */

          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 */

  /*  printf("INSN: %08x\n",insn);  */
  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;

          /*
          printf("fix_new_exp: where:%x size:%d\n    ",where, fx->fix[i].size);
          print_expr_1(stdout,&(fx->fix[i].exp));
          printf("\n");
          */

          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 && opcode2->exec_type != PARONLY)
    {
      /* subroutines must be called from 32-bit boundaries */
      /* so the return address will be correct */
      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))
        {
          /* 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 ( !parallel_ok (opcode1, insn1, opcode2, insn2)
           && (opcode1->exec_type & PARONLY) == 0
           && (opcode2->exec_type & PARONLY) == 0)
        as_fatal ("Two instructions may not be executed in parallel with each other.");

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

  /*  printf("INSN: %08x\n",insn); */
  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;       

              /*
                printf("fix_new_exp: where:%x reloc:%d\n    ",where,fx->fix[i].operand);
                print_expr_1(stdout,&(fx->fix[i].exp));
                printf("\n");
                */

              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) 
     struct d10v_opcode *op1, *op2;
     unsigned long insn1, insn2;
{
  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;

  /* 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 neither instruction modifies any registers */
  /* the other is using.  Accesses to control registers, PSW, and memory are treated */
  /* as accesses to a single register.  So if both instructions write memory or one */
  /* instruction writes memory and the other reads, then they cannot be done in parallel. */
  /* Likewise, if one instruction mucks with the psw and the other 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_ACC)     
                regno += 16;
              else if (flags & OPERAND_CONTROL) /* mvtc or mvfc */
                { 
                  if (regno == 0)
                    regno = 19;
                  else
                    regno = 18; 
                }
              else if (flags & OPERAND_FLAG)  
                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);
                }
            }
        }
      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 && (mod[1] & used[0]) == 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;

void
md_assemble (str)
     char *str;
{
  struct d10v_opcode *opcode;
  unsigned long insn;
  int extype=0;                 /* execution type; parallel, etc */
  static int etype=0;           /* saved extype.  used for multiline instructions */
  char *str2;

  /*  printf("md_assemble: str=%s\n",str); */

  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 */
          if (prev_opcode) 
            write_1_short (prev_opcode, prev_insn, fixups->next);
          
          /* 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");
      if (prev_opcode) 
        {
          write_1_short (prev_opcode, prev_insn, fixups->next);
          prev_opcode = NULL;
        }
      write_long (opcode, insn, fixups);
      prev_opcode = NULL;
      return;
    }
  
  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;

  /* printf("do_assemble: str=%s\n",str); */

  /* 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] = 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); 
  /* printf("sub-insn = %lx\n",insn);  */
  return (insn);
}

/* 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, numops;
  struct d10v_opcode *next_opcode;

  /* get all the operands and save them as expressions */
  numops = 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];
                         
      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;
        }

      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)))
        {
          next_opcode=opcode+1;
          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;

                  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 (myops[opnum].X_add_number == AT_WORD)
                    {
                      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) ||
                      ((flags & OPERAND_ACC) != (num & OPERAND_ACC)) ||
                      ((flags & OPERAND_FLAG) != (num & OPERAND_FLAG)) ||
                      ((flags & OPERAND_CONTROL) != (num & 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;
                }             
            }
          /* 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 *) bfd_alloc_by_size_t (stdoutput, 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;
    }
  reloc->addend = fixp->fx_addnumber;
  /* printf("tc_gen_reloc: addr=%x  addend=%x\n", reloc->address, reloc->addend); */
  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))
    return 0;
  /* printf("pcrel_from_section: %x\n", fixp->fx_frag->fr_address + fixp->fx_where); */
  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");
            }
        }
    }
  
  /* printf("md_apply_fix: value=0x%x  type=0x%x  where=0x%x size=%d line=%d\n", value, fixp->fx_r_type,fixp->fx_where,fixp->fx_size, fixp->fx_line); */
  
  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 >>= 2;
      if (fixp->fx_size == 2)
        bfd_putb16 ((bfd_vma) value, (unsigned char *) where);
      else
        {
          /* printf("   insn=%x  value=%x where=%x  pcrel=%x\n",insn,value,fixp->fx_where,fixp->fx_pcrel); */
          insn = d10v_insert_operand (insn, op_type, (offsetT)value, left, fixp);
          /* printf("   new insn=%x\n",insn); */
          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;
    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 (done)
     int done;
{
  segT seg;
  subsegT subseg;

  if ( prev_opcode && (done  || (now_seg == prev_seg) && (now_subseg == prev_subseg)))
    {
      seg = now_seg;
      subseg = now_subseg;
      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);
    }
}