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[thirdparty/binutils-gdb.git] / gas / config / tc-i860.c

/* tc-i860.c -- Assembler for the Intel i860 architecture.
   Copyright (C) 1989-2014 Free Software Foundation, Inc.

   Brought back from the dead and completely reworked
   by Jason Eckhardt <jle@cygnus.com>.

   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 3, 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, 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */

#include "as.h"
#include "safe-ctype.h"
#include "subsegs.h"
#include "opcode/i860.h"
#include "elf/i860.h"


/* The opcode hash table.  */
static struct hash_control *op_hash = NULL;

/* These characters always start a comment.  */
const char comment_chars[] = "#!/";

/* These characters start a comment at the beginning of a line.  */
const char line_comment_chars[] = "#/";

const char line_separator_chars[] = ";";

/* Characters that can be used to separate the mantissa from the exponent
   in floating point numbers.  */
const char EXP_CHARS[] = "eE";

/* Characters that indicate this number is a floating point constant.
   As in 0f12.456 or 0d1.2345e12.  */
const char FLT_CHARS[] = "rRsSfFdDxXpP";

/* Register prefix (depends on syntax).  */
static char reg_prefix;

#define MAX_FIXUPS 2

struct i860_it
{
  char *error;
  unsigned long opcode;
  enum expand_type expand;
  struct i860_fi
  {
    expressionS exp;
    bfd_reloc_code_real_type reloc;
    int pcrel;
    valueT fup;
  } fi[MAX_FIXUPS];
} the_insn;

/* The current fixup count.  */
static int fc;

static char *expr_end;

/* Indicates error if a pseudo operation was expanded after a branch.  */
static char last_expand;

/* If true, then warn if any pseudo operations were expanded.  */
static int target_warn_expand = 0;

/* If true, then XP support is enabled.  */
static int target_xp = 0;

/* If true, then Intel syntax is enabled (default to AT&T/SVR4 syntax).  */
static int target_intel_syntax = 0;


/* Prototypes.  */
static void i860_process_insn (char *);
static void s_dual (int);
static void s_enddual (int);
static void s_atmp (int);
static void s_align_wrapper (int);
static int i860_get_expression (char *);
static bfd_reloc_code_real_type obtain_reloc_for_imm16 (fixS *, long *); 
#ifdef DEBUG_I860
static void print_insn (struct i860_it *);
#endif

const pseudo_typeS md_pseudo_table[] =
{
  {"align",   s_align_wrapper, 0},
  {"dual",    s_dual,          0},
  {"enddual", s_enddual,       0},
  {"atmp",    s_atmp,          0},
  {NULL,      0,               0},
};

/* Dual-instruction mode handling.  */
enum dual
{
  DUAL_OFF = 0, DUAL_ON, DUAL_DDOT, DUAL_ONDDOT,
};
static enum dual dual_mode = DUAL_OFF;

/* Handle ".dual" directive.  */
static void
s_dual (int ignore ATTRIBUTE_UNUSED)
{
  if (target_intel_syntax)
    dual_mode = DUAL_ON;
  else
    as_bad (_("Directive .dual available only with -mintel-syntax option"));
}

/* Handle ".enddual" directive.  */
static void
s_enddual (int ignore ATTRIBUTE_UNUSED)
{
  if (target_intel_syntax)
    dual_mode = DUAL_OFF;
  else
    as_bad (_("Directive .enddual available only with -mintel-syntax option"));
}

/* Temporary register used when expanding assembler pseudo operations.  */
static int atmp = 31;

static void
s_atmp (int ignore ATTRIBUTE_UNUSED)
{
  int temp;

  if (! target_intel_syntax)
    {
      as_bad (_("Directive .atmp available only with -mintel-syntax option"));
      demand_empty_rest_of_line ();
      return;
    }

  if (strncmp (input_line_pointer, "sp", 2) == 0)
    {
      input_line_pointer += 2;
      atmp = 2;
    }
  else if (strncmp (input_line_pointer, "fp", 2) == 0)
    {
      input_line_pointer += 2;
      atmp = 3;
    }
  else if (strncmp (input_line_pointer, "r", 1) == 0)
    {
      input_line_pointer += 1;
      temp = get_absolute_expression ();
      if (temp >= 0 && temp <= 31)
        atmp = temp;
      else
        as_bad (_("Unknown temporary pseudo register"));
    }
  else
    {
      as_bad (_("Unknown temporary pseudo register"));
    }
  demand_empty_rest_of_line ();
}

/* Handle ".align" directive depending on syntax mode.
   AT&T/SVR4 syntax uses the standard align directive.  However, 
   the Intel syntax additionally allows keywords for the alignment
   parameter: ".align type", where type is one of {.short, .long,
   .quad, .single, .double} representing alignments of 2, 4,
   16, 4, and 8, respectively.  */
static void
s_align_wrapper (int arg)
{
  char *parm = input_line_pointer;

  if (target_intel_syntax)
    {
      /* Replace a keyword with the equivalent integer so the
         standard align routine can parse the directive.  */
      if (strncmp (parm, ".short", 6) == 0)
        strncpy (parm, "     2", 6);
      else if (strncmp (parm, ".long", 5) == 0)
        strncpy (parm, "    4", 5);
      else if (strncmp (parm, ".quad", 5) == 0)
        strncpy (parm, "   16", 5);
      else if (strncmp (parm, ".single", 7) == 0)
        strncpy (parm, "      4", 7);
      else if (strncmp (parm, ".double", 7) == 0)
        strncpy (parm, "      8", 7);
     
      while (*input_line_pointer == ' ')
        ++input_line_pointer;
    }

  s_align_bytes (arg);
}

/* This function is called once, at assembler startup time.  It should
   set up all the tables and data structures that the MD part of the
   assembler will need.  */
void
md_begin (void)
{
  const char *retval = NULL;
  int lose = 0;
  unsigned int i = 0;

  op_hash = hash_new ();

  while (i860_opcodes[i].name != NULL)
    {
      const char *name = i860_opcodes[i].name;
      retval = hash_insert (op_hash, name, (void *) &i860_opcodes[i]);
      if (retval != NULL)
        {
          fprintf (stderr, _("internal error: can't hash `%s': %s\n"),
                   i860_opcodes[i].name, retval);
          lose = 1;
        }
      do
        {
          if (i860_opcodes[i].match & i860_opcodes[i].lose)
            {
              fprintf (stderr,
                       _("internal error: losing opcode: `%s' \"%s\"\n"),
                       i860_opcodes[i].name, i860_opcodes[i].args);
              lose = 1;
            }
          ++i;
        }
      while (i860_opcodes[i].name != NULL
             && strcmp (i860_opcodes[i].name, name) == 0);
    }

  if (lose)
    as_fatal (_("Defective assembler.  No assembly attempted."));

  /* Set the register prefix for either Intel or AT&T/SVR4 syntax.  */
  reg_prefix = target_intel_syntax ? 0 : '%';
}

/* This is the core of the machine-dependent assembler.  STR points to a
   machine dependent instruction.  This function emits the frags/bytes
   it assembles to.  */
void
md_assemble (char *str)
{
  char *destp;
  int num_opcodes = 1;
  int i;
  struct i860_it pseudo[3];

  gas_assert (str);
  fc = 0;

  /* Assemble the instruction.  */
  i860_process_insn (str);

  /* Check for expandable flag to produce pseudo-instructions.  This
     is an undesirable feature that should be avoided.  */
  if (the_insn.expand != 0 && the_insn.expand != XP_ONLY
      && ! (the_insn.fi[0].fup & (OP_SEL_HA | OP_SEL_H | OP_SEL_L | OP_SEL_GOT
                            | OP_SEL_GOTOFF | OP_SEL_PLT)))
    {
      for (i = 0; i < 3; i++)
        pseudo[i] = the_insn;

      fc = 1;
      switch (the_insn.expand)
        {

        case E_DELAY:
          num_opcodes = 1;
          break;

        case E_MOV:
          if (the_insn.fi[0].exp.X_add_symbol == NULL
              && the_insn.fi[0].exp.X_op_symbol == NULL
              && (the_insn.fi[0].exp.X_add_number < (1 << 15)
                  && the_insn.fi[0].exp.X_add_number >= -(1 << 15)))
            break;

          /* Emit "or l%const,r0,ireg_dest".  */
          pseudo[0].opcode = (the_insn.opcode & 0x001f0000) | 0xe4000000;
          pseudo[0].fi[0].fup = (OP_IMM_S16 | OP_SEL_L);

          /* Emit "orh h%const,ireg_dest,ireg_dest".  */
          pseudo[1].opcode = (the_insn.opcode & 0x03ffffff) | 0xec000000
                              | ((the_insn.opcode & 0x001f0000) << 5);
          pseudo[1].fi[0].fup = (OP_IMM_S16 | OP_SEL_H);

          num_opcodes = 2;
          break;

        case E_ADDR:
          if (the_insn.fi[0].exp.X_add_symbol == NULL
              && the_insn.fi[0].exp.X_op_symbol == NULL
              && (the_insn.fi[0].exp.X_add_number < (1 << 15)
                  && the_insn.fi[0].exp.X_add_number >= -(1 << 15)))
            break;

          /* Emit "orh ha%addr_expr,ireg_src2,r31".  */
          pseudo[0].opcode = 0xec000000 | (the_insn.opcode & 0x03e00000)
                             | (atmp << 16);
          pseudo[0].fi[0].fup = (OP_IMM_S16 | OP_SEL_HA);

          /* Emit "l%addr_expr(r31),ireg_dest".  We pick up the fixup
             information from the original instruction.   */
          pseudo[1].opcode = (the_insn.opcode & ~0x03e00000) | (atmp << 21);
          pseudo[1].fi[0].fup = the_insn.fi[0].fup | OP_SEL_L;

          num_opcodes = 2;
          break;

        case E_U32:
          if (the_insn.fi[0].exp.X_add_symbol == NULL
              && the_insn.fi[0].exp.X_op_symbol == NULL
              && (the_insn.fi[0].exp.X_add_number < (1 << 16)
                  && the_insn.fi[0].exp.X_add_number >= 0))
            break;

          /* Emit "$(opcode)h h%const,ireg_src2,r31".  */
          pseudo[0].opcode = (the_insn.opcode & 0xf3e0ffff) | 0x0c000000
                              | (atmp << 16);
          pseudo[0].fi[0].fup = (OP_IMM_S16 | OP_SEL_H);

          /* Emit "$(opcode) l%const,r31,ireg_dest".  */
          pseudo[1].opcode = (the_insn.opcode & 0xf01f0000) | 0x04000000
                              | (atmp << 21);
          pseudo[1].fi[0].fup = (OP_IMM_S16 | OP_SEL_L);

          num_opcodes = 2;
          break;

        case E_AND:
          if (the_insn.fi[0].exp.X_add_symbol == NULL
              && the_insn.fi[0].exp.X_op_symbol == NULL
              && (the_insn.fi[0].exp.X_add_number < (1 << 16)
                  && the_insn.fi[0].exp.X_add_number >= 0))
            break;

          /* Emit "andnot h%const,ireg_src2,r31".  */
          pseudo[0].opcode = (the_insn.opcode & 0x03e0ffff) | 0xd4000000
                              | (atmp << 16);
          pseudo[0].fi[0].fup = (OP_IMM_S16 | OP_SEL_H);
          pseudo[0].fi[0].exp.X_add_number =
            -1 - the_insn.fi[0].exp.X_add_number;

          /* Emit "andnot l%const,r31,ireg_dest".  */
          pseudo[1].opcode = (the_insn.opcode & 0x001f0000) | 0xd4000000
                              | (atmp << 21);
          pseudo[1].fi[0].fup = (OP_IMM_S16 | OP_SEL_L);
          pseudo[1].fi[0].exp.X_add_number =
            -1 - the_insn.fi[0].exp.X_add_number;

          num_opcodes = 2;
          break;

        case E_S32:
          if (the_insn.fi[0].exp.X_add_symbol == NULL
              && the_insn.fi[0].exp.X_op_symbol == NULL
              && (the_insn.fi[0].exp.X_add_number < (1 << 15)
                  && the_insn.fi[0].exp.X_add_number >= -(1 << 15)))
            break;

          /* Emit "orh h%const,r0,r31".  */
          pseudo[0].opcode = 0xec000000 | (atmp << 16);
          pseudo[0].fi[0].fup = (OP_IMM_S16 | OP_SEL_H);

          /* Emit "or l%const,r31,r31".  */
          pseudo[1].opcode = 0xe4000000 | (atmp << 21) | (atmp << 16);
          pseudo[1].fi[0].fup = (OP_IMM_S16 | OP_SEL_L);

          /* Emit "r31,ireg_src2,ireg_dest".  */
          pseudo[2].opcode = (the_insn.opcode & ~0x0400ffff) | (atmp << 11);
          pseudo[2].fi[0].fup = OP_IMM_S16;

          num_opcodes = 3;
          break;

        default:
          as_fatal (_("failed sanity check."));
        }

      the_insn = pseudo[0];

      /* Warn if an opcode is expanded after a delayed branch.  */
      if (num_opcodes > 1 && last_expand == 1)
        as_warn (_("Expanded opcode after delayed branch: `%s'"), str);

      /* Warn if an opcode is expanded in dual mode.  */
      if (num_opcodes > 1 && dual_mode != DUAL_OFF)
        as_warn (_("Expanded opcode in dual mode: `%s'"), str);

      /* Notify if any expansions happen.  */
      if (target_warn_expand && num_opcodes > 1)
        as_warn (_("An instruction was expanded (%s)"), str);
    }

  dwarf2_emit_insn (0);
  i = 0;
  do
    {
      int tmp;

      /* Output the opcode.  Note that the i860 always reads instructions
         as little-endian data.  */
      destp = frag_more (4);
      number_to_chars_littleendian (destp, the_insn.opcode, 4);

      /* Check for expanded opcode after branch or in dual mode.  */
      last_expand = the_insn.fi[0].pcrel;

      /* Output the symbol-dependent stuff.  Only btne and bte will ever
         loop more than once here, since only they (possibly) have more
         than one fixup.  */
      for (tmp = 0; tmp < fc; tmp++)
        {
          if (the_insn.fi[tmp].fup != OP_NONE)
            {
              fixS *fix;
              fix = fix_new_exp (frag_now,
                                 destp - frag_now->fr_literal,
                                 4,
                                 &the_insn.fi[tmp].exp,
                                 the_insn.fi[tmp].pcrel,
                                 the_insn.fi[tmp].reloc);

             /* Despite the odd name, this is a scratch field.  We use
                it to encode operand type information.  */
             fix->fx_addnumber = the_insn.fi[tmp].fup;
           }
        }
      the_insn = pseudo[++i];
    }
  while (--num_opcodes > 0);

}

/* Assemble the instruction pointed to by STR.  */
static void
i860_process_insn (char *str)
{
  char *s;
  const char *args;
  char c;
  struct i860_opcode *insn;
  char *args_start;
  unsigned long opcode;
  unsigned int mask;
  int match = 0;
  int comma = 0;

#if 1 /* For compiler warnings.  */
  args = 0;
  insn = 0;
  args_start = 0;
  opcode = 0;
#endif

  for (s = str; ISLOWER (*s) || *s == '.' || *s == '3'
       || *s == '2' || *s == '1'; ++s)
    ;

  switch (*s)
    {
    case '\0':
      break;

    case ',':
      comma = 1;

      /*FALLTHROUGH*/

    case ' ':
      *s++ = '\0';
      break;

    default:
      as_fatal (_("Unknown opcode: `%s'"), str);
    }

  /* Check for dual mode ("d.") opcode prefix.  */
  if (strncmp (str, "d.", 2) == 0)
    {
      if (dual_mode == DUAL_ON)
        dual_mode = DUAL_ONDDOT;
      else
        dual_mode = DUAL_DDOT;
      str += 2;
    }

  if ((insn = (struct i860_opcode *) hash_find (op_hash, str)) == NULL)
    {
      if (dual_mode == DUAL_DDOT || dual_mode == DUAL_ONDDOT)
        str -= 2;
      as_bad (_("Unknown opcode: `%s'"), str);
      return;
    }

  if (comma)
    *--s = ',';

  args_start = s;
  for (;;)
    {
      int t;
      opcode = insn->match;
      memset (&the_insn, '\0', sizeof (the_insn));
      fc = 0;
      for (t = 0; t < MAX_FIXUPS; t++)
        {
          the_insn.fi[t].reloc = BFD_RELOC_NONE;
          the_insn.fi[t].pcrel = 0;
          the_insn.fi[t].fup = OP_NONE;
        }

      /* Build the opcode, checking as we go that the operands match.  */
      for (args = insn->args; ; ++args)
        {
          if (fc > MAX_FIXUPS)
            abort ();

          switch (*args)
            {

            /* End of args.  */
            case '\0':
              if (*s == '\0')
                match = 1;
              break;

            /* These must match exactly.  */
            case '+':
            case '(':
            case ')':
            case ',':
            case ' ':
              if (*s++ == *args)
                continue;
              break;

            /* Must be at least one digit.  */
            case '#':
              if (ISDIGIT (*s++))
                {
                  while (ISDIGIT (*s))
                    ++s;
                  continue;
                }
              break;

            /* Next operand must be a register.  */
            case '1':
            case '2':
            case 'd':
              /* Check for register prefix if necessary.  */
              if (reg_prefix && *s != reg_prefix)
                goto error;
              else if (reg_prefix)
                s++;

              switch (*s)
                {
                /* Frame pointer.  */
                case 'f':
                  s++;
                  if (*s++ == 'p')
                    {
                      mask = 0x3;
                      break;
                    }
                  goto error;

                /* Stack pointer.  */
                case 's':
                  s++;
                  if (*s++ == 'p')
                    {
                      mask = 0x2;
                      break;
                    }
                  goto error;

                /* Any register r0..r31.  */
                case 'r':
                  s++;
                  if (!ISDIGIT (c = *s++))
                    {
                      goto error;
                    }
                  if (ISDIGIT (*s))
                    {
                      if ((c = 10 * (c - '0') + (*s++ - '0')) >= 32)
                        goto error;
                    }
                  else
                    c -= '0';
                  mask = c;
                  break;

                /* Not this opcode.  */
                default:
                  goto error;
                }

              /* Obtained the register, now place it in the opcode.  */
              switch (*args)
                {
                case '1':
                  opcode |= mask << 11;
                  continue;

                case '2':
                  opcode |= mask << 21;
                  continue;

                case 'd':
                  opcode |= mask << 16;
                  continue;

                }
              break;

            /* Next operand is a floating point register.  */
            case 'e':
            case 'f':
            case 'g':
              /* Check for register prefix if necessary.  */
              if (reg_prefix && *s != reg_prefix)
                goto error;
              else if (reg_prefix)
                s++;

              if (*s++ == 'f' && ISDIGIT (*s))
                {
                  mask = *s++;
                  if (ISDIGIT (*s))
                    {
                      mask = 10 * (mask - '0') + (*s++ - '0');
                      if (mask >= 32)
                        {
                          break;
                        }
                    }
                  else
                    mask -= '0';

                  switch (*args)
                    {

                    case 'e':
                      opcode |= mask << 11;
                      continue;

                    case 'f':
                      opcode |= mask << 21;
                      continue;

                    case 'g':
                      opcode |= mask << 16;
                      if ((opcode & (1 << 10)) && mask != 0
                          && (mask == ((opcode >> 11) & 0x1f)))
                        as_warn (_("Pipelined instruction: fsrc1 = fdest"));
                      continue;
                    }
                }
              break;

            /* Next operand must be a control register.  */
            case 'c':
              /* Check for register prefix if necessary.  */
              if (reg_prefix && *s != reg_prefix)
                goto error;
              else if (reg_prefix)
                s++;

              if (strncmp (s, "fir", 3) == 0)
                {
                  opcode |= 0x0 << 21;
                  s += 3;
                  continue;
                }
              if (strncmp (s, "psr", 3) == 0)
                {
                  opcode |= 0x1 << 21;
                  s += 3;
                  continue;
                }
              if (strncmp (s, "dirbase", 7) == 0)
                {
                  opcode |= 0x2 << 21;
                  s += 7;
                  continue;
                }
              if (strncmp (s, "db", 2) == 0)
                {
                  opcode |= 0x3 << 21;
                  s += 2;
                  continue;
                }
              if (strncmp (s, "fsr", 3) == 0)
                {
                  opcode |= 0x4 << 21;
                  s += 3;
                  continue;
                }
              if (strncmp (s, "epsr", 4) == 0)
                {
                  opcode |= 0x5 << 21;
                  s += 4;
                  continue;
                }
              /* The remaining control registers are XP only.  */
              if (target_xp && strncmp (s, "bear", 4) == 0)
                {
                  opcode |= 0x6 << 21;
                  s += 4;
                  continue;
                }
              if (target_xp && strncmp (s, "ccr", 3) == 0)
                {
                  opcode |= 0x7 << 21;
                  s += 3;
                  continue;
                }
              if (target_xp && strncmp (s, "p0", 2) == 0)
                {
                  opcode |= 0x8 << 21;
                  s += 2;
                  continue;
                }
              if (target_xp && strncmp (s, "p1", 2) == 0)
                {
                  opcode |= 0x9 << 21;
                  s += 2;
                  continue;
                }
              if (target_xp && strncmp (s, "p2", 2) == 0)
                {
                  opcode |= 0xa << 21;
                  s += 2;
                  continue;
                }
              if (target_xp && strncmp (s, "p3", 2) == 0)
                {
                  opcode |= 0xb << 21;
                  s += 2;
                  continue;
                }
              break;

            /* 5-bit immediate in src1.  */
            case '5':
              if (! i860_get_expression (s))
                {
                  s = expr_end;
                  the_insn.fi[fc].fup |= OP_IMM_U5;
                  fc++;
                  continue;
                }
              break;

            /* 26-bit immediate, relative branch (lbroff).  */
            case 'l':
              the_insn.fi[fc].pcrel = 1;
              the_insn.fi[fc].fup |= OP_IMM_BR26;
              goto immediate;

            /* 16-bit split immediate, relative branch (sbroff).  */
            case 'r':
              the_insn.fi[fc].pcrel = 1;
              the_insn.fi[fc].fup |= OP_IMM_BR16;
              goto immediate;

            /* 16-bit split immediate.  */
            case 's':
              the_insn.fi[fc].fup |= OP_IMM_SPLIT16;
              goto immediate;

            /* 16-bit split immediate, byte aligned (st.b).  */
            case 'S':
              the_insn.fi[fc].fup |= OP_IMM_SPLIT16;
              goto immediate;

            /* 16-bit split immediate, half-word aligned (st.s).  */
            case 'T':
              the_insn.fi[fc].fup |= (OP_IMM_SPLIT16 | OP_ENCODE1 | OP_ALIGN2);
              goto immediate;

            /* 16-bit split immediate, word aligned (st.l).  */
            case 'U':
              the_insn.fi[fc].fup |= (OP_IMM_SPLIT16 | OP_ENCODE1 | OP_ALIGN4);
              goto immediate;

            /* 16-bit immediate.  */
            case 'i':
              the_insn.fi[fc].fup |= OP_IMM_S16;
              goto immediate;

            /* 16-bit immediate, byte aligned (ld.b).  */
            case 'I':
              the_insn.fi[fc].fup |= OP_IMM_S16;
              goto immediate;

            /* 16-bit immediate, half-word aligned (ld.s).  */
            case 'J':
              the_insn.fi[fc].fup |= (OP_IMM_S16 | OP_ENCODE1 | OP_ALIGN2);
              goto immediate;

            /* 16-bit immediate, word aligned (ld.l, {p}fld.l, fst.l).  */
            case 'K':
              if (insn->name[0] == 'l')
                the_insn.fi[fc].fup |= (OP_IMM_S16 | OP_ENCODE1 | OP_ALIGN4);
              else
                the_insn.fi[fc].fup |= (OP_IMM_S16 | OP_ENCODE2 | OP_ALIGN4);
              goto immediate;

            /* 16-bit immediate, double-word aligned ({p}fld.d, fst.d).  */
            case 'L':
              the_insn.fi[fc].fup |= (OP_IMM_S16 | OP_ENCODE3 | OP_ALIGN8);
              goto immediate;

            /* 16-bit immediate, quad-word aligned (fld.q, fst.q).  */
            case 'M':
              the_insn.fi[fc].fup |= (OP_IMM_S16 | OP_ENCODE3 | OP_ALIGN16);

              /*FALLTHROUGH*/

              /* Handle the immediate for either the Intel syntax or
                 SVR4 syntax. The Intel syntax is "ha%immediate"
                 whereas SVR4 syntax is "[immediate]@ha".  */
            immediate:
              if (target_intel_syntax == 0)
                {
                  /* AT&T/SVR4 syntax.  */
                  if (*s == ' ')
                    s++;

                  /* Note that if i860_get_expression() fails, we will still
                     have created U entries in the symbol table for the
                     'symbols' in the input string.  Try not to create U
                     symbols for registers, etc.  */
                  if (! i860_get_expression (s))
                    s = expr_end;
                  else
                    goto error;

                  if (strncmp (s, "@ha", 3) == 0)
                    {
                      the_insn.fi[fc].fup |= OP_SEL_HA;
                      s += 3;
                    }
                  else if (strncmp (s, "@h", 2) == 0)
                    {
                      the_insn.fi[fc].fup |= OP_SEL_H;
                      s += 2;
                    }
                  else if (strncmp (s, "@l", 2) == 0)
                    {
                      the_insn.fi[fc].fup |= OP_SEL_L;
                      s += 2;
                    }
                  else if (strncmp (s, "@gotoff", 7) == 0
                           || strncmp (s, "@GOTOFF", 7) == 0)
                    {
                      as_bad (_("Assembler does not yet support PIC"));
                      the_insn.fi[fc].fup |= OP_SEL_GOTOFF;
                      s += 7;
                    }
                  else if (strncmp (s, "@got", 4) == 0
                           || strncmp (s, "@GOT", 4) == 0)
                    {
                      as_bad (_("Assembler does not yet support PIC"));
                      the_insn.fi[fc].fup |= OP_SEL_GOT;
                      s += 4;
                    }
                  else if (strncmp (s, "@plt", 4) == 0
                           || strncmp (s, "@PLT", 4) == 0)
                    {
                      as_bad (_("Assembler does not yet support PIC"));
                      the_insn.fi[fc].fup |= OP_SEL_PLT;
                      s += 4;
                    }

                  the_insn.expand = insn->expand;
                  fc++;
              
                  continue;
                }
              else
                {
                  /* Intel syntax.  */
                  if (*s == ' ')
                    s++;
                  if (strncmp (s, "ha%", 3) == 0)
                    {
                      the_insn.fi[fc].fup |= OP_SEL_HA;
                      s += 3;
                    }
                  else if (strncmp (s, "h%", 2) == 0)
                    {
                      the_insn.fi[fc].fup |= OP_SEL_H;
                      s += 2;
                    }
                  else if (strncmp (s, "l%", 2) == 0)
                    {
                      the_insn.fi[fc].fup |= OP_SEL_L;
                      s += 2;
                    }
                  the_insn.expand = insn->expand;

                  /* Note that if i860_get_expression() fails, we will still
                     have created U entries in the symbol table for the
                     'symbols' in the input string.  Try not to create U
                     symbols for registers, etc.  */
                  if (! i860_get_expression (s))
                    s = expr_end;
                  else
                    goto error;

                  fc++;
                  continue;
                }
              break;

            default:
              as_fatal (_("failed sanity check."));
            }
          break;
        }
    error:
      if (match == 0)
        {
          /* Args don't match.  */
          if (insn[1].name != NULL
              && ! strcmp (insn->name, insn[1].name))
            {
              ++insn;
              s = args_start;
              continue;
            }
          else
            {
              as_bad (_("Illegal operands for %s"), insn->name);
              return;
            }
        }
      break;
    }

  /* Set the dual bit on this instruction if necessary.  */
  if (dual_mode != DUAL_OFF)
    {
      if ((opcode & 0xfc000000) == 0x48000000 || opcode == 0xb0000000)
        {
          /* The instruction is a flop or a fnop, so set its dual bit
             (but check that it is 8-byte aligned).  */
          if (((frag_now->fr_address + frag_now_fix_octets ()) & 7) == 0)
            opcode |= (1 << 9);
          else
            as_bad (_("'d.%s' must be 8-byte aligned"), insn->name);

          if (dual_mode == DUAL_DDOT)
            dual_mode = DUAL_OFF;
          else if (dual_mode == DUAL_ONDDOT)
            dual_mode = DUAL_ON;
        }
      else if (dual_mode == DUAL_DDOT || dual_mode == DUAL_ONDDOT)
        as_bad (_("Prefix 'd.' invalid for instruction `%s'"), insn->name);
    }

  the_insn.opcode = opcode;

  /* Only recognize XP instructions when the user has requested it.  */
  if (insn->expand == XP_ONLY && ! target_xp)
    as_bad (_("Unknown opcode: `%s'"), insn->name);
}

static int
i860_get_expression (char *str)
{
  char *save_in;
  segT seg;

  save_in = input_line_pointer;
  input_line_pointer = str;
  seg = expression (&the_insn.fi[fc].exp);
  if (seg != absolute_section
      && seg != undefined_section
      && ! SEG_NORMAL (seg))
    {
      the_insn.error = _("bad segment");
      expr_end = input_line_pointer;
      input_line_pointer = save_in;
      return 1;
    }
  expr_end = input_line_pointer;
  input_line_pointer = save_in;
  return 0;
}

char *
md_atof (int type, char *litP, int *sizeP)
{
  return ieee_md_atof (type, litP, sizeP, TRUE);
}

/* Write out in current endian mode.  */
void
md_number_to_chars (char *buf, valueT val, int n)
{
  if (target_big_endian)
    number_to_chars_bigendian (buf, val, n);
  else
    number_to_chars_littleendian (buf, val, n);
}

/* This should never be called for i860.  */
int
md_estimate_size_before_relax (register fragS *fragP ATTRIBUTE_UNUSED,
                               segT segtype ATTRIBUTE_UNUSED)
{
  as_fatal (_("relaxation not supported\n"));
}

#ifdef DEBUG_I860
static void
print_insn (struct i860_it *insn)
{
  if (insn->error)
    fprintf (stderr, "ERROR: %s\n", insn->error);

  fprintf (stderr, "opcode = 0x%08lx\t", insn->opcode);
  fprintf (stderr, "expand = 0x%x\t", insn->expand);
  fprintf (stderr, "reloc = %s\t\n",
           bfd_get_reloc_code_name (insn->reloc));
  fprintf (stderr, "exp =  {\n");
  fprintf (stderr, "\t\tX_add_symbol = %s\n",
           insn->exp.X_add_symbol ?
           (S_GET_NAME (insn->exp.X_add_symbol) ?
            S_GET_NAME (insn->exp.X_add_symbol) : "???") : "0");
  fprintf (stderr, "\t\tX_op_symbol = %s\n",
           insn->exp.X_op_symbol ?
           (S_GET_NAME (insn->exp.X_op_symbol) ?
            S_GET_NAME (insn->exp.X_op_symbol) : "???") : "0");
  fprintf (stderr, "\t\tX_add_number = %lx\n",
           insn->exp.X_add_number);
  fprintf (stderr, "}\n");
}
#endif /* DEBUG_I860 */

\f
#ifdef OBJ_ELF
const char *md_shortopts = "VQ:";
#else
const char *md_shortopts = "";
#endif

#define OPTION_EB               (OPTION_MD_BASE + 0)
#define OPTION_EL               (OPTION_MD_BASE + 1)
#define OPTION_WARN_EXPAND      (OPTION_MD_BASE + 2)
#define OPTION_XP               (OPTION_MD_BASE + 3)
#define OPTION_INTEL_SYNTAX     (OPTION_MD_BASE + 4)

struct option md_longopts[] = {
  { "EB",           no_argument, NULL, OPTION_EB },
  { "EL",           no_argument, NULL, OPTION_EL },
  { "mwarn-expand", no_argument, NULL, OPTION_WARN_EXPAND },
  { "mxp",          no_argument, NULL, OPTION_XP },
  { "mintel-syntax",no_argument, NULL, OPTION_INTEL_SYNTAX },
  { NULL,           no_argument, NULL, 0 }
};
size_t md_longopts_size = sizeof (md_longopts);

int
md_parse_option (int c, char *arg ATTRIBUTE_UNUSED)
{
  switch (c)
    {
    case OPTION_EB:
      target_big_endian = 1;
      break;

    case OPTION_EL:
      target_big_endian = 0;
      break;

    case OPTION_WARN_EXPAND:
      target_warn_expand = 1;
      break;

    case OPTION_XP:
      target_xp = 1;
      break;

    case OPTION_INTEL_SYNTAX:
      target_intel_syntax = 1;
      break;

#ifdef OBJ_ELF
    /* SVR4 argument compatibility (-V): print version ID.  */
    case 'V':
      print_version_id ();
      break;

    /* SVR4 argument compatibility (-Qy, -Qn): controls whether
       a .comment section should be emitted or not (ignored).  */
    case 'Q':
      break;
#endif

    default:
      return 0;
    }

  return 1;
}

void
md_show_usage (FILE *stream)
{
  fprintf (stream, _("\
  -EL                     generate code for little endian mode (default)\n\
  -EB                     generate code for big endian mode\n\
  -mwarn-expand           warn if pseudo operations are expanded\n\
  -mxp                    enable i860XP support (disabled by default)\n\
  -mintel-syntax          enable Intel syntax (default to AT&T/SVR4)\n"));
#ifdef OBJ_ELF
  /* SVR4 compatibility flags.  */
  fprintf (stream, _("\
  -V                      print assembler version number\n\
  -Qy, -Qn                ignored\n"));
#endif
}

\f
/* We have no need to default values of symbols.  */
symbolS *
md_undefined_symbol (char *name ATTRIBUTE_UNUSED)
{
  return 0;
}

/* The i860 denotes auto-increment with '++'.  */
void
md_operand (expressionS *exp)
{
  char *s;

  for (s = input_line_pointer; *s; s++)
    {
      if (s[0] == '+' && s[1] == '+')
        {
          input_line_pointer += 2;
          exp->X_op = O_register;
          break;
        }
    }
}

/* Round up a section size to the appropriate boundary.  */
valueT
md_section_align (segT segment ATTRIBUTE_UNUSED,
                  valueT size ATTRIBUTE_UNUSED)
{
  /* Byte alignment is fine.  */
  return size;
}

/* On the i860, a PC-relative offset is relative to the address of the
   offset plus its size.  */
long
md_pcrel_from (fixS *fixP)
{
  return fixP->fx_size + fixP->fx_where + fixP->fx_frag->fr_address;
}

/* Determine the relocation needed for non PC-relative 16-bit immediates.
   Also adjust the given immediate as necessary.  Finally, check that
   all constraints (such as alignment) are satisfied.   */
static bfd_reloc_code_real_type
obtain_reloc_for_imm16 (fixS *fix, long *val)
{
  valueT fup = fix->fx_addnumber;
  bfd_reloc_code_real_type reloc;

  if (fix->fx_pcrel)
    abort ();

  /* Check alignment restrictions.  */
  if ((fup & OP_ALIGN2) && (*val & 0x1))
    as_bad_where (fix->fx_file, fix->fx_line,
                  _("This immediate requires 0 MOD 2 alignment"));
  else if ((fup & OP_ALIGN4) && (*val & 0x3))
    as_bad_where (fix->fx_file, fix->fx_line,
                  _("This immediate requires 0 MOD 4 alignment"));
  else if ((fup & OP_ALIGN8) && (*val & 0x7))
    as_bad_where (fix->fx_file, fix->fx_line,
                  _("This immediate requires 0 MOD 8 alignment"));
  else if ((fup & OP_ALIGN16) && (*val & 0xf))
    as_bad_where (fix->fx_file, fix->fx_line,
                  _("This immediate requires 0 MOD 16 alignment"));

  if (fup & OP_SEL_HA)
    {
      *val = (*val >> 16) + (*val & 0x8000 ? 1 : 0);
      reloc = BFD_RELOC_860_HIGHADJ;
    }
  else if (fup & OP_SEL_H)
    {
      *val >>= 16;
      reloc = BFD_RELOC_860_HIGH;
    }
  else if (fup & OP_SEL_L)
    {
      int num_encode;
      if (fup & OP_IMM_SPLIT16)
        {
          if (fup & OP_ENCODE1)
            {
              num_encode = 1;
              reloc = BFD_RELOC_860_SPLIT1;
            }
          else if (fup & OP_ENCODE2)
            {
              num_encode = 2;
              reloc = BFD_RELOC_860_SPLIT2;
            }
          else
            {
              num_encode = 0;
              reloc = BFD_RELOC_860_SPLIT0;
            }
        }
      else
        {
          if (fup & OP_ENCODE1)
            {
              num_encode = 1;
              reloc = BFD_RELOC_860_LOW1;
            }
          else if (fup & OP_ENCODE2)
            {
              num_encode = 2;
              reloc = BFD_RELOC_860_LOW2;
            }
          else if (fup & OP_ENCODE3)
            {
              num_encode = 3;
              reloc = BFD_RELOC_860_LOW3;
            }
          else
            {
              num_encode = 0;
              reloc = BFD_RELOC_860_LOW0;
            }
        }

      /* Preserve size encode bits.  */
      *val &= ~((1 << num_encode) - 1);
    }
  else
    {
      /* No selector.  What reloc do we generate (???)?  */
      reloc = BFD_RELOC_32;
    }

  return reloc;
}

/* Attempt to simplify or eliminate a fixup. To indicate that a fixup
   has been eliminated, set fix->fx_done. If fix->fx_addsy is non-NULL,
   we will have to generate a reloc entry.  */

void
md_apply_fix (fixS *fix, valueT *valP, segT seg ATTRIBUTE_UNUSED)
{
  char *buf;
  long val = *valP;
  unsigned long insn;
  valueT fup;

  buf = fix->fx_frag->fr_literal + fix->fx_where;

  /* Recall that earlier we stored the opcode little-endian.  */
  insn = bfd_getl32 (buf);

  /* We stored a fix-up in this oddly-named scratch field.  */
  fup = fix->fx_addnumber;

  /* Determine the necessary relocations as well as inserting an
     immediate into the instruction.   */
  if (fup & OP_IMM_U5)
    {
      if (val & ~0x1f)
        as_bad_where (fix->fx_file, fix->fx_line,
                      _("5-bit immediate too large"));
      if (fix->fx_addsy)
        as_bad_where (fix->fx_file, fix->fx_line,
                      _("5-bit field must be absolute"));

      insn |= (val & 0x1f) << 11;
      bfd_putl32 (insn, buf);
      fix->fx_r_type = BFD_RELOC_NONE;
      fix->fx_done = 1;
    }
  else if (fup & OP_IMM_S16)
    {
      fix->fx_r_type = obtain_reloc_for_imm16 (fix, &val);

      /* Insert the immediate.  */
      if (fix->fx_addsy)
        fix->fx_done = 0;
      else
        {
          insn |= val & 0xffff;
          bfd_putl32 (insn, buf);
          fix->fx_r_type = BFD_RELOC_NONE;
          fix->fx_done = 1;
        }
    }
  else if (fup & OP_IMM_U16)
    abort ();

  else if (fup & OP_IMM_SPLIT16)
    {
      fix->fx_r_type = obtain_reloc_for_imm16 (fix, &val);

      /* Insert the immediate.  */
      if (fix->fx_addsy)
        fix->fx_done = 0;
      else
        {
          insn |= val & 0x7ff;
          insn |= (val & 0xf800) << 5;
          bfd_putl32 (insn, buf);
          fix->fx_r_type = BFD_RELOC_NONE;
          fix->fx_done = 1;
        }
    }
  else if (fup & OP_IMM_BR16)
    {
      if (val & 0x3)
        as_bad_where (fix->fx_file, fix->fx_line,
                      _("A branch offset requires 0 MOD 4 alignment"));

      val = val >> 2;

      /* Insert the immediate.  */
      if (fix->fx_addsy)
        {
          fix->fx_done = 0;
          fix->fx_r_type = BFD_RELOC_860_PC16;
        }
      else
        {
          insn |= (val & 0x7ff);
          insn |= ((val & 0xf800) << 5);
          bfd_putl32 (insn, buf);
          fix->fx_r_type = BFD_RELOC_NONE;
          fix->fx_done = 1;
        }
    }
  else if (fup & OP_IMM_BR26)
    {
      if (val & 0x3)
        as_bad_where (fix->fx_file, fix->fx_line,
                      _("A branch offset requires 0 MOD 4 alignment"));

      val >>= 2;

      /* Insert the immediate.  */
      if (fix->fx_addsy)
        {
          fix->fx_r_type = BFD_RELOC_860_PC26;
          fix->fx_done = 0;
        }
      else
        {
          insn |= (val & 0x3ffffff);
          bfd_putl32 (insn, buf);
          fix->fx_r_type = BFD_RELOC_NONE;
          fix->fx_done = 1;
        }
    }
  else if (fup != OP_NONE)
    {
      as_bad_where (fix->fx_file, fix->fx_line,
                    _("Unrecognized fix-up (0x%08lx)"), (unsigned long) fup);
      abort ();
    }
  else
    {
      /* I believe only fix-ups such as ".long .ep.main-main+0xc8000000"
         reach here (???).  */
      if (fix->fx_addsy)
        {
          fix->fx_r_type = BFD_RELOC_32;
          fix->fx_done = 0;
        }
      else
        {
          insn |= (val & 0xffffffff);
          bfd_putl32 (insn, buf);
          fix->fx_r_type = BFD_RELOC_NONE;
          fix->fx_done = 1;
        }
    }
}

/* Generate a machine dependent reloc from a fixup.  */
arelent*
tc_gen_reloc (asection *section ATTRIBUTE_UNUSED,
              fixS *fixp)
{
  arelent *reloc;

  reloc = xmalloc (sizeof (*reloc));
  reloc->sym_ptr_ptr = (asymbol **) xmalloc (sizeof (asymbol *));
  *reloc->sym_ptr_ptr = symbol_get_bfdsym (fixp->fx_addsy);
  reloc->address = fixp->fx_frag->fr_address + fixp->fx_where;
  reloc->addend = fixp->fx_offset;
  reloc->howto = bfd_reloc_type_lookup (stdoutput, fixp->fx_r_type);

  if (! reloc->howto)
    {
      as_bad_where (fixp->fx_file, fixp->fx_line,
                    "Cannot represent %s relocation in object file",
                    bfd_get_reloc_code_name (fixp->fx_r_type));
    }
  return reloc;
}

/* This is called from HANDLE_ALIGN in write.c.  Fill in the contents
   of an rs_align_code fragment.  */

void
i860_handle_align (fragS *fragp)
{
  /* Instructions are always stored little-endian on the i860.  */
  static const unsigned char le_nop[] = { 0x00, 0x00, 0x00, 0xA0 };

  int bytes;
  char *p;

  if (fragp->fr_type != rs_align_code)
    return;

  bytes = fragp->fr_next->fr_address - fragp->fr_address - fragp->fr_fix;
  p = fragp->fr_literal + fragp->fr_fix;

  /* Make sure we are on a 4-byte boundary, in case someone has been
     putting data into a text section.  */
  if (bytes & 3)
    {
      int fix = bytes & 3;
      memset (p, 0, fix);
      p += fix;
      fragp->fr_fix += fix;
    }

  memcpy (p, le_nop, 4);
  fragp->fr_var = 4;
}

/* This is called after a user-defined label is seen.  We check
   if the label has a double colon (valid in Intel syntax mode only),
   in which case it should be externalized.  */

void
i860_check_label (symbolS *labelsym)
{
  /* At this point, the current line pointer is sitting on the character
     just after the first colon on the label.  */ 
  if (target_intel_syntax && *input_line_pointer == ':')
    {
      S_SET_EXTERNAL (labelsym);
      input_line_pointer++;
    }
}