gas/config/tc-openrisc.c

   1 /* tc-openrisc.c -- Assembler for the OpenRISC family.
   2    Copyright (C) 2001 Free Software Foundation.
   3    Contributed by Johan Rydberg, jrydberg@opencores.org
   4
   5    This file is part of GAS, the GNU Assembler.
   6
   7    GAS is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    GAS is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GAS; see the file COPYING.  If not, write to
  19    the Free Software Foundation, 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include <stdio.h>
  23 #include <ctype.h>
  24 #include "as.h"
  25 #include "subsegs.h"
  26 #include "symcat.h"
  27 #include "opcodes/openrisc-desc.h"
  28 #include "opcodes/openrisc-opc.h"
  29 #include "cgen.h"
  30
  31 /* Structure to hold all of the different components describing
  32    an individual instruction.  */
  33 typedef struct openrisc_insn openrisc_insn;
  34
  35 struct openrisc_insn
  36 {
  37   const CGEN_INSN *     insn;
  38   const CGEN_INSN *     orig_insn;
  39   CGEN_FIELDS           fields;
  40 #if CGEN_INT_INSN_P
  41   CGEN_INSN_INT         buffer [1];
  42 #define INSN_VALUE(buf) (*(buf))
  43 #else
  44   unsigned char         buffer [CGEN_MAX_INSN_SIZE];
  45 #define INSN_VALUE(buf) (buf)
  46 #endif
  47   char *                addr;
  48   fragS *               frag;
  49   int                   num_fixups;
  50   fixS *                fixups [GAS_CGEN_MAX_FIXUPS];
  51   int                   indices [MAX_OPERAND_INSTANCES];
  52 };
  53
  54
  55 const char comment_chars[]        = "#";
  56 const char line_comment_chars[]   = "#";
  57 const char line_separator_chars[] = ";";
  58 const char EXP_CHARS[]            = "eE";
  59 const char FLT_CHARS[]            = "dD";
  60
  61 \f
  62 #define OPENRISC_SHORTOPTS "m:"
  63 const char * md_shortopts = OPENRISC_SHORTOPTS;
  64
  65 struct option md_longopts[] =
  66 {
  67   {NULL, no_argument, NULL, 0}
  68 };
  69 size_t md_longopts_size = sizeof (md_longopts);
  70
  71 unsigned long openrisc_machine = 0; /* default */
  72
  73 int
  74 md_parse_option (c, arg)
  75      int    c ATTRIBUTE_UNUSED;
  76      char * arg ATTRIBUTE_UNUSED;
  77 {
  78   return 0;
  79 }
  80
  81 void
  82 md_show_usage (stream)
  83   FILE * stream ATTRIBUTE_UNUSED;
  84 {
  85 }
  86
  87 static void
  88 ignore_pseudo (val)
  89      int val ATTRIBUTE_UNUSED;
  90 {
  91   discard_rest_of_line ();
  92 }
  93
  94 const char openrisc_comment_chars [] = ";#";
  95
  96 /* The target specific pseudo-ops which we support.  */
  97 const pseudo_typeS md_pseudo_table[] =
  98 {
  99   { "word",     cons,           4 },
 100   { "proc",     ignore_pseudo,  0 },
 101   { "endproc",  ignore_pseudo,  0 },
 102   { NULL,       NULL,           0 }
 103 };
 104
 105
 106 \f
 107 void
 108 md_begin ()
 109 {
 110   /* Initialize the `cgen' interface.  */
 111
 112   /* Set the machine number and endian.  */
 113   gas_cgen_cpu_desc = openrisc_cgen_cpu_open (CGEN_CPU_OPEN_MACHS, 0,
 114                                               CGEN_CPU_OPEN_ENDIAN,
 115                                               CGEN_ENDIAN_BIG,
 116                                               CGEN_CPU_OPEN_END);
 117   openrisc_cgen_init_asm (gas_cgen_cpu_desc);
 118
 119   /* This is a callback from cgen to gas to parse operands.  */
 120   cgen_set_parse_operand_fn (gas_cgen_cpu_desc, gas_cgen_parse_operand);
 121 }
 122
 123 void
 124 md_assemble (str)
 125      char * str;
 126 {
 127   static int last_insn_had_delay_slot = 0;
 128   openrisc_insn insn;
 129   char *    errmsg;
 130
 131   /* Initialize GAS's cgen interface for a new instruction.  */
 132   gas_cgen_init_parse ();
 133
 134   insn.insn = openrisc_cgen_assemble_insn
 135     (gas_cgen_cpu_desc, str, & insn.fields, insn.buffer, & errmsg);
 136
 137   if (!insn.insn)
 138     {
 139       as_bad (errmsg);
 140       return;
 141     }
 142
 143   /* Doesn't really matter what we pass for RELAX_P here.  */
 144   gas_cgen_finish_insn (insn.insn, insn.buffer,
 145                         CGEN_FIELDS_BITSIZE (& insn.fields), 1, NULL);
 146
 147 #if 0 /* Currently disabled  */
 148   /* Warn about invalid insns in delay slots.  */
 149   if (last_insn_had_delay_slot
 150       && CGEN_INSN_ATTR_VALUE (insn.insn, CGEN_INSN_NOT_IN_DELAY_SLOT))
 151     as_warn (_("Instruction %s not allowed in a delay slot."),
 152              CGEN_INSN_NAME (insn.insn));
 153 #endif
 154
 155   last_insn_had_delay_slot
 156     = CGEN_INSN_ATTR_VALUE (insn.insn, CGEN_INSN_DELAY_SLOT);
 157 }
 158
 159
 160 /* The syntax in the manual says constants begin with '#'.
 161    We just ignore it.  */
 162
 163 void
 164 md_operand (expressionP)
 165      expressionS * expressionP;
 166 {
 167   if (* input_line_pointer == '#')
 168     {
 169       input_line_pointer ++;
 170       expression (expressionP);
 171     }
 172 }
 173
 174 valueT
 175 md_section_align (segment, size)
 176      segT   segment;
 177      valueT size;
 178 {
 179   int align = bfd_get_section_alignment (stdoutput, segment);
 180   return ((size + (1 << align) - 1) & (-1 << align));
 181 }
 182
 183 symbolS *
 184 md_undefined_symbol (name)
 185      char * name ATTRIBUTE_UNUSED;
 186 {
 187   return 0;
 188 }
 189
 190 \f
 191 /* Interface to relax_segment.  */
 192
 193 /* FIXME: Look through this.  */
 194
 195 const relax_typeS md_relax_table[] =
 196 {
 197 /* The fields are:
 198    1) most positive reach of this state,
 199    2) most negative reach of this state,
 200    3) how many bytes this mode will add to the size of the current frag
 201    4) which index into the table to try if we can't fit into this one.  */
 202
 203   /* The first entry must be unused because an `rlx_more' value of zero ends
 204      each list.  */
 205   {1, 1, 0, 0},
 206
 207   /* The displacement used by GAS is from the end of the 2 byte insn,
 208      so we subtract 2 from the following.  */
 209   /* 16 bit insn, 8 bit disp -> 10 bit range.
 210      This doesn't handle a branch in the right slot at the border:
 211      the "& -4" isn't taken into account.  It's not important enough to
 212      complicate things over it, so we subtract an extra 2 (or + 2 in -ve
 213      case).  */
 214   {511 - 2 - 2, -512 - 2 + 2, 0, 2 },
 215   /* 32 bit insn, 24 bit disp -> 26 bit range.  */
 216   {0x2000000 - 1 - 2, -0x2000000 - 2, 2, 0 },
 217   /* Same thing, but with leading nop for alignment.  */
 218   {0x2000000 - 1 - 2, -0x2000000 - 2, 4, 0 }
 219 };
 220
 221 long
 222 openrisc_relax_frag (segment, fragP, stretch)
 223      segT    segment;
 224      fragS * fragP;
 225      long    stretch;
 226 {
 227   /* Address of branch insn.  */
 228   long address = fragP->fr_address + fragP->fr_fix - 2;
 229   long growth = 0;
 230
 231   /* Keep 32 bit insns aligned on 32 bit boundaries.  */
 232   if (fragP->fr_subtype == 2)
 233     {
 234       if ((address & 3) != 0)
 235         {
 236           fragP->fr_subtype = 3;
 237           growth = 2;
 238         }
 239     }
 240   else if (fragP->fr_subtype == 3)
 241     {
 242       if ((address & 3) == 0)
 243         {
 244           fragP->fr_subtype = 2;
 245           growth = -2;
 246         }
 247     }
 248   else
 249     {
 250       growth = relax_frag (segment, fragP, stretch);
 251
 252       /* Long jump on odd halfword boundary?  */
 253       if (fragP->fr_subtype == 2 && (address & 3) != 0)
 254         {
 255           fragP->fr_subtype = 3;
 256           growth += 2;
 257         }
 258     }
 259
 260   return growth;
 261 }
 262
 263
 264 /* Return an initial guess of the length by which a fragment must grow to
 265    hold a branch to reach its destination.
 266    Also updates fr_type/fr_subtype as necessary.
 267
 268    Called just before doing relaxation.
 269    Any symbol that is now undefined will not become defined.
 270    The guess for fr_var is ACTUALLY the growth beyond fr_fix.
 271    Whatever we do to grow fr_fix or fr_var contributes to our returned value.
 272    Although it may not be explicit in the frag, pretend fr_var starts with a
 273    0 value.  */
 274
 275 int
 276 md_estimate_size_before_relax (fragP, segment)
 277      fragS * fragP;
 278      segT    segment;
 279 {
 280   /* The only thing we have to handle here are symbols outside of the
 281      current segment.  They may be undefined or in a different segment in
 282      which case linker scripts may place them anywhere.
 283      However, we can't finish the fragment here and emit the reloc as insn
 284      alignment requirements may move the insn about.  */
 285
 286   if (S_GET_SEGMENT (fragP->fr_symbol) != segment)
 287     {
 288       /* The symbol is undefined in this segment.
 289          Change the relaxation subtype to the max allowable and leave
 290          all further handling to md_convert_frag.  */
 291       fragP->fr_subtype = 2;
 292
 293       {
 294         const CGEN_INSN * insn;
 295         int               i;
 296
 297         /* Update the recorded insn.
 298            Fortunately we don't have to look very far.
 299            FIXME: Change this to record in the instruction the next higher
 300            relaxable insn to use.  */
 301         for (i = 0, insn = fragP->fr_cgen.insn; i < 4; i++, insn++)
 302           {
 303             if ((strcmp (CGEN_INSN_MNEMONIC (insn),
 304                          CGEN_INSN_MNEMONIC (fragP->fr_cgen.insn))
 305                  == 0)
 306                 && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAX))
 307               break;
 308           }
 309         if (i == 4)
 310           abort ();
 311
 312         fragP->fr_cgen.insn = insn;
 313         return 2;
 314       }
 315     }
 316
 317   return md_relax_table[fragP->fr_subtype].rlx_length;
 318 }
 319
 320 /* *fragP has been relaxed to its final size, and now needs to have
 321    the bytes inside it modified to conform to the new size.
 322
 323    Called after relaxation is finished.
 324    fragP->fr_type == rs_machine_dependent.
 325    fragP->fr_subtype is the subtype of what the address relaxed to.  */
 326
 327 void
 328 md_convert_frag (abfd, sec, fragP)
 329   bfd *   abfd ATTRIBUTE_UNUSED;
 330   segT    sec  ATTRIBUTE_UNUSED;
 331   fragS * fragP ATTRIBUTE_UNUSED;
 332 {
 333   /* FIXME */
 334 }
 335
 336 \f
 337 /* Functions concerning relocs.  */
 338
 339 /* The location from which a PC relative jump should be calculated,
 340    given a PC relative reloc.  */
 341
 342 long
 343 md_pcrel_from_section (fixP, sec)
 344      fixS * fixP;
 345      segT   sec;
 346 {
 347   if (fixP->fx_addsy != (symbolS *) NULL
 348       && (! S_IS_DEFINED (fixP->fx_addsy)
 349           || S_GET_SEGMENT (fixP->fx_addsy) != sec))
 350     {
 351       /* The symbol is undefined (or is defined but not in this section).
 352          Let the linker figure it out.  */
 353       return 0;
 354     }
 355
 356   return (fixP->fx_frag->fr_address + fixP->fx_where) & ~1;
 357 }
 358
 359
 360 /* Return the bfd reloc type for OPERAND of INSN at fixup FIXP.
 361    Returns BFD_RELOC_NONE if no reloc type can be found.
 362    *FIXP may be modified if desired.  */
 363
 364 bfd_reloc_code_real_type
 365 md_cgen_lookup_reloc (insn, operand, fixP)
 366      const CGEN_INSN *    insn ATTRIBUTE_UNUSED;
 367      const CGEN_OPERAND * operand;
 368      fixS *               fixP;
 369 {
 370   bfd_reloc_code_real_type type;
 371
 372   switch (operand->type)
 373     {
 374     case OPENRISC_OPERAND_ABS_26:
 375       fixP->fx_pcrel = 0;
 376       type = BFD_RELOC_OPENRISC_ABS_26;
 377       goto emit;
 378     case OPENRISC_OPERAND_DISP_26:
 379       fixP->fx_pcrel = 1;
 380       type = BFD_RELOC_OPENRISC_REL_26;
 381       goto emit;
 382
 383     case OPENRISC_OPERAND_HI16:
 384       type = BFD_RELOC_HI16;
 385       goto emit;
 386
 387     case OPENRISC_OPERAND_LO16:
 388       type = BFD_RELOC_LO16;
 389       goto emit;
 390
 391     emit:
 392       return type;
 393
 394     default : /* avoid -Wall warning */
 395       break;
 396     }
 397
 398   return BFD_RELOC_NONE;
 399 }
 400
 401 /* See whether we need to force a relocation into the output file.
 402    This is used to force out switch and PC relative relocations when
 403    relaxing.  */
 404
 405 int
 406 openrisc_force_relocation (fix)
 407      fixS * fix ATTRIBUTE_UNUSED;
 408 {
 409   if (fix->fx_r_type == BFD_RELOC_VTABLE_INHERIT
 410       || fix->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
 411     return 1;
 412
 413   return 0;
 414 }
 415
 416
 417 \f
 418 /* Write a value out to the object file, using the appropriate endianness.  */
 419
 420 void
 421 md_number_to_chars (buf, val, n)
 422      char * buf;
 423      valueT val;
 424      int    n;
 425 {
 426   number_to_chars_bigendian (buf, val, n);
 427 }
 428
 429 /* Turn a string in input_line_pointer into a floating point constant of type
 430    type, and store the appropriate bytes in *litP.  The number of LITTLENUMS
 431    emitted is stored in *sizeP .  An error message is returned, or NULL on OK.
 432 */
 433
 434 /* Equal to MAX_PRECISION in atof-ieee.c */
 435 #define MAX_LITTLENUMS 6
 436
 437 char *
 438 md_atof (type, litP, sizeP)
 439      char   type;
 440      char * litP;
 441      int *  sizeP;
 442 {
 443   int              i;
 444   int              prec;
 445   LITTLENUM_TYPE   words [MAX_LITTLENUMS];
 446   char *           t;
 447   char *           atof_ieee ();
 448
 449   switch (type)
 450     {
 451     case 'f':
 452     case 'F':
 453     case 's':
 454     case 'S':
 455       prec = 2;
 456       break;
 457
 458     case 'd':
 459     case 'D':
 460     case 'r':
 461     case 'R':
 462       prec = 4;
 463       break;
 464
 465    /* FIXME: Some targets allow other format chars for bigger sizes here.  */
 466
 467     default:
 468       * sizeP = 0;
 469       return _("Bad call to md_atof()");
 470     }
 471
 472   t = atof_ieee (input_line_pointer, type, words);
 473   if (t)
 474     input_line_pointer = t;
 475   * sizeP = prec * sizeof (LITTLENUM_TYPE);
 476
 477   for (i = 0; i < prec; i++)
 478     {
 479       md_number_to_chars (litP, (valueT) words[i],
 480                           sizeof (LITTLENUM_TYPE));
 481       litP += sizeof (LITTLENUM_TYPE);
 482     }
 483
 484   return 0;
 485 }
 486
 487 boolean
 488 openrisc_fix_adjustable (fixP)
 489    fixS * fixP;
 490 {
 491   if (fixP->fx_addsy == NULL)
 492     return 1;
 493
 494   /* We need the symbol name for the VTABLE entries */
 495   if (fixP->fx_r_type == BFD_RELOC_VTABLE_INHERIT
 496       || fixP->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
 497     return 0;
 498
 499   return 1;
 500 }
 501
 502
 503