gas/config/tc-openrisc.c

   1 /* tc-openrisc.c -- Assembler for the OpenRISC family.
   2    Copyright 2001, 2002, 2003, 2005 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 "as.h"
  24 #include "subsegs.h"
  25 #include "symcat.h"
  26 #include "opcodes/openrisc-desc.h"
  27 #include "opcodes/openrisc-opc.h"
  28 #include "cgen.h"
  29
  30 /* Structure to hold all of the different components describing
  31    an individual instruction.  */
  32 typedef struct openrisc_insn openrisc_insn;
  33
  34 struct openrisc_insn
  35 {
  36   const CGEN_INSN *     insn;
  37   const CGEN_INSN *     orig_insn;
  38   CGEN_FIELDS           fields;
  39 #if CGEN_INT_INSN_P
  40   CGEN_INSN_INT         buffer [1];
  41 #define INSN_VALUE(buf) (*(buf))
  42 #else
  43   unsigned char         buffer [CGEN_MAX_INSN_SIZE];
  44 #define INSN_VALUE(buf) (buf)
  45 #endif
  46   char *                addr;
  47   fragS *               frag;
  48   int                   num_fixups;
  49   fixS *                fixups [GAS_CGEN_MAX_FIXUPS];
  50   int                   indices [MAX_OPERAND_INSTANCES];
  51 };
  52
  53
  54 const char comment_chars[]        = "#";
  55 const char line_comment_chars[]   = "#";
  56 const char line_separator_chars[] = ";";
  57 const char EXP_CHARS[]            = "eE";
  58 const char FLT_CHARS[]            = "dD";
  59
  60 \f
  61 #define OPENRISC_SHORTOPTS "m:"
  62 const char * md_shortopts = OPENRISC_SHORTOPTS;
  63
  64 struct option md_longopts[] =
  65 {
  66   {NULL, no_argument, NULL, 0}
  67 };
  68 size_t md_longopts_size = sizeof (md_longopts);
  69
  70 unsigned long openrisc_machine = 0; /* default */
  71
  72 int
  73 md_parse_option (c, arg)
  74      int    c ATTRIBUTE_UNUSED;
  75      char * arg ATTRIBUTE_UNUSED;
  76 {
  77   return 0;
  78 }
  79
  80 void
  81 md_show_usage (stream)
  82   FILE * stream ATTRIBUTE_UNUSED;
  83 {
  84 }
  85
  86 static void ignore_pseudo PARAMS ((int));
  87
  88 static void
  89 ignore_pseudo (val)
  90      int val ATTRIBUTE_UNUSED;
  91 {
  92   discard_rest_of_line ();
  93 }
  94
  95 const char openrisc_comment_chars [] = ";#";
  96
  97 /* The target specific pseudo-ops which we support.  */
  98 const pseudo_typeS md_pseudo_table[] =
  99 {
 100   { "word",     cons,           4 },
 101   { "proc",     ignore_pseudo,  0 },
 102   { "endproc",  ignore_pseudo,  0 },
 103   { NULL,       NULL,           0 }
 104 };
 105
 106
 107 \f
 108 void
 109 md_begin ()
 110 {
 111   /* Initialize the `cgen' interface.  */
 112
 113   /* Set the machine number and endian.  */
 114   gas_cgen_cpu_desc = openrisc_cgen_cpu_open (CGEN_CPU_OPEN_MACHS, 0,
 115                                               CGEN_CPU_OPEN_ENDIAN,
 116                                               CGEN_ENDIAN_BIG,
 117                                               CGEN_CPU_OPEN_END);
 118   openrisc_cgen_init_asm (gas_cgen_cpu_desc);
 119
 120   /* This is a callback from cgen to gas to parse operands.  */
 121   cgen_set_parse_operand_fn (gas_cgen_cpu_desc, gas_cgen_parse_operand);
 122 }
 123
 124 void
 125 md_assemble (str)
 126      char * str;
 127 {
 128   static int last_insn_had_delay_slot = 0;
 129   openrisc_insn insn;
 130   char *    errmsg;
 131
 132   /* Initialize GAS's cgen interface for a new instruction.  */
 133   gas_cgen_init_parse ();
 134
 135   insn.insn = openrisc_cgen_assemble_insn
 136     (gas_cgen_cpu_desc, str, & insn.fields, insn.buffer, & errmsg);
 137
 138   if (!insn.insn)
 139     {
 140       as_bad (errmsg);
 141       return;
 142     }
 143
 144   /* Doesn't really matter what we pass for RELAX_P here.  */
 145   gas_cgen_finish_insn (insn.insn, insn.buffer,
 146                         CGEN_FIELDS_BITSIZE (& insn.fields), 1, NULL);
 147
 148   last_insn_had_delay_slot
 149     = CGEN_INSN_ATTR_VALUE (insn.insn, CGEN_INSN_DELAY_SLOT);
 150 }
 151
 152
 153 /* The syntax in the manual says constants begin with '#'.
 154    We just ignore it.  */
 155
 156 void
 157 md_operand (expressionP)
 158      expressionS * expressionP;
 159 {
 160   if (* input_line_pointer == '#')
 161     {
 162       input_line_pointer ++;
 163       expression (expressionP);
 164     }
 165 }
 166
 167 valueT
 168 md_section_align (segment, size)
 169      segT   segment;
 170      valueT size;
 171 {
 172   int align = bfd_get_section_alignment (stdoutput, segment);
 173   return ((size + (1 << align) - 1) & (-1 << align));
 174 }
 175
 176 symbolS *
 177 md_undefined_symbol (name)
 178      char * name ATTRIBUTE_UNUSED;
 179 {
 180   return 0;
 181 }
 182
 183 \f
 184 /* Interface to relax_segment.  */
 185
 186 /* FIXME: Look through this.  */
 187
 188 const relax_typeS md_relax_table[] =
 189 {
 190 /* The fields are:
 191    1) most positive reach of this state,
 192    2) most negative reach of this state,
 193    3) how many bytes this mode will add to the size of the current frag
 194    4) which index into the table to try if we can't fit into this one.  */
 195
 196   /* The first entry must be unused because an `rlx_more' value of zero ends
 197      each list.  */
 198   {1, 1, 0, 0},
 199
 200   /* The displacement used by GAS is from the end of the 2 byte insn,
 201      so we subtract 2 from the following.  */
 202   /* 16 bit insn, 8 bit disp -> 10 bit range.
 203      This doesn't handle a branch in the right slot at the border:
 204      the "& -4" isn't taken into account.  It's not important enough to
 205      complicate things over it, so we subtract an extra 2 (or + 2 in -ve
 206      case).  */
 207   {511 - 2 - 2, -512 - 2 + 2, 0, 2 },
 208   /* 32 bit insn, 24 bit disp -> 26 bit range.  */
 209   {0x2000000 - 1 - 2, -0x2000000 - 2, 2, 0 },
 210   /* Same thing, but with leading nop for alignment.  */
 211   {0x2000000 - 1 - 2, -0x2000000 - 2, 4, 0 }
 212 };
 213
 214 /* Return an initial guess of the length by which a fragment must grow to
 215    hold a branch to reach its destination.
 216    Also updates fr_type/fr_subtype as necessary.
 217
 218    Called just before doing relaxation.
 219    Any symbol that is now undefined will not become defined.
 220    The guess for fr_var is ACTUALLY the growth beyond fr_fix.
 221    Whatever we do to grow fr_fix or fr_var contributes to our returned value.
 222    Although it may not be explicit in the frag, pretend fr_var starts with a
 223    0 value.  */
 224
 225 int
 226 md_estimate_size_before_relax (fragP, segment)
 227      fragS * fragP;
 228      segT    segment;
 229 {
 230   /* The only thing we have to handle here are symbols outside of the
 231      current segment.  They may be undefined or in a different segment in
 232      which case linker scripts may place them anywhere.
 233      However, we can't finish the fragment here and emit the reloc as insn
 234      alignment requirements may move the insn about.  */
 235
 236   if (S_GET_SEGMENT (fragP->fr_symbol) != segment)
 237     {
 238       /* The symbol is undefined in this segment.
 239          Change the relaxation subtype to the max allowable and leave
 240          all further handling to md_convert_frag.  */
 241       fragP->fr_subtype = 2;
 242
 243       {
 244         const CGEN_INSN * insn;
 245         int               i;
 246
 247         /* Update the recorded insn.
 248            Fortunately we don't have to look very far.
 249            FIXME: Change this to record in the instruction the next higher
 250            relaxable insn to use.  */
 251         for (i = 0, insn = fragP->fr_cgen.insn; i < 4; i++, insn++)
 252           {
 253             if ((strcmp (CGEN_INSN_MNEMONIC (insn),
 254                          CGEN_INSN_MNEMONIC (fragP->fr_cgen.insn))
 255                  == 0)
 256                 && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXED))
 257               break;
 258           }
 259         if (i == 4)
 260           abort ();
 261
 262         fragP->fr_cgen.insn = insn;
 263         return 2;
 264       }
 265     }
 266
 267   return md_relax_table[fragP->fr_subtype].rlx_length;
 268 }
 269
 270 /* *fragP has been relaxed to its final size, and now needs to have
 271    the bytes inside it modified to conform to the new size.
 272
 273    Called after relaxation is finished.
 274    fragP->fr_type == rs_machine_dependent.
 275    fragP->fr_subtype is the subtype of what the address relaxed to.  */
 276
 277 void
 278 md_convert_frag (abfd, sec, fragP)
 279   bfd *   abfd ATTRIBUTE_UNUSED;
 280   segT    sec  ATTRIBUTE_UNUSED;
 281   fragS * fragP ATTRIBUTE_UNUSED;
 282 {
 283   /* FIXME */
 284 }
 285
 286 \f
 287 /* Functions concerning relocs.  */
 288
 289 /* The location from which a PC relative jump should be calculated,
 290    given a PC relative reloc.  */
 291
 292 long
 293 md_pcrel_from_section (fixP, sec)
 294      fixS * fixP;
 295      segT   sec;
 296 {
 297   if (fixP->fx_addsy != (symbolS *) NULL
 298       && (! S_IS_DEFINED (fixP->fx_addsy)
 299           || S_GET_SEGMENT (fixP->fx_addsy) != sec))
 300     {
 301       /* The symbol is undefined (or is defined but not in this section).
 302          Let the linker figure it out.  */
 303       return 0;
 304     }
 305
 306   return (fixP->fx_frag->fr_address + fixP->fx_where) & ~1;
 307 }
 308
 309
 310 /* Return the bfd reloc type for OPERAND of INSN at fixup FIXP.
 311    Returns BFD_RELOC_NONE if no reloc type can be found.
 312    *FIXP may be modified if desired.  */
 313
 314 bfd_reloc_code_real_type
 315 md_cgen_lookup_reloc (insn, operand, fixP)
 316      const CGEN_INSN *    insn ATTRIBUTE_UNUSED;
 317      const CGEN_OPERAND * operand;
 318      fixS *               fixP;
 319 {
 320   bfd_reloc_code_real_type type;
 321
 322   switch (operand->type)
 323     {
 324     case OPENRISC_OPERAND_ABS_26:
 325       fixP->fx_pcrel = 0;
 326       type = BFD_RELOC_OPENRISC_ABS_26;
 327       goto emit;
 328     case OPENRISC_OPERAND_DISP_26:
 329       fixP->fx_pcrel = 1;
 330       type = BFD_RELOC_OPENRISC_REL_26;
 331       goto emit;
 332
 333     case OPENRISC_OPERAND_HI16:
 334       type = BFD_RELOC_HI16;
 335       goto emit;
 336
 337     case OPENRISC_OPERAND_LO16:
 338       type = BFD_RELOC_LO16;
 339       goto emit;
 340
 341     emit:
 342       return type;
 343
 344     default : /* avoid -Wall warning */
 345       break;
 346     }
 347
 348   return BFD_RELOC_NONE;
 349 }
 350 \f
 351 /* Write a value out to the object file, using the appropriate endianness.  */
 352
 353 void
 354 md_number_to_chars (buf, val, n)
 355      char * buf;
 356      valueT val;
 357      int    n;
 358 {
 359   number_to_chars_bigendian (buf, val, n);
 360 }
 361
 362 /* Turn a string in input_line_pointer into a floating point constant of type
 363    type, and store the appropriate bytes in *litP.  The number of LITTLENUMS
 364    emitted is stored in *sizeP .  An error message is returned, or NULL on OK.
 365 */
 366
 367 /* Equal to MAX_PRECISION in atof-ieee.c */
 368 #define MAX_LITTLENUMS 6
 369
 370 char *
 371 md_atof (type, litP, sizeP)
 372      char   type;
 373      char * litP;
 374      int *  sizeP;
 375 {
 376   int              i;
 377   int              prec;
 378   LITTLENUM_TYPE   words [MAX_LITTLENUMS];
 379   char *           t;
 380
 381   switch (type)
 382     {
 383     case 'f':
 384     case 'F':
 385     case 's':
 386     case 'S':
 387       prec = 2;
 388       break;
 389
 390     case 'd':
 391     case 'D':
 392     case 'r':
 393     case 'R':
 394       prec = 4;
 395       break;
 396
 397    /* FIXME: Some targets allow other format chars for bigger sizes here.  */
 398
 399     default:
 400       * sizeP = 0;
 401       return _("Bad call to md_atof()");
 402     }
 403
 404   t = atof_ieee (input_line_pointer, type, words);
 405   if (t)
 406     input_line_pointer = t;
 407   * sizeP = prec * sizeof (LITTLENUM_TYPE);
 408
 409   for (i = 0; i < prec; i++)
 410     {
 411       md_number_to_chars (litP, (valueT) words[i],
 412                           sizeof (LITTLENUM_TYPE));
 413       litP += sizeof (LITTLENUM_TYPE);
 414     }
 415
 416   return 0;
 417 }
 418
 419 bfd_boolean
 420 openrisc_fix_adjustable (fixP)
 421    fixS * fixP;
 422 {
 423   /* We need the symbol name for the VTABLE entries */
 424   if (fixP->fx_r_type == BFD_RELOC_VTABLE_INHERIT
 425       || fixP->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
 426     return 0;
 427
 428   return 1;
 429 }
 430
 431
 432