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, 51 Franklin Street - Fifth Floor,
  20    Boston, MA 02110-1301, 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 (int c ATTRIBUTE_UNUSED, char * arg ATTRIBUTE_UNUSED)
  74 {
  75   return 0;
  76 }
  77
  78 void
  79 md_show_usage (FILE * stream ATTRIBUTE_UNUSED)
  80 {
  81 }
  82
  83 static void
  84 ignore_pseudo (int val ATTRIBUTE_UNUSED)
  85 {
  86   discard_rest_of_line ();
  87 }
  88
  89 const char openrisc_comment_chars [] = ";#";
  90
  91 /* The target specific pseudo-ops which we support.  */
  92 const pseudo_typeS md_pseudo_table[] =
  93 {
  94   { "word",     cons,           4 },
  95   { "proc",     ignore_pseudo,  0 },
  96   { "endproc",  ignore_pseudo,  0 },
  97   { NULL,       NULL,           0 }
  98 };
  99
 100
 101 \f
 102 void
 103 md_begin (void)
 104 {
 105   /* Initialize the `cgen' interface.  */
 106
 107   /* Set the machine number and endian.  */
 108   gas_cgen_cpu_desc = openrisc_cgen_cpu_open (CGEN_CPU_OPEN_MACHS, 0,
 109                                               CGEN_CPU_OPEN_ENDIAN,
 110                                               CGEN_ENDIAN_BIG,
 111                                               CGEN_CPU_OPEN_END);
 112   openrisc_cgen_init_asm (gas_cgen_cpu_desc);
 113
 114   /* This is a callback from cgen to gas to parse operands.  */
 115   cgen_set_parse_operand_fn (gas_cgen_cpu_desc, gas_cgen_parse_operand);
 116 }
 117
 118 void
 119 md_assemble (char * str)
 120 {
 121   static int last_insn_had_delay_slot = 0;
 122   openrisc_insn insn;
 123   char *    errmsg;
 124
 125   /* Initialize GAS's cgen interface for a new instruction.  */
 126   gas_cgen_init_parse ();
 127
 128   insn.insn = openrisc_cgen_assemble_insn
 129     (gas_cgen_cpu_desc, str, & insn.fields, insn.buffer, & errmsg);
 130
 131   if (!insn.insn)
 132     {
 133       as_bad (errmsg);
 134       return;
 135     }
 136
 137   /* Doesn't really matter what we pass for RELAX_P here.  */
 138   gas_cgen_finish_insn (insn.insn, insn.buffer,
 139                         CGEN_FIELDS_BITSIZE (& insn.fields), 1, NULL);
 140
 141   last_insn_had_delay_slot
 142     = CGEN_INSN_ATTR_VALUE (insn.insn, CGEN_INSN_DELAY_SLOT);
 143 }
 144
 145
 146 /* The syntax in the manual says constants begin with '#'.
 147    We just ignore it.  */
 148
 149 void
 150 md_operand (expressionS * expressionP)
 151 {
 152   if (* input_line_pointer == '#')
 153     {
 154       input_line_pointer ++;
 155       expression (expressionP);
 156     }
 157 }
 158
 159 valueT
 160 md_section_align (segT segment, valueT size)
 161 {
 162   int align = bfd_get_section_alignment (stdoutput, segment);
 163   return ((size + (1 << align) - 1) & (-1 << align));
 164 }
 165
 166 symbolS *
 167 md_undefined_symbol (char * name ATTRIBUTE_UNUSED)
 168 {
 169   return 0;
 170 }
 171
 172 \f
 173 /* Interface to relax_segment.  */
 174
 175 /* FIXME: Look through this.  */
 176
 177 const relax_typeS md_relax_table[] =
 178 {
 179 /* The fields are:
 180    1) most positive reach of this state,
 181    2) most negative reach of this state,
 182    3) how many bytes this mode will add to the size of the current frag
 183    4) which index into the table to try if we can't fit into this one.  */
 184
 185   /* The first entry must be unused because an `rlx_more' value of zero ends
 186      each list.  */
 187   {1, 1, 0, 0},
 188
 189   /* The displacement used by GAS is from the end of the 2 byte insn,
 190      so we subtract 2 from the following.  */
 191   /* 16 bit insn, 8 bit disp -> 10 bit range.
 192      This doesn't handle a branch in the right slot at the border:
 193      the "& -4" isn't taken into account.  It's not important enough to
 194      complicate things over it, so we subtract an extra 2 (or + 2 in -ve
 195      case).  */
 196   {511 - 2 - 2, -512 - 2 + 2, 0, 2 },
 197   /* 32 bit insn, 24 bit disp -> 26 bit range.  */
 198   {0x2000000 - 1 - 2, -0x2000000 - 2, 2, 0 },
 199   /* Same thing, but with leading nop for alignment.  */
 200   {0x2000000 - 1 - 2, -0x2000000 - 2, 4, 0 }
 201 };
 202
 203 /* Return an initial guess of the length by which a fragment must grow to
 204    hold a branch to reach its destination.
 205    Also updates fr_type/fr_subtype as necessary.
 206
 207    Called just before doing relaxation.
 208    Any symbol that is now undefined will not become defined.
 209    The guess for fr_var is ACTUALLY the growth beyond fr_fix.
 210    Whatever we do to grow fr_fix or fr_var contributes to our returned value.
 211    Although it may not be explicit in the frag, pretend fr_var starts with a
 212    0 value.  */
 213
 214 int
 215 md_estimate_size_before_relax (fragS * fragP, segT segment)
 216 {
 217   /* The only thing we have to handle here are symbols outside of the
 218      current segment.  They may be undefined or in a different segment in
 219      which case linker scripts may place them anywhere.
 220      However, we can't finish the fragment here and emit the reloc as insn
 221      alignment requirements may move the insn about.  */
 222
 223   if (S_GET_SEGMENT (fragP->fr_symbol) != segment)
 224     {
 225       /* The symbol is undefined in this segment.
 226          Change the relaxation subtype to the max allowable and leave
 227          all further handling to md_convert_frag.  */
 228       fragP->fr_subtype = 2;
 229
 230       {
 231         const CGEN_INSN * insn;
 232         int               i;
 233
 234         /* Update the recorded insn.
 235            Fortunately we don't have to look very far.
 236            FIXME: Change this to record in the instruction the next higher
 237            relaxable insn to use.  */
 238         for (i = 0, insn = fragP->fr_cgen.insn; i < 4; i++, insn++)
 239           {
 240             if ((strcmp (CGEN_INSN_MNEMONIC (insn),
 241                          CGEN_INSN_MNEMONIC (fragP->fr_cgen.insn))
 242                  == 0)
 243                 && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXED))
 244               break;
 245           }
 246         if (i == 4)
 247           abort ();
 248
 249         fragP->fr_cgen.insn = insn;
 250         return 2;
 251       }
 252     }
 253
 254   return md_relax_table[fragP->fr_subtype].rlx_length;
 255 }
 256
 257 /* *fragP has been relaxed to its final size, and now needs to have
 258    the bytes inside it modified to conform to the new size.
 259
 260    Called after relaxation is finished.
 261    fragP->fr_type == rs_machine_dependent.
 262    fragP->fr_subtype is the subtype of what the address relaxed to.  */
 263
 264 void
 265 md_convert_frag (bfd *   abfd ATTRIBUTE_UNUSED,
 266                  segT    sec  ATTRIBUTE_UNUSED,
 267                  fragS * fragP ATTRIBUTE_UNUSED)
 268 {
 269   /* FIXME */
 270 }
 271
 272 \f
 273 /* Functions concerning relocs.  */
 274
 275 /* The location from which a PC relative jump should be calculated,
 276    given a PC relative reloc.  */
 277
 278 long
 279 md_pcrel_from_section (fixS * fixP, segT sec)
 280 {
 281   if (fixP->fx_addsy != (symbolS *) NULL
 282       && (! S_IS_DEFINED (fixP->fx_addsy)
 283           || S_GET_SEGMENT (fixP->fx_addsy) != sec))
 284     /* The symbol is undefined (or is defined but not in this section).
 285        Let the linker figure it out.  */
 286     return 0;
 287
 288   return (fixP->fx_frag->fr_address + fixP->fx_where) & ~1;
 289 }
 290
 291
 292 /* Return the bfd reloc type for OPERAND of INSN at fixup FIXP.
 293    Returns BFD_RELOC_NONE if no reloc type can be found.
 294    *FIXP may be modified if desired.  */
 295
 296 bfd_reloc_code_real_type
 297 md_cgen_lookup_reloc (const CGEN_INSN *    insn ATTRIBUTE_UNUSED,
 298                       const CGEN_OPERAND * operand,
 299                       fixS *               fixP)
 300 {
 301   bfd_reloc_code_real_type type;
 302
 303   switch (operand->type)
 304     {
 305     case OPENRISC_OPERAND_ABS_26:
 306       fixP->fx_pcrel = 0;
 307       type = BFD_RELOC_OPENRISC_ABS_26;
 308       goto emit;
 309     case OPENRISC_OPERAND_DISP_26:
 310       fixP->fx_pcrel = 1;
 311       type = BFD_RELOC_OPENRISC_REL_26;
 312       goto emit;
 313
 314     case OPENRISC_OPERAND_HI16:
 315       type = BFD_RELOC_HI16;
 316       goto emit;
 317
 318     case OPENRISC_OPERAND_LO16:
 319       type = BFD_RELOC_LO16;
 320       goto emit;
 321
 322     emit:
 323       return type;
 324
 325     default : /* avoid -Wall warning */
 326       break;
 327     }
 328
 329   return BFD_RELOC_NONE;
 330 }
 331 \f
 332 /* Write a value out to the object file, using the appropriate endianness.  */
 333
 334 void
 335 md_number_to_chars (char * buf, valueT val, int n)
 336 {
 337   number_to_chars_bigendian (buf, val, n);
 338 }
 339
 340 /* Turn a string in input_line_pointer into a floating point constant of type
 341    type, and store the appropriate bytes in *litP.  The number of LITTLENUMS
 342    emitted is stored in *sizeP .  An error message is returned, or NULL on OK.
 343 */
 344
 345 /* Equal to MAX_PRECISION in atof-ieee.c */
 346 #define MAX_LITTLENUMS 6
 347
 348 char *
 349 md_atof (int type, char * litP, int *  sizeP)
 350 {
 351   int              i;
 352   int              prec;
 353   LITTLENUM_TYPE   words [MAX_LITTLENUMS];
 354   char *           t;
 355
 356   switch (type)
 357     {
 358     case 'f':
 359     case 'F':
 360     case 's':
 361     case 'S':
 362       prec = 2;
 363       break;
 364
 365     case 'd':
 366     case 'D':
 367     case 'r':
 368     case 'R':
 369       prec = 4;
 370       break;
 371
 372    /* FIXME: Some targets allow other format chars for bigger sizes here.  */
 373
 374     default:
 375       * sizeP = 0;
 376       return _("Bad call to md_atof()");
 377     }
 378
 379   t = atof_ieee (input_line_pointer, type, words);
 380   if (t)
 381     input_line_pointer = t;
 382   * sizeP = prec * sizeof (LITTLENUM_TYPE);
 383
 384   for (i = 0; i < prec; i++)
 385     {
 386       md_number_to_chars (litP, (valueT) words[i],
 387                           sizeof (LITTLENUM_TYPE));
 388       litP += sizeof (LITTLENUM_TYPE);
 389     }
 390
 391   return 0;
 392 }
 393
 394 bfd_boolean
 395 openrisc_fix_adjustable (fixS * fixP)
 396 {
 397   /* We need the symbol name for the VTABLE entries.  */
 398   if (fixP->fx_r_type == BFD_RELOC_VTABLE_INHERIT
 399       || fixP->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
 400     return 0;
 401
 402   return 1;
 403 }