gas/config/tc-openrisc.c

   1 /* tc-openrisc.c -- Assembler for the OpenRISC family.
   2    Copyright 2001, 2002, 2003, 2005, 2006, 2007 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 3, 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 "as.h"
  23 #include "subsegs.h"
  24 #include "symcat.h"
  25 #include "opcodes/openrisc-desc.h"
  26 #include "opcodes/openrisc-opc.h"
  27 #include "cgen.h"
  28
  29 /* Structure to hold all of the different components describing
  30    an individual instruction.  */
  31 typedef struct openrisc_insn openrisc_insn;
  32
  33 struct openrisc_insn
  34 {
  35   const CGEN_INSN *     insn;
  36   const CGEN_INSN *     orig_insn;
  37   CGEN_FIELDS           fields;
  38 #if CGEN_INT_INSN_P
  39   CGEN_INSN_INT         buffer [1];
  40 #define INSN_VALUE(buf) (*(buf))
  41 #else
  42   unsigned char         buffer [CGEN_MAX_INSN_SIZE];
  43 #define INSN_VALUE(buf) (buf)
  44 #endif
  45   char *                addr;
  46   fragS *               frag;
  47   int                   num_fixups;
  48   fixS *                fixups [GAS_CGEN_MAX_FIXUPS];
  49   int                   indices [MAX_OPERAND_INSTANCES];
  50 };
  51
  52
  53 const char comment_chars[]        = "#";
  54 const char line_comment_chars[]   = "#";
  55 const char line_separator_chars[] = ";";
  56 const char EXP_CHARS[]            = "eE";
  57 const char FLT_CHARS[]            = "dD";
  58
  59 \f
  60 #define OPENRISC_SHORTOPTS "m:"
  61 const char * md_shortopts = OPENRISC_SHORTOPTS;
  62
  63 struct option md_longopts[] =
  64 {
  65   {NULL, no_argument, NULL, 0}
  66 };
  67 size_t md_longopts_size = sizeof (md_longopts);
  68
  69 unsigned long openrisc_machine = 0; /* default */
  70
  71 int
  72 md_parse_option (int c ATTRIBUTE_UNUSED, char * arg ATTRIBUTE_UNUSED)
  73 {
  74   return 0;
  75 }
  76
  77 void
  78 md_show_usage (FILE * stream ATTRIBUTE_UNUSED)
  79 {
  80 }
  81
  82 static void
  83 ignore_pseudo (int val ATTRIBUTE_UNUSED)
  84 {
  85   discard_rest_of_line ();
  86 }
  87
  88 const char openrisc_comment_chars [] = ";#";
  89
  90 /* The target specific pseudo-ops which we support.  */
  91 const pseudo_typeS md_pseudo_table[] =
  92 {
  93   { "word",     cons,           4 },
  94   { "proc",     ignore_pseudo,  0 },
  95   { "endproc",  ignore_pseudo,  0 },
  96   { NULL,       NULL,           0 }
  97 };
  98
  99
 100 \f
 101 void
 102 md_begin (void)
 103 {
 104   /* Initialize the `cgen' interface.  */
 105
 106   /* Set the machine number and endian.  */
 107   gas_cgen_cpu_desc = openrisc_cgen_cpu_open (CGEN_CPU_OPEN_MACHS, 0,
 108                                               CGEN_CPU_OPEN_ENDIAN,
 109                                               CGEN_ENDIAN_BIG,
 110                                               CGEN_CPU_OPEN_END);
 111   openrisc_cgen_init_asm (gas_cgen_cpu_desc);
 112
 113   /* This is a callback from cgen to gas to parse operands.  */
 114   cgen_set_parse_operand_fn (gas_cgen_cpu_desc, gas_cgen_parse_operand);
 115 }
 116
 117 void
 118 md_assemble (char * str)
 119 {
 120   static int last_insn_had_delay_slot = 0;
 121   openrisc_insn insn;
 122   char *    errmsg;
 123
 124   /* Initialize GAS's cgen interface for a new instruction.  */
 125   gas_cgen_init_parse ();
 126
 127   insn.insn = openrisc_cgen_assemble_insn
 128     (gas_cgen_cpu_desc, str, & insn.fields, insn.buffer, & errmsg);
 129
 130   if (!insn.insn)
 131     {
 132       as_bad (errmsg);
 133       return;
 134     }
 135
 136   /* Doesn't really matter what we pass for RELAX_P here.  */
 137   gas_cgen_finish_insn (insn.insn, insn.buffer,
 138                         CGEN_FIELDS_BITSIZE (& insn.fields), 1, NULL);
 139
 140   last_insn_had_delay_slot
 141     = CGEN_INSN_ATTR_VALUE (insn.insn, CGEN_INSN_DELAY_SLOT);
 142 }
 143
 144
 145 /* The syntax in the manual says constants begin with '#'.
 146    We just ignore it.  */
 147
 148 void
 149 md_operand (expressionS * expressionP)
 150 {
 151   if (* input_line_pointer == '#')
 152     {
 153       input_line_pointer ++;
 154       expression (expressionP);
 155     }
 156 }
 157
 158 valueT
 159 md_section_align (segT segment, valueT size)
 160 {
 161   int align = bfd_get_section_alignment (stdoutput, segment);
 162   return ((size + (1 << align) - 1) & (-1 << align));
 163 }
 164
 165 symbolS *
 166 md_undefined_symbol (char * name ATTRIBUTE_UNUSED)
 167 {
 168   return 0;
 169 }
 170
 171 \f
 172 /* Interface to relax_segment.  */
 173
 174 /* FIXME: Look through this.  */
 175
 176 const relax_typeS md_relax_table[] =
 177 {
 178 /* The fields are:
 179    1) most positive reach of this state,
 180    2) most negative reach of this state,
 181    3) how many bytes this mode will add to the size of the current frag
 182    4) which index into the table to try if we can't fit into this one.  */
 183
 184   /* The first entry must be unused because an `rlx_more' value of zero ends
 185      each list.  */
 186   {1, 1, 0, 0},
 187
 188   /* The displacement used by GAS is from the end of the 2 byte insn,
 189      so we subtract 2 from the following.  */
 190   /* 16 bit insn, 8 bit disp -> 10 bit range.
 191      This doesn't handle a branch in the right slot at the border:
 192      the "& -4" isn't taken into account.  It's not important enough to
 193      complicate things over it, so we subtract an extra 2 (or + 2 in -ve
 194      case).  */
 195   {511 - 2 - 2, -512 - 2 + 2, 0, 2 },
 196   /* 32 bit insn, 24 bit disp -> 26 bit range.  */
 197   {0x2000000 - 1 - 2, -0x2000000 - 2, 2, 0 },
 198   /* Same thing, but with leading nop for alignment.  */
 199   {0x2000000 - 1 - 2, -0x2000000 - 2, 4, 0 }
 200 };
 201
 202 /* Return an initial guess of the length by which a fragment must grow to
 203    hold a branch to reach its destination.
 204    Also updates fr_type/fr_subtype as necessary.
 205
 206    Called just before doing relaxation.
 207    Any symbol that is now undefined will not become defined.
 208    The guess for fr_var is ACTUALLY the growth beyond fr_fix.
 209    Whatever we do to grow fr_fix or fr_var contributes to our returned value.
 210    Although it may not be explicit in the frag, pretend fr_var starts with a
 211    0 value.  */
 212
 213 int
 214 md_estimate_size_before_relax (fragS * fragP, segT segment)
 215 {
 216   /* The only thing we have to handle here are symbols outside of the
 217      current segment.  They may be undefined or in a different segment in
 218      which case linker scripts may place them anywhere.
 219      However, we can't finish the fragment here and emit the reloc as insn
 220      alignment requirements may move the insn about.  */
 221
 222   if (S_GET_SEGMENT (fragP->fr_symbol) != segment)
 223     {
 224       /* The symbol is undefined in this segment.
 225          Change the relaxation subtype to the max allowable and leave
 226          all further handling to md_convert_frag.  */
 227       fragP->fr_subtype = 2;
 228
 229       {
 230         const CGEN_INSN * insn;
 231         int               i;
 232
 233         /* Update the recorded insn.
 234            Fortunately we don't have to look very far.
 235            FIXME: Change this to record in the instruction the next higher
 236            relaxable insn to use.  */
 237         for (i = 0, insn = fragP->fr_cgen.insn; i < 4; i++, insn++)
 238           {
 239             if ((strcmp (CGEN_INSN_MNEMONIC (insn),
 240                          CGEN_INSN_MNEMONIC (fragP->fr_cgen.insn))
 241                  == 0)
 242                 && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXED))
 243               break;
 244           }
 245         if (i == 4)
 246           abort ();
 247
 248         fragP->fr_cgen.insn = insn;
 249         return 2;
 250       }
 251     }
 252
 253   return md_relax_table[fragP->fr_subtype].rlx_length;
 254 }
 255
 256 /* *fragP has been relaxed to its final size, and now needs to have
 257    the bytes inside it modified to conform to the new size.
 258
 259    Called after relaxation is finished.
 260    fragP->fr_type == rs_machine_dependent.
 261    fragP->fr_subtype is the subtype of what the address relaxed to.  */
 262
 263 void
 264 md_convert_frag (bfd *   abfd ATTRIBUTE_UNUSED,
 265                  segT    sec  ATTRIBUTE_UNUSED,
 266                  fragS * fragP ATTRIBUTE_UNUSED)
 267 {
 268   /* FIXME */
 269 }
 270
 271 \f
 272 /* Functions concerning relocs.  */
 273
 274 /* The location from which a PC relative jump should be calculated,
 275    given a PC relative reloc.  */
 276
 277 long
 278 md_pcrel_from_section (fixS * fixP, segT sec)
 279 {
 280   if (fixP->fx_addsy != (symbolS *) NULL
 281       && (! S_IS_DEFINED (fixP->fx_addsy)
 282           || S_GET_SEGMENT (fixP->fx_addsy) != sec))
 283     /* The symbol is undefined (or is defined but not in this section).
 284        Let the linker figure it out.  */
 285     return 0;
 286
 287   return (fixP->fx_frag->fr_address + fixP->fx_where) & ~1;
 288 }
 289
 290
 291 /* Return the bfd reloc type for OPERAND of INSN at fixup FIXP.
 292    Returns BFD_RELOC_NONE if no reloc type can be found.
 293    *FIXP may be modified if desired.  */
 294
 295 bfd_reloc_code_real_type
 296 md_cgen_lookup_reloc (const CGEN_INSN *    insn ATTRIBUTE_UNUSED,
 297                       const CGEN_OPERAND * operand,
 298                       fixS *               fixP)
 299 {
 300   bfd_reloc_code_real_type type;
 301
 302   switch (operand->type)
 303     {
 304     case OPENRISC_OPERAND_ABS_26:
 305       fixP->fx_pcrel = 0;
 306       type = BFD_RELOC_OPENRISC_ABS_26;
 307       goto emit;
 308     case OPENRISC_OPERAND_DISP_26:
 309       fixP->fx_pcrel = 1;
 310       type = BFD_RELOC_OPENRISC_REL_26;
 311       goto emit;
 312
 313     case OPENRISC_OPERAND_HI16:
 314       type = BFD_RELOC_HI16;
 315       goto emit;
 316
 317     case OPENRISC_OPERAND_LO16:
 318       type = BFD_RELOC_LO16;
 319       goto emit;
 320
 321     emit:
 322       return type;
 323
 324     default : /* avoid -Wall warning */
 325       break;
 326     }
 327
 328   return BFD_RELOC_NONE;
 329 }
 330 \f
 331 /* Write a value out to the object file, using the appropriate endianness.  */
 332
 333 void
 334 md_number_to_chars (char * buf, valueT val, int n)
 335 {
 336   number_to_chars_bigendian (buf, val, n);
 337 }
 338
 339 /* Turn a string in input_line_pointer into a floating point constant of type
 340    type, and store the appropriate bytes in *litP.  The number of LITTLENUMS
 341    emitted is stored in *sizeP .  An error message is returned, or NULL on OK.
 342 */
 343
 344 /* Equal to MAX_PRECISION in atof-ieee.c */
 345 #define MAX_LITTLENUMS 6
 346
 347 char *
 348 md_atof (int type, char * litP, int *  sizeP)
 349 {
 350   return ieee_md_atof (type, litP, sizeP, TRUE);
 351 }
 352
 353 bfd_boolean
 354 openrisc_fix_adjustable (fixS * fixP)
 355 {
 356   /* We need the symbol name for the VTABLE entries.  */
 357   if (fixP->fx_r_type == BFD_RELOC_VTABLE_INHERIT
 358       || fixP->fx_r_type == BFD_RELOC_VTABLE_ENTRY)
 359     return 0;
 360
 361   return 1;
 362 }