1 /* GAS interface for targets using CGEN: Cpu tools GENerator.
2 Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
4 This file is part of GAS, the GNU Assembler.
6 GAS is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GAS is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GAS; see the file COPYING. If not, write to the Free Software
18 Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
22 #include "libiberty.h"
25 #include "cgen-desc.h"
30 /* Opcode table descriptor, must be set by md_begin. */
32 CGEN_CPU_DESC gas_cgen_cpu_desc;
34 /* Callback to insert a register into the symbol table.
35 A target may choose to let GAS parse the registers.
36 ??? Not currently used. */
39 cgen_asm_record_register (name, number)
43 /* Use symbol_create here instead of symbol_new so we don't try to
44 output registers into the object file's symbol table. */
45 symbol_table_insert (symbol_create (name, reg_section,
46 number, & zero_address_frag));
49 /* We need to keep a list of fixups. We can't simply generate them as
50 we go, because that would require us to first create the frag, and
51 that would screw up references to ``.''.
53 This is used by cpu's with simple operands. It keeps knowledge of what
54 an `expressionS' is and what a `fixup' is out of CGEN which for the time
57 OPINDEX is the index in the operand table.
58 OPINFO is something the caller chooses to help in reloc determination. */
67 static struct fixup fixups [GAS_CGEN_MAX_FIXUPS];
68 static int num_fixups;
70 /* Prepare to parse an instruction.
71 ??? May wish to make this static and delete calls in md_assemble. */
74 gas_cgen_init_parse ()
82 queue_fixup (opindex, opinfo, expP)
86 /* We need to generate a fixup for this expression. */
87 if (num_fixups >= GAS_CGEN_MAX_FIXUPS)
88 as_fatal (_("too many fixups"));
89 fixups[num_fixups].exp = * expP;
90 fixups[num_fixups].opindex = opindex;
91 fixups[num_fixups].opinfo = opinfo;
95 /* The following three functions allow a backup of the fixup chain to be made,
96 and to have this backup be swapped with the current chain. This allows
97 certain ports, eg the m32r, to swap two instructions and swap their fixups
99 /* ??? I think with cgen_asm_finish_insn (or something else) there is no
100 more need for this. */
102 static struct fixup saved_fixups [GAS_CGEN_MAX_FIXUPS];
103 static int saved_num_fixups;
106 gas_cgen_save_fixups ()
108 saved_num_fixups = num_fixups;
110 memcpy (saved_fixups, fixups, sizeof (fixups[0]) * num_fixups);
116 gas_cgen_restore_fixups ()
118 num_fixups = saved_num_fixups;
120 memcpy (fixups, saved_fixups, sizeof (fixups[0]) * num_fixups);
122 saved_num_fixups = 0;
126 gas_cgen_swap_fixups ()
129 struct fixup tmp_fixup;
133 gas_cgen_restore_fixups ();
135 else if (saved_num_fixups == 0)
137 gas_cgen_save_fixups ();
141 tmp = saved_num_fixups;
142 saved_num_fixups = num_fixups;
145 for (tmp = GAS_CGEN_MAX_FIXUPS; tmp--;)
147 tmp_fixup = saved_fixups [tmp];
148 saved_fixups [tmp] = fixups [tmp];
149 fixups [tmp] = tmp_fixup;
154 /* Default routine to record a fixup.
155 This is a cover function to fix_new.
156 It exists because we record INSN with the fixup.
158 FRAG and WHERE are their respective arguments to fix_new_exp.
160 OPINFO is something the caller chooses to help in reloc determination.
162 At this point we do not use a bfd_reloc_code_real_type for
163 operands residing in the insn, but instead just use the
164 operand index. This lets us easily handle fixups for any
165 operand type. We pick a BFD reloc type in md_apply_fix. */
168 gas_cgen_record_fixup (frag, where, insn, length, operand, opinfo, symbol, offset)
171 const CGEN_INSN * insn;
173 const CGEN_OPERAND * operand;
180 /* It may seem strange to use operand->attrs and not insn->attrs here,
181 but it is the operand that has a pc relative relocation. */
183 fixP = fix_new (frag, where, length / 8, symbol, offset,
184 CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR),
185 (bfd_reloc_code_real_type)
186 ((int) BFD_RELOC_UNUSED
187 + (int) operand->type));
188 fixP->fx_cgen.insn = insn;
189 fixP->fx_cgen.opinfo = opinfo;
194 /* Default routine to record a fixup given an expression.
195 This is a cover function to fix_new_exp.
196 It exists because we record INSN with the fixup.
198 FRAG and WHERE are their respective arguments to fix_new_exp.
200 OPINFO is something the caller chooses to help in reloc determination.
202 At this point we do not use a bfd_reloc_code_real_type for
203 operands residing in the insn, but instead just use the
204 operand index. This lets us easily handle fixups for any
205 operand type. We pick a BFD reloc type in md_apply_fix. */
208 gas_cgen_record_fixup_exp (frag, where, insn, length, operand, opinfo, exp)
211 const CGEN_INSN * insn;
213 const CGEN_OPERAND * operand;
219 /* It may seem strange to use operand->attrs and not insn->attrs here,
220 but it is the operand that has a pc relative relocation. */
222 fixP = fix_new_exp (frag, where, length / 8, exp,
223 CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR),
224 (bfd_reloc_code_real_type)
225 ((int) BFD_RELOC_UNUSED
226 + (int) operand->type));
227 fixP->fx_cgen.insn = insn;
228 fixP->fx_cgen.opinfo = opinfo;
233 /* Used for communication between the next two procedures. */
234 static jmp_buf expr_jmp_buf;
236 /* Callback for cgen interface. Parse the expression at *STRP.
237 The result is an error message or NULL for success (in which case
238 *STRP is advanced past the parsed text).
239 WANT is an indication of what the caller is looking for.
240 If WANT == CGEN_ASM_PARSE_INIT the caller is beginning to try to match
241 a table entry with the insn, reset the queued fixups counter.
242 An enum cgen_parse_operand_result is stored in RESULTP.
243 OPINDEX is the operand's table entry index.
244 OPINFO is something the caller chooses to help in reloc determination.
245 The resulting value is stored in VALUEP. */
248 gas_cgen_parse_operand (cd, want, strP, opindex, opinfo, resultP, valueP)
250 enum cgen_parse_operand_type want;
254 enum cgen_parse_operand_result * resultP;
258 /* These are volatile to survive the setjmp. */
259 char * volatile hold;
260 enum cgen_parse_operand_result * volatile resultP_1;
263 static enum cgen_parse_operand_result * resultP_1;
265 const char * errmsg = NULL;
268 if (want == CGEN_PARSE_OPERAND_INIT)
270 gas_cgen_init_parse ();
275 hold = input_line_pointer;
276 input_line_pointer = (char *) * strP;
278 /* We rely on md_operand to longjmp back to us.
279 This is done via gas_cgen_md_operand. */
280 if (setjmp (expr_jmp_buf) != 0)
282 input_line_pointer = (char *) hold;
283 * resultP_1 = CGEN_PARSE_OPERAND_RESULT_ERROR;
284 return "illegal operand";
289 * strP = input_line_pointer;
290 input_line_pointer = hold;
292 /* FIXME: Need to check `want'. */
297 errmsg = _("illegal operand");
298 * resultP = CGEN_PARSE_OPERAND_RESULT_ERROR;
301 errmsg = _("missing operand");
302 * resultP = CGEN_PARSE_OPERAND_RESULT_ERROR;
305 * valueP = exp.X_add_number;
306 * resultP = CGEN_PARSE_OPERAND_RESULT_NUMBER;
309 * valueP = exp.X_add_number;
310 * resultP = CGEN_PARSE_OPERAND_RESULT_REGISTER;
313 queue_fixup (opindex, opinfo, & exp);
315 * resultP = CGEN_PARSE_OPERAND_RESULT_QUEUED;
322 /* md_operand handler to catch unrecognized expressions and halt the
323 parsing process so the next entry can be tried.
325 ??? This could be done differently by adding code to `expression'. */
328 gas_cgen_md_operand (expressionP)
329 expressionS * expressionP;
331 longjmp (expr_jmp_buf, 1);
334 /* Finish assembling instruction INSN.
335 BUF contains what we've built up so far.
336 LENGTH is the size of the insn in bits.
337 RELAX_P is non-zero if relaxable insns should be emitted as such.
338 Otherwise they're emitted in non-relaxable forms.
339 The "result" is stored in RESULT if non-NULL. */
342 gas_cgen_finish_insn (insn, buf, length, relax_p, result)
343 const CGEN_INSN * insn;
344 CGEN_INSN_BYTES_PTR buf;
347 finished_insnS * result;
352 unsigned int byte_len = length / 8;
354 /* ??? Target foo issues various warnings here, so one might want to provide
355 a hook here. However, our caller is defined in tc-foo.c so there
356 shouldn't be a need for a hook. */
358 /* Write out the instruction.
359 It is important to fetch enough space in one call to `frag_more'.
360 We use (f - frag_now->fr_literal) to compute where we are and we
361 don't want frag_now to change between calls.
363 Relaxable instructions: We need to ensure we allocate enough
364 space for the largest insn. */
366 if (CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAX))
367 abort (); /* These currently shouldn't get here. */
369 /* Is there a relaxable insn with the relaxable operand needing a fixup? */
372 if (relax_p && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXABLE))
374 /* Scan the fixups for the operand affected by relaxing
375 (i.e. the branch address). */
377 for (i = 0; i < num_fixups; ++ i)
379 if (CGEN_OPERAND_ATTR_VALUE (cgen_operand_lookup_by_num (gas_cgen_cpu_desc, fixups[i].opindex),
388 if (relax_operand != -1)
393 #ifdef TC_CGEN_MAX_RELAX
394 max_len = TC_CGEN_MAX_RELAX (insn, byte_len);
396 max_len = CGEN_MAX_INSN_SIZE;
398 /* Ensure variable part and fixed part are in same fragment. */
399 /* FIXME: Having to do this seems like a hack. */
402 /* Allocate space for the fixed part. */
403 f = frag_more (byte_len);
405 /* Create a relaxable fragment for this instruction. */
408 frag_var (rs_machine_dependent,
409 max_len - byte_len /* max chars */,
410 0 /* variable part already allocated */,
411 /* FIXME: When we machine generate the relax table,
412 machine generate a macro to compute subtype. */
414 fixups[relax_operand].exp.X_add_symbol,
415 fixups[relax_operand].exp.X_add_number,
418 /* Record the operand number with the fragment so md_convert_frag
419 can use gas_cgen_md_record_fixup to record the appropriate reloc. */
420 old_frag->fr_cgen.insn = insn;
421 old_frag->fr_cgen.opindex = fixups[relax_operand].opindex;
422 old_frag->fr_cgen.opinfo = fixups[relax_operand].opinfo;
424 result->frag = old_frag;
428 f = frag_more (byte_len);
430 result->frag = frag_now;
433 /* If we're recording insns as numbers (rather than a string of bytes),
434 target byte order handling is deferred until now. */
436 cgen_put_insn_value (gas_cgen_cpu_desc, f, length, *buf);
438 memcpy (f, buf, byte_len);
441 /* Create any fixups. */
442 for (i = 0; i < num_fixups; ++i)
445 const CGEN_OPERAND *operand =
446 cgen_operand_lookup_by_num (gas_cgen_cpu_desc, fixups[i].opindex);
448 /* Don't create fixups for these. That's done during relaxation.
449 We don't need to test for CGEN_INSN_RELAX as they can't get here
452 && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXABLE)
453 && CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_RELAX))
456 #ifndef md_cgen_record_fixup_exp
457 #define md_cgen_record_fixup_exp gas_cgen_record_fixup_exp
460 fixP = md_cgen_record_fixup_exp (frag_now, f - frag_now->fr_literal,
461 insn, length, operand,
465 result->fixups[i] = fixP;
470 result->num_fixups = num_fixups;
475 /* Apply a fixup to the object code. This is called for all the
476 fixups we generated by the call to fix_new_exp, above. In the call
477 above we used a reloc code which was the largest legal reloc code
478 plus the operand index. Here we undo that to recover the operand
479 index. At this point all symbol values should be fully resolved,
480 and we attempt to completely resolve the reloc. If we can not do
481 that, we determine the correct reloc code and put it back in the fixup. */
483 /* FIXME: This function handles some of the fixups and bfd_install_relocation
484 handles the rest. bfd_install_relocation (or some other bfd function)
485 should handle them all. */
488 gas_cgen_md_apply_fix3 (fixP, valueP, seg)
493 char * where = fixP->fx_frag->fr_literal + fixP->fx_where;
495 /* canonical name, since used a lot */
496 CGEN_CPU_DESC cd = gas_cgen_cpu_desc;
498 /* FIXME FIXME FIXME: The value we are passed in *valuep includes
499 the symbol values. Since we are using BFD_ASSEMBLER, if we are
500 doing this relocation the code in write.c is going to call
501 bfd_install_relocation, which is also going to use the symbol
502 value. That means that if the reloc is fully resolved we want to
503 use *valuep since bfd_install_relocation is not being used.
504 However, if the reloc is not fully resolved we do not want to use
505 *valuep, and must use fx_offset instead. However, if the reloc
506 is PC relative, we do want to use *valuep since it includes the
507 result of md_pcrel_from. This is confusing. */
509 if (fixP->fx_addsy == (symbolS *) NULL)
514 else if (fixP->fx_pcrel)
518 value = fixP->fx_offset;
519 if (fixP->fx_subsy != (symbolS *) NULL)
521 if (S_GET_SEGMENT (fixP->fx_subsy) == absolute_section)
522 value -= S_GET_VALUE (fixP->fx_subsy);
525 /* We don't actually support subtracting a symbol. */
526 as_bad_where (fixP->fx_file, fixP->fx_line,
527 _("expression too complex"));
532 if ((int) fixP->fx_r_type >= (int) BFD_RELOC_UNUSED)
534 int opindex = (int) fixP->fx_r_type - (int) BFD_RELOC_UNUSED;
535 const CGEN_OPERAND *operand = cgen_operand_lookup_by_num (cd, opindex);
537 bfd_reloc_code_real_type reloc_type;
538 CGEN_FIELDS *fields = alloca (CGEN_CPU_SIZEOF_FIELDS (cd));
539 const CGEN_INSN *insn = fixP->fx_cgen.insn;
541 /* If the reloc has been fully resolved finish the operand here. */
542 /* FIXME: This duplicates the capabilities of code in BFD. */
544 /* FIXME: If partial_inplace isn't set bfd_install_relocation won't
545 finish the job. Testing for pcrel is a temporary hack. */
548 CGEN_CPU_SET_FIELDS_BITSIZE (cd) (fields, CGEN_INSN_BITSIZE (insn));
549 CGEN_CPU_SET_VMA_OPERAND (cd) (cd, opindex, fields, (bfd_vma) value);
553 CGEN_INSN_INT insn_value =
554 cgen_get_insn_value (cd, where, CGEN_INSN_BITSIZE (insn));
556 /* ??? 0 is passed for `pc' */
557 errmsg = CGEN_CPU_INSERT_OPERAND (cd) (cd, opindex, fields,
558 &insn_value, (bfd_vma) 0);
559 cgen_put_insn_value (cd, where, CGEN_INSN_BITSIZE (insn),
563 /* ??? 0 is passed for `pc' */
564 errmsg = CGEN_CPU_INSERT_OPERAND (cd) (cd, opindex, fields, where,
568 as_bad_where (fixP->fx_file, fixP->fx_line, "%s", errmsg);
574 /* The operand isn't fully resolved. Determine a BFD reloc value
575 based on the operand information and leave it to
576 bfd_install_relocation. Note that this doesn't work when
577 partial_inplace == false. */
579 reloc_type = md_cgen_lookup_reloc (insn, operand, fixP);
580 if (reloc_type != BFD_RELOC_NONE)
582 fixP->fx_r_type = reloc_type;
586 as_bad_where (fixP->fx_file, fixP->fx_line,
587 _("unresolved expression that must be resolved"));
592 else if (fixP->fx_done)
594 /* We're finished with this fixup. Install it because
595 bfd_install_relocation won't be called to do it. */
596 switch (fixP->fx_r_type)
599 md_number_to_chars (where, value, 1);
602 md_number_to_chars (where, value, 2);
605 md_number_to_chars (where, value, 4);
607 /* FIXME: later add support for 64 bits. */
609 as_bad_where (fixP->fx_file, fixP->fx_line,
610 _("internal error: can't install fix for reloc type %d (`%s')"),
611 fixP->fx_r_type, bfd_get_reloc_code_name (fixP->fx_r_type));
617 /* bfd_install_relocation will be called to finish things up. */
620 /* Tuck `value' away for use by tc_gen_reloc.
621 See the comment describing fx_addnumber in write.h.
622 This field is misnamed (or misused :-). */
623 fixP->fx_addnumber = value;
628 /* Translate internal representation of relocation info to BFD target format.
630 FIXME: To what extent can we get all relevant targets to use this? */
633 gas_cgen_tc_gen_reloc (section, fixP)
639 reloc = (arelent *) xmalloc (sizeof (arelent));
641 reloc->howto = bfd_reloc_type_lookup (stdoutput, fixP->fx_r_type);
642 if (reloc->howto == (reloc_howto_type *) NULL)
644 as_bad_where (fixP->fx_file, fixP->fx_line,
645 _("internal error: can't export reloc type %d (`%s')"),
646 fixP->fx_r_type, bfd_get_reloc_code_name (fixP->fx_r_type));
650 assert (!fixP->fx_pcrel == !reloc->howto->pc_relative);
652 reloc->sym_ptr_ptr = (asymbol **) xmalloc (sizeof (asymbol *));
653 *reloc->sym_ptr_ptr = symbol_get_bfdsym (fixP->fx_addsy);
655 /* Use fx_offset for these cases */
656 if ( fixP->fx_r_type == BFD_RELOC_VTABLE_ENTRY
657 || fixP->fx_r_type == BFD_RELOC_VTABLE_INHERIT)
658 reloc->addend = fixP->fx_offset;
660 reloc->addend = fixP->fx_addnumber;
662 reloc->address = fixP->fx_frag->fr_address + fixP->fx_where;