aboutsummaryrefslogtreecommitdiff
path: root/gdb/ppc-sysv-tdep.c
blob: 51f9c0a06baf3b4158a6a4e1d660c6eb9f3cb012 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
/* Target-dependent code for PowerPC systems using the SVR4 ABI
   for GDB, the GNU debugger.

   Copyright (C) 2000, 2001, 2002, 2003, 2005, 2007
   Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.  */

#include "defs.h"
#include "gdbcore.h"
#include "inferior.h"
#include "regcache.h"
#include "value.h"
#include "gdb_string.h"
#include "gdb_assert.h"
#include "ppc-tdep.h"
#include "target.h"
#include "objfiles.h"
#include "infcall.h"

/* Pass the arguments in either registers, or in the stack. Using the
   ppc sysv ABI, the first eight words of the argument list (that might
   be less than eight parameters if some parameters occupy more than one
   word) are passed in r3..r10 registers.  float and double parameters are
   passed in fpr's, in addition to that. Rest of the parameters if any
   are passed in user stack. 

   If the function is returning a structure, then the return address is passed
   in r3, then the first 7 words of the parametes can be passed in registers,
   starting from r4. */

CORE_ADDR
ppc_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
			      struct regcache *regcache, CORE_ADDR bp_addr,
			      int nargs, struct value **args, CORE_ADDR sp,
			      int struct_return, CORE_ADDR struct_addr)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
  ULONGEST saved_sp;
  int argspace = 0;		/* 0 is an initial wrong guess.  */
  int write_pass;

  regcache_cooked_read_unsigned (regcache, SP_REGNUM, &saved_sp);

  /* Go through the argument list twice.

     Pass 1: Figure out how much new stack space is required for
     arguments and pushed values.  Unlike the PowerOpen ABI, the SysV
     ABI doesn't reserve any extra space for parameters which are put
     in registers, but does always push structures and then pass their
     address.

     Pass 2: Replay the same computation but this time also write the
     values out to the target.  */

  for (write_pass = 0; write_pass < 2; write_pass++)
    {
      int argno;
      /* Next available floating point register for float and double
         arguments.  */
      int freg = 1;
      /* Next available general register for non-float, non-vector
         arguments.  */
      int greg = 3;
      /* Next available vector register for vector arguments.  */
      int vreg = 2;
      /* Arguments start above the "LR save word" and "Back chain".  */
      int argoffset = 2 * tdep->wordsize;
      /* Structures start after the arguments.  */
      int structoffset = argoffset + argspace;

      /* If the function is returning a `struct', then the first word
         (which will be passed in r3) is used for struct return
         address.  In that case we should advance one word and start
         from r4 register to copy parameters.  */
      if (struct_return)
	{
	  if (write_pass)
	    regcache_cooked_write_signed (regcache,
					  tdep->ppc_gp0_regnum + greg,
					  struct_addr);
	  greg++;
	}

      for (argno = 0; argno < nargs; argno++)
	{
	  struct value *arg = args[argno];
	  struct type *type = check_typedef (value_type (arg));
	  int len = TYPE_LENGTH (type);
	  const bfd_byte *val = value_contents (arg);

	  if (TYPE_CODE (type) == TYPE_CODE_FLT
	      && ppc_floating_point_unit_p (current_gdbarch) && len <= 8)
	    {
	      /* Floating point value converted to "double" then
	         passed in an FP register, when the registers run out,
	         8 byte aligned stack is used.  */
	      if (freg <= 8)
		{
		  if (write_pass)
		    {
		      /* Always store the floating point value using
		         the register's floating-point format.  */
		      gdb_byte regval[MAX_REGISTER_SIZE];
		      struct type *regtype
			= register_type (gdbarch, tdep->ppc_fp0_regnum + freg);
		      convert_typed_floating (val, type, regval, regtype);
		      regcache_cooked_write (regcache,
                                             tdep->ppc_fp0_regnum + freg,
					     regval);
		    }
		  freg++;
		}
	      else
		{
		  /* SysV ABI converts floats to doubles before
		     writing them to an 8 byte aligned stack location.  */
		  argoffset = align_up (argoffset, 8);
		  if (write_pass)
		    {
		      char memval[8];
		      convert_typed_floating (val, type, memval,
					      builtin_type_ieee_double);
		      write_memory (sp + argoffset, val, len);
		    }
		  argoffset += 8;
		}
	    }
	  else if (len == 8 && (TYPE_CODE (type) == TYPE_CODE_INT	/* long long */
				|| (!ppc_floating_point_unit_p (current_gdbarch) && TYPE_CODE (type) == TYPE_CODE_FLT)))	/* double */
	    {
	      /* "long long" or "double" passed in an odd/even
	         register pair with the low addressed word in the odd
	         register and the high addressed word in the even
	         register, or when the registers run out an 8 byte
	         aligned stack location.  */
	      if (greg > 9)
		{
		  /* Just in case GREG was 10.  */
		  greg = 11;
		  argoffset = align_up (argoffset, 8);
		  if (write_pass)
		    write_memory (sp + argoffset, val, len);
		  argoffset += 8;
		}
	      else if (tdep->wordsize == 8)
		{
		  if (write_pass)
		    regcache_cooked_write (regcache,
					   tdep->ppc_gp0_regnum + greg, val);
		  greg += 1;
		}
	      else
		{
		  /* Must start on an odd register - r3/r4 etc.  */
		  if ((greg & 1) == 0)
		    greg++;
		  if (write_pass)
		    {
		      regcache_cooked_write (regcache,
					     tdep->ppc_gp0_regnum + greg + 0,
					     val + 0);
		      regcache_cooked_write (regcache,
					     tdep->ppc_gp0_regnum + greg + 1,
					     val + 4);
		    }
		  greg += 2;
		}
	    }
	  else if (len == 16
		   && TYPE_CODE (type) == TYPE_CODE_ARRAY
		   && TYPE_VECTOR (type) && tdep->ppc_vr0_regnum >= 0)
	    {
	      /* Vector parameter passed in an Altivec register, or
	         when that runs out, 16 byte aligned stack location.  */
	      if (vreg <= 13)
		{
		  if (write_pass)
		    regcache_cooked_write (current_regcache,
					   tdep->ppc_vr0_regnum + vreg, val);
		  vreg++;
		}
	      else
		{
		  argoffset = align_up (argoffset, 16);
		  if (write_pass)
		    write_memory (sp + argoffset, val, 16);
		  argoffset += 16;
		}
	    }
	  else if (len == 8
		   && TYPE_CODE (type) == TYPE_CODE_ARRAY
		   && TYPE_VECTOR (type) && tdep->ppc_ev0_regnum >= 0)
	    {
	      /* Vector parameter passed in an e500 register, or when
	         that runs out, 8 byte aligned stack location.  Note
	         that since e500 vector and general purpose registers
	         both map onto the same underlying register set, a
	         "greg" and not a "vreg" is consumed here.  A cooked
	         write stores the value in the correct locations
	         within the raw register cache.  */
	      if (greg <= 10)
		{
		  if (write_pass)
		    regcache_cooked_write (current_regcache,
					   tdep->ppc_ev0_regnum + greg, val);
		  greg++;
		}
	      else
		{
		  argoffset = align_up (argoffset, 8);
		  if (write_pass)
		    write_memory (sp + argoffset, val, 8);
		  argoffset += 8;
		}
	    }
	  else
	    {
	      /* Reduce the parameter down to something that fits in a
	         "word".  */
	      gdb_byte word[MAX_REGISTER_SIZE];
	      memset (word, 0, MAX_REGISTER_SIZE);
	      if (len > tdep->wordsize
		  || TYPE_CODE (type) == TYPE_CODE_STRUCT
		  || TYPE_CODE (type) == TYPE_CODE_UNION)
		{
		  /* Structs and large values are put on an 8 byte
		     aligned stack ... */
		  structoffset = align_up (structoffset, 8);
		  if (write_pass)
		    write_memory (sp + structoffset, val, len);
		  /* ... and then a "word" pointing to that address is
		     passed as the parameter.  */
		  store_unsigned_integer (word, tdep->wordsize,
					  sp + structoffset);
		  structoffset += len;
		}
	      else if (TYPE_CODE (type) == TYPE_CODE_INT)
		/* Sign or zero extend the "int" into a "word".  */
		store_unsigned_integer (word, tdep->wordsize,
					unpack_long (type, val));
	      else
		/* Always goes in the low address.  */
		memcpy (word, val, len);
	      /* Store that "word" in a register, or on the stack.
	         The words have "4" byte alignment.  */
	      if (greg <= 10)
		{
		  if (write_pass)
		    regcache_cooked_write (regcache,
					   tdep->ppc_gp0_regnum + greg, word);
		  greg++;
		}
	      else
		{
		  argoffset = align_up (argoffset, tdep->wordsize);
		  if (write_pass)
		    write_memory (sp + argoffset, word, tdep->wordsize);
		  argoffset += tdep->wordsize;
		}
	    }
	}

      /* Compute the actual stack space requirements.  */
      if (!write_pass)
	{
	  /* Remember the amount of space needed by the arguments.  */
	  argspace = argoffset;
	  /* Allocate space for both the arguments and the structures.  */
	  sp -= (argoffset + structoffset);
	  /* Ensure that the stack is still 16 byte aligned.  */
	  sp = align_down (sp, 16);
	}

      /* The psABI says that "A caller of a function that takes a
	 variable argument list shall set condition register bit 6 to
	 1 if it passes one or more arguments in the floating-point
	 registers. It is strongly recommended that the caller set the
	 bit to 0 otherwise..."  Doing this for normal functions too
	 shouldn't hurt.  */
      if (write_pass)
	{
	  ULONGEST cr;

	  regcache_cooked_read_unsigned (regcache, tdep->ppc_cr_regnum, &cr);
	  if (freg > 1)
	    cr |= 0x02000000;
	  else
	    cr &= ~0x02000000;
	  regcache_cooked_write_unsigned (regcache, tdep->ppc_cr_regnum, cr);
	}
    }

  /* Update %sp.   */
  regcache_cooked_write_signed (regcache, SP_REGNUM, sp);

  /* Write the backchain (it occupies WORDSIZED bytes).  */
  write_memory_signed_integer (sp, tdep->wordsize, saved_sp);

  /* Point the inferior function call's return address at the dummy's
     breakpoint.  */
  regcache_cooked_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr);

  return sp;
}

/* Handle the return-value conventions specified by the SysV 32-bit
   PowerPC ABI (including all the supplements):

   no floating-point: floating-point values returned using 32-bit
   general-purpose registers.

   Altivec: 128-bit vectors returned using vector registers.

   e500: 64-bit vectors returned using the full full 64 bit EV
   register, floating-point values returned using 32-bit
   general-purpose registers.

   GCC (broken): Small struct values right (instead of left) aligned
   when returned in general-purpose registers.  */

static enum return_value_convention
do_ppc_sysv_return_value (struct gdbarch *gdbarch, struct type *type,
			  struct regcache *regcache, void *readbuf,
			  const void *writebuf, int broken_gcc)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
  gdb_assert (tdep->wordsize == 4);
  if (TYPE_CODE (type) == TYPE_CODE_FLT
      && TYPE_LENGTH (type) <= 8
      && ppc_floating_point_unit_p (gdbarch))
    {
      if (readbuf)
	{
	  /* Floats and doubles stored in "f1".  Convert the value to
	     the required type.  */
	  gdb_byte regval[MAX_REGISTER_SIZE];
	  struct type *regtype = register_type (gdbarch,
                                                tdep->ppc_fp0_regnum + 1);
	  regcache_cooked_read (regcache, tdep->ppc_fp0_regnum + 1, regval);
	  convert_typed_floating (regval, regtype, readbuf, type);
	}
      if (writebuf)
	{
	  /* Floats and doubles stored in "f1".  Convert the value to
	     the register's "double" type.  */
	  gdb_byte regval[MAX_REGISTER_SIZE];
	  struct type *regtype = register_type (gdbarch, tdep->ppc_fp0_regnum);
	  convert_typed_floating (writebuf, type, regval, regtype);
	  regcache_cooked_write (regcache, tdep->ppc_fp0_regnum + 1, regval);
	}
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  if ((TYPE_CODE (type) == TYPE_CODE_INT && TYPE_LENGTH (type) == 8)
      || (TYPE_CODE (type) == TYPE_CODE_FLT && TYPE_LENGTH (type) == 8))
    {
      if (readbuf)
	{
	  /* A long long, or a double stored in the 32 bit r3/r4.  */
	  regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 3,
				(bfd_byte *) readbuf + 0);
	  regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 4,
				(bfd_byte *) readbuf + 4);
	}
      if (writebuf)
	{
	  /* A long long, or a double stored in the 32 bit r3/r4.  */
	  regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3,
				 (const bfd_byte *) writebuf + 0);
	  regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 4,
				 (const bfd_byte *) writebuf + 4);
	}
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  if (TYPE_CODE (type) == TYPE_CODE_INT
      && TYPE_LENGTH (type) <= tdep->wordsize)
    {
      if (readbuf)
	{
	  /* Some sort of integer stored in r3.  Since TYPE isn't
	     bigger than the register, sign extension isn't a problem
	     - just do everything unsigned.  */
	  ULONGEST regval;
	  regcache_cooked_read_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
					 &regval);
	  store_unsigned_integer (readbuf, TYPE_LENGTH (type), regval);
	}
      if (writebuf)
	{
	  /* Some sort of integer stored in r3.  Use unpack_long since
	     that should handle any required sign extension.  */
	  regcache_cooked_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
					  unpack_long (type, writebuf));
	}
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  if (TYPE_LENGTH (type) == 16
      && TYPE_CODE (type) == TYPE_CODE_ARRAY
      && TYPE_VECTOR (type) && tdep->ppc_vr0_regnum >= 0)
    {
      if (readbuf)
	{
	  /* Altivec places the return value in "v2".  */
	  regcache_cooked_read (regcache, tdep->ppc_vr0_regnum + 2, readbuf);
	}
      if (writebuf)
	{
	  /* Altivec places the return value in "v2".  */
	  regcache_cooked_write (regcache, tdep->ppc_vr0_regnum + 2, writebuf);
	}
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  if (TYPE_LENGTH (type) == 8
      && TYPE_CODE (type) == TYPE_CODE_ARRAY
      && TYPE_VECTOR (type) && tdep->ppc_ev0_regnum >= 0)
    {
      /* The e500 ABI places return values for the 64-bit DSP types
	 (__ev64_opaque__) in r3.  However, in GDB-speak, ev3
	 corresponds to the entire r3 value for e500, whereas GDB's r3
	 only corresponds to the least significant 32-bits.  So place
	 the 64-bit DSP type's value in ev3.  */
      if (readbuf)
	regcache_cooked_read (regcache, tdep->ppc_ev0_regnum + 3, readbuf);
      if (writebuf)
	regcache_cooked_write (regcache, tdep->ppc_ev0_regnum + 3, writebuf);
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  if (broken_gcc && TYPE_LENGTH (type) <= 8)
    {
      /* GCC screwed up for structures or unions whose size is less
	 than or equal to 8 bytes..  Instead of left-aligning, it
	 right-aligns the data into the buffer formed by r3, r4.  */
      gdb_byte regvals[MAX_REGISTER_SIZE * 2];
      int len = TYPE_LENGTH (type);
      int offset = (2 * tdep->wordsize - len) % tdep->wordsize;

      if (readbuf)
	{
	  regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 3,
				regvals + 0 * tdep->wordsize);
	  if (len > tdep->wordsize)
	    regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 4,
				  regvals + 1 * tdep->wordsize);
	  memcpy (readbuf, regvals + offset, len);
	}
      if (writebuf)
	{
	  memset (regvals, 0, sizeof regvals);
	  memcpy (regvals + offset, writebuf, len);
	  regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3,
				 regvals + 0 * tdep->wordsize);
	  if (len > tdep->wordsize)
	    regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 4,
				   regvals + 1 * tdep->wordsize);
	}

      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  if (TYPE_LENGTH (type) <= 8)
    {
      if (readbuf)
	{
	  /* This matches SVr4 PPC, it does not match GCC.  */
	  /* The value is right-padded to 8 bytes and then loaded, as
	     two "words", into r3/r4.  */
	  gdb_byte regvals[MAX_REGISTER_SIZE * 2];
	  regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 3,
				regvals + 0 * tdep->wordsize);
	  if (TYPE_LENGTH (type) > tdep->wordsize)
	    regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 4,
				  regvals + 1 * tdep->wordsize);
	  memcpy (readbuf, regvals, TYPE_LENGTH (type));
	}
      if (writebuf)
	{
	  /* This matches SVr4 PPC, it does not match GCC.  */
	  /* The value is padded out to 8 bytes and then loaded, as
	     two "words" into r3/r4.  */
	  gdb_byte regvals[MAX_REGISTER_SIZE * 2];
	  memset (regvals, 0, sizeof regvals);
	  memcpy (regvals, writebuf, TYPE_LENGTH (type));
	  regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3,
				 regvals + 0 * tdep->wordsize);
	  if (TYPE_LENGTH (type) > tdep->wordsize)
	    regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 4,
				   regvals + 1 * tdep->wordsize);
	}
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  return RETURN_VALUE_STRUCT_CONVENTION;
}

enum return_value_convention
ppc_sysv_abi_return_value (struct gdbarch *gdbarch, struct type *valtype,
			   struct regcache *regcache, gdb_byte *readbuf,
			   const gdb_byte *writebuf)
{
  return do_ppc_sysv_return_value (gdbarch, valtype, regcache, readbuf,
				   writebuf, 0);
}

enum return_value_convention
ppc_sysv_abi_broken_return_value (struct gdbarch *gdbarch,
				  struct type *valtype,
				  struct regcache *regcache,
				  gdb_byte *readbuf, const gdb_byte *writebuf)
{
  return do_ppc_sysv_return_value (gdbarch, valtype, regcache, readbuf,
				   writebuf, 1);
}

/* The helper function for 64-bit SYSV push_dummy_call.  Converts the
   function's code address back into the function's descriptor
   address.

   Find a value for the TOC register.  Every symbol should have both
   ".FN" and "FN" in the minimal symbol table.  "FN" points at the
   FN's descriptor, while ".FN" points at the entry point (which
   matches FUNC_ADDR).  Need to reverse from FUNC_ADDR back to the
   FN's descriptor address (while at the same time being careful to
   find "FN" in the same object file as ".FN").  */

static int
convert_code_addr_to_desc_addr (CORE_ADDR code_addr, CORE_ADDR *desc_addr)
{
  struct obj_section *dot_fn_section;
  struct minimal_symbol *dot_fn;
  struct minimal_symbol *fn;
  CORE_ADDR toc;
  /* Find the minimal symbol that corresponds to CODE_ADDR (should
     have a name of the form ".FN").  */
  dot_fn = lookup_minimal_symbol_by_pc (code_addr);
  if (dot_fn == NULL || SYMBOL_LINKAGE_NAME (dot_fn)[0] != '.')
    return 0;
  /* Get the section that contains CODE_ADDR.  Need this for the
     "objfile" that it contains.  */
  dot_fn_section = find_pc_section (code_addr);
  if (dot_fn_section == NULL || dot_fn_section->objfile == NULL)
    return 0;
  /* Now find the corresponding "FN" (dropping ".") minimal symbol's
     address.  Only look for the minimal symbol in ".FN"'s object file
     - avoids problems when two object files (i.e., shared libraries)
     contain a minimal symbol with the same name.  */
  fn = lookup_minimal_symbol (SYMBOL_LINKAGE_NAME (dot_fn) + 1, NULL,
			      dot_fn_section->objfile);
  if (fn == NULL)
    return 0;
  /* Found a descriptor.  */
  (*desc_addr) = SYMBOL_VALUE_ADDRESS (fn);
  return 1;
}

/* Pass the arguments in either registers, or in the stack. Using the
   ppc 64 bit SysV ABI.

   This implements a dumbed down version of the ABI.  It always writes
   values to memory, GPR and FPR, even when not necessary.  Doing this
   greatly simplifies the logic. */

CORE_ADDR
ppc64_sysv_abi_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
				struct regcache *regcache, CORE_ADDR bp_addr,
				int nargs, struct value **args, CORE_ADDR sp,
				int struct_return, CORE_ADDR struct_addr)
{
  CORE_ADDR func_addr = find_function_addr (function, NULL);
  struct gdbarch_tdep *tdep = gdbarch_tdep (current_gdbarch);
  ULONGEST back_chain;
  /* See for-loop comment below.  */
  int write_pass;
  /* Size of the Altivec's vector parameter region, the final value is
     computed in the for-loop below.  */
  LONGEST vparam_size = 0;
  /* Size of the general parameter region, the final value is computed
     in the for-loop below.  */
  LONGEST gparam_size = 0;
  /* Kevin writes ... I don't mind seeing tdep->wordsize used in the
     calls to align_up(), align_down(), etc.  because this makes it
     easier to reuse this code (in a copy/paste sense) in the future,
     but it is a 64-bit ABI and asserting that the wordsize is 8 bytes
     at some point makes it easier to verify that this function is
     correct without having to do a non-local analysis to figure out
     the possible values of tdep->wordsize.  */
  gdb_assert (tdep->wordsize == 8);

  /* By this stage in the proceedings, SP has been decremented by "red
     zone size" + "struct return size".  Fetch the stack-pointer from
     before this and use that as the BACK_CHAIN.  */
  regcache_cooked_read_unsigned (regcache, SP_REGNUM, &back_chain);

  /* Go through the argument list twice.

     Pass 1: Compute the function call's stack space and register
     requirements.

     Pass 2: Replay the same computation but this time also write the
     values out to the target.  */

  for (write_pass = 0; write_pass < 2; write_pass++)
    {
      int argno;
      /* Next available floating point register for float and double
         arguments.  */
      int freg = 1;
      /* Next available general register for non-vector (but possibly
         float) arguments.  */
      int greg = 3;
      /* Next available vector register for vector arguments.  */
      int vreg = 2;
      /* The address, at which the next general purpose parameter
         (integer, struct, float, ...) should be saved.  */
      CORE_ADDR gparam;
      /* Address, at which the next Altivec vector parameter should be
         saved.  */
      CORE_ADDR vparam;

      if (!write_pass)
	{
	  /* During the first pass, GPARAM and VPARAM are more like
	     offsets (start address zero) than addresses.  That way
	     the accumulate the total stack space each region
	     requires.  */
	  gparam = 0;
	  vparam = 0;
	}
      else
	{
	  /* Decrement the stack pointer making space for the Altivec
	     and general on-stack parameters.  Set vparam and gparam
	     to their corresponding regions.  */
	  vparam = align_down (sp - vparam_size, 16);
	  gparam = align_down (vparam - gparam_size, 16);
	  /* Add in space for the TOC, link editor double word,
	     compiler double word, LR save area, CR save area.  */
	  sp = align_down (gparam - 48, 16);
	}

      /* If the function is returning a `struct', then there is an
         extra hidden parameter (which will be passed in r3)
         containing the address of that struct..  In that case we
         should advance one word and start from r4 register to copy
         parameters.  This also consumes one on-stack parameter slot.  */
      if (struct_return)
	{
	  if (write_pass)
	    regcache_cooked_write_signed (regcache,
					  tdep->ppc_gp0_regnum + greg,
					  struct_addr);
	  greg++;
	  gparam = align_up (gparam + tdep->wordsize, tdep->wordsize);
	}

      for (argno = 0; argno < nargs; argno++)
	{
	  struct value *arg = args[argno];
	  struct type *type = check_typedef (value_type (arg));
	  const bfd_byte *val = value_contents (arg);
	  if (TYPE_CODE (type) == TYPE_CODE_FLT && TYPE_LENGTH (type) <= 8)
	    {
	      /* Floats and Doubles go in f1 .. f13.  They also
	         consume a left aligned GREG,, and can end up in
	         memory.  */
	      if (write_pass)
		{
		  if (ppc_floating_point_unit_p (current_gdbarch)
		      && freg <= 13)
		    {
		      gdb_byte regval[MAX_REGISTER_SIZE];
		      struct type *regtype
                        = register_type (gdbarch, tdep->ppc_fp0_regnum);
		      convert_typed_floating (val, type, regval, regtype);
		      regcache_cooked_write (regcache,
                                             tdep->ppc_fp0_regnum + freg,
					     regval);
		    }
		  if (greg <= 10)
		    {
		      /* The ABI states "Single precision floating
		         point values are mapped to the first word in
		         a single doubleword" and "... floating point
		         values mapped to the first eight doublewords
		         of the parameter save area are also passed in
		         general registers").

		         This code interprets that to mean: store it,
		         left aligned, in the general register.  */
		      gdb_byte regval[MAX_REGISTER_SIZE];
		      memset (regval, 0, sizeof regval);
		      memcpy (regval, val, TYPE_LENGTH (type));
		      regcache_cooked_write (regcache,
					     tdep->ppc_gp0_regnum + greg,
					     regval);
		    }
		  write_memory (gparam, val, TYPE_LENGTH (type));
		}
	      /* Always consume parameter stack space.  */
	      freg++;
	      greg++;
	      gparam = align_up (gparam + TYPE_LENGTH (type), tdep->wordsize);
	    }
	  else if (TYPE_LENGTH (type) == 16 && TYPE_VECTOR (type)
		   && TYPE_CODE (type) == TYPE_CODE_ARRAY
		   && tdep->ppc_vr0_regnum >= 0)
	    {
	      /* In the Altivec ABI, vectors go in the vector
	         registers v2 .. v13, or when that runs out, a vector
	         annex which goes above all the normal parameters.
	         NOTE: cagney/2003-09-21: This is a guess based on the
	         PowerOpen Altivec ABI.  */
	      if (vreg <= 13)
		{
		  if (write_pass)
		    regcache_cooked_write (regcache,
					   tdep->ppc_vr0_regnum + vreg, val);
		  vreg++;
		}
	      else
		{
		  if (write_pass)
		    write_memory (vparam, val, TYPE_LENGTH (type));
		  vparam = align_up (vparam + TYPE_LENGTH (type), 16);
		}
	    }
	  else if ((TYPE_CODE (type) == TYPE_CODE_INT
		    || TYPE_CODE (type) == TYPE_CODE_ENUM
		    || TYPE_CODE (type) == TYPE_CODE_PTR)
		   && TYPE_LENGTH (type) <= 8)
	    {
	      /* Scalars and Pointers get sign[un]extended and go in
	         gpr3 .. gpr10.  They can also end up in memory.  */
	      if (write_pass)
		{
		  /* Sign extend the value, then store it unsigned.  */
		  ULONGEST word = unpack_long (type, val);
		  /* Convert any function code addresses into
		     descriptors.  */
		  if (TYPE_CODE (type) == TYPE_CODE_PTR
		      && TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_FUNC)
		    {
		      CORE_ADDR desc = word;
		      convert_code_addr_to_desc_addr (word, &desc);
		      word = desc;
		    }
		  if (greg <= 10)
		    regcache_cooked_write_unsigned (regcache,
						    tdep->ppc_gp0_regnum +
						    greg, word);
		  write_memory_unsigned_integer (gparam, tdep->wordsize,
						 word);
		}
	      greg++;
	      gparam = align_up (gparam + TYPE_LENGTH (type), tdep->wordsize);
	    }
	  else
	    {
	      int byte;
	      for (byte = 0; byte < TYPE_LENGTH (type);
		   byte += tdep->wordsize)
		{
		  if (write_pass && greg <= 10)
		    {
		      gdb_byte regval[MAX_REGISTER_SIZE];
		      int len = TYPE_LENGTH (type) - byte;
		      if (len > tdep->wordsize)
			len = tdep->wordsize;
		      memset (regval, 0, sizeof regval);
		      /* WARNING: cagney/2003-09-21: As best I can
		         tell, the ABI specifies that the value should
		         be left aligned.  Unfortunately, GCC doesn't
		         do this - it instead right aligns even sized
		         values and puts odd sized values on the
		         stack.  Work around that by putting both a
		         left and right aligned value into the
		         register (hopefully no one notices :-^).
		         Arrrgh!  */
		      /* Left aligned (8 byte values such as pointers
		         fill the buffer).  */
		      memcpy (regval, val + byte, len);
		      /* Right aligned (but only if even).  */
		      if (len == 1 || len == 2 || len == 4)
			memcpy (regval + tdep->wordsize - len,
				val + byte, len);
		      regcache_cooked_write (regcache, greg, regval);
		    }
		  greg++;
		}
	      if (write_pass)
		/* WARNING: cagney/2003-09-21: Strictly speaking, this
		   isn't necessary, unfortunately, GCC appears to get
		   "struct convention" parameter passing wrong putting
		   odd sized structures in memory instead of in a
		   register.  Work around this by always writing the
		   value to memory.  Fortunately, doing this
		   simplifies the code.  */
		write_memory (gparam, val, TYPE_LENGTH (type));
	      if (write_pass)
		/* WARNING: cagney/2004-06-20: It appears that GCC
		   likes to put structures containing a single
		   floating-point member in an FP register instead of
		   general general purpose.  */
	      /* Always consume parameter stack space.  */
	      gparam = align_up (gparam + TYPE_LENGTH (type), tdep->wordsize);
	    }
	}

      if (!write_pass)
	{
	  /* Save the true region sizes ready for the second pass.  */
	  vparam_size = vparam;
	  /* Make certain that the general parameter save area is at
	     least the minimum 8 registers (or doublewords) in size.  */
	  if (greg < 8)
	    gparam_size = 8 * tdep->wordsize;
	  else
	    gparam_size = gparam;
	}
    }

  /* Update %sp.   */
  regcache_cooked_write_signed (regcache, SP_REGNUM, sp);

  /* Write the backchain (it occupies WORDSIZED bytes).  */
  write_memory_signed_integer (sp, tdep->wordsize, back_chain);

  /* Point the inferior function call's return address at the dummy's
     breakpoint.  */
  regcache_cooked_write_signed (regcache, tdep->ppc_lr_regnum, bp_addr);

  /* Use the func_addr to find the descriptor, and use that to find
     the TOC.  */
  {
    CORE_ADDR desc_addr;
    if (convert_code_addr_to_desc_addr (func_addr, &desc_addr))
      {
	/* The TOC is the second double word in the descriptor.  */
	CORE_ADDR toc =
	  read_memory_unsigned_integer (desc_addr + tdep->wordsize,
					tdep->wordsize);
	regcache_cooked_write_unsigned (regcache,
					tdep->ppc_gp0_regnum + 2, toc);
      }
  }

  return sp;
}


/* The 64 bit ABI retun value convention.

   Return non-zero if the return-value is stored in a register, return
   0 if the return-value is instead stored on the stack (a.k.a.,
   struct return convention).

   For a return-value stored in a register: when WRITEBUF is non-NULL,
   copy the buffer to the corresponding register return-value location
   location; when READBUF is non-NULL, fill the buffer from the
   corresponding register return-value location.  */
enum return_value_convention
ppc64_sysv_abi_return_value (struct gdbarch *gdbarch, struct type *valtype,
			     struct regcache *regcache, gdb_byte *readbuf,
			     const gdb_byte *writebuf)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  /* This function exists to support a calling convention that
     requires floating-point registers.  It shouldn't be used on
     processors that lack them.  */
  gdb_assert (ppc_floating_point_unit_p (gdbarch));

  /* Floats and doubles in F1.  */
  if (TYPE_CODE (valtype) == TYPE_CODE_FLT && TYPE_LENGTH (valtype) <= 8)
    {
      gdb_byte regval[MAX_REGISTER_SIZE];
      struct type *regtype = register_type (gdbarch, tdep->ppc_fp0_regnum);
      if (writebuf != NULL)
	{
	  convert_typed_floating (writebuf, valtype, regval, regtype);
	  regcache_cooked_write (regcache, tdep->ppc_fp0_regnum + 1, regval);
	}
      if (readbuf != NULL)
	{
	  regcache_cooked_read (regcache, tdep->ppc_fp0_regnum + 1, regval);
	  convert_typed_floating (regval, regtype, readbuf, valtype);
	}
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  /* Integers in r3.  */
  if ((TYPE_CODE (valtype) == TYPE_CODE_INT
       || TYPE_CODE (valtype) == TYPE_CODE_ENUM)
      && TYPE_LENGTH (valtype) <= 8)
    {
      if (writebuf != NULL)
	{
	  /* Be careful to sign extend the value.  */
	  regcache_cooked_write_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
					  unpack_long (valtype, writebuf));
	}
      if (readbuf != NULL)
	{
	  /* Extract the integer from r3.  Since this is truncating the
	     value, there isn't a sign extension problem.  */
	  ULONGEST regval;
	  regcache_cooked_read_unsigned (regcache, tdep->ppc_gp0_regnum + 3,
					 &regval);
	  store_unsigned_integer (readbuf, TYPE_LENGTH (valtype), regval);
	}
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  /* All pointers live in r3.  */
  if (TYPE_CODE (valtype) == TYPE_CODE_PTR)
    {
      /* All pointers live in r3.  */
      if (writebuf != NULL)
	regcache_cooked_write (regcache, tdep->ppc_gp0_regnum + 3, writebuf);
      if (readbuf != NULL)
	regcache_cooked_read (regcache, tdep->ppc_gp0_regnum + 3, readbuf);
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  /* Array type has more than one use.  */
  if (TYPE_CODE (valtype) == TYPE_CODE_ARRAY)
    {
      /* Small character arrays are returned, right justified, in r3.  */
      if (TYPE_LENGTH (valtype) <= 8
        && TYPE_CODE (TYPE_TARGET_TYPE (valtype)) == TYPE_CODE_INT
        && TYPE_LENGTH (TYPE_TARGET_TYPE (valtype)) == 1)
        {
          int offset = (register_size (gdbarch, tdep->ppc_gp0_regnum + 3)
                       - TYPE_LENGTH (valtype));
          if (writebuf != NULL)
           regcache_cooked_write_part (regcache, tdep->ppc_gp0_regnum + 3,
                                      offset, TYPE_LENGTH (valtype), writebuf);
          if (readbuf != NULL)
           regcache_cooked_read_part (regcache, tdep->ppc_gp0_regnum + 3,
                                      offset, TYPE_LENGTH (valtype), readbuf);
          return RETURN_VALUE_REGISTER_CONVENTION;
	}
      /* A VMX vector is returned in v2.  */
      if (TYPE_CODE (valtype) == TYPE_CODE_ARRAY
        && TYPE_VECTOR (valtype) && tdep->ppc_vr0_regnum >= 0)
        {
          if (readbuf)
            regcache_cooked_read (regcache, tdep->ppc_vr0_regnum + 2, readbuf);
          if (writebuf)
            regcache_cooked_write (regcache, tdep->ppc_vr0_regnum + 2, writebuf);
          return RETURN_VALUE_REGISTER_CONVENTION;
        }
    }
  /* Big floating point values get stored in adjacent floating
     point registers, starting with F1.  */
  if (TYPE_CODE (valtype) == TYPE_CODE_FLT
      && (TYPE_LENGTH (valtype) == 16 || TYPE_LENGTH (valtype) == 32))
    {
      if (writebuf || readbuf != NULL)
	{
	  int i;
	  for (i = 0; i < TYPE_LENGTH (valtype) / 8; i++)
	    {
	      if (writebuf != NULL)
		regcache_cooked_write (regcache, tdep->ppc_fp0_regnum + 1 + i,
				       (const bfd_byte *) writebuf + i * 8);
	      if (readbuf != NULL)
		regcache_cooked_read (regcache, tdep->ppc_fp0_regnum + 1 + i,
				      (bfd_byte *) readbuf + i * 8);
	    }
	}
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  /* Complex values get returned in f1:f2, need to convert.  */
  if (TYPE_CODE (valtype) == TYPE_CODE_COMPLEX
      && (TYPE_LENGTH (valtype) == 8 || TYPE_LENGTH (valtype) == 16))
    {
      if (regcache != NULL)
	{
	  int i;
	  for (i = 0; i < 2; i++)
	    {
	      gdb_byte regval[MAX_REGISTER_SIZE];
	      struct type *regtype =
		register_type (current_gdbarch, tdep->ppc_fp0_regnum);
	      if (writebuf != NULL)
		{
		  convert_typed_floating ((const bfd_byte *) writebuf +
					  i * (TYPE_LENGTH (valtype) / 2),
					  valtype, regval, regtype);
		  regcache_cooked_write (regcache,
                                         tdep->ppc_fp0_regnum + 1 + i,
					 regval);
		}
	      if (readbuf != NULL)
		{
		  regcache_cooked_read (regcache,
                                        tdep->ppc_fp0_regnum + 1 + i,
                                        regval);
		  convert_typed_floating (regval, regtype,
					  (bfd_byte *) readbuf +
					  i * (TYPE_LENGTH (valtype) / 2),
					  valtype);
		}
	    }
	}
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  /* Big complex values get stored in f1:f4.  */
  if (TYPE_CODE (valtype) == TYPE_CODE_COMPLEX && TYPE_LENGTH (valtype) == 32)
    {
      if (regcache != NULL)
	{
	  int i;
	  for (i = 0; i < 4; i++)
	    {
	      if (writebuf != NULL)
		regcache_cooked_write (regcache, tdep->ppc_fp0_regnum + 1 + i,
				       (const bfd_byte *) writebuf + i * 8);
	      if (readbuf != NULL)
		regcache_cooked_read (regcache, tdep->ppc_fp0_regnum + 1 + i,
				      (bfd_byte *) readbuf + i * 8);
	    }
	}
      return RETURN_VALUE_REGISTER_CONVENTION;
    }
  return RETURN_VALUE_STRUCT_CONVENTION;
}

CORE_ADDR
ppc64_sysv_abi_adjust_breakpoint_address (struct gdbarch *gdbarch,
					  CORE_ADDR bpaddr)
{
  /* PPC64 SYSV specifies that the minimal-symbol "FN" should point at
     a function-descriptor while the corresponding minimal-symbol
     ".FN" should point at the entry point.  Consequently, a command
     like "break FN" applied to an object file with only minimal
     symbols, will insert the breakpoint into the descriptor at "FN"
     and not the function at ".FN".  Avoid this confusion by adjusting
     any attempt to set a descriptor breakpoint into a corresponding
     function breakpoint.  Note that GDB warns the user when this
     adjustment is applied - that's ok as otherwise the user will have
     no way of knowing why their breakpoint at "FN" resulted in the
     program stopping at ".FN".  */
  return gdbarch_convert_from_func_ptr_addr (gdbarch, bpaddr, &current_target);
}