summaryrefslogtreecommitdiff
path: root/gdb/dve3900-rom.c
blob: 60a177dbed1963482571862014814d7bf94469a8 (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
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
/* Remote debugging interface for Densan DVE-R3900 ROM monitor for
   GDB, the GNU debugger.
   Copyright 1997 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., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "defs.h"
#include "gdbcore.h"
#include "target.h"
#include "monitor.h"
#include "serial.h"
#include "inferior.h"
#include "command.h"
#include "gdb_string.h"
#include <time.h>

/* Type of function passed to bfd_map_over_sections.  */

typedef void (*section_map_func) PARAMS ((bfd * abfd, asection * sect, PTR obj));

/* Packet escape character used by Densan monitor.  */

#define PESC 0xdc

/* Maximum packet size.  This is actually smaller than necessary
   just to be safe.  */

#define MAXPSIZE 1024

/* External functions.  */

extern void report_transfer_performance PARAMS ((unsigned long,
						 time_t, time_t));

/* Certain registers are "bitmapped", in that the monitor can only display
   them or let the user modify them as a series of named bitfields.
   This structure describes a field in a bitmapped register.  */

struct bit_field
  {
    char *prefix;		/* string appearing before the value */
    char *suffix;		/* string appearing after the value */
    char *user_name;		/* name used by human when entering field value */
    int length;			/* number of bits in the field */
    int start;			/* starting (least significant) bit number of field */
  };

/* Local functions for register manipulation.  */

static void r3900_supply_register PARAMS ((char *regname, int regnamelen,
					   char *val, int vallen));
static void fetch_bad_vaddr PARAMS ((void));
static unsigned long fetch_fields PARAMS ((struct bit_field * bf));
static void fetch_bitmapped_register PARAMS ((int regno,
					      struct bit_field * bf));
static void r3900_fetch_registers PARAMS ((int regno));
static void store_bitmapped_register PARAMS ((int regno,
					      struct bit_field * bf));
static void r3900_store_registers PARAMS ((int regno));

/* Local functions for fast binary loading.  */

static void write_long PARAMS ((char *buf, long n));
static void write_long_le PARAMS ((char *buf, long n));
static int debug_readchar PARAMS ((int hex));
static void debug_write PARAMS ((unsigned char *buf, int buflen));
static void ignore_packet PARAMS ((void));
static void send_packet PARAMS ((char type, unsigned char *buf, int buflen,
				 int seq));
static void process_read_request PARAMS ((unsigned char *buf, int buflen));
static void count_section PARAMS ((bfd * abfd, asection * s,
				   unsigned int *section_count));
static void load_section PARAMS ((bfd * abfd, asection * s,
				  unsigned int *data_count));
static void r3900_load PARAMS ((char *filename, int from_tty));

/* Miscellaneous local functions.  */

static void r3900_open PARAMS ((char *args, int from_tty));


/* Pointers to static functions in monitor.c for fetching and storing
   registers.  We can't use these function in certain cases where the Densan
   monitor acts perversely: for registers that it displays in bit-map
   format, and those that can't be modified at all.  In those cases
   we have to use our own functions to fetch and store their values.  */

static void (*orig_monitor_fetch_registers) PARAMS ((int regno));
static void (*orig_monitor_store_registers) PARAMS ((int regno));

/* Pointer to static function in monitor. for loading programs.
   We use this function for loading S-records via the serial link.  */

static void (*orig_monitor_load) PARAMS ((char *file, int from_tty));

/* This flag is set if a fast ethernet download should be used.  */

static int ethernet = 0;

/* This array of registers needs to match the indexes used by GDB. The
   whole reason this exists is because the various ROM monitors use
   different names than GDB does, and don't support all the registers
   either.  */

static char *r3900_regnames[NUM_REGS] =
{
  "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
  "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
  "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
  "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",

  "S",				/* PS_REGNUM */
  "l",				/* LO_REGNUM */
  "h",				/* HI_REGNUM */
  "B",				/* BADVADDR_REGNUM */
  "Pcause",			/* CAUSE_REGNUM */
  "p"				/* PC_REGNUM */
};


/* Table of register names produced by monitor's register dump command.  */

static struct reg_entry
  {
    char *name;
    int regno;
  }
reg_table[] =
{
  {
    "r0_zero", 0
  }
  ,
  {
    "r1_at", 1
  }
  ,
  {
    "r2_v0", 2
  }
  ,
  {
    "r3_v1", 3
  }
  ,
  {
    "r4_a0", 4
  }
  ,
  {
    "r5_a1", 5
  }
  ,
  {
    "r6_a2", 6
  }
  ,
  {
    "r7_a3", 7
  }
  ,
  {
    "r8_t0", 8
  }
  ,
  {
    "r9_t1", 9
  }
  ,
  {
    "r10_t2", 10
  }
  ,
  {
    "r11_t3", 11
  }
  ,
  {
    "r12_t4", 12
  }
  ,
  {
    "r13_t5", 13
  }
  ,
  {
    "r14_t6", 14
  }
  ,
  {
    "r15_t7", 15
  }
  ,
  {
    "r16_s0", 16
  }
  ,
  {
    "r17_s1", 17
  }
  ,
  {
    "r18_s2", 18
  }
  ,
  {
    "r19_s3", 19
  }
  ,
  {
    "r20_s4", 20
  }
  ,
  {
    "r21_s5", 21
  }
  ,
  {
    "r22_s6", 22
  }
  ,
  {
    "r23_s7", 23
  }
  ,
  {
    "r24_t8", 24
  }
  ,
  {
    "r25_t9", 25
  }
  ,
  {
    "r26_k0", 26
  }
  ,
  {
    "r27_k1", 27
  }
  ,
  {
    "r28_gp", 28
  }
  ,
  {
    "r29_sp", 29
  }
  ,
  {
    "r30_fp", 30
  }
  ,
  {
    "r31_ra", 31
  }
  ,
  {
    "HI", HI_REGNUM
  }
  ,
  {
    "LO", LO_REGNUM
  }
  ,
  {
    "PC", PC_REGNUM
  }
  ,
  {
    "BadV", BADVADDR_REGNUM
  }
  ,
  {
    NULL, 0
  }
};


/* The monitor displays the cache register along with the status register,
   as if they were a single register.  So when we want to fetch the
   status register, parse but otherwise ignore the fields of the
   cache register that the monitor displays.  Register fields that should
   be ignored have a length of zero in the tables below.  */

static struct bit_field status_fields[] =
{
  /* Status register portion */
  {"SR[<CU=", " ", "cu", 4, 28},
  {"RE=", " ", "re", 1, 25},
  {"BEV=", " ", "bev", 1, 22},
  {"TS=", " ", "ts", 1, 21},
  {"Nmi=", " ", "nmi", 1, 20},
  {"INT=", " ", "int", 6, 10},
  {"SW=", ">]", "sw", 2, 8},
  {"[<KUO=", " ", "kuo", 1, 5},
  {"IEO=", " ", "ieo", 1, 4},
  {"KUP=", " ", "kup", 1, 3},
  {"IEP=", " ", "iep", 1, 2},
  {"KUC=", " ", "kuc", 1, 1},
  {"IEC=", ">]", "iec", 1, 0},

  /* Cache register portion (dummy for parsing only) */
  {"CR[<IalO=", " ", "ialo", 0, 13},
  {"DalO=", " ", "dalo", 0, 12},
  {"IalP=", " ", "ialp", 0, 11},
  {"DalP=", " ", "dalp", 0, 10},
  {"IalC=", " ", "ialc", 0, 9},
  {"DalC=", ">] ", "dalc", 0, 8},

  {NULL, NULL, 0, 0}		/* end of table marker */
};


#if 0				/* FIXME: Enable when we add support for modifying cache register.  */
static struct bit_field cache_fields[] =
{
  /* Status register portion (dummy for parsing only) */
  {"SR[<CU=", " ", "cu", 0, 28},
  {"RE=", " ", "re", 0, 25},
  {"BEV=", " ", "bev", 0, 22},
  {"TS=", " ", "ts", 0, 21},
  {"Nmi=", " ", "nmi", 0, 20},
  {"INT=", " ", "int", 0, 10},
  {"SW=", ">]", "sw", 0, 8},
  {"[<KUO=", " ", "kuo", 0, 5},
  {"IEO=", " ", "ieo", 0, 4},
  {"KUP=", " ", "kup", 0, 3},
  {"IEP=", " ", "iep", 0, 2},
  {"KUC=", " ", "kuc", 0, 1},
  {"IEC=", ">]", "iec", 0, 0},

  /* Cache register portion  */
  {"CR[<IalO=", " ", "ialo", 1, 13},
  {"DalO=", " ", "dalo", 1, 12},
  {"IalP=", " ", "ialp", 1, 11},
  {"DalP=", " ", "dalp", 1, 10},
  {"IalC=", " ", "ialc", 1, 9},
  {"DalC=", ">] ", "dalc", 1, 8},

  {NULL, NULL, NULL, 0, 0}	/* end of table marker */
};
#endif


static struct bit_field cause_fields[] =
{
  {"<BD=", " ", "bd", 1, 31},
  {"CE=", " ", "ce", 2, 28},
  {"IP=", " ", "ip", 6, 10},
  {"SW=", " ", "sw", 2, 8},
  {"EC=", ">]", "ec", 5, 2},

  {NULL, NULL, NULL, 0, 0}	/* end of table marker */
};


/* The monitor prints register values in the form

   regname = xxxx xxxx

   We look up the register name in a table, and remove the embedded space in
   the hex value before passing it to monitor_supply_register.  */

static void
r3900_supply_register (regname, regnamelen, val, vallen)
     char *regname;
     int regnamelen;
     char *val;
     int vallen;
{
  int regno = -1;
  int i;
  char valbuf[10];
  char *p;

  /* Perform some sanity checks on the register name and value.  */
  if (regnamelen < 2 || regnamelen > 7 || vallen != 9)
    return;

  /* Look up the register name.  */
  for (i = 0; reg_table[i].name != NULL; i++)
    {
      int rlen = strlen (reg_table[i].name);
      if (rlen == regnamelen && strncmp (regname, reg_table[i].name, rlen) == 0)
	{
	  regno = reg_table[i].regno;
	  break;
	}
    }
  if (regno == -1)
    return;

  /* Copy the hex value to a buffer and eliminate the embedded space. */
  for (i = 0, p = valbuf; i < vallen; i++)
    if (val[i] != ' ')
      *p++ = val[i];
  *p = '\0';

  monitor_supply_register (regno, valbuf);
}


/* Fetch the BadVaddr register.  Unlike the other registers, this
   one can't be modified, and the monitor won't even prompt to let
   you modify it.  */

static void
fetch_bad_vaddr ()
{
  char buf[20];

  monitor_printf ("xB\r");
  monitor_expect ("BadV=", NULL, 0);
  monitor_expect_prompt (buf, sizeof (buf));
  monitor_supply_register (BADVADDR_REGNUM, buf);
}


/* Read a series of bit fields from the monitor, and return their
   combined binary value.  */

static unsigned long
fetch_fields (bf)
     struct bit_field *bf;
{
  char buf[20];
  unsigned long val = 0;
  unsigned long bits;

  for (; bf->prefix != NULL; bf++)
    {
      monitor_expect (bf->prefix, NULL, 0);	/* get prefix */
      monitor_expect (bf->suffix, buf, sizeof (buf));	/* hex value, suffix */
      if (bf->length != 0)
	{
	  bits = strtoul (buf, NULL, 16);	/* get field value */
	  bits &= ((1 << bf->length) - 1);	/* mask out useless bits */
	  val |= bits << bf->start;	/* insert into register */
	}

    }

  return val;
}


static void
fetch_bitmapped_register (regno, bf)
     int regno;
     struct bit_field *bf;
{
  unsigned long val;
  unsigned char regbuf[MAX_REGISTER_RAW_SIZE];

  monitor_printf ("x%s\r", r3900_regnames[regno]);
  val = fetch_fields (bf);
  monitor_printf (".\r");
  monitor_expect_prompt (NULL, 0);

  /* supply register stores in target byte order, so swap here */

  store_unsigned_integer (regbuf, REGISTER_RAW_SIZE (regno), val);
  supply_register (regno, regbuf);

}


/* Fetch all registers (if regno is -1), or one register from the
   monitor.  For most registers, we can use the generic monitor_
   monitor_fetch_registers function.  But others are displayed in
   a very unusual fashion by the monitor, and must be handled specially.  */

static void
r3900_fetch_registers (regno)
     int regno;
{
  switch (regno)
    {
    case BADVADDR_REGNUM:
      fetch_bad_vaddr ();
      return;
    case PS_REGNUM:
      fetch_bitmapped_register (PS_REGNUM, status_fields);
      return;
    case CAUSE_REGNUM:
      fetch_bitmapped_register (CAUSE_REGNUM, cause_fields);
      return;
    default:
      orig_monitor_fetch_registers (regno);
    }
}


/* Write the new value of the bitmapped register to the monitor.  */

static void
store_bitmapped_register (regno, bf)
     int regno;
     struct bit_field *bf;
{
  unsigned long oldval, newval;

  /* Fetch the current value of the register.  */
  monitor_printf ("x%s\r", r3900_regnames[regno]);
  oldval = fetch_fields (bf);
  newval = read_register (regno);

  /* To save time, write just the fields that have changed.  */
  for (; bf->prefix != NULL; bf++)
    {
      if (bf->length != 0)
	{
	  unsigned long oldbits, newbits, mask;

	  mask = (1 << bf->length) - 1;
	  oldbits = (oldval >> bf->start) & mask;
	  newbits = (newval >> bf->start) & mask;
	  if (oldbits != newbits)
	    monitor_printf ("%s %lx ", bf->user_name, newbits);
	}
    }

  monitor_printf (".\r");
  monitor_expect_prompt (NULL, 0);
}


static void
r3900_store_registers (regno)
     int regno;
{
  switch (regno)
    {
    case PS_REGNUM:
      store_bitmapped_register (PS_REGNUM, status_fields);
      return;
    case CAUSE_REGNUM:
      store_bitmapped_register (CAUSE_REGNUM, cause_fields);
      return;
    default:
      orig_monitor_store_registers (regno);
    }
}


/* Write a 4-byte integer to the buffer in big-endian order.  */

static void
write_long (buf, n)
     char *buf;
     long n;
{
  buf[0] = (n >> 24) & 0xff;
  buf[1] = (n >> 16) & 0xff;
  buf[2] = (n >> 8) & 0xff;
  buf[3] = n & 0xff;
}


/* Write a 4-byte integer to the buffer in little-endian order.  */

static void
write_long_le (buf, n)
     char *buf;
     long n;
{
  buf[0] = n & 0xff;
  buf[1] = (n >> 8) & 0xff;
  buf[2] = (n >> 16) & 0xff;
  buf[3] = (n >> 24) & 0xff;
}


/* Read a character from the monitor.  If remote debugging is on,
   print the received character.  If HEX is non-zero, print the
   character in hexadecimal; otherwise, print it in ASCII.  */

static int
debug_readchar (hex)
     int hex;
{
  char buf[10];
  int c = monitor_readchar ();

  if (remote_debug > 0)
    {
      if (hex)
	sprintf (buf, "[%02x]", c & 0xff);
      else if (c == '\0')
	strcpy (buf, "\\0");
      else
	{
	  buf[0] = c;
	  buf[1] = '\0';
	}
      puts_debug ("Read -->", buf, "<--");
    }
  return c;
}


/* Send a buffer of characters to the monitor.  If remote debugging is on,
   print the sent buffer in hex.  */

static void
debug_write (buf, buflen)
     unsigned char *buf;
     int buflen;
{
  char s[10];

  monitor_write (buf, buflen);

  if (remote_debug > 0)
    {
      while (buflen-- > 0)
	{
	  sprintf (s, "[%02x]", *buf & 0xff);
	  puts_debug ("Sent -->", s, "<--");
	  buf++;
	}
    }
}


/* Ignore a packet sent to us by the monitor.  It send packets
   when its console is in "communications interface" mode.   A packet
   is of this form:

   start of packet flag (one byte: 0xdc)
   packet type (one byte)
   length (low byte)
   length (high byte)
   data (length bytes)

   The last two bytes of the data field are a checksum, but we don't
   bother to verify it.
 */

static void
ignore_packet ()
{
  int c;
  int len;

  /* Ignore lots of trash (messages about section addresses, for example)
     until we see the start of a packet.  */
  for (len = 0; len < 256; len++)
    {
      c = debug_readchar (0);
      if (c == PESC)
	break;
    }
  if (len == 8)
    error ("Packet header byte not found; %02x seen instead.", c);

  /* Read the packet type and length.  */
  c = debug_readchar (1);	/* type */

  c = debug_readchar (1);	/* low byte of length */
  len = c & 0xff;

  c = debug_readchar (1);	/* high byte of length */
  len += (c & 0xff) << 8;

  /* Ignore the rest of the packet.  */
  while (len-- > 0)
    c = debug_readchar (1);
}


/* Encapsulate some data into a packet and send it to the monitor.

   The 'p' packet is a special case.  This is a packet we send
   in response to a read ('r') packet from the monitor.  This function
   appends a one-byte sequence number to the data field of such a packet.
 */

static void
send_packet (type, buf, buflen, seq)
     char type;
     unsigned char *buf;
     int buflen, seq;
{
  unsigned char hdr[4];
  int len = buflen;
  int sum, i;

  /* If this is a 'p' packet, add one byte for a sequence number.  */
  if (type == 'p')
    len++;

  /* If the buffer has a non-zero length, add two bytes for a checksum.  */
  if (len > 0)
    len += 2;

  /* Write the packet header.  */
  hdr[0] = PESC;
  hdr[1] = type;
  hdr[2] = len & 0xff;
  hdr[3] = (len >> 8) & 0xff;
  debug_write (hdr, sizeof (hdr));

  if (len)
    {
      /* Write the packet data.  */
      debug_write (buf, buflen);

      /* Write the sequence number if this is a 'p' packet.  */
      if (type == 'p')
	{
	  hdr[0] = seq;
	  debug_write (hdr, 1);
	}

      /* Write the checksum.  */
      sum = 0;
      for (i = 0; i < buflen; i++)
	{
	  int tmp = (buf[i] & 0xff);
	  if (i & 1)
	    sum += tmp;
	  else
	    sum += tmp << 8;
	}
      if (type == 'p')
	{
	  if (buflen & 1)
	    sum += (seq & 0xff);
	  else
	    sum += (seq & 0xff) << 8;
	}
      sum = (sum & 0xffff) + ((sum >> 16) & 0xffff);
      sum += (sum >> 16) & 1;
      sum = ~sum;

      hdr[0] = (sum >> 8) & 0xff;
      hdr[1] = sum & 0xff;
      debug_write (hdr, 2);
    }
}


/* Respond to an expected read request from the monitor by sending
   data in chunks.  Handle all acknowledgements and handshaking packets.

   The monitor expects a response consisting of a one or more 'p' packets,
   each followed by a portion of the data requested.  The 'p' packet
   contains only a four-byte integer, the value of which is the number
   of bytes of data we are about to send.  Following the 'p' packet,
   the monitor expects the data bytes themselves in raw, unpacketized,
   form, without even a checksum.
 */

static void
process_read_request (buf, buflen)
     unsigned char *buf;
     int buflen;
{
  unsigned char len[4];
  int i, chunk;
  unsigned char seq;

  /* Discard the read request.  FIXME: we have to hope it's for
     the exact number of bytes we want to send; should check for this.  */
  ignore_packet ();

  for (i = chunk = 0, seq = 0; i < buflen; i += chunk, seq++)
    {
      /* Don't send more than MAXPSIZE bytes at a time.  */
      chunk = buflen - i;
      if (chunk > MAXPSIZE)
	chunk = MAXPSIZE;

      /* Write a packet containing the number of bytes we are sending.  */
      write_long_le (len, chunk);
      send_packet ('p', len, sizeof (len), seq);

      /* Write the data in raw form following the packet.  */
      debug_write (&buf[i], chunk);

      /* Discard the ACK packet.  */
      ignore_packet ();
    }

  /* Send an "end of data" packet.  */
  send_packet ('e', "", 0, 0);
}


/* Count loadable sections (helper function for r3900_load).  */

static void
count_section (abfd, s, section_count)
     bfd *abfd;
     asection *s;
     unsigned int *section_count;
{
  if (s->flags & SEC_LOAD && bfd_section_size (abfd, s) != 0)
    (*section_count)++;
}


/* Load a single BFD section (helper function for r3900_load).

   WARNING: this code is filled with assumptions about how
   the Densan monitor loads programs.  The monitor issues
   packets containing read requests, but rather than respond
   to them in an general way, we expect them to following
   a certain pattern.

   For example, we know that the monitor will start loading by
   issuing an 8-byte read request for the binary file header.
   We know this is coming and ignore the actual contents
   of the read request packet.
 */

static void
load_section (abfd, s, data_count)
     bfd *abfd;
     asection *s;
     unsigned int *data_count;
{
  if (s->flags & SEC_LOAD)
    {
      bfd_size_type section_size = bfd_section_size (abfd, s);
      bfd_vma section_base = bfd_section_lma (abfd, s);
      unsigned char *buffer;
      unsigned char header[8];

      /* Don't output zero-length sections.  */
      if (section_size == 0)
	return;
      if (data_count)
	*data_count += section_size;

      /* Print some fluff about the section being loaded.  */
      printf_filtered ("Loading section %s, size 0x%lx lma ",
		       bfd_section_name (abfd, s), (long) section_size);
      print_address_numeric (section_base, 1, gdb_stdout);
      printf_filtered ("\n");
      gdb_flush (gdb_stdout);

      /* Write the section header (location and size).  */
      write_long (&header[0], (long) section_base);
      write_long (&header[4], (long) section_size);
      process_read_request (header, sizeof (header));

      /* Read the section contents into a buffer, write it out,
         then free the buffer.  */
      buffer = (unsigned char *) xmalloc (section_size);
      bfd_get_section_contents (abfd, s, buffer, 0, section_size);
      process_read_request (buffer, section_size);
      free (buffer);
    }
}


/* When the ethernet is used as the console port on the Densan board,
   we can use the "Rm" command to do a fast binary load.  The format
   of the download data is:

   number of sections (4 bytes)
   starting address (4 bytes)
   repeat for each section:
   location address (4 bytes)
   section size (4 bytes)
   binary data

   The 4-byte fields are all in big-endian order.

   Using this command is tricky because we have to put the monitor
   into a special funky "communications interface" mode, in which
   it sends and receives packets of data along with the normal prompt.
 */

static void
r3900_load (filename, from_tty)
     char *filename;
     int from_tty;
{
  bfd *abfd;
  unsigned int data_count = 0;
  time_t start_time, end_time;	/* for timing of download */
  int section_count = 0;
  unsigned char buffer[8];

  /* If we are not using the ethernet, use the normal monitor load,
     which sends S-records over the serial link.  */
  if (!ethernet)
    {
      orig_monitor_load (filename, from_tty);
      return;
    }

  /* Open the file.  */
  if (filename == NULL || filename[0] == 0)
    filename = get_exec_file (1);
  abfd = bfd_openr (filename, 0);
  if (!abfd)
    error ("Unable to open file %s\n", filename);
  if (bfd_check_format (abfd, bfd_object) == 0)
    error ("File is not an object file\n");

  /* Output the "vconsi" command to get the monitor in the communication
     state where it will accept a load command.  This will cause
     the monitor to emit a packet before each prompt, so ignore the packet.  */
  monitor_printf ("vconsi\r");
  ignore_packet ();
  monitor_expect_prompt (NULL, 0);

  /* Output the "Rm" (load) command and respond to the subsequent "open"
     packet by sending an ACK packet.  */
  monitor_printf ("Rm\r");
  ignore_packet ();
  send_packet ('a', "", 0, 0);

  /* Output the fast load header (number of sections and starting address).  */
  bfd_map_over_sections ((bfd *) abfd, (section_map_func) count_section,
			 &section_count);
  write_long (&buffer[0], (long) section_count);
  if (exec_bfd)
    write_long (&buffer[4], (long) bfd_get_start_address (exec_bfd));
  else
    write_long (&buffer[4], 0);
  process_read_request (buffer, sizeof (buffer));

  /* Output the section data.  */
  start_time = time (NULL);
  bfd_map_over_sections (abfd, (section_map_func) load_section, &data_count);
  end_time = time (NULL);

  /* Acknowledge the close packet and put the monitor back into
     "normal" mode so it won't send packets any more.  */
  ignore_packet ();
  send_packet ('a', "", 0, 0);
  monitor_expect_prompt (NULL, 0);
  monitor_printf ("vconsx\r");
  monitor_expect_prompt (NULL, 0);

  /* Print start address and download performance information.  */
  printf_filtered ("Start address 0x%lx\n", (long) bfd_get_start_address (abfd));
  report_transfer_performance (data_count, start_time, end_time);

  /* Finally, make the PC point at the start address */
  if (exec_bfd)
    write_pc (bfd_get_start_address (exec_bfd));

  inferior_pid = 0;		/* No process now */

  /* This is necessary because many things were based on the PC at the
     time that we attached to the monitor, which is no longer valid
     now that we have loaded new code (and just changed the PC).
     Another way to do this might be to call normal_stop, except that
     the stack may not be valid, and things would get horribly
     confused... */
  clear_symtab_users ();
}


/* Commands to send to the monitor when first connecting:
   * The bare carriage return forces a prompt from the monitor
   (monitor doesn't prompt immediately after a reset).
   * The "vconsx" switches the monitor back to interactive mode
   in case an aborted download had left it in packet mode.
   * The "Xtr" command causes subsequent "t" (trace) commands to display
   the general registers only.
   * The "Xxr" command does the same thing for the "x" (examine
   registers) command.
   * The "bx" command clears all breakpoints.
 */

static char *r3900_inits[] =
{"\r", "vconsx\r", "Xtr\r", "Xxr\r", "bx\r", NULL};
static char *dummy_inits[] =
{NULL};

static struct target_ops r3900_ops;
static struct monitor_ops r3900_cmds;

static void
r3900_open (args, from_tty)
     char *args;
     int from_tty;
{
  char buf[64];
  int i;

  monitor_open (args, &r3900_cmds, from_tty);

  /* We have to handle sending the init strings ourselves, because
     the first two strings we send (carriage returns) may not be echoed
     by the monitor, but the rest will be.  */
  monitor_printf_noecho ("\r\r");
  for (i = 0; r3900_inits[i] != NULL; i++)
    {
      monitor_printf (r3900_inits[i]);
      monitor_expect_prompt (NULL, 0);
    }

  /* Attempt to determine whether the console device is ethernet or serial.
     This will tell us which kind of load to use (S-records over a serial
     link, or the Densan fast binary multi-section format over the net).  */

  ethernet = 0;
  monitor_printf ("v\r");
  if (monitor_expect ("console device :", NULL, 0) != -1)
    if (monitor_expect ("\n", buf, sizeof (buf)) != -1)
      if (strstr (buf, "ethernet") != NULL)
	ethernet = 1;
  monitor_expect_prompt (NULL, 0);
}

void
_initialize_r3900_rom ()
{
  r3900_cmds.flags = MO_NO_ECHO_ON_OPEN |
    MO_ADDR_BITS_REMOVE |
    MO_CLR_BREAK_USES_ADDR |
    MO_GETMEM_READ_SINGLE |
    MO_PRINT_PROGRAM_OUTPUT;

  r3900_cmds.init = dummy_inits;
  r3900_cmds.cont = "g\r";
  r3900_cmds.step = "t\r";
  r3900_cmds.set_break = "b %A\r";	/* COREADDR */
  r3900_cmds.clr_break = "b %A,0\r";	/* COREADDR */
  r3900_cmds.fill = "fx %A s %x %x\r";	/* COREADDR, len, val */

  r3900_cmds.setmem.cmdb = "sx %A %x\r";	/* COREADDR, val */
  r3900_cmds.setmem.cmdw = "sh %A %x\r";	/* COREADDR, val */
  r3900_cmds.setmem.cmdl = "sw %A %x\r";	/* COREADDR, val */

  r3900_cmds.getmem.cmdb = "sx %A\r";	/* COREADDR */
  r3900_cmds.getmem.cmdw = "sh %A\r";	/* COREADDR */
  r3900_cmds.getmem.cmdl = "sw %A\r";	/* COREADDR */
  r3900_cmds.getmem.resp_delim = " : ";
  r3900_cmds.getmem.term = " ";
  r3900_cmds.getmem.term_cmd = ".\r";

  r3900_cmds.setreg.cmd = "x%s %x\r";	/* regname, val */

  r3900_cmds.getreg.cmd = "x%s\r";	/* regname */
  r3900_cmds.getreg.resp_delim = "=";
  r3900_cmds.getreg.term = " ";
  r3900_cmds.getreg.term_cmd = ".\r";

  r3900_cmds.dump_registers = "x\r";
  r3900_cmds.register_pattern =
    "\\([a-zA-Z0-9_]+\\) *=\\([0-9a-f]+ [0-9a-f]+\\b\\)";
  r3900_cmds.supply_register = r3900_supply_register;
  /* S-record download, via "keyboard port".  */
  r3900_cmds.load = "r0\r";
  r3900_cmds.prompt = "#";
  r3900_cmds.line_term = "\r";
  r3900_cmds.target = &r3900_ops;
  r3900_cmds.stopbits = SERIAL_1_STOPBITS;
  r3900_cmds.regnames = r3900_regnames;
  r3900_cmds.magic = MONITOR_OPS_MAGIC;

  init_monitor_ops (&r3900_ops);

  r3900_ops.to_shortname = "r3900";
  r3900_ops.to_longname = "R3900 monitor";
  r3900_ops.to_doc = "Debug using the DVE R3900 monitor.\n\
Specify the serial device it is connected to (e.g. /dev/ttya).";
  r3900_ops.to_open = r3900_open;

  /* Override the functions to fetch and store registers.  But save the
     addresses of the default functions, because we will use those functions
     for "normal" registers.  */

  orig_monitor_fetch_registers = r3900_ops.to_fetch_registers;
  orig_monitor_store_registers = r3900_ops.to_store_registers;
  r3900_ops.to_fetch_registers = r3900_fetch_registers;
  r3900_ops.to_store_registers = r3900_store_registers;

  /* Override the load function, but save the address of the default
     function to use when loading S-records over a serial link.  */
  orig_monitor_load = r3900_ops.to_load;
  r3900_ops.to_load = r3900_load;

  add_target (&r3900_ops);
}