summaryrefslogtreecommitdiff
path: root/sim/ppc/emul_bugapi.c
blob: 97028bf9de91fffc2ec8d177001bc39390f010ac (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
/*  This file is part of the program psim.

    Copyright (C) 1994-1997, Andrew Cagney <cagney@highland.com.au>

    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.

    */


#ifndef _EMUL_BUGAPI_C_
#define _EMUL_BUGAPI_C_

/* Note: this module is called via a table.  There is no benefit in
   making it inline */

#include "emul_generic.h"
#include "emul_bugapi.h"

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#ifdef HAVE_STRING_H
#include <string.h>
#else
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#endif


/* EMULATION

   BUG - Motorola's embeded firmware BUG interface

   DESCRIPTION

   

   */


/* from PowerPCBug Debugging Package User's Manual, part 2 of 2 and also bug.S - Dale Rahn */
#define _INCHR		0x000		/* Input character */
#define _INSTAT		0x001		/* Input serial port status */
#define _INLN		0x002		/* Input line (pointer / pointer format) */
#define _READSTR	0x003		/* Input string (pointer / count format) */
#define _READLN		0x004		/* Input line (pointer / count format) */
#define _CHKBRK		0x005		/* Check for break */
#define _DSKRD		0x010		/* Disk read */
#define _DSKWR		0x011		/* Disk write */
#define _DSKCFIG	0x012		/* Disk configure */
#define _DSKFMT		0x014		/* Disk format */
#define _DSKCTRL	0x015		/* Disk control */
#define _NETRD		0x018		/* Read from host */
#define _NETWR		0x019		/* Write to host */
#define _NETCFIG	0x01a		/* Configure network parameters */
#define _NETOPN		0x01b		/* Open file for reading */
#define _NETFRD		0x01c		/* Retreive specified file blocks */
#define _NETCTRL	0x01d		/* Implement special control functions */
#define _OUTCHR		0x020		/* Output character (pointer / pointer format) */
#define _OUTSTR		0x021		/* Output string (pointer / pointer format) */
#define _OUTLN		0x022		/* Output line (pointer / pointer format) */
#define _WRITE		0x023		/* Output string (pointer / count format) */
#define _WRITELN	0x024		/* Output line (pointer / count format) */
#define _WRITDLN	0x025		/* Output line with data (pointer / count format) */
#define _PCRLF		0x026		/* Output carriage return and line feed */
#define _ERASLN		0x027		/* Erase line */
#define _WRITD		0x028		/* Output string with data (pointer / count format) */
#define _SNDBRK		0x029		/* Send break */
#define _DELAY		0x043		/* Timer delay */
#define _RTC_TM		0x050		/* Time initialization for RTC */
#define _RTC_DT		0x051		/* Date initialization for RTC */
#define _RTC_DSP	0x052		/* Display RTC time and date */
#define _RTC_RD		0x053		/* Read the RTC registers */
#define _REDIR		0x060		/* Redirect I/O of a system call function */
#define _REDIR_I	0x061		/* Redirect input */
#define _REDIR_O	0x062		/* Redirect output */
#define _RETURN		0x063		/* Return to PPCbug */
#define _BINDEC		0x064		/* Convert binary to binary coded decimal (BCD) */
#define _CHANGEV	0x067		/* Parse value */
#define _STRCMP		0x068		/* Compare two strings (pointer / count format) */
#define _MULU32		0x069		/* Multiply two 32-bit unsigned integers */
#define _DIVU32		0x06a		/* Divide two 32-bit unsigned integers */
#define _CHK_SUM	0x06b		/* Generate checksum */
#define _BRD_ID		0x070		/* Return pointer to board ID packet */
#define _ENVIRON	0x071		/* Access boot environment parameters */
#define _DIAGFCN	0x074		/* Diagnostic function(s) */
#define _SIOPEPS	0x090		/* Retrieve SCSI pointers */
#define _IOINQ		0x120		/* Port inquire */
#define _IOINFORM	0x124		/* Port inform */
#define _IOCONFIG	0x128		/* Port configure */
#define _IODELETE	0x12c		/* Port delete */
#define _SYMBOLTA	0x130		/* Attach symbol table */
#define _SYMBOLDA	0x131		/* Detach symbol table */

struct bug_map {
  int value;
  const char *info;
};

static const struct bug_map bug_mapping[] = {
  { _INCHR,	".INCHR -- Input character" },
  { _INSTAT,	".INSTAT -- Input serial port status" },
  { _INLN,	".INLN -- Input line (pointer / pointer format)" },
  { _READSTR,	".READSTR -- Input string (pointer / count format)" },
  { _READLN,	".READLN -- Input line (pointer / count format)" },
  { _CHKBRK,	".CHKBRK -- Check for break" },
  { _DSKRD,	".DSKRD -- Disk read" },
  { _DSKWR,	".DSKWR -- Disk write" },
  { _DSKCFIG,	".DSKCFIG -- Disk configure" },
  { _DSKFMT,	".DSKFMT -- Disk format" },
  { _DSKCTRL,	".DSKCTRL -- Disk control" },
  { _NETRD,	".NETRD -- Read from host" },
  { _NETWR,	".NETWR -- Write to host" },
  { _NETCFIG,	".NETCFIG -- Configure network parameters" },
  { _NETOPN,	".NETOPN -- Open file for reading" },
  { _NETFRD,	".NETFRD -- Retreive specified file blocks" },
  { _NETCTRL,	".NETCTRL -- Implement special control functions" },
  { _OUTCHR,	".OUTCHR -- Output character" },
  { _OUTSTR,	".OUTSTR -- Output string (pointer / pointer format)" },
  { _OUTLN,	".OUTLN -- Output line (pointer / pointer format)" },
  { _WRITE,	".WRITE -- Output string (pointer / count format)" },
  { _WRITELN,	".WRITELN -- Output line (pointer / count format)" },
  { _WRITDLN,	".WRITDLN -- Output line with data (pointer / count format)" },
  { _PCRLF,	".PCRLF -- Output carriage return and line feed" },
  { _ERASLN,	".ERASLN -- Erase line" },
  { _WRITD,	".WRITD -- Output string with data (pointer / count format)" },
  { _SNDBRK,	".SNDBRK -- Send break" },
  { _DELAY,	".DELAY -- Timer delay" },
  { _RTC_TM,	".RTC_TM -- Time initialization for RTC" },
  { _RTC_DT,	".RTC_DT -- Date initialization for RTC" },
  { _RTC_DSP,	".RTC_DSP -- Display RTC time and date" },
  { _RTC_RD,	".RTC_RD -- Read the RTC registers" },
  { _REDIR,	".REDIR -- Redirect I/O of a system call function" },
  { _REDIR,	".REDIR -- Redirect input" },
  { _REDIR,	".REDIR -- Redirect output" },
  { _RETURN,	".RETURN -- Return to PPCbug" },
  { _BINDEC,	".BINDEC -- Convert binary to binary coded decimal (BCD)" },
  { _CHANGEV,	".CHANGEV -- Parse value" },
  { _STRCMP,	".STRCMP -- Compare two strings (pointer / count format)" },
  { _MULU32,	".MULU32 -- Multiply two 32-bit unsigned integers" },
  { _DIVU32,	".DIVU32 -- Divide two 32-bit unsigned integers" },
  { _CHK_SUM,	".CHK_SUM -- Generate checksum" },
  { _BRD_ID,	".BRD_ID -- Return pointer to board ID packet" },
  { _ENVIRON,	".ENVIRON -- Access boot environment parameters" },
  { _DIAGFCN,	".DIAGFCN -- Diagnostic function(s)" },
  { _SIOPEPS,	".SIOPEPS -- Retrieve SCSI pointers" },
  { _IOINQ,	".IOINQ -- Port inquire" },
  { _IOINFORM,	".IOINFORM -- Port inform" },
  { _IOCONFIG,	".IOCONFIG -- Port configure" },
  { _IODELETE,	".IODELETE -- Port delete" },
  { _SYMBOLTA,	".SYMBOLTA -- Attach symbol table" },
  { _SYMBOLDA,	".SYMBOLDA -- Detach symbol table" },
};

#ifndef BUGAPI_END_ADDRESS
#define BUGAPI_END_ADDRESS 0x100000
#endif

enum {
  nr_bugapi_disks = 2,
};


struct _os_emul_data {
  device *root;
  unsigned_word memory_size;
  unsigned_word top_of_stack;
  int interrupt_prefix;
  unsigned_word interrupt_vector_address;
  unsigned_word system_call_address;
  unsigned_word stall_cpu_loop_address;
  int little_endian;
  int floating_point_available;
  /* I/O devices */
  device_instance *output;
  device_instance *input;
  device_instance *(disk[nr_bugapi_disks]);
};


static os_emul_data *
emul_bugapi_create(device *root,
		   bfd *image,
		   const char *name)
{
  device *node;
  os_emul_data *bugapi;

  /* check it really is for us */
  if (name != NULL
      && strcmp(name, "bugapi") != 0
      && strcmp(name, "bug") != 0)
    return NULL;
  if (image != NULL
      && name == NULL
      && bfd_get_start_address(image) >= BUGAPI_END_ADDRESS)
    return NULL;

  bugapi = ZALLOC(os_emul_data);

  /* options */
  emul_add_tree_options(root, image, "bug", "oea",
			1 /*oea-interrupt-prefix*/);

  /* add some real hardware, include eeprom memory for the eeprom trap
     addresses */
  emul_add_tree_hardware(root);
  node = tree_parse(root, "/openprom/memory@0xfff00000");
  tree_parse(node, "./psim,description \"eeprom trap addresses");
  tree_parse(node, "./reg 0xfff00000 0x3000");

  bugapi->root = root;

  bugapi->memory_size
    = tree_find_integer_property(root, "/openprom/options/oea-memory-size");
  bugapi->interrupt_prefix =
    tree_find_integer_property(root, "/openprom/options/oea-interrupt-prefix");
  bugapi->interrupt_vector_address = (bugapi->interrupt_prefix
				      ? MASK(0, 43)
				      : 0);
  bugapi->system_call_address = (bugapi->interrupt_vector_address + 0x00c00);
  bugapi->stall_cpu_loop_address = (bugapi->system_call_address + 0x000f0);
  bugapi->top_of_stack = bugapi->memory_size - 0x1000;
  bugapi->little_endian
    = tree_find_boolean_property(root, "/options/little-endian?");
  bugapi->floating_point_available
    = tree_find_boolean_property(root, "/openprom/options/floating-point?");
  bugapi->input = NULL;
  bugapi->output = NULL;

  /* initialization */
  if (image != NULL)
    tree_parse(root, "/openprom/init/register/0.pc 0x%lx",
	       (unsigned long)bfd_get_start_address(image));
  tree_parse(root, "/openprom/init/register/pc 0x%lx",
	     (unsigned long)bugapi->stall_cpu_loop_address);
  tree_parse(root, "/openprom/init/register/sp 0x%lx",
	     (unsigned long)(bugapi->top_of_stack - 16));
  tree_parse(root, "/openprom/init/register/msr 0x%x",
	     (msr_recoverable_interrupt
	      | (bugapi->little_endian
		 ? (msr_little_endian_mode
		    | msr_interrupt_little_endian_mode)
		 : 0)
	      | (bugapi->floating_point_available
		 ? msr_floating_point_available
		 : 0)
	      | (bugapi->interrupt_prefix
		 ? msr_interrupt_prefix
		 : 0)
	      ));

  /* patch the system call instruction to call this emulation and then
     do an rfi */
  node = tree_parse(root, "/openprom/init/data@0x%lx",
		    (unsigned long)bugapi->system_call_address);
  tree_parse(node, "./psim,description \"system-call trap instruction");
  tree_parse(node, "./real-address 0x%lx",
	     (unsigned long)bugapi->system_call_address);
  tree_parse(node, "./data 0x%x", emul_call_instruction);
  node = tree_parse(root, "/openprom/init/data@0x%lx",
		    (unsigned long)bugapi->system_call_address + 4);
  tree_parse(node, "./psim,description \"return from interrupt instruction");
  tree_parse(node, "./real-address 0x%lx",
	     (unsigned long)bugapi->system_call_address + 4);
  tree_parse(node, "./data 0x%x",
	     emul_rfi_instruction);

  /* patch the end of the system call instruction so that it contains
     a loop to self instruction and point all the cpu's at this */
  node = tree_parse(root, "/openprom/init/data@0x%lx",
		    (unsigned long)bugapi->stall_cpu_loop_address);
  tree_parse(node, "./psim,description \"cpu-loop instruction");
  tree_parse(node, "./real-address 0x%lx",
	     (unsigned long)bugapi->stall_cpu_loop_address);
  tree_parse(node, "./data 0x%lx",
	     (unsigned long)emul_loop_instruction);

  if (image != NULL)
    tree_parse(root, "/openprom/init/stack/stack-type %s",
	       (image->xvec->flavour == bfd_target_elf_flavour
		? "ppc-elf"
		: "ppc-xcoff"));

  if (image != NULL)
    tree_parse(root, "/openprom/init/load-binary/file-name \"%s",
	       bfd_get_filename(image));

  return bugapi;
}

static void
emul_bugapi_init(os_emul_data *bugapi,
		 int nr_cpus)
{
  int i;
  /* get the current input/output devices that were created during
     device tree initialization */
  bugapi->input = tree_find_ihandle_property(bugapi->root, "/chosen/stdin");
  bugapi->output = tree_find_ihandle_property(bugapi->root, "/chosen/stdout");
  /* if present, extract the selected disk devices */
  for (i = 0; i < nr_bugapi_disks; i++) {
    char disk[32];
    char *chp;
    strcpy(disk, "/chosen/disk0");
    ASSERT(sizeof(disk) > strlen(disk));
    chp = strchr(disk, '0');
    *chp = *chp + i;
    if (tree_find_property(bugapi->root, disk) != NULL)
      bugapi->disk[i] = tree_find_ihandle_property(bugapi->root, disk);
  }
}

static const char *
emul_bugapi_instruction_name(int call_id)
{
  static char buffer[40];
  int i;

  for (i = 0; i < sizeof (bug_mapping) / sizeof (bug_mapping[0]); i++)
    {
      if (bug_mapping[i].value == call_id)
	return bug_mapping[i].info;
    }

  (void) sprintf (buffer, "Unknown bug call 0x%x", call_id);
  return buffer;
}

static int
emul_bugapi_do_read(os_emul_data *bugapi,
		    cpu *processor,
		    unsigned_word cia,
		    unsigned_word buf,
		    int nbytes)
{
  unsigned char *scratch_buffer;
  int status;

  /* get a tempoary bufer */
  scratch_buffer = (unsigned char *) zalloc(nbytes);

  /* check if buffer exists by reading it */
  emul_read_buffer((void *)scratch_buffer, buf, nbytes, processor, cia);

  /* read */
  status = device_instance_read(bugapi->input,
				(void *)scratch_buffer, nbytes);

  /* -1 = error, -2 = nothing available - see "serial" [IEEE1275] */
  if (status < 0) {
    status = 0;
  }

  if (status > 0) {
    emul_write_buffer((void *)scratch_buffer, buf, status, processor, cia);

    /* Bugapi chops off the trailing n, but leaves it in the buffer */
    if (scratch_buffer[status-1] == '\n' || scratch_buffer[status-1] == '\r')
      status--;
  }

  zfree(scratch_buffer);
  return status;
}

static void
emul_bugapi_do_diskio(os_emul_data *bugapi,
		      cpu *processor,
		      unsigned_word cia,
		      unsigned_word descriptor_addr,
		      int call_id)
{
  struct dskio_descriptor {
    unsigned_1 ctrl_lun;
    unsigned_1 dev_lun;
    unsigned_2 status;
    unsigned_word pbuffer;
    unsigned_4 blk_num;
    unsigned_2 blk_cnt;
    unsigned_1 flag;
#define BUG_FILE_MARK	 0x80
#define IGNORE_FILENUM	 0x02
#define END_OF_FILE	 0x01
    unsigned_1 addr_mod;
  } descriptor;
  int block;
  emul_read_buffer(&descriptor, descriptor_addr, sizeof(descriptor),
		   processor, cia);
  T2H(descriptor.ctrl_lun);
  T2H(descriptor.dev_lun);
  T2H(descriptor.status);
  T2H(descriptor.pbuffer);
  T2H(descriptor.blk_num);
  T2H(descriptor.blk_cnt);
  T2H(descriptor.flag);
  T2H(descriptor.addr_mod);
  if (descriptor.dev_lun >= nr_bugapi_disks
      || bugapi->disk[descriptor.dev_lun] == NULL) {
    error("emul_bugapi_do_diskio: attempt to access unconfigured disk /chosen/disk%d",
	  descriptor.dev_lun);
  }
  else {
    for (block = 0; block < descriptor.blk_cnt; block++) {
      device_instance *disk = bugapi->disk[descriptor.dev_lun];
      unsigned_1 buf[512]; /*????*/
      unsigned_word block_nr = descriptor.blk_num + block;
      unsigned_word byte_nr = block_nr * sizeof(buf);
      unsigned_word block_addr = descriptor.pbuffer + block*sizeof(buf);
      if (device_instance_seek(disk, 0, byte_nr) < 0)
	error("emul_bugapi_do_diskio: bad seek\n");
      switch (call_id) {
      case _DSKRD:
	if (device_instance_read(disk, buf, sizeof(buf)) != sizeof(buf))
	  error("emul_`bugapi_do_diskio: bad read\n");
	emul_write_buffer(buf, block_addr, sizeof(buf), processor, cia);
	break;
      case _DSKWR:
	emul_read_buffer(buf, block_addr, sizeof(buf), processor, cia);
	if (device_instance_write(disk, buf, sizeof(buf)) != sizeof(buf))
	  error("emul_bugapi_do_diskio: bad write\n");
	break;
      default:
	error("emul_bugapi_do_diskio: bad switch\n");
      }
    }
  }
}

static void
emul_bugapi_do_write(os_emul_data *bugapi,
		     cpu *processor,
		     unsigned_word cia,
		     unsigned_word buf,
		     int nbytes,
		     const char *suffix)
{
  void *scratch_buffer = NULL;

  /* get a tempoary bufer */
  if (nbytes > 0)
    {
      scratch_buffer = zalloc(nbytes);

      /* copy in */
      emul_read_buffer(scratch_buffer, buf, nbytes,
		       processor, cia);

      /* write */
      device_instance_write(bugapi->output, scratch_buffer, nbytes);

      zfree(scratch_buffer);
    }

  if (suffix)
    device_instance_write(bugapi->output, suffix, strlen(suffix));

  flush_stdoutput ();
}

static int
emul_bugapi_instruction_call(cpu *processor,
			     unsigned_word cia,
			     unsigned_word ra,
			     os_emul_data *bugapi)
{
  const int call_id = cpu_registers(processor)->gpr[10];
  unsigned char uc;

#define MY_INDEX itable_instruction_call
  ITRACE (trace_os_emul,
	  (" 0x%x %s, r3 = 0x%lx, r4 = 0x%lx\n",
	   call_id, emul_bugapi_instruction_name (call_id),
	   (long)cpu_registers(processor)->gpr[3],
	   (long)cpu_registers(processor)->gpr[4]));;

  /* check that this isn't an invalid instruction */
  if (cia != bugapi->system_call_address)
    return 0;

  switch (call_id) {
  default:
    error("emul-bugapi: unimplemented bugapi %s from address 0x%lx\n",
	  emul_bugapi_instruction_name (call_id), SRR0);
    break;

  /* read a single character, output r3 = byte */
  /* FIXME: Add support to unbuffer input */
  case _INCHR:
    if (device_instance_read(bugapi->input, (void *)&uc, 1) <= 0)
      uc = 0;
    cpu_registers(processor)->gpr[3] = uc;
    break;

  /* read a line of at most 256 bytes, r3 = ptr to 1st byte, output r3 = ptr to last byte+1  */
  case _INLN:
    cpu_registers(processor)->gpr[3] += emul_bugapi_do_read(bugapi,
							    processor, cia,
							    cpu_registers(processor)->gpr[3],
							    256);
    break;

  /* output a character, r3 = character */
  case _OUTCHR:
    {
      char out = (char)cpu_registers(processor)->gpr[3];
      device_instance_write(bugapi->output, &out, 1);
      break;
    }

  /* output a string, r3 = ptr to 1st byte, r4 = ptr to last byte+1 */
  case _OUTSTR:
    emul_bugapi_do_write(bugapi,
			 processor, cia,
			 cpu_registers(processor)->gpr[3],
			 cpu_registers(processor)->gpr[4] - cpu_registers(processor)->gpr[3],
			 (const char *)0);
    break;

  /* output a string followed by \r\n, r3 = ptr to 1st byte, r4 = ptr to last byte+1 */
  case _OUTLN:

    emul_bugapi_do_write(bugapi,
			 processor, cia,
			 cpu_registers(processor)->gpr[3],
			 cpu_registers(processor)->gpr[4] - cpu_registers(processor)->gpr[3],
			 "\n");
    break;

  /* output a \r\n */
  case _PCRLF:
    device_instance_write(bugapi->output, "\n", 1);
    break;

  /* read/write blocks of data to/from the disk */
  case _DSKWR:
  case _DSKRD:
    emul_bugapi_do_diskio(bugapi, processor, cia,
			  cpu_registers(processor)->gpr[3],
			  call_id);
    break;

  /* return to ppcbug monitor (exiting with gpr[3] as status is not
     part of the bug monitor) */
  case _RETURN:
    cpu_halt(processor, cia, was_exited, cpu_registers(processor)->gpr[3]);
    break;
  }
  return 1;
  /* the instruction following this one is a RFI.  Thus by just
     continuing the return from system call is performed */
}

const os_emul emul_bugapi = {
  "bugapi",
  emul_bugapi_create,
  emul_bugapi_init,
  0, /*system_call*/
  emul_bugapi_instruction_call,
  0 /*data*/
};

#endif