dtutils.c revision 1.20 1 /******************************************************************************
2 *
3 * Module Name: dtutils.c - Utility routines for the data table compiler
4 *
5 *****************************************************************************/
6
7 /*
8 * Copyright (C) 2000 - 2022, Intel Corp.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions, and the following disclaimer,
16 * without modification.
17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18 * substantially similar to the "NO WARRANTY" disclaimer below
19 * ("Disclaimer") and any redistribution must be conditioned upon
20 * including a substantially similar Disclaimer requirement for further
21 * binary redistribution.
22 * 3. Neither the names of the above-listed copyright holders nor the names
23 * of any contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * Alternatively, this software may be distributed under the terms of the
27 * GNU General Public License ("GPL") version 2 as published by the Free
28 * Software Foundation.
29 *
30 * NO WARRANTY
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41 * POSSIBILITY OF SUCH DAMAGES.
42 */
43
44 #include "aslcompiler.h"
45 #include "actables.h"
46
47 #define _COMPONENT DT_COMPILER
48 ACPI_MODULE_NAME ("dtutils")
49
50 /* Local prototypes */
51
52 static void
53 DtSum (
54 DT_SUBTABLE *Subtable,
55 void *Context,
56 void *ReturnValue);
57
58
59 /******************************************************************************
60 *
61 * FUNCTION: DtError
62 *
63 * PARAMETERS: Level - Seriousness (Warning/error, etc.)
64 * MessageId - Index into global message buffer
65 * Op - Parse node where error happened
66 * ExtraMessage - additional error message
67 *
68 * RETURN: None
69 *
70 * DESCRIPTION: Common error interface for data table compiler
71 *
72 *****************************************************************************/
73
74 void
75 DtError (
76 UINT8 Level,
77 UINT16 MessageId,
78 DT_FIELD *FieldObject,
79 char *ExtraMessage)
80 {
81 UINT32 Line = 0;
82
83
84 /* Field object could be NULL */
85
86 if (FieldObject)
87 {
88 Line = FieldObject->Line;
89 }
90
91 /* Check if user wants to ignore this exception */
92
93 if (AslIsExceptionIgnored (AslGbl_Files[ASL_FILE_INPUT].Filename,
94 Line, Level, MessageId))
95 {
96 return;
97 }
98
99 if (FieldObject)
100 {
101 AslCommonError (Level, MessageId,
102 FieldObject->Line,
103 FieldObject->Line,
104 FieldObject->ByteOffset,
105 FieldObject->Column,
106 AslGbl_Files[ASL_FILE_INPUT].Filename, ExtraMessage);
107 }
108 else
109 {
110 AslCommonError (Level, MessageId, 0,
111 0, 0, 0, 0, ExtraMessage);
112 }
113 }
114
115
116 /******************************************************************************
117 *
118 * FUNCTION: DtNameError
119 *
120 * PARAMETERS: Level - Seriousness (Warning/error, etc.)
121 * MessageId - Index into global message buffer
122 * Op - Parse node where error happened
123 * ExtraMessage - additional error message
124 *
125 * RETURN: None
126 *
127 * DESCRIPTION: Error interface for named objects
128 *
129 *****************************************************************************/
130
131 void
132 DtNameError (
133 UINT8 Level,
134 UINT16 MessageId,
135 DT_FIELD *FieldObject,
136 char *ExtraMessage)
137 {
138
139 switch (Level)
140 {
141 case ASL_WARNING2:
142 case ASL_WARNING3:
143
144 if (AslGbl_WarningLevel < Level)
145 {
146 return;
147 }
148 break;
149
150 default:
151
152 break;
153 }
154
155 if (FieldObject)
156 {
157 AslCommonError (Level, MessageId,
158 FieldObject->Line,
159 FieldObject->Line,
160 FieldObject->ByteOffset,
161 FieldObject->NameColumn,
162 AslGbl_Files[ASL_FILE_INPUT].Filename, ExtraMessage);
163 }
164 else
165 {
166 AslCommonError (Level, MessageId, 0,
167 0, 0, 0, 0, ExtraMessage);
168 }
169 }
170
171
172 /*******************************************************************************
173 *
174 * FUNCTION: DtFatal
175 *
176 * PARAMETERS: None
177 *
178 * RETURN: None
179 *
180 * DESCRIPTION: Dump the error log and abort the compiler. Used for serious
181 * compile or I/O errors
182 *
183 ******************************************************************************/
184
185 void
186 DtFatal (
187 UINT16 MessageId,
188 DT_FIELD *FieldObject,
189 char *ExtraMessage)
190 {
191
192 DtError (ASL_ERROR, MessageId, FieldObject, ExtraMessage);
193
194 /*
195 * TBD: remove this entire function, DtFatal
196 *
197 * We cannot abort the compiler on error, because we may be compiling a
198 * list of files. We must move on to the next file.
199 */
200 #ifdef __OBSOLETE
201 CmCleanupAndExit ();
202 exit (1);
203 #endif
204 }
205
206
207 /*******************************************************************************
208 *
209 * FUNCTION: DtDoConstant
210 *
211 * PARAMETERS: String - Only hex constants are supported,
212 * regardless of whether the 0x prefix
213 * is used
214 *
215 * RETURN: Converted Integer
216 *
217 * DESCRIPTION: Convert a string to an integer, with overflow/error checking.
218 *
219 ******************************************************************************/
220
221 UINT64
222 DtDoConstant (
223 char *String)
224 {
225 UINT64 ConvertedInteger;
226
227
228 /*
229 * TBD: The ImplicitStrtoul64 function does not report overflow
230 * conditions. The input string is simply truncated. If it is
231 * desired to report overflow to the table compiler, this should
232 * somehow be added here. Note: integers that are prefixed with 0x
233 * or not are both hex integers.
234 */
235 ConvertedInteger = AcpiUtImplicitStrtoul64 (String);
236 return (ConvertedInteger);
237 }
238
239 /******************************************************************************
240 *
241 * FUNCTION: DtGetFieldValue
242 *
243 * PARAMETERS: Field - Current field list pointer
244 *
245 * RETURN: Field value
246 *
247 * DESCRIPTION: Get field value
248 *
249 *****************************************************************************/
250
251 char *
252 DtGetFieldValue (
253 DT_FIELD *Field)
254 {
255 if (!Field)
256 {
257 return (NULL);
258 }
259
260 return (Field->Value);
261 }
262
263
264 /******************************************************************************
265 *
266 * FUNCTION: DtGetFieldType
267 *
268 * PARAMETERS: Info - Data table info
269 *
270 * RETURN: Field type
271 *
272 * DESCRIPTION: Get field type
273 *
274 *****************************************************************************/
275
276 UINT8
277 DtGetFieldType (
278 ACPI_DMTABLE_INFO *Info)
279 {
280 UINT8 Type;
281
282
283 /* DT_FLAG means that this is the start of a block of flag bits */
284 /* TBD - we can make these a separate opcode later */
285
286 if (Info->Flags & DT_FLAG)
287 {
288 return (DT_FIELD_TYPE_FLAGS_INTEGER);
289 }
290
291 /* Type is based upon the opcode for this field in the info table */
292
293 switch (Info->Opcode)
294 {
295 case ACPI_DMT_FLAG0:
296 case ACPI_DMT_FLAG1:
297 case ACPI_DMT_FLAG2:
298 case ACPI_DMT_FLAG3:
299 case ACPI_DMT_FLAG4:
300 case ACPI_DMT_FLAG5:
301 case ACPI_DMT_FLAG6:
302 case ACPI_DMT_FLAG7:
303 case ACPI_DMT_FLAGS0:
304 case ACPI_DMT_FLAGS1:
305 case ACPI_DMT_FLAGS2:
306 case ACPI_DMT_FLAGS8_2:
307 case ACPI_DMT_FLAGS4:
308 case ACPI_DMT_FLAGS4_0:
309 case ACPI_DMT_FLAGS4_4:
310 case ACPI_DMT_FLAGS4_8:
311 case ACPI_DMT_FLAGS4_12:
312 case ACPI_DMT_FLAGS16_16:
313
314 Type = DT_FIELD_TYPE_FLAG;
315 break;
316
317 case ACPI_DMT_NAME4:
318 case ACPI_DMT_SIG:
319 case ACPI_DMT_NAME6:
320 case ACPI_DMT_NAME8:
321 case ACPI_DMT_STRING:
322 case ACPI_DMT_IVRS_UNTERMINATED_STRING:
323
324 Type = DT_FIELD_TYPE_STRING;
325 break;
326
327 case ACPI_DMT_BUFFER:
328 case ACPI_DMT_RAW_BUFFER:
329 case ACPI_DMT_BUF7:
330 case ACPI_DMT_BUF10:
331 case ACPI_DMT_BUF12:
332 case ACPI_DMT_BUF16:
333 case ACPI_DMT_BUF18:
334 case ACPI_DMT_BUF128:
335 case ACPI_DMT_PCI_PATH:
336 case ACPI_DMT_PMTT_VENDOR:
337
338 Type = DT_FIELD_TYPE_BUFFER;
339 break;
340
341 case ACPI_DMT_GAS:
342 case ACPI_DMT_HESTNTFY:
343 case ACPI_DMT_IORTMEM:
344
345 Type = DT_FIELD_TYPE_INLINE_SUBTABLE;
346 break;
347
348 case ACPI_DMT_UNICODE:
349 case ACPI_DMT_WPBT_UNICODE:
350
351 Type = DT_FIELD_TYPE_UNICODE;
352 break;
353
354 case ACPI_DMT_UUID:
355
356 Type = DT_FIELD_TYPE_UUID;
357 break;
358
359 case ACPI_DMT_DEVICE_PATH:
360
361 Type = DT_FIELD_TYPE_DEVICE_PATH;
362 break;
363
364 case ACPI_DMT_LABEL:
365
366 Type = DT_FIELD_TYPE_LABEL;
367 break;
368
369 default:
370
371 Type = DT_FIELD_TYPE_INTEGER;
372 break;
373 }
374
375 return (Type);
376 }
377
378
379 /******************************************************************************
380 *
381 * FUNCTION: DtGetBufferLength
382 *
383 * PARAMETERS: Buffer - List of integers,
384 * for example "10 3A 4F 2E"
385 *
386 * RETURN: Count of integer
387 *
388 * DESCRIPTION: Get length of bytes needed to store the integers
389 *
390 *****************************************************************************/
391
392 UINT32
393 DtGetBufferLength (
394 char *Buffer)
395 {
396 UINT32 ByteLength = 0;
397
398
399 while (*Buffer)
400 {
401 if (*Buffer == ' ')
402 {
403 ByteLength++;
404
405 while (*Buffer == ' ')
406 {
407 Buffer++;
408 }
409 }
410
411 Buffer++;
412 }
413
414 return (++ByteLength);
415 }
416
417
418 /******************************************************************************
419 *
420 * FUNCTION: DtGetFieldLength
421 *
422 * PARAMETERS: Field - Current field
423 * Info - Data table info
424 *
425 * RETURN: Field length
426 *
427 * DESCRIPTION: Get length of bytes needed to compile the field
428 *
429 * Note: This function must remain in sync with AcpiDmDumpTable.
430 *
431 *****************************************************************************/
432
433 UINT32
434 DtGetFieldLength (
435 DT_FIELD *Field,
436 ACPI_DMTABLE_INFO *Info)
437 {
438 UINT32 ByteLength = 0;
439 char *Value;
440
441
442 /* Length is based upon the opcode for this field in the info table */
443
444 switch (Info->Opcode)
445 {
446 case ACPI_DMT_FLAG0:
447 case ACPI_DMT_FLAG1:
448 case ACPI_DMT_FLAG2:
449 case ACPI_DMT_FLAG3:
450 case ACPI_DMT_FLAG4:
451 case ACPI_DMT_FLAG5:
452 case ACPI_DMT_FLAG6:
453 case ACPI_DMT_FLAG7:
454 case ACPI_DMT_FLAGS0:
455 case ACPI_DMT_FLAGS1:
456 case ACPI_DMT_FLAGS2:
457 case ACPI_DMT_FLAGS8_2:
458 case ACPI_DMT_FLAGS4:
459 case ACPI_DMT_FLAGS4_0:
460 case ACPI_DMT_FLAGS4_4:
461 case ACPI_DMT_FLAGS4_8:
462 case ACPI_DMT_FLAGS4_12:
463 case ACPI_DMT_FLAGS16_16:
464 case ACPI_DMT_LABEL:
465 case ACPI_DMT_EXTRA_TEXT:
466
467 ByteLength = 0;
468 break;
469
470 case ACPI_DMT_UINT8:
471 case ACPI_DMT_CHKSUM:
472 case ACPI_DMT_SPACEID:
473 case ACPI_DMT_ACCWIDTH:
474 case ACPI_DMT_CEDT:
475 case ACPI_DMT_IVRS:
476 case ACPI_DMT_IVRS_DE:
477 case ACPI_DMT_GTDT:
478 case ACPI_DMT_MADT:
479 case ACPI_DMT_NHLT1:
480 case ACPI_DMT_NHLT1a:
481 case ACPI_DMT_NHLT1b:
482 case ACPI_DMT_NHLT1c:
483 case ACPI_DMT_NHLT1d:
484 case ACPI_DMT_NHLT1f:
485 case ACPI_DMT_PCCT:
486 case ACPI_DMT_PMTT:
487 case ACPI_DMT_PPTT:
488 case ACPI_DMT_RGRT:
489 case ACPI_DMT_SDEV:
490 case ACPI_DMT_SRAT:
491 case ACPI_DMT_AEST:
492 case ACPI_DMT_AEST_RES:
493 case ACPI_DMT_AEST_XFACE:
494 case ACPI_DMT_AEST_XRUPT:
495 case ACPI_DMT_ASF:
496 case ACPI_DMT_HESTNTYP:
497 case ACPI_DMT_FADTPM:
498 case ACPI_DMT_EINJACT:
499 case ACPI_DMT_EINJINST:
500 case ACPI_DMT_ERSTACT:
501 case ACPI_DMT_ERSTINST:
502 case ACPI_DMT_DMAR_SCOPE:
503 case ACPI_DMT_VIOT:
504
505 ByteLength = 1;
506 break;
507
508 case ACPI_DMT_UINT16:
509 case ACPI_DMT_DMAR:
510 case ACPI_DMT_HEST:
511 case ACPI_DMT_HMAT:
512 case ACPI_DMT_NFIT:
513 case ACPI_DMT_NHLT1e:
514 case ACPI_DMT_PCI_PATH:
515 case ACPI_DMT_PHAT:
516
517 ByteLength = 2;
518 break;
519
520 case ACPI_DMT_UINT24:
521
522 ByteLength = 3;
523 break;
524
525 case ACPI_DMT_UINT32:
526 case ACPI_DMT_AEST_CACHE:
527 case ACPI_DMT_AEST_GIC:
528 case ACPI_DMT_NAME4:
529 case ACPI_DMT_SIG:
530 case ACPI_DMT_LPIT:
531 case ACPI_DMT_TPM2:
532
533 ByteLength = 4;
534 break;
535
536 case ACPI_DMT_UINT40:
537
538 ByteLength = 5;
539 break;
540
541 case ACPI_DMT_UINT48:
542 case ACPI_DMT_NAME6:
543
544 ByteLength = 6;
545 break;
546
547 case ACPI_DMT_UINT56:
548 case ACPI_DMT_BUF7:
549
550 ByteLength = 7;
551 break;
552
553 case ACPI_DMT_UINT64:
554 case ACPI_DMT_NAME8:
555
556 ByteLength = 8;
557 break;
558
559 case ACPI_DMT_STRING:
560
561 Value = DtGetFieldValue (Field);
562 if (Value)
563 {
564 ByteLength = strlen (Value) + 1;
565 }
566 else
567 { /* At this point, this is a fatal error */
568
569 snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer), "Expected \"%s\"", Info->Name);
570 DtFatal (ASL_MSG_COMPILER_INTERNAL, NULL, AslGbl_MsgBuffer);
571 return (0);
572 }
573 break;
574
575 case ACPI_DMT_IVRS_UNTERMINATED_STRING:
576
577 Value = DtGetFieldValue (Field);
578 if (Value)
579 {
580 ByteLength = strlen (Value);
581 }
582 else
583 { /* At this point, this is a fatal error */
584
585 snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer), "Expected \"%s\"", Info->Name);
586 DtFatal (ASL_MSG_COMPILER_INTERNAL, NULL, AslGbl_MsgBuffer);
587 return (0);
588 }
589 break;
590
591 case ACPI_DMT_GAS:
592
593 ByteLength = sizeof (ACPI_GENERIC_ADDRESS);
594 break;
595
596 case ACPI_DMT_HESTNTFY:
597
598 ByteLength = sizeof (ACPI_HEST_NOTIFY);
599 break;
600
601 case ACPI_DMT_IORTMEM:
602
603 ByteLength = sizeof (ACPI_IORT_MEMORY_ACCESS);
604 break;
605
606 case ACPI_DMT_BUFFER:
607 case ACPI_DMT_RAW_BUFFER:
608 case ACPI_DMT_PMTT_VENDOR:
609
610 Value = DtGetFieldValue (Field);
611 if (Value)
612 {
613 ByteLength = DtGetBufferLength (Value);
614 }
615 else
616 { /* At this point, this is a fatal error */
617
618 snprintf (AslGbl_MsgBuffer, sizeof(AslGbl_MsgBuffer), "Expected \"%s\"", Info->Name);
619 DtFatal (ASL_MSG_COMPILER_INTERNAL, NULL, AslGbl_MsgBuffer);
620 return (0);
621 }
622 break;
623
624 case ACPI_DMT_BUF10:
625
626 ByteLength = 10;
627 break;
628
629 case ACPI_DMT_BUF12:
630
631 ByteLength = 12;
632 break;
633
634 case ACPI_DMT_BUF16:
635 case ACPI_DMT_UUID:
636
637 ByteLength = 16;
638 break;
639
640 case ACPI_DMT_BUF18:
641
642 ByteLength = 18;
643 break;
644
645 case ACPI_DMT_BUF128:
646
647 ByteLength = 128;
648 break;
649
650 case ACPI_DMT_UNICODE:
651 case ACPI_DMT_WPBT_UNICODE:
652
653 Value = DtGetFieldValue (Field);
654
655 /* TBD: error if Value is NULL? (as below?) */
656
657 ByteLength = (strlen (Value) + 1) * sizeof (UINT16);
658 break;
659
660 default:
661
662 DtFatal (ASL_MSG_COMPILER_INTERNAL, Field, "Invalid table opcode");
663 return (0);
664 }
665
666 return (ByteLength);
667 }
668
669
670 /******************************************************************************
671 *
672 * FUNCTION: DtSum
673 *
674 * PARAMETERS: DT_WALK_CALLBACK:
675 * Subtable - Subtable
676 * Context - Unused
677 * ReturnValue - Store the checksum of subtable
678 *
679 * RETURN: Status
680 *
681 * DESCRIPTION: Get the checksum of subtable
682 *
683 *****************************************************************************/
684
685 static void
686 DtSum (
687 DT_SUBTABLE *Subtable,
688 void *Context,
689 void *ReturnValue)
690 {
691 UINT8 Checksum;
692 UINT8 *Sum = ReturnValue;
693
694
695 Checksum = AcpiTbChecksum (Subtable->Buffer, Subtable->Length);
696 *Sum = (UINT8) (*Sum + Checksum);
697 }
698
699
700 /******************************************************************************
701 *
702 * FUNCTION: DtSetTableChecksum
703 *
704 * PARAMETERS: ChecksumPointer - Where to return the checksum
705 *
706 * RETURN: None
707 *
708 * DESCRIPTION: Set checksum of the whole data table into the checksum field
709 *
710 *****************************************************************************/
711
712 void
713 DtSetTableChecksum (
714 UINT8 *ChecksumPointer)
715 {
716 UINT8 Checksum = 0;
717 UINT8 OldSum;
718
719
720 DtWalkTableTree (AslGbl_RootTable, DtSum, NULL, &Checksum);
721
722 OldSum = *ChecksumPointer;
723 Checksum = (UINT8) (Checksum - OldSum);
724
725 /* Compute the final checksum */
726
727 Checksum = (UINT8) (0 - Checksum);
728 *ChecksumPointer = Checksum;
729 }
730
731
732 /******************************************************************************
733 *
734 * FUNCTION: DtSetTableLength
735 *
736 * PARAMETERS: None
737 *
738 * RETURN: None
739 *
740 * DESCRIPTION: Walk the subtables and set all the length fields
741 *
742 *****************************************************************************/
743
744 void
745 DtSetTableLength (
746 void)
747 {
748 DT_SUBTABLE *ParentTable;
749 DT_SUBTABLE *ChildTable;
750
751
752 ParentTable = AslGbl_RootTable;
753 ChildTable = NULL;
754
755 if (!ParentTable)
756 {
757 return;
758 }
759
760 DtSetSubtableLength (ParentTable);
761
762 while (1)
763 {
764 ChildTable = DtGetNextSubtable (ParentTable, ChildTable);
765 if (ChildTable)
766 {
767 if (ChildTable->LengthField)
768 {
769 DtSetSubtableLength (ChildTable);
770 }
771
772 if (ChildTable->Child)
773 {
774 ParentTable = ChildTable;
775 ChildTable = NULL;
776 }
777 else
778 {
779 ParentTable->TotalLength += ChildTable->TotalLength;
780 if (ParentTable->LengthField)
781 {
782 DtSetSubtableLength (ParentTable);
783 }
784 }
785 }
786 else
787 {
788 ChildTable = ParentTable;
789
790 if (ChildTable == AslGbl_RootTable)
791 {
792 break;
793 }
794
795 ParentTable = DtGetParentSubtable (ParentTable);
796
797 ParentTable->TotalLength += ChildTable->TotalLength;
798 if (ParentTable->LengthField)
799 {
800 DtSetSubtableLength (ParentTable);
801 }
802 }
803 }
804 }
805
806
807 /******************************************************************************
808 *
809 * FUNCTION: DtWalkTableTree
810 *
811 * PARAMETERS: StartTable - Subtable in the tree where walking begins
812 * UserFunction - Called during the walk
813 * Context - Passed to user function
814 * ReturnValue - The return value of UserFunction
815 *
816 * RETURN: None
817 *
818 * DESCRIPTION: Performs a depth-first walk of the subtable tree
819 *
820 *****************************************************************************/
821
822 void
823 DtWalkTableTree (
824 DT_SUBTABLE *StartTable,
825 DT_WALK_CALLBACK UserFunction,
826 void *Context,
827 void *ReturnValue)
828 {
829 DT_SUBTABLE *ParentTable;
830 DT_SUBTABLE *ChildTable;
831
832
833 ParentTable = StartTable;
834 ChildTable = NULL;
835
836 if (!ParentTable)
837 {
838 return;
839 }
840
841 UserFunction (ParentTable, Context, ReturnValue);
842
843 while (1)
844 {
845 ChildTable = DtGetNextSubtable (ParentTable, ChildTable);
846 if (ChildTable)
847 {
848 UserFunction (ChildTable, Context, ReturnValue);
849
850 if (ChildTable->Child)
851 {
852 ParentTable = ChildTable;
853 ChildTable = NULL;
854 }
855 }
856 else
857 {
858 ChildTable = ParentTable;
859 if (ChildTable == AslGbl_RootTable)
860 {
861 break;
862 }
863
864 ParentTable = DtGetParentSubtable (ParentTable);
865
866 if (ChildTable->Peer == StartTable)
867 {
868 break;
869 }
870 }
871 }
872 }
873