aboutsummaryrefslogtreecommitdiff
path: root/sys/contrib/dev/acpica/exconvrt.c
blob: fd3854a556c342d1ed7987ab369a7ca5749f99e1 (plain) (blame)
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
/******************************************************************************
 *
 * Module Name: exconvrt - Object conversion routines
 *              $Revision: 59 $
 *
 *****************************************************************************/

/******************************************************************************
 *
 * 1. Copyright Notice
 *
 * Some or all of this work - Copyright (c) 1999 - 2004, Intel Corp.
 * All rights reserved.
 *
 * 2. License
 *
 * 2.1. This is your license from Intel Corp. under its intellectual property
 * rights.  You may have additional license terms from the party that provided
 * you this software, covering your right to use that party's intellectual
 * property rights.
 *
 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
 * copy of the source code appearing in this file ("Covered Code") an
 * irrevocable, perpetual, worldwide license under Intel's copyrights in the
 * base code distributed originally by Intel ("Original Intel Code") to copy,
 * make derivatives, distribute, use and display any portion of the Covered
 * Code in any form, with the right to sublicense such rights; and
 *
 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
 * license (with the right to sublicense), under only those claims of Intel
 * patents that are infringed by the Original Intel Code, to make, use, sell,
 * offer to sell, and import the Covered Code and derivative works thereof
 * solely to the minimum extent necessary to exercise the above copyright
 * license, and in no event shall the patent license extend to any additions
 * to or modifications of the Original Intel Code.  No other license or right
 * is granted directly or by implication, estoppel or otherwise;
 *
 * The above copyright and patent license is granted only if the following
 * conditions are met:
 *
 * 3. Conditions
 *
 * 3.1. Redistribution of Source with Rights to Further Distribute Source.
 * Redistribution of source code of any substantial portion of the Covered
 * Code or modification with rights to further distribute source must include
 * the above Copyright Notice, the above License, this list of Conditions,
 * and the following Disclaimer and Export Compliance provision.  In addition,
 * Licensee must cause all Covered Code to which Licensee contributes to
 * contain a file documenting the changes Licensee made to create that Covered
 * Code and the date of any change.  Licensee must include in that file the
 * documentation of any changes made by any predecessor Licensee.  Licensee
 * must include a prominent statement that the modification is derived,
 * directly or indirectly, from Original Intel Code.
 *
 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
 * Redistribution of source code of any substantial portion of the Covered
 * Code or modification without rights to further distribute source must
 * include the following Disclaimer and Export Compliance provision in the
 * documentation and/or other materials provided with distribution.  In
 * addition, Licensee may not authorize further sublicense of source of any
 * portion of the Covered Code, and must include terms to the effect that the
 * license from Licensee to its licensee is limited to the intellectual
 * property embodied in the software Licensee provides to its licensee, and
 * not to intellectual property embodied in modifications its licensee may
 * make.
 *
 * 3.3. Redistribution of Executable. Redistribution in executable form of any
 * substantial portion of the Covered Code or modification must reproduce the
 * above Copyright Notice, and the following Disclaimer and Export Compliance
 * provision in the documentation and/or other materials provided with the
 * distribution.
 *
 * 3.4. Intel retains all right, title, and interest in and to the Original
 * Intel Code.
 *
 * 3.5. Neither the name Intel nor any other trademark owned or controlled by
 * Intel shall be used in advertising or otherwise to promote the sale, use or
 * other dealings in products derived from or relating to the Covered Code
 * without prior written authorization from Intel.
 *
 * 4. Disclaimer and Export Compliance
 *
 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
 * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
 * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
 * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
 * PARTICULAR PURPOSE.
 *
 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
 * LIMITED REMEDY.
 *
 * 4.3. Licensee shall not export, either directly or indirectly, any of this
 * software or system incorporating such software without first obtaining any
 * required license or other approval from the U. S. Department of Commerce or
 * any other agency or department of the United States Government.  In the
 * event Licensee exports any such software from the United States or
 * re-exports any such software from a foreign destination, Licensee shall
 * ensure that the distribution and export/re-export of the software is in
 * compliance with all laws, regulations, orders, or other restrictions of the
 * U.S. Export Administration Regulations. Licensee agrees that neither it nor
 * any of its subsidiaries will export/re-export any technical data, process,
 * software, or service, directly or indirectly, to any country for which the
 * United States government or any agency thereof requires an export license,
 * other governmental approval, or letter of assurance, without first obtaining
 * such license, approval or letter.
 *
 *****************************************************************************/


#define __EXCONVRT_C__

#include "acpi.h"
#include "acinterp.h"
#include "amlcode.h"


#define _COMPONENT          ACPI_EXECUTER
        ACPI_MODULE_NAME    ("exconvrt")


/*******************************************************************************
 *
 * FUNCTION:    AcpiExConvertToInteger
 *
 * PARAMETERS:  ObjDesc         - Object to be converted.  Must be an
 *                                Integer, Buffer, or String
 *              ResultDesc      - Where the new Integer object is returned
 *              Flags           - Used for string conversion
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Convert an ACPI Object to an integer.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiExConvertToInteger (
    ACPI_OPERAND_OBJECT     *ObjDesc,
    ACPI_OPERAND_OBJECT     **ResultDesc,
    UINT32                  Flags)
{
    ACPI_OPERAND_OBJECT     *ReturnDesc;
    UINT8                   *Pointer;
    ACPI_INTEGER            Result;
    UINT32                  i;
    UINT32                  Count;
    ACPI_STATUS             Status;


    ACPI_FUNCTION_TRACE_PTR ("ExConvertToInteger", ObjDesc);


    switch (ACPI_GET_OBJECT_TYPE (ObjDesc))
    {
    case ACPI_TYPE_INTEGER:

        /* No conversion necessary */

        *ResultDesc = ObjDesc;
        return_ACPI_STATUS (AE_OK);

    case ACPI_TYPE_BUFFER:
    case ACPI_TYPE_STRING:

        /* Note: Takes advantage of common buffer/string fields */

        Pointer = ObjDesc->Buffer.Pointer;
        Count   = ObjDesc->Buffer.Length;
        break;

    default:
        return_ACPI_STATUS (AE_TYPE);
    }

    /*
     * Convert the buffer/string to an integer.  Note that both buffers and
     * strings are treated as raw data - we don't convert ascii to hex for
     * strings.
     *
     * There are two terminating conditions for the loop:
     * 1) The size of an integer has been reached, or
     * 2) The end of the buffer or string has been reached
     */
    Result = 0;

    /*
     * String conversion is different than Buffer conversion
     */
    switch (ACPI_GET_OBJECT_TYPE (ObjDesc))
    {
    case ACPI_TYPE_STRING:

        /*
         * Convert string to an integer - for most cases, the string must be
         * hexadecimal as per the ACPI specification.  The only exception (as
         * of ACPI 3.0) is that the ToInteger() operator allows both decimal
         * and hexadecimal strings (hex prefixed with "0x").
         */
        Status = AcpiUtStrtoul64 ((char *) Pointer, Flags, &Result);
        if (ACPI_FAILURE (Status))
        {
            return_ACPI_STATUS (Status);
        }
        break;


    case ACPI_TYPE_BUFFER:

        /* Transfer no more than an integer's worth of data */

        if (Count > AcpiGbl_IntegerByteWidth)
        {
            Count = AcpiGbl_IntegerByteWidth;
        }

        /*
         * Convert buffer to an integer - we simply grab enough raw data
         * from the buffer to fill an integer
         */
        for (i = 0; i < Count; i++)
        {
            /*
             * Get next byte and shift it into the Result.
             * Little endian is used, meaning that the first byte of the buffer
             * is the LSB of the integer
             */
            Result |= (((ACPI_INTEGER) Pointer[i]) << (i * 8));
        }
        break;


    default:
        /* No other types can get here */
        break;
    }

    /*
     * Create a new integer
     */
    ReturnDesc = AcpiUtCreateInternalObject (ACPI_TYPE_INTEGER);
    if (!ReturnDesc)
    {
        return_ACPI_STATUS (AE_NO_MEMORY);
    }

    /* Save the Result */

    ReturnDesc->Integer.Value = Result;
    AcpiExTruncateFor32bitTable (ReturnDesc);
    *ResultDesc = ReturnDesc;
    return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiExConvertToBuffer
 *
 * PARAMETERS:  ObjDesc         - Object to be converted.  Must be an
 *                                Integer, Buffer, or String
 *              ResultDesc      - Where the new buffer object is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Convert an ACPI Object to a Buffer
 *
 ******************************************************************************/

ACPI_STATUS
AcpiExConvertToBuffer (
    ACPI_OPERAND_OBJECT     *ObjDesc,
    ACPI_OPERAND_OBJECT     **ResultDesc)
{
    ACPI_OPERAND_OBJECT     *ReturnDesc;
    UINT8                   *NewBuf;


    ACPI_FUNCTION_TRACE_PTR ("ExConvertToBuffer", ObjDesc);


    switch (ACPI_GET_OBJECT_TYPE (ObjDesc))
    {
    case ACPI_TYPE_BUFFER:

        /* No conversion necessary */

        *ResultDesc = ObjDesc;
        return_ACPI_STATUS (AE_OK);


    case ACPI_TYPE_INTEGER:

        /*
         * Create a new Buffer object.
         * Need enough space for one integer
         */
        ReturnDesc = AcpiUtCreateBufferObject (AcpiGbl_IntegerByteWidth);
        if (!ReturnDesc)
        {
            return_ACPI_STATUS (AE_NO_MEMORY);
        }

        /* Copy the integer to the buffer, LSB first */

        NewBuf = ReturnDesc->Buffer.Pointer;
        ACPI_MEMCPY (NewBuf,
                        &ObjDesc->Integer.Value,
                        AcpiGbl_IntegerByteWidth);
        break;


    case ACPI_TYPE_STRING:

        /*
         * Create a new Buffer object
         * Size will be the string length
         */
        ReturnDesc = AcpiUtCreateBufferObject ((ACPI_SIZE) ObjDesc->String.Length);
        if (!ReturnDesc)
        {
            return_ACPI_STATUS (AE_NO_MEMORY);
        }

        /* Copy the string to the buffer */

        NewBuf = ReturnDesc->Buffer.Pointer;
        ACPI_STRNCPY ((char *) NewBuf, (char *) ObjDesc->String.Pointer,
            ObjDesc->String.Length);
        break;


    default:
        return_ACPI_STATUS (AE_TYPE);
    }

    /* Mark buffer initialized */

    ReturnDesc->Common.Flags |= AOPOBJ_DATA_VALID;
    *ResultDesc = ReturnDesc;
    return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiExConvertToAscii
 *
 * PARAMETERS:  Integer         - Value to be converted
 *              Base            - ACPI_STRING_DECIMAL or ACPI_STRING_HEX
 *              String          - Where the string is returned
 *              DataWidth       - Size of data item to be converted, in bytes
 *
 * RETURN:      Actual string length
 *
 * DESCRIPTION: Convert an ACPI Integer to a hex or decimal string
 *
 ******************************************************************************/

UINT32
AcpiExConvertToAscii (
    ACPI_INTEGER            Integer,
    UINT16                  Base,
    UINT8                   *String,
    UINT8                   DataWidth)
{
    ACPI_INTEGER            Digit;
    ACPI_NATIVE_UINT        i;
    ACPI_NATIVE_UINT        j;
    ACPI_NATIVE_UINT        k = 0;
    ACPI_NATIVE_UINT        HexLength;
    ACPI_NATIVE_UINT        DecimalLength;
    UINT32                  Remainder;
    BOOLEAN                 SupressZeros;


    ACPI_FUNCTION_ENTRY ();


    switch (Base)
    {
    case 10:

        /* Setup max length for the decimal number */

        switch (DataWidth)
        {
        case 1:
            DecimalLength = ACPI_MAX8_DECIMAL_DIGITS;
            break;

        case 4:
            DecimalLength = ACPI_MAX32_DECIMAL_DIGITS;
            break;

        case 8:
        default:
            DecimalLength = ACPI_MAX64_DECIMAL_DIGITS;
            break;
        }

        SupressZeros = TRUE;     /* No leading zeros */
        Remainder = 0;

        for (i = DecimalLength; i > 0; i--)
        {
            /* Divide by nth factor of 10 */

            Digit = Integer;
            for (j = 0; j < i; j++)
            {
                (void) AcpiUtShortDivide (Digit, 10, &Digit, &Remainder);
            }

            /* Handle leading zeros */

            if (Remainder != 0)
            {
                SupressZeros = FALSE;
            }

            if (!SupressZeros)
            {
                String[k] = (UINT8) (ACPI_ASCII_ZERO + Remainder);
                k++;
            }
        }
        break;

    case 16:

        HexLength = ACPI_MUL_2 (DataWidth); /* 2 ascii hex chars per data byte */

        for (i = 0, j = (HexLength-1); i < HexLength; i++, j--)
        {
            /* Get one hex digit, most significant digits first */

            String[k] = (UINT8) AcpiUtHexToAsciiChar (Integer, ACPI_MUL_4 (j));
            k++;
        }
        break;

    default:
        return (0);
    }

    /*
     * Since leading zeros are supressed, we must check for the case where
     * the integer equals 0
     *
     * Finally, null terminate the string and return the length
     */
    if (!k)
    {
        String [0] = ACPI_ASCII_ZERO;
        k = 1;
    }

    String [k] = 0;
    return ((UINT32) k);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiExConvertToString
 *
 * PARAMETERS:  ObjDesc         - Object to be converted.  Must be an
 *                                Integer, Buffer, or String
 *              ResultDesc      - Where the string object is returned
 *              Type            - String flags (base and conversion type)
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Convert an ACPI Object to a string
 *
 ******************************************************************************/

ACPI_STATUS
AcpiExConvertToString (
    ACPI_OPERAND_OBJECT     *ObjDesc,
    ACPI_OPERAND_OBJECT     **ResultDesc,
    UINT32                  Type)
{
    ACPI_OPERAND_OBJECT     *ReturnDesc;
    UINT8                   *NewBuf;
    UINT32                  StringLength = 0;
    UINT16                  Base = 16;
    UINT32                  i;
    UINT8                   Separator = ',';


    ACPI_FUNCTION_TRACE_PTR ("ExConvertToString", ObjDesc);


    switch (ACPI_GET_OBJECT_TYPE (ObjDesc))
    {
    case ACPI_TYPE_STRING:

        /* No conversion necessary */

        *ResultDesc = ObjDesc;
        return_ACPI_STATUS (AE_OK);


    case ACPI_TYPE_INTEGER:

        switch (Type)
        {
        case ACPI_EXPLICIT_CONVERT_DECIMAL:

            /* Make room for maximum decimal number */

            StringLength = ACPI_MAX_DECIMAL_DIGITS;
            Base = 10;
            break;

        default:

            /* Two hex string characters for each integer byte */

            StringLength = ACPI_MUL_2 (AcpiGbl_IntegerByteWidth);
            break;
        }

        /*
         * Create a new String
         * Need enough space for one ASCII integer (plus null terminator)
         */
        ReturnDesc = AcpiUtCreateStringObject ((ACPI_SIZE) StringLength);
        if (!ReturnDesc)
        {
            return_ACPI_STATUS (AE_NO_MEMORY);
        }

        NewBuf = ReturnDesc->Buffer.Pointer;

        /* Convert integer to string */

        StringLength = AcpiExConvertToAscii (ObjDesc->Integer.Value, Base,
                            NewBuf, AcpiGbl_IntegerByteWidth);

        /* Null terminate at the correct place */

        ReturnDesc->String.Length = StringLength;
        NewBuf [StringLength] = 0;
        break;


    case ACPI_TYPE_BUFFER:

        switch (Type)
        {
        case ACPI_EXPLICIT_CONVERT_DECIMAL: /* Used by ToDecimalString operator */
            /*
             * From ACPI: "If Data is a buffer, it is converted to a string of
             * decimal values separated by commas."
             */
            Base = 10;
            StringLength = ObjDesc->Buffer.Length; /* 4 chars for each decimal */

            /*lint -fallthrough */

        case ACPI_IMPLICIT_CONVERT_HEX:
            /*
             * From the ACPI spec:
             *"The entire contents of the buffer are converted to a string of
             * two-character hexadecimal numbers, each separated by a space."
             */
            if (Type == ACPI_IMPLICIT_CONVERT_HEX)
            {
                Separator = ' ';
            }

            /*lint -fallthrough */

        case ACPI_EXPLICIT_CONVERT_HEX:     /* Used by ToHexString operator */
            /*
             * From ACPI: "If Data is a buffer, it is converted to a string of
             * hexadecimal values separated by commas."
             */
            StringLength += (ObjDesc->Buffer.Length * 3);
            if (StringLength > ACPI_MAX_STRING_CONVERSION)  /* ACPI limit */
            {
                return_ACPI_STATUS (AE_AML_STRING_LIMIT);
            }

            /* Create a new string object and string buffer */

            ReturnDesc = AcpiUtCreateStringObject ((ACPI_SIZE) StringLength -1);
            if (!ReturnDesc)
            {
                return_ACPI_STATUS (AE_NO_MEMORY);
            }

            NewBuf = ReturnDesc->Buffer.Pointer;

            /*
             * Convert buffer bytes to hex or decimal values
             * (separated by commas)
             */
            for (i = 0; i < ObjDesc->Buffer.Length; i++)
            {
                NewBuf += AcpiExConvertToAscii (
                            (ACPI_INTEGER) ObjDesc->Buffer.Pointer[i], Base,
                            NewBuf, 1);
                *NewBuf++ = Separator; /* each separated by a comma or space */
            }

            /* Null terminate the string (overwrites final comma from above) */

            NewBuf--;
            *NewBuf = 0;

            /* Recalculate length */

            ReturnDesc->String.Length = (UINT32) 
                ACPI_STRLEN (ReturnDesc->String.Pointer);
            break;

        default:
            return_ACPI_STATUS (AE_BAD_PARAMETER);
        }
        break;

    default:
        return_ACPI_STATUS (AE_TYPE);
    }

    *ResultDesc = ReturnDesc;
    return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiExConvertToTargetType
 *
 * PARAMETERS:  DestinationType     - Current type of the destination
 *              SourceDesc          - Source object to be converted.
 *              ResultDesc          - Where the converted object is returned
 *              WalkState           - Current method state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Implements "implicit conversion" rules for storing an object.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiExConvertToTargetType (
    ACPI_OBJECT_TYPE        DestinationType,
    ACPI_OPERAND_OBJECT     *SourceDesc,
    ACPI_OPERAND_OBJECT     **ResultDesc,
    ACPI_WALK_STATE         *WalkState)
{
    ACPI_STATUS             Status = AE_OK;


    ACPI_FUNCTION_TRACE ("ExConvertToTargetType");


    /* Default behavior */

    *ResultDesc = SourceDesc;

    /*
     * If required by the target,
     * perform implicit conversion on the source before we store it.
     */
    switch (GET_CURRENT_ARG_TYPE (WalkState->OpInfo->RuntimeArgs))
    {
    case ARGI_SIMPLE_TARGET:
    case ARGI_FIXED_TARGET:
    case ARGI_INTEGER_REF:      /* Handles Increment, Decrement cases */

        switch (DestinationType)
        {
        case ACPI_TYPE_LOCAL_REGION_FIELD:
            /*
             * Named field can always handle conversions
             */
            break;

        default:
            /* No conversion allowed for these types */

            if (DestinationType != ACPI_GET_OBJECT_TYPE (SourceDesc))
            {
                ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
                    "Explicit operator, will store (%s) over existing type (%s)\n",
                    AcpiUtGetObjectTypeName (SourceDesc),
                    AcpiUtGetTypeName (DestinationType)));
                Status = AE_TYPE;
            }
        }
        break;


    case ARGI_TARGETREF:

        switch (DestinationType)
        {
        case ACPI_TYPE_INTEGER:
        case ACPI_TYPE_BUFFER_FIELD:
        case ACPI_TYPE_LOCAL_BANK_FIELD:
        case ACPI_TYPE_LOCAL_INDEX_FIELD:
            /*
             * These types require an Integer operand.  We can convert
             * a Buffer or a String to an Integer if necessary.
             */
            Status = AcpiExConvertToInteger (SourceDesc, ResultDesc,
                        16);
            break;


        case ACPI_TYPE_STRING:

            /*
             * The operand must be a String.  We can convert an
             * Integer or Buffer if necessary
             */
            Status = AcpiExConvertToString (SourceDesc, ResultDesc,
                        ACPI_IMPLICIT_CONVERT_HEX);
            break;


        case ACPI_TYPE_BUFFER:

            /*
             * The operand must be a Buffer.  We can convert an
             * Integer or String if necessary
             */
            Status = AcpiExConvertToBuffer (SourceDesc, ResultDesc);
            break;


        default:
            ACPI_REPORT_ERROR (("Bad destination type during conversion: %X\n",
                DestinationType));
            Status = AE_AML_INTERNAL;
            break;
        }
        break;


    case ARGI_REFERENCE:
        /*
         * CreateXxxxField cases - we are storing the field object into the name
         */
        break;


    default:
        ACPI_DEBUG_PRINT ((ACPI_DB_ERROR,
            "Unknown Target type ID 0x%X Op %s DestType %s\n",
            GET_CURRENT_ARG_TYPE (WalkState->OpInfo->RuntimeArgs),
            WalkState->OpInfo->Name, AcpiUtGetTypeName (DestinationType)));

        ACPI_REPORT_ERROR (("Bad Target Type (ARGI): %X\n",
            GET_CURRENT_ARG_TYPE (WalkState->OpInfo->RuntimeArgs)))
        Status = AE_AML_INTERNAL;
    }

    /*
     * Source-to-Target conversion semantics:
     *
     * If conversion to the target type cannot be performed, then simply
     * overwrite the target with the new object and type.
     */
    if (Status == AE_TYPE)
    {
        Status = AE_OK;
    }

    return_ACPI_STATUS (Status);
}