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exmisc.c revision 1.1.1.3
      1 /******************************************************************************
      2  *
      3  * Module Name: exmisc - ACPI AML (p-code) execution - specific opcodes
      4  *
      5  *****************************************************************************/
      6 
      7 /*
      8  * Copyright (C) 2000 - 2013, 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 MERCHANTIBILITY 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 #define __EXMISC_C__
     45 
     46 #include "acpi.h"
     47 #include "accommon.h"
     48 #include "acinterp.h"
     49 #include "amlcode.h"
     50 #include "amlresrc.h"
     51 
     52 
     53 #define _COMPONENT          ACPI_EXECUTER
     54         ACPI_MODULE_NAME    ("exmisc")
     55 
     56 
     57 /*******************************************************************************
     58  *
     59  * FUNCTION:    AcpiExGetObjectReference
     60  *
     61  * PARAMETERS:  ObjDesc             - Create a reference to this object
     62  *              ReturnDesc          - Where to store the reference
     63  *              WalkState           - Current state
     64  *
     65  * RETURN:      Status
     66  *
     67  * DESCRIPTION: Obtain and return a "reference" to the target object
     68  *              Common code for the RefOfOp and the CondRefOfOp.
     69  *
     70  ******************************************************************************/
     71 
     72 ACPI_STATUS
     73 AcpiExGetObjectReference (
     74     ACPI_OPERAND_OBJECT     *ObjDesc,
     75     ACPI_OPERAND_OBJECT     **ReturnDesc,
     76     ACPI_WALK_STATE         *WalkState)
     77 {
     78     ACPI_OPERAND_OBJECT     *ReferenceObj;
     79     ACPI_OPERAND_OBJECT     *ReferencedObj;
     80 
     81 
     82     ACPI_FUNCTION_TRACE_PTR (ExGetObjectReference, ObjDesc);
     83 
     84 
     85     *ReturnDesc = NULL;
     86 
     87     switch (ACPI_GET_DESCRIPTOR_TYPE (ObjDesc))
     88     {
     89     case ACPI_DESC_TYPE_OPERAND:
     90 
     91         if (ObjDesc->Common.Type != ACPI_TYPE_LOCAL_REFERENCE)
     92         {
     93             return_ACPI_STATUS (AE_AML_OPERAND_TYPE);
     94         }
     95 
     96         /*
     97          * Must be a reference to a Local or Arg
     98          */
     99         switch (ObjDesc->Reference.Class)
    100         {
    101         case ACPI_REFCLASS_LOCAL:
    102         case ACPI_REFCLASS_ARG:
    103         case ACPI_REFCLASS_DEBUG:
    104 
    105             /* The referenced object is the pseudo-node for the local/arg */
    106 
    107             ReferencedObj = ObjDesc->Reference.Object;
    108             break;
    109 
    110         default:
    111 
    112             ACPI_ERROR ((AE_INFO, "Unknown Reference Class 0x%2.2X",
    113                 ObjDesc->Reference.Class));
    114             return_ACPI_STATUS (AE_AML_INTERNAL);
    115         }
    116         break;
    117 
    118     case ACPI_DESC_TYPE_NAMED:
    119         /*
    120          * A named reference that has already been resolved to a Node
    121          */
    122         ReferencedObj = ObjDesc;
    123         break;
    124 
    125     default:
    126 
    127         ACPI_ERROR ((AE_INFO, "Invalid descriptor type 0x%X",
    128             ACPI_GET_DESCRIPTOR_TYPE (ObjDesc)));
    129         return_ACPI_STATUS (AE_TYPE);
    130     }
    131 
    132 
    133     /* Create a new reference object */
    134 
    135     ReferenceObj = AcpiUtCreateInternalObject (ACPI_TYPE_LOCAL_REFERENCE);
    136     if (!ReferenceObj)
    137     {
    138         return_ACPI_STATUS (AE_NO_MEMORY);
    139     }
    140 
    141     ReferenceObj->Reference.Class = ACPI_REFCLASS_REFOF;
    142     ReferenceObj->Reference.Object = ReferencedObj;
    143     *ReturnDesc = ReferenceObj;
    144 
    145     ACPI_DEBUG_PRINT ((ACPI_DB_EXEC,
    146         "Object %p Type [%s], returning Reference %p\n",
    147         ObjDesc, AcpiUtGetObjectTypeName (ObjDesc), *ReturnDesc));
    148 
    149     return_ACPI_STATUS (AE_OK);
    150 }
    151 
    152 
    153 /*******************************************************************************
    154  *
    155  * FUNCTION:    AcpiExConcatTemplate
    156  *
    157  * PARAMETERS:  Operand0            - First source object
    158  *              Operand1            - Second source object
    159  *              ActualReturnDesc    - Where to place the return object
    160  *              WalkState           - Current walk state
    161  *
    162  * RETURN:      Status
    163  *
    164  * DESCRIPTION: Concatenate two resource templates
    165  *
    166  ******************************************************************************/
    167 
    168 ACPI_STATUS
    169 AcpiExConcatTemplate (
    170     ACPI_OPERAND_OBJECT     *Operand0,
    171     ACPI_OPERAND_OBJECT     *Operand1,
    172     ACPI_OPERAND_OBJECT     **ActualReturnDesc,
    173     ACPI_WALK_STATE         *WalkState)
    174 {
    175     ACPI_STATUS             Status;
    176     ACPI_OPERAND_OBJECT     *ReturnDesc;
    177     UINT8                   *NewBuf;
    178     UINT8                   *EndTag;
    179     ACPI_SIZE               Length0;
    180     ACPI_SIZE               Length1;
    181     ACPI_SIZE               NewLength;
    182 
    183 
    184     ACPI_FUNCTION_TRACE (ExConcatTemplate);
    185 
    186 
    187     /*
    188      * Find the EndTag descriptor in each resource template.
    189      * Note1: returned pointers point TO the EndTag, not past it.
    190      * Note2: zero-length buffers are allowed; treated like one EndTag
    191      */
    192 
    193     /* Get the length of the first resource template */
    194 
    195     Status = AcpiUtGetResourceEndTag (Operand0, &EndTag);
    196     if (ACPI_FAILURE (Status))
    197     {
    198         return_ACPI_STATUS (Status);
    199     }
    200 
    201     Length0 = ACPI_PTR_DIFF (EndTag, Operand0->Buffer.Pointer);
    202 
    203     /* Get the length of the second resource template */
    204 
    205     Status = AcpiUtGetResourceEndTag (Operand1, &EndTag);
    206     if (ACPI_FAILURE (Status))
    207     {
    208         return_ACPI_STATUS (Status);
    209     }
    210 
    211     Length1 = ACPI_PTR_DIFF (EndTag, Operand1->Buffer.Pointer);
    212 
    213     /* Combine both lengths, minimum size will be 2 for EndTag */
    214 
    215     NewLength = Length0 + Length1 + sizeof (AML_RESOURCE_END_TAG);
    216 
    217     /* Create a new buffer object for the result (with one EndTag) */
    218 
    219     ReturnDesc = AcpiUtCreateBufferObject (NewLength);
    220     if (!ReturnDesc)
    221     {
    222         return_ACPI_STATUS (AE_NO_MEMORY);
    223     }
    224 
    225     /*
    226      * Copy the templates to the new buffer, 0 first, then 1 follows. One
    227      * EndTag descriptor is copied from Operand1.
    228      */
    229     NewBuf = ReturnDesc->Buffer.Pointer;
    230     ACPI_MEMCPY (NewBuf, Operand0->Buffer.Pointer, Length0);
    231     ACPI_MEMCPY (NewBuf + Length0, Operand1->Buffer.Pointer, Length1);
    232 
    233     /* Insert EndTag and set the checksum to zero, means "ignore checksum" */
    234 
    235     NewBuf[NewLength - 1] = 0;
    236     NewBuf[NewLength - 2] = ACPI_RESOURCE_NAME_END_TAG | 1;
    237 
    238     /* Return the completed resource template */
    239 
    240     *ActualReturnDesc = ReturnDesc;
    241     return_ACPI_STATUS (AE_OK);
    242 }
    243 
    244 
    245 /*******************************************************************************
    246  *
    247  * FUNCTION:    AcpiExDoConcatenate
    248  *
    249  * PARAMETERS:  Operand0            - First source object
    250  *              Operand1            - Second source object
    251  *              ActualReturnDesc    - Where to place the return object
    252  *              WalkState           - Current walk state
    253  *
    254  * RETURN:      Status
    255  *
    256  * DESCRIPTION: Concatenate two objects OF THE SAME TYPE.
    257  *
    258  ******************************************************************************/
    259 
    260 ACPI_STATUS
    261 AcpiExDoConcatenate (
    262     ACPI_OPERAND_OBJECT     *Operand0,
    263     ACPI_OPERAND_OBJECT     *Operand1,
    264     ACPI_OPERAND_OBJECT     **ActualReturnDesc,
    265     ACPI_WALK_STATE         *WalkState)
    266 {
    267     ACPI_OPERAND_OBJECT     *LocalOperand1 = Operand1;
    268     ACPI_OPERAND_OBJECT     *ReturnDesc;
    269     char                    *NewBuf;
    270     ACPI_STATUS             Status;
    271 
    272 
    273     ACPI_FUNCTION_TRACE (ExDoConcatenate);
    274 
    275 
    276     /*
    277      * Convert the second operand if necessary. The first operand
    278      * determines the type of the second operand, (See the Data Types
    279      * section of the ACPI specification.)  Both object types are
    280      * guaranteed to be either Integer/String/Buffer by the operand
    281      * resolution mechanism.
    282      */
    283     switch (Operand0->Common.Type)
    284     {
    285     case ACPI_TYPE_INTEGER:
    286 
    287         Status = AcpiExConvertToInteger (Operand1, &LocalOperand1, 16);
    288         break;
    289 
    290     case ACPI_TYPE_STRING:
    291 
    292         Status = AcpiExConvertToString (Operand1, &LocalOperand1,
    293                     ACPI_IMPLICIT_CONVERT_HEX);
    294         break;
    295 
    296     case ACPI_TYPE_BUFFER:
    297 
    298         Status = AcpiExConvertToBuffer (Operand1, &LocalOperand1);
    299         break;
    300 
    301     default:
    302 
    303         ACPI_ERROR ((AE_INFO, "Invalid object type: 0x%X",
    304             Operand0->Common.Type));
    305         Status = AE_AML_INTERNAL;
    306     }
    307 
    308     if (ACPI_FAILURE (Status))
    309     {
    310         goto Cleanup;
    311     }
    312 
    313     /*
    314      * Both operands are now known to be the same object type
    315      * (Both are Integer, String, or Buffer), and we can now perform the
    316      * concatenation.
    317      */
    318 
    319     /*
    320      * There are three cases to handle:
    321      *
    322      * 1) Two Integers concatenated to produce a new Buffer
    323      * 2) Two Strings concatenated to produce a new String
    324      * 3) Two Buffers concatenated to produce a new Buffer
    325      */
    326     switch (Operand0->Common.Type)
    327     {
    328     case ACPI_TYPE_INTEGER:
    329 
    330         /* Result of two Integers is a Buffer */
    331         /* Need enough buffer space for two integers */
    332 
    333         ReturnDesc = AcpiUtCreateBufferObject ((ACPI_SIZE)
    334                             ACPI_MUL_2 (AcpiGbl_IntegerByteWidth));
    335         if (!ReturnDesc)
    336         {
    337             Status = AE_NO_MEMORY;
    338             goto Cleanup;
    339         }
    340 
    341         NewBuf = (char *) ReturnDesc->Buffer.Pointer;
    342 
    343         /* Copy the first integer, LSB first */
    344 
    345         ACPI_MEMCPY (NewBuf, &Operand0->Integer.Value,
    346                         AcpiGbl_IntegerByteWidth);
    347 
    348         /* Copy the second integer (LSB first) after the first */
    349 
    350         ACPI_MEMCPY (NewBuf + AcpiGbl_IntegerByteWidth,
    351                         &LocalOperand1->Integer.Value,
    352                         AcpiGbl_IntegerByteWidth);
    353         break;
    354 
    355     case ACPI_TYPE_STRING:
    356 
    357         /* Result of two Strings is a String */
    358 
    359         ReturnDesc = AcpiUtCreateStringObject (
    360                         ((ACPI_SIZE) Operand0->String.Length +
    361                         LocalOperand1->String.Length));
    362         if (!ReturnDesc)
    363         {
    364             Status = AE_NO_MEMORY;
    365             goto Cleanup;
    366         }
    367 
    368         NewBuf = ReturnDesc->String.Pointer;
    369 
    370         /* Concatenate the strings */
    371 
    372         ACPI_STRCPY (NewBuf, Operand0->String.Pointer);
    373         ACPI_STRCPY (NewBuf + Operand0->String.Length,
    374                         LocalOperand1->String.Pointer);
    375         break;
    376 
    377     case ACPI_TYPE_BUFFER:
    378 
    379         /* Result of two Buffers is a Buffer */
    380 
    381         ReturnDesc = AcpiUtCreateBufferObject (
    382                         ((ACPI_SIZE) Operand0->Buffer.Length +
    383                         LocalOperand1->Buffer.Length));
    384         if (!ReturnDesc)
    385         {
    386             Status = AE_NO_MEMORY;
    387             goto Cleanup;
    388         }
    389 
    390         NewBuf = (char *) ReturnDesc->Buffer.Pointer;
    391 
    392         /* Concatenate the buffers */
    393 
    394         ACPI_MEMCPY (NewBuf, Operand0->Buffer.Pointer,
    395                         Operand0->Buffer.Length);
    396         ACPI_MEMCPY (NewBuf + Operand0->Buffer.Length,
    397                         LocalOperand1->Buffer.Pointer,
    398                         LocalOperand1->Buffer.Length);
    399         break;
    400 
    401     default:
    402 
    403         /* Invalid object type, should not happen here */
    404 
    405         ACPI_ERROR ((AE_INFO, "Invalid object type: 0x%X",
    406             Operand0->Common.Type));
    407         Status =AE_AML_INTERNAL;
    408         goto Cleanup;
    409     }
    410 
    411     *ActualReturnDesc = ReturnDesc;
    412 
    413 Cleanup:
    414     if (LocalOperand1 != Operand1)
    415     {
    416         AcpiUtRemoveReference (LocalOperand1);
    417     }
    418     return_ACPI_STATUS (Status);
    419 }
    420 
    421 
    422 /*******************************************************************************
    423  *
    424  * FUNCTION:    AcpiExDoMathOp
    425  *
    426  * PARAMETERS:  Opcode              - AML opcode
    427  *              Integer0            - Integer operand #0
    428  *              Integer1            - Integer operand #1
    429  *
    430  * RETURN:      Integer result of the operation
    431  *
    432  * DESCRIPTION: Execute a math AML opcode. The purpose of having all of the
    433  *              math functions here is to prevent a lot of pointer dereferencing
    434  *              to obtain the operands.
    435  *
    436  ******************************************************************************/
    437 
    438 UINT64
    439 AcpiExDoMathOp (
    440     UINT16                  Opcode,
    441     UINT64                  Integer0,
    442     UINT64                  Integer1)
    443 {
    444 
    445     ACPI_FUNCTION_ENTRY ();
    446 
    447 
    448     switch (Opcode)
    449     {
    450     case AML_ADD_OP:                /* Add (Integer0, Integer1, Result) */
    451 
    452         return (Integer0 + Integer1);
    453 
    454     case AML_BIT_AND_OP:            /* And (Integer0, Integer1, Result) */
    455 
    456         return (Integer0 & Integer1);
    457 
    458     case AML_BIT_NAND_OP:           /* NAnd (Integer0, Integer1, Result) */
    459 
    460         return (~(Integer0 & Integer1));
    461 
    462     case AML_BIT_OR_OP:             /* Or (Integer0, Integer1, Result) */
    463 
    464         return (Integer0 | Integer1);
    465 
    466     case AML_BIT_NOR_OP:            /* NOr (Integer0, Integer1, Result) */
    467 
    468         return (~(Integer0 | Integer1));
    469 
    470     case AML_BIT_XOR_OP:            /* XOr (Integer0, Integer1, Result) */
    471 
    472         return (Integer0 ^ Integer1);
    473 
    474     case AML_MULTIPLY_OP:           /* Multiply (Integer0, Integer1, Result) */
    475 
    476         return (Integer0 * Integer1);
    477 
    478     case AML_SHIFT_LEFT_OP:         /* ShiftLeft (Operand, ShiftCount, Result)*/
    479 
    480         /*
    481          * We need to check if the shiftcount is larger than the integer bit
    482          * width since the behavior of this is not well-defined in the C language.
    483          */
    484         if (Integer1 >= AcpiGbl_IntegerBitWidth)
    485         {
    486             return (0);
    487         }
    488         return (Integer0 << Integer1);
    489 
    490     case AML_SHIFT_RIGHT_OP:        /* ShiftRight (Operand, ShiftCount, Result) */
    491 
    492         /*
    493          * We need to check if the shiftcount is larger than the integer bit
    494          * width since the behavior of this is not well-defined in the C language.
    495          */
    496         if (Integer1 >= AcpiGbl_IntegerBitWidth)
    497         {
    498             return (0);
    499         }
    500         return (Integer0 >> Integer1);
    501 
    502     case AML_SUBTRACT_OP:           /* Subtract (Integer0, Integer1, Result) */
    503 
    504         return (Integer0 - Integer1);
    505 
    506     default:
    507 
    508         return (0);
    509     }
    510 }
    511 
    512 
    513 /*******************************************************************************
    514  *
    515  * FUNCTION:    AcpiExDoLogicalNumericOp
    516  *
    517  * PARAMETERS:  Opcode              - AML opcode
    518  *              Integer0            - Integer operand #0
    519  *              Integer1            - Integer operand #1
    520  *              LogicalResult       - TRUE/FALSE result of the operation
    521  *
    522  * RETURN:      Status
    523  *
    524  * DESCRIPTION: Execute a logical "Numeric" AML opcode. For these Numeric
    525  *              operators (LAnd and LOr), both operands must be integers.
    526  *
    527  *              Note: cleanest machine code seems to be produced by the code
    528  *              below, rather than using statements of the form:
    529  *                  Result = (Integer0 && Integer1);
    530  *
    531  ******************************************************************************/
    532 
    533 ACPI_STATUS
    534 AcpiExDoLogicalNumericOp (
    535     UINT16                  Opcode,
    536     UINT64                  Integer0,
    537     UINT64                  Integer1,
    538     BOOLEAN                 *LogicalResult)
    539 {
    540     ACPI_STATUS             Status = AE_OK;
    541     BOOLEAN                 LocalResult = FALSE;
    542 
    543 
    544     ACPI_FUNCTION_TRACE (ExDoLogicalNumericOp);
    545 
    546 
    547     switch (Opcode)
    548     {
    549     case AML_LAND_OP:               /* LAnd (Integer0, Integer1) */
    550 
    551         if (Integer0 && Integer1)
    552         {
    553             LocalResult = TRUE;
    554         }
    555         break;
    556 
    557     case AML_LOR_OP:                /* LOr (Integer0, Integer1) */
    558 
    559         if (Integer0 || Integer1)
    560         {
    561             LocalResult = TRUE;
    562         }
    563         break;
    564 
    565     default:
    566 
    567         Status = AE_AML_INTERNAL;
    568         break;
    569     }
    570 
    571     /* Return the logical result and status */
    572 
    573     *LogicalResult = LocalResult;
    574     return_ACPI_STATUS (Status);
    575 }
    576 
    577 
    578 /*******************************************************************************
    579  *
    580  * FUNCTION:    AcpiExDoLogicalOp
    581  *
    582  * PARAMETERS:  Opcode              - AML opcode
    583  *              Operand0            - operand #0
    584  *              Operand1            - operand #1
    585  *              LogicalResult       - TRUE/FALSE result of the operation
    586  *
    587  * RETURN:      Status
    588  *
    589  * DESCRIPTION: Execute a logical AML opcode. The purpose of having all of the
    590  *              functions here is to prevent a lot of pointer dereferencing
    591  *              to obtain the operands and to simplify the generation of the
    592  *              logical value. For the Numeric operators (LAnd and LOr), both
    593  *              operands must be integers. For the other logical operators,
    594  *              operands can be any combination of Integer/String/Buffer. The
    595  *              first operand determines the type to which the second operand
    596  *              will be converted.
    597  *
    598  *              Note: cleanest machine code seems to be produced by the code
    599  *              below, rather than using statements of the form:
    600  *                  Result = (Operand0 == Operand1);
    601  *
    602  ******************************************************************************/
    603 
    604 ACPI_STATUS
    605 AcpiExDoLogicalOp (
    606     UINT16                  Opcode,
    607     ACPI_OPERAND_OBJECT     *Operand0,
    608     ACPI_OPERAND_OBJECT     *Operand1,
    609     BOOLEAN                 *LogicalResult)
    610 {
    611     ACPI_OPERAND_OBJECT     *LocalOperand1 = Operand1;
    612     UINT64                  Integer0;
    613     UINT64                  Integer1;
    614     UINT32                  Length0;
    615     UINT32                  Length1;
    616     ACPI_STATUS             Status = AE_OK;
    617     BOOLEAN                 LocalResult = FALSE;
    618     int                     Compare;
    619 
    620 
    621     ACPI_FUNCTION_TRACE (ExDoLogicalOp);
    622 
    623 
    624     /*
    625      * Convert the second operand if necessary. The first operand
    626      * determines the type of the second operand, (See the Data Types
    627      * section of the ACPI 3.0+ specification.)  Both object types are
    628      * guaranteed to be either Integer/String/Buffer by the operand
    629      * resolution mechanism.
    630      */
    631     switch (Operand0->Common.Type)
    632     {
    633     case ACPI_TYPE_INTEGER:
    634 
    635         Status = AcpiExConvertToInteger (Operand1, &LocalOperand1, 16);
    636         break;
    637 
    638     case ACPI_TYPE_STRING:
    639 
    640         Status = AcpiExConvertToString (Operand1, &LocalOperand1,
    641                     ACPI_IMPLICIT_CONVERT_HEX);
    642         break;
    643 
    644     case ACPI_TYPE_BUFFER:
    645 
    646         Status = AcpiExConvertToBuffer (Operand1, &LocalOperand1);
    647         break;
    648 
    649     default:
    650 
    651         Status = AE_AML_INTERNAL;
    652         break;
    653     }
    654 
    655     if (ACPI_FAILURE (Status))
    656     {
    657         goto Cleanup;
    658     }
    659 
    660     /*
    661      * Two cases: 1) Both Integers, 2) Both Strings or Buffers
    662      */
    663     if (Operand0->Common.Type == ACPI_TYPE_INTEGER)
    664     {
    665         /*
    666          * 1) Both operands are of type integer
    667          *    Note: LocalOperand1 may have changed above
    668          */
    669         Integer0 = Operand0->Integer.Value;
    670         Integer1 = LocalOperand1->Integer.Value;
    671 
    672         switch (Opcode)
    673         {
    674         case AML_LEQUAL_OP:             /* LEqual (Operand0, Operand1) */
    675 
    676             if (Integer0 == Integer1)
    677             {
    678                 LocalResult = TRUE;
    679             }
    680             break;
    681 
    682         case AML_LGREATER_OP:           /* LGreater (Operand0, Operand1) */
    683 
    684             if (Integer0 > Integer1)
    685             {
    686                 LocalResult = TRUE;
    687             }
    688             break;
    689 
    690         case AML_LLESS_OP:              /* LLess (Operand0, Operand1) */
    691 
    692             if (Integer0 < Integer1)
    693             {
    694                 LocalResult = TRUE;
    695             }
    696             break;
    697 
    698         default:
    699 
    700             Status = AE_AML_INTERNAL;
    701             break;
    702         }
    703     }
    704     else
    705     {
    706         /*
    707          * 2) Both operands are Strings or both are Buffers
    708          *    Note: Code below takes advantage of common Buffer/String
    709          *          object fields. LocalOperand1 may have changed above. Use
    710          *          memcmp to handle nulls in buffers.
    711          */
    712         Length0 = Operand0->Buffer.Length;
    713         Length1 = LocalOperand1->Buffer.Length;
    714 
    715         /* Lexicographic compare: compare the data bytes */
    716 
    717         Compare = ACPI_MEMCMP (Operand0->Buffer.Pointer,
    718                     LocalOperand1->Buffer.Pointer,
    719                     (Length0 > Length1) ? Length1 : Length0);
    720 
    721         switch (Opcode)
    722         {
    723         case AML_LEQUAL_OP:             /* LEqual (Operand0, Operand1) */
    724 
    725             /* Length and all bytes must be equal */
    726 
    727             if ((Length0 == Length1) &&
    728                 (Compare == 0))
    729             {
    730                 /* Length and all bytes match ==> TRUE */
    731 
    732                 LocalResult = TRUE;
    733             }
    734             break;
    735 
    736         case AML_LGREATER_OP:           /* LGreater (Operand0, Operand1) */
    737 
    738             if (Compare > 0)
    739             {
    740                 LocalResult = TRUE;
    741                 goto Cleanup;   /* TRUE */
    742             }
    743             if (Compare < 0)
    744             {
    745                 goto Cleanup;   /* FALSE */
    746             }
    747 
    748             /* Bytes match (to shortest length), compare lengths */
    749 
    750             if (Length0 > Length1)
    751             {
    752                 LocalResult = TRUE;
    753             }
    754             break;
    755 
    756         case AML_LLESS_OP:              /* LLess (Operand0, Operand1) */
    757 
    758             if (Compare > 0)
    759             {
    760                 goto Cleanup;   /* FALSE */
    761             }
    762             if (Compare < 0)
    763             {
    764                 LocalResult = TRUE;
    765                 goto Cleanup;   /* TRUE */
    766             }
    767 
    768             /* Bytes match (to shortest length), compare lengths */
    769 
    770             if (Length0 < Length1)
    771             {
    772                 LocalResult = TRUE;
    773             }
    774             break;
    775 
    776         default:
    777 
    778             Status = AE_AML_INTERNAL;
    779             break;
    780         }
    781     }
    782 
    783 Cleanup:
    784 
    785     /* New object was created if implicit conversion performed - delete */
    786 
    787     if (LocalOperand1 != Operand1)
    788     {
    789         AcpiUtRemoveReference (LocalOperand1);
    790     }
    791 
    792     /* Return the logical result and status */
    793 
    794     *LogicalResult = LocalResult;
    795     return_ACPI_STATUS (Status);
    796 }
    797