acpica/source/compiler/aslcodegen.c

/******************************************************************************
 *
 * Module Name: aslcodegen - AML code generation
 *
 *****************************************************************************/

/******************************************************************************
 *
 * 1. Copyright Notice
 *
 * Some or all of this work - Copyright (c) 1999 - 2019, 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.
 *
 *****************************************************************************
 *
 * Alternatively, you may choose to be licensed under the terms of the
 * following license:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, you may choose to be licensed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 *****************************************************************************/

#include "aslcompiler.h"
#include "aslcompiler.y.h"
#include "amlcode.h"
#include "acconvert.h"

#define _COMPONENT          ACPI_COMPILER
        ACPI_MODULE_NAME    ("aslcodegen")

/* Local prototypes */

static ACPI_STATUS
CgAmlWriteWalk (
    ACPI_PARSE_OBJECT       *Op,
    UINT32                  Level,
    void                    *Context);

static void
CgWriteAmlOpcode (
    ACPI_PARSE_OBJECT       *Op);

static void
CgWriteTableHeader (
    ACPI_PARSE_OBJECT       *Op);

static void
CgWriteNode (
    ACPI_PARSE_OBJECT       *Op);

static void
CgUpdateHeader (
    ACPI_PARSE_OBJECT       *Op);


/*******************************************************************************
 *
 * FUNCTION:    CgGenerateAmlOutput
 *
 * PARAMETERS:  None.
 *
 * RETURN:      None
 *
 * DESCRIPTION: Generate AML code. Currently generates the listing file
 *              simultaneously.
 *
 ******************************************************************************/

void
CgGenerateAmlOutput (
    void)
{

    /* Generate the AML output file */

    TrWalkParseTree (AslGbl_CurrentDB,
        ASL_WALK_VISIT_DOWNWARD | ASL_WALK_VISIT_DB_SEPARATELY, CgAmlWriteWalk,
        NULL, NULL);

    DbgPrint (ASL_TREE_OUTPUT, ASL_PARSE_TREE_HEADER2);
    CgUpdateHeader (AslGbl_CurrentDB);
}


/*******************************************************************************
 *
 * FUNCTION:    CgAmlWriteWalk
 *
 * PARAMETERS:  ASL_WALK_CALLBACK
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Parse tree walk to generate the AML code.
 *
 ******************************************************************************/

static ACPI_STATUS
CgAmlWriteWalk (
    ACPI_PARSE_OBJECT       *Op,
    UINT32                  Level,
    void                    *Context)
{

    /* Generate the AML for this node */

    CgWriteNode (Op);

    if (!AslGbl_DebugFlag)
    {
        return (AE_OK);
    }

    /* Print header at level 0. Alignment assumes 32-bit pointers */

    if (!Level)
    {
        DbgPrint (ASL_TREE_OUTPUT,
            "\nFinal parse tree used for AML output:\n");
        DbgPrint (ASL_TREE_OUTPUT, ASL_PARSE_TREE_HEADER2);
    }

    /* Dump ParseOp name and possible value */

    switch (Op->Asl.ParseOpcode)
    {
    case PARSEOP_NAMESEG:
    case PARSEOP_NAMESTRING:
    case PARSEOP_METHODCALL:
    case PARSEOP_STRING_LITERAL:

        UtDumpStringOp (Op, Level);
        break;

    default:

        UtDumpBasicOp (Op, Level);
        break;
    }

    DbgPrint (ASL_TREE_OUTPUT, ASL_PARSE_TREE_DEBUG2,
        /* 1  */ (UINT32) Op->Asl.Value.Integer,
        /* 2  */ Op->Asl.ParseOpcode,
        /* 3  */ Op->Asl.AmlOpcode,
        /* 4  */ Op->Asl.AmlOpcodeLength,
        /* 5  */ Op->Asl.AmlPkgLenBytes,
        /* 6  */ Op->Asl.AmlLength,
        /* 7  */ Op->Asl.AmlSubtreeLength,
        /* 8  */ Op->Asl.Parent ? Op->Asl.Parent->Asl.AmlSubtreeLength : 0,
        /* 9  */ Op,
        /* 10 */ Op->Asl.Parent,
        /* 11 */ Op->Asl.Child,
        /* 12 */ Op->Asl.Next,
        /* 13 */ Op->Asl.CompileFlags,
        /* 14 */ Op->Asl.AcpiBtype,
        /* 15 */ Op->Asl.FinalAmlLength,
        /* 16 */ Op->Asl.Column,
        /* 17 */ Op->Asl.LineNumber,
        /* 18 */ Op->Asl.EndLine,
        /* 19 */ Op->Asl.LogicalLineNumber,
        /* 20 */ Op->Asl.EndLogicalLine);

    TrPrintOpFlags (Op->Asl.CompileFlags, ASL_TREE_OUTPUT);
    DbgPrint (ASL_TREE_OUTPUT, "\n");
    return (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    CgLocalWriteAmlData
 *
 * PARAMETERS:  Op              - Current parse op
 *              Buffer          - Buffer to write
 *              Length          - Size of data in buffer
 *
 * RETURN:      None
 *
 * DESCRIPTION: Write a buffer of AML data to the AML output file.
 *
 ******************************************************************************/

void
CgLocalWriteAmlData (
    ACPI_PARSE_OBJECT       *Op,
    void                    *Buffer,
    UINT32                  Length)
{

    /* Write the raw data to the AML file */

    FlWriteFile (ASL_FILE_AML_OUTPUT, Buffer, Length);

    /* Update the final AML length for this node (used for listings) */

    if (Op)
    {
        Op->Asl.FinalAmlLength += Length;
    }
}


/*******************************************************************************
 *
 * FUNCTION:    CgWriteAmlOpcode
 *
 * PARAMETERS:  Op            - Parse node with an AML opcode
 *
 * RETURN:      None.
 *
 * DESCRIPTION: Write the AML opcode corresponding to a parse node.
 *
 ******************************************************************************/

static void
CgWriteAmlOpcode (
    ACPI_PARSE_OBJECT       *Op)
{
    UINT8                   PkgLenFirstByte;
    UINT32                  i;
    union {
        UINT16                  Opcode;
        UINT8                   OpcodeBytes[2];
    } Aml;
    union {
        UINT32                  Len;
        UINT8                   LenBytes[4];
    } PkgLen;


    /* We expect some DEFAULT_ARGs, just ignore them */

    if (Op->Asl.ParseOpcode == PARSEOP_DEFAULT_ARG)
    {
        return;
    }

    /*
     * Before printing the bytecode, generate comment byte codes
     * associated with this node.
     */
    if (AcpiGbl_CaptureComments)
    {
        CgWriteAmlComment(Op);
    }

    switch (Op->Asl.AmlOpcode)
    {
    case AML_UNASSIGNED_OPCODE:

        /* These opcodes should not get here */

        printf ("Found a node with an unassigned AML opcode\n");
        FlPrintFile (ASL_FILE_STDERR,
            "Found a node with an unassigned AML opcode\n");
        return;

    case AML_INT_RESERVEDFIELD_OP:

        /* Special opcodes for within a field definition */

        Aml.Opcode = AML_FIELD_OFFSET_OP;
        break;

    case AML_INT_ACCESSFIELD_OP:

        Aml.Opcode = AML_FIELD_ACCESS_OP;
        break;

    case AML_INT_CONNECTION_OP:

        Aml.Opcode = AML_FIELD_CONNECTION_OP;
        break;

    default:

        Aml.Opcode = Op->Asl.AmlOpcode;
        break;
    }


    switch (Aml.Opcode)
    {
    case AML_PACKAGE_LENGTH:

        /* Value is the length to be encoded (Used in field definitions) */

        PkgLen.Len = (UINT32) Op->Asl.Value.Integer;
        break;

    default:

        /* Check for two-byte opcode */

        if (Aml.Opcode > 0x00FF)
        {
            /* Write the high byte first */

            CgLocalWriteAmlData (Op, &Aml.OpcodeBytes[1], 1);
        }

        CgLocalWriteAmlData (Op, &Aml.OpcodeBytes[0], 1);

        /* Subtreelength doesn't include length of package length bytes */

        PkgLen.Len = Op->Asl.AmlSubtreeLength + Op->Asl.AmlPkgLenBytes;
        break;
    }

    /* Does this opcode have an associated "PackageLength" field? */

    if (Op->Asl.CompileFlags & OP_AML_PACKAGE)
    {
        if (Op->Asl.AmlPkgLenBytes == 1)
        {
            /* Simplest case -- no bytes to follow, just write the count */

            CgLocalWriteAmlData (Op, &PkgLen.LenBytes[0], 1);
        }
        else if (Op->Asl.AmlPkgLenBytes != 0)
        {
            /*
             * Encode the "bytes to follow" in the first byte, top two bits.
             * The low-order nybble of the length is in the bottom 4 bits
             */
            PkgLenFirstByte = (UINT8)
                (((UINT32) (Op->Asl.AmlPkgLenBytes - 1) << 6) |
                (PkgLen.LenBytes[0] & 0x0F));

            CgLocalWriteAmlData (Op, &PkgLenFirstByte, 1);

            /*
             * Shift the length over by the 4 bits we just stuffed
             * in the first byte
             */
            PkgLen.Len >>= 4;

            /*
             * Now we can write the remaining bytes -
             * either 1, 2, or 3 bytes
             */
            for (i = 0; i < (UINT32) (Op->Asl.AmlPkgLenBytes - 1); i++)
            {
                CgLocalWriteAmlData (Op, &PkgLen.LenBytes[i], 1);
            }
        }
    }

    switch (Aml.Opcode)
    {
    case AML_BYTE_OP:

        CgLocalWriteAmlData (Op, &Op->Asl.Value.Integer, 1);
        break;

    case AML_WORD_OP:

        CgLocalWriteAmlData (Op, &Op->Asl.Value.Integer, 2);
       break;

    case AML_DWORD_OP:

        CgLocalWriteAmlData (Op, &Op->Asl.Value.Integer, 4);
        break;

    case AML_QWORD_OP:

        CgLocalWriteAmlData (Op, &Op->Asl.Value.Integer, 8);
        break;

    case AML_STRING_OP:

        CgLocalWriteAmlData (Op, Op->Asl.Value.String, Op->Asl.AmlLength);
        break;

    default:

        /* All data opcodes must appear above */

        break;
    }
}


/*******************************************************************************
 *
 * FUNCTION:    CgWriteTableHeader
 *
 * PARAMETERS:  Op        - The DEFINITIONBLOCK node
 *
 * RETURN:      None
 *
 * DESCRIPTION: Write a table header corresponding to the DEFINITIONBLOCK
 *
 * NOTE: Input strings should be validated before this function is invoked.
 *
 ******************************************************************************/

static void
CgWriteTableHeader (
    ACPI_PARSE_OBJECT       *Op)
{
    ACPI_PARSE_OBJECT       *Child;
    UINT32                  CommentLength;
    ACPI_COMMENT_NODE       *Current;


    memset (&AslGbl_TableHeader, 0, sizeof (ACPI_TABLE_HEADER));

    /* AML filename */

    Child = Op->Asl.Child;

    /* Signature */

    Child = Child->Asl.Next;

    /*
     * For ASL-/ASL+ converter: replace the table signature with
     * "XXXX" and save the original table signature. This results in an AML
     * file with the signature "XXXX". The converter should remove this AML
     * file. In the event where this AML file does not get deleted, the
     * "XXXX" table signature prevents this AML file from running on the AML
     * interpreter.
     */
    if (AcpiGbl_CaptureComments)
    {
        ACPI_COPY_NAMESEG (AcpiGbl_TableSig, Child->Asl.Value.String);
        Child->Asl.Value.String = ACPI_SIG_XXXX;
    }

    ACPI_COPY_NAMESEG (AslGbl_TableHeader.Signature, Child->Asl.Value.String);

    /* Revision */

    Child = Child->Asl.Next;
    AslGbl_TableHeader.Revision = (UINT8) Child->Asl.Value.Integer;

    /* Command-line Revision override */

    if (AslGbl_RevisionOverride)
    {
        AslGbl_TableHeader.Revision = AslGbl_RevisionOverride;
    }

    /* OEMID */

    Child = Child->Asl.Next;
    memcpy (AslGbl_TableHeader.OemId, Child->Asl.Value.String,
        strlen (Child->Asl.Value.String));

    /* OEM TableID */

    Child = Child->Asl.Next;
    memcpy (AslGbl_TableHeader.OemTableId, Child->Asl.Value.String,
        strlen (Child->Asl.Value.String));

    /* OEM Revision */

    Child = Child->Asl.Next;
    AslGbl_TableHeader.OemRevision = (UINT32) Child->Asl.Value.Integer;

    /* Compiler ID */

    ACPI_COPY_NAMESEG (AslGbl_TableHeader.AslCompilerId, ASL_CREATOR_ID);

    /* Compiler version */

    AslGbl_TableHeader.AslCompilerRevision = ACPI_CA_VERSION;

    /* Table length. Checksum zero for now, will rewrite later */

    AslGbl_TableHeader.Length = sizeof (ACPI_TABLE_HEADER) +
        Op->Asl.AmlSubtreeLength;

    /* Calculate the comment lengths for this definition block parseOp */

    if (AcpiGbl_CaptureComments)
    {
        CvDbgPrint ("Calculating comment lengths for %s in write header\n",
            Op->Asl.ParseOpName);

        /*
         * Take the filename without extensions, add 3 for the new extension
         * and another 3 for the a908 bytecode and null terminator.
         */
        AslGbl_TableHeader.Length += strrchr (AslGbl_ParseTreeRoot->Asl.Filename, '.')
            - AslGbl_ParseTreeRoot->Asl.Filename + 1 + 3 + 3;

        Op->Asl.AmlSubtreeLength +=
            strlen (AslGbl_ParseTreeRoot->Asl.Filename) + 3;

        CvDbgPrint ("     Length: %lu\n",
            strlen (AslGbl_ParseTreeRoot->Asl.Filename) + 3);

        if (Op->Asl.CommentList)
        {
            Current = Op->Asl.CommentList;
            while (Current)
            {
                CommentLength = strlen (Current->Comment)+3;
                CvDbgPrint ("Length of standard comment): %d\n", CommentLength);
                CvDbgPrint ("    Comment string: %s\n\n", Current->Comment);
                AslGbl_TableHeader.Length += CommentLength;
                Op->Asl.AmlSubtreeLength += CommentLength;
                Current = Current->Next;
                CvDbgPrint ("    Length: %u\n", CommentLength);
            }
        }
        if (Op->Asl.CloseBraceComment)
        {
            CommentLength = strlen (Op->Asl.CloseBraceComment)+3;
            CvDbgPrint ("Length of inline comment +3: %d\n", CommentLength);
            CvDbgPrint ("    Comment string: %s\n\n", Op->Asl.CloseBraceComment);
            AslGbl_TableHeader.Length += CommentLength;
            Op->Asl.AmlSubtreeLength += CommentLength;
            CvDbgPrint ("    Length: %u\n", CommentLength);
        }
    }

    AslGbl_TableHeader.Checksum = 0;
    Op->Asl.FinalAmlOffset = ftell (AslGbl_Files[ASL_FILE_AML_OUTPUT].Handle);

    /* Write entire header and clear the table header global */

    CgLocalWriteAmlData (Op, &AslGbl_TableHeader, sizeof (ACPI_TABLE_HEADER));
    memset (&AslGbl_TableHeader, 0, sizeof (ACPI_TABLE_HEADER));
}


/*******************************************************************************
 *
 * FUNCTION:    CgUpdateHeader
 *
 * PARAMETERS:  Op                  - Op for the Definition Block
 *
 * RETURN:      None.
 *
 * DESCRIPTION: Complete the ACPI table by calculating the checksum and
 *              re-writing the header for the input definition block
 *
 ******************************************************************************/

static void
CgUpdateHeader (
    ACPI_PARSE_OBJECT       *Op)
{
    signed char             Sum;
    UINT32                  i;
    UINT32                  Length;
    UINT8                   FileByte;
    UINT8                   Checksum;


    /* Calculate the checksum over the entire definition block */

    Sum = 0;
    Length = sizeof (ACPI_TABLE_HEADER) + Op->Asl.AmlSubtreeLength;
    FlSeekFile (ASL_FILE_AML_OUTPUT, Op->Asl.FinalAmlOffset);

    for (i = 0; i < Length; i++)
    {
        if (FlReadFile (ASL_FILE_AML_OUTPUT, &FileByte, 1) != AE_OK)
        {
            printf ("EOF while reading checksum bytes\n");
            return;
        }

        Sum = (signed char) (Sum + FileByte);
    }

    Checksum = (UINT8) (0 - Sum);

    /* Re-write the the checksum byte */

    FlSeekFile (ASL_FILE_AML_OUTPUT, Op->Asl.FinalAmlOffset +
        ACPI_OFFSET (ACPI_TABLE_HEADER, Checksum));

    FlWriteFile (ASL_FILE_AML_OUTPUT, &Checksum, 1);

    /*
     * Seek to the end of the file. This is done to support multiple file
     * compilation. Doing this simplifies other parts of the codebase because
     * it eliminates the need to seek for a different starting place.
     */
    FlSeekFile (ASL_FILE_AML_OUTPUT, Op->Asl.FinalAmlOffset + Length);
}


/*******************************************************************************
 *
 * FUNCTION:    CgWriteNode
 *
 * PARAMETERS:  Op            - Parse node to write.
 *
 * RETURN:      None.
 *
 * DESCRIPTION: Write the AML that corresponds to a parse node.
 *
 ******************************************************************************/

static void
CgWriteNode (
    ACPI_PARSE_OBJECT       *Op)
{
    ASL_RESOURCE_NODE       *Rnode;


    /* Write all comments here. */

    if (AcpiGbl_CaptureComments)
    {
        CgWriteAmlComment(Op);
    }

    /* Always check for DEFAULT_ARG and other "Noop" nodes */
    /* TBD: this may not be the best place for this check */

    if ((Op->Asl.ParseOpcode == PARSEOP_DEFAULT_ARG)  ||
        (Op->Asl.ParseOpcode == PARSEOP_INCLUDE)      ||
        (Op->Asl.ParseOpcode == PARSEOP_INCLUDE_END))
    {
        return;
    }

    Op->Asl.FinalAmlLength = 0;

    switch (Op->Asl.AmlOpcode)
    {
    case AML_RAW_DATA_BYTE:
    case AML_RAW_DATA_WORD:
    case AML_RAW_DATA_DWORD:
    case AML_RAW_DATA_QWORD:

        CgLocalWriteAmlData (Op, &Op->Asl.Value.Integer, Op->Asl.AmlLength);
        return;


    case AML_RAW_DATA_BUFFER:

        CgLocalWriteAmlData (Op, Op->Asl.Value.Buffer, Op->Asl.AmlLength);
        return;


    case AML_RAW_DATA_CHAIN:

        Rnode = ACPI_CAST_PTR (ASL_RESOURCE_NODE, Op->Asl.Value.Buffer);
        while (Rnode)
        {
            CgLocalWriteAmlData (Op, Rnode->Buffer, Rnode->BufferLength);
            Rnode = Rnode->Next;
        }
        return;

    default:

        /* Internal data opcodes must all appear above */

        break;
    }

    switch (Op->Asl.ParseOpcode)
    {
    case PARSEOP_DEFAULT_ARG:

        break;

    case PARSEOP_DEFINITION_BLOCK:

        CgWriteTableHeader (Op);
        if (AcpiGbl_CaptureComments)
        {
            CgWriteAmlDefBlockComment (Op);
        }
        break;

    case PARSEOP_NAMESEG:
    case PARSEOP_NAMESTRING:
    case PARSEOP_METHODCALL:

        CgLocalWriteAmlData (Op, Op->Asl.Value.String, Op->Asl.AmlLength);
        break;

    default:

        CgWriteAmlOpcode (Op);
        break;
    }
}