C++ ACPI_IS_ROOT_PREFIX函數代碼示例

void acpi_ns_get_internal_name_length(struct acpi_namestring_info *info)
{
	const char *next_external_char;
	u32 i;

	ACPI_FUNCTION_ENTRY();

	next_external_char = info->external_name;
	info->num_carats = 0;
	info->num_segments = 0;
	info->fully_qualified = FALSE;

	/*
	 * For the internal name, the required length is 4 bytes per segment,
	 * plus 1 each for root_prefix, multi_name_prefix_op, segment count,
	 * trailing null (which is not really needed, but no there's harm in
	 * putting it there)
	 *
	 * strlen() + 1 covers the first name_seg, which has no path separator
	 */
	if (ACPI_IS_ROOT_PREFIX(*next_external_char)) {
		info->fully_qualified = TRUE;
		next_external_char++;

		/* Skip redundant root_prefix, like \\_SB.PCI0.SBRG.EC0 */

		while (ACPI_IS_ROOT_PREFIX(*next_external_char)) {
			next_external_char++;
		}
	} else {
		/* Handle Carat prefixes */

		while (ACPI_IS_PARENT_PREFIX(*next_external_char)) {
			info->num_carats++;
			next_external_char++;
		}
	}

	/*
	 * Determine the number of ACPI name "segments" by counting the number of
	 * path separators within the string. Start with one segment since the
	 * segment count is [(# separators) + 1], and zero separators is ok.
	 */
	if (*next_external_char) {
		info->num_segments = 1;
		for (i = 0; next_external_char[i]; i++) {
			if (ACPI_IS_PATH_SEPARATOR(next_external_char[i])) {
				info->num_segments++;
			}
		}
	}

	info->length = (ACPI_NAME_SIZE * info->num_segments) +
	    4 + info->num_carats;

	info->next_external_char = next_external_char;
}

acpi_status
acpi_get_handle(acpi_handle parent,
		acpi_string pathname, acpi_handle * ret_handle)
{
	acpi_status status;
	struct acpi_namespace_node *node = NULL;
	struct acpi_namespace_node *prefix_node = NULL;

	ACPI_FUNCTION_ENTRY();

	/* Parameter Validation */

	if (!ret_handle || !pathname) {
		return (AE_BAD_PARAMETER);
	}

	/* Convert a parent handle to a prefix node */

	if (parent) {
		prefix_node = acpi_ns_validate_handle(parent);
		if (!prefix_node) {
			return (AE_BAD_PARAMETER);
		}
	}

	/*
	 * Valid cases are:
	 * 1) Fully qualified pathname
	 * 2) Parent + Relative pathname
	 *
	 * Error for <null Parent + relative path>
	 */
	if (ACPI_IS_ROOT_PREFIX(pathname[0])) {

		/* Pathname is fully qualified (starts with '\') */

		/* Special case for root-only, since we can't search for it */

		if (!strcmp(pathname, ACPI_NS_ROOT_PATH)) {
			*ret_handle =
			    ACPI_CAST_PTR(acpi_handle, acpi_gbl_root_node);
			return (AE_OK);
		}
	} else if (!prefix_node) {

		/* Relative path with null prefix is disallowed */

		return (AE_BAD_PARAMETER);
	}

	/* Find the Node and convert to a handle */

	status =
	    acpi_ns_get_node(prefix_node, pathname, ACPI_NS_NO_UPSEARCH, &node);
	if (ACPI_SUCCESS(status)) {
		*ret_handle = ACPI_CAST_PTR(acpi_handle, node);
	}

	return (status);
}

void acpi_db_prep_namestring(char *name)
{

	if (!name) {
		return;
	}

	acpi_ut_strupr(name);

	/* Convert a leading forward slash to a backslash */

	if (*name == '/') {
		*name = '\\';
	}

	/* Ignore a leading backslash, this is the root prefix */

	if (ACPI_IS_ROOT_PREFIX(*name)) {
		name++;
	}

	/* Convert all slash path separators to dots */

	while (*name) {
		if ((*name == '/') || (*name == '\\')) {
			*name = '.';
		}

		name++;
	}
}

void
AcpiDmNamestring (
    char                    *Name)
{
    UINT32                  SegCount;


    if (!Name)
    {
        return;
    }

    /* Handle all Scope Prefix operators */

    while (ACPI_IS_ROOT_PREFIX (ACPI_GET8 (Name)) ||
           ACPI_IS_PARENT_PREFIX (ACPI_GET8 (Name)))
    {
        /* Append prefix character */

        AcpiOsPrintf ("%1c", ACPI_GET8 (Name));
        Name++;
    }

    switch (ACPI_GET8 (Name))
    {
    case 0:
        SegCount = 0;
        break;

    case AML_DUAL_NAME_PREFIX:
        SegCount = 2;
        Name++;
        break;

    case AML_MULTI_NAME_PREFIX_OP:
        SegCount = (UINT32) ACPI_GET8 (Name + 1);
        Name += 2;
        break;

    default:
        SegCount = 1;
        break;
    }

    while (SegCount)
    {
        /* Append Name segment */

        AcpiDmDumpName (*ACPI_CAST_PTR (UINT32, Name));

        SegCount--;
        if (SegCount)
        {
            /* Not last name, append dot separator */

            AcpiOsPrintf (".");
        }
        Name += ACPI_NAME_SIZE;
    }
}

void acpi_db_set_scope(char *name)
{
	acpi_status status;
	struct acpi_namespace_node *node;

	if (!name || name[0] == 0) {
		acpi_os_printf("Current scope: %s\n", acpi_gbl_db_scope_buf);
		return;
	}

	acpi_db_prep_namestring(name);

	if (ACPI_IS_ROOT_PREFIX(name[0])) {

		/* Validate new scope from the root */

		status = acpi_ns_get_node(acpi_gbl_root_node, name,
					  ACPI_NS_NO_UPSEARCH, &node);
		if (ACPI_FAILURE(status)) {
			goto error_exit;
		}

		acpi_gbl_db_scope_buf[0] = 0;
	} else {
		/* Validate new scope relative to old scope */

		status = acpi_ns_get_node(acpi_gbl_db_scope_node, name,
					  ACPI_NS_NO_UPSEARCH, &node);
		if (ACPI_FAILURE(status)) {
			goto error_exit;
		}
	}

	/* Build the final pathname */

	if (acpi_ut_safe_strcat
	    (acpi_gbl_db_scope_buf, sizeof(acpi_gbl_db_scope_buf), name)) {
		status = AE_BUFFER_OVERFLOW;
		goto error_exit;
	}

	if (acpi_ut_safe_strcat
	    (acpi_gbl_db_scope_buf, sizeof(acpi_gbl_db_scope_buf), "\\")) {
		status = AE_BUFFER_OVERFLOW;
		goto error_exit;
	}

	acpi_gbl_db_scope_node = node;
	acpi_os_printf("New scope: %s\n", acpi_gbl_db_scope_buf);
	return;

error_exit:

	acpi_os_printf("Could not attach scope: %s, %s\n",
		       name, acpi_format_exception(status));
}

acpi_status
acpi_ns_get_node_unlocked(struct acpi_namespace_node *prefix_node,
			  const char *pathname,
			  u32 flags, struct acpi_namespace_node **return_node)
{
	union acpi_generic_state scope_info;
	acpi_status status;
	char *internal_path;

	ACPI_FUNCTION_TRACE_PTR(ns_get_node_unlocked,
				ACPI_CAST_PTR(char, pathname));

	/* Simplest case is a null pathname */

	if (!pathname) {
		*return_node = prefix_node;
		if (!prefix_node) {
			*return_node = acpi_gbl_root_node;
		}

		return_ACPI_STATUS(AE_OK);
	}

	/* Quick check for a reference to the root */

	if (ACPI_IS_ROOT_PREFIX(pathname[0]) && (!pathname[1])) {
		*return_node = acpi_gbl_root_node;
		return_ACPI_STATUS(AE_OK);
	}

	/* Convert path to internal representation */

	status = acpi_ns_internalize_name(pathname, &internal_path);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	/* Setup lookup scope (search starting point) */

	scope_info.scope.node = prefix_node;

	/* Lookup the name in the namespace */

	status = acpi_ns_lookup(&scope_info, internal_path, ACPI_TYPE_ANY,
				ACPI_IMODE_EXECUTE,
				(flags | ACPI_NS_DONT_OPEN_SCOPE), NULL,
				return_node);
	if (ACPI_FAILURE(status)) {
		ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s, %s\n",
				  pathname, acpi_format_exception(status)));
	}

	ACPI_FREE(internal_path);
	return_ACPI_STATUS(status);
}

void
AcpiDbSetScope (
    char                    *Name)
{
    ACPI_STATUS             Status;
    ACPI_NAMESPACE_NODE     *Node;


    if (!Name || Name[0] == 0)
    {
        AcpiOsPrintf ("Current scope: %s\n", AcpiGbl_DbScopeBuf);
        return;
    }

    AcpiDbPrepNamestring (Name);

    if (ACPI_IS_ROOT_PREFIX (Name[0]))
    {
        /* Validate new scope from the root */

        Status = AcpiNsGetNode (AcpiGbl_RootNode, Name, ACPI_NS_NO_UPSEARCH,
                    &Node);
        if (ACPI_FAILURE (Status))
        {
            goto ErrorExit;
        }

        ACPI_STRCPY (AcpiGbl_DbScopeBuf, Name);
        ACPI_STRCAT (AcpiGbl_DbScopeBuf, "\\");
    }
    else
    {
        /* Validate new scope relative to old scope */

        Status = AcpiNsGetNode (AcpiGbl_DbScopeNode, Name, ACPI_NS_NO_UPSEARCH,
                    &Node);
        if (ACPI_FAILURE (Status))
        {
            goto ErrorExit;
        }

        ACPI_STRCAT (AcpiGbl_DbScopeBuf, Name);
        ACPI_STRCAT (AcpiGbl_DbScopeBuf, "\\");
    }

    AcpiGbl_DbScopeNode = Node;
    AcpiOsPrintf ("New scope: %s\n", AcpiGbl_DbScopeBuf);
    return;

ErrorExit:

    AcpiOsPrintf ("Could not attach scope: %s, %s\n",
        Name, AcpiFormatException (Status));
}

static void
UtAttachNameseg (
    ACPI_PARSE_OBJECT       *Op,
    char                    *Name)
{
    char                    *NameSeg;
    char                    PaddedNameSeg[4];


    if (!Name)
    {
        return;
    }

    /* Look for the last dot in the namepath */

    NameSeg = strrchr (Name, '.');
    if (NameSeg)
    {
        /* Found last dot, we have also found the final nameseg */

        NameSeg++;
        UtPadNameWithUnderscores (NameSeg, PaddedNameSeg);
    }
    else
    {
        /* No dots in the namepath, there is only a single nameseg. */
        /* Handle prefixes */

        while (ACPI_IS_ROOT_PREFIX (*Name) ||
               ACPI_IS_PARENT_PREFIX (*Name))
        {
            Name++;
        }

        /* Remaining string should be one single nameseg */

        UtPadNameWithUnderscores (Name, PaddedNameSeg);
    }

    ACPI_MOVE_NAME (Op->Asl.NameSeg, PaddedNameSeg);
}

void
AcpiDbPrepNamestring (
    char                    *Name)
{

    if (!Name)
    {
        return;
    }

    AcpiUtStrupr (Name);

    /* Convert a leading forward slash to a backslash */

    if (*Name == '/')
    {
        *Name = '\\';
    }

    /* Ignore a leading backslash, this is the root prefix */

    if (ACPI_IS_ROOT_PREFIX (*Name))
    {
        Name++;
    }

    /* Convert all slash path separators to dots */

    while (*Name)
    {
        if ((*Name == '/') ||
            (*Name == '\\'))
        {
            *Name = '.';
        }

        Name++;
    }
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_evaluate_object
 *
 * PARAMETERS:  handle              - Object handle (optional)
 *              pathname            - Object pathname (optional)
 *              external_params     - List of parameters to pass to method,
 *                                    terminated by NULL. May be NULL
 *                                    if no parameters are being passed.
 *              return_buffer       - Where to put method's return value (if
 *                                    any). If NULL, no value is returned.
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Find and evaluate the given object, passing the given
 *              parameters if necessary. One of "Handle" or "Pathname" must
 *              be valid (non-null)
 *
 ******************************************************************************/
acpi_status
acpi_evaluate_object(acpi_handle handle,
		     acpi_string pathname,
		     struct acpi_object_list *external_params,
		     struct acpi_buffer *return_buffer)
{
	acpi_status status;
	struct acpi_evaluate_info *info;
	acpi_size buffer_space_needed;
	u32 i;

	ACPI_FUNCTION_TRACE(acpi_evaluate_object);

	/* Allocate and initialize the evaluation information block */

	info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
	if (!info) {
		return_ACPI_STATUS(AE_NO_MEMORY);
	}

	info->pathname = pathname;

	/* Convert and validate the device handle */

	info->prefix_node = acpi_ns_validate_handle(handle);
	if (!info->prefix_node) {
		status = AE_BAD_PARAMETER;
		goto cleanup;
	}

	/*
	 * If there are parameters to be passed to a control method, the external
	 * objects must all be converted to internal objects
	 */
	if (external_params && external_params->count) {
		/*
		 * Allocate a new parameter block for the internal objects
		 * Add 1 to count to allow for null terminated internal list
		 */
		info->parameters = ACPI_ALLOCATE_ZEROED(((acpi_size)
							 external_params->
							 count +
							 1) * sizeof(void *));
		if (!info->parameters) {
			status = AE_NO_MEMORY;
			goto cleanup;
		}

		/* Convert each external object in the list to an internal object */

		for (i = 0; i < external_params->count; i++) {
			status =
			    acpi_ut_copy_eobject_to_iobject(&external_params->
							    pointer[i],
							    &info->
							    parameters[i]);
			if (ACPI_FAILURE(status)) {
				goto cleanup;
			}
		}
		info->parameters[external_params->count] = NULL;
	}

	/*
	 * Three major cases:
	 * 1) Fully qualified pathname
	 * 2) No handle, not fully qualified pathname (error)
	 * 3) Valid handle
	 */
	if ((pathname) && (ACPI_IS_ROOT_PREFIX(pathname[0]))) {

		/* The path is fully qualified, just evaluate by name */

		info->prefix_node = NULL;
		status = acpi_ns_evaluate(info);
	} else if (!handle) {
		/*
		 * A handle is optional iff a fully qualified pathname is specified.
		 * Since we've already handled fully qualified names above, this is
		 * an error
		 */
//.........這裏部分代碼省略.........

ACPI_STATUS
AcpiEvaluateObject (
    ACPI_HANDLE             Handle,
    ACPI_STRING             Pathname,
    ACPI_OBJECT_LIST        *ExternalParams,
    ACPI_BUFFER             *ReturnBuffer)
{
    ACPI_STATUS             Status;
    ACPI_EVALUATE_INFO      *Info;
    ACPI_SIZE               BufferSpaceNeeded;
    UINT32                  i;


    ACPI_FUNCTION_TRACE (AcpiEvaluateObject);


    /* Allocate and initialize the evaluation information block */

    Info = ACPI_ALLOCATE_ZEROED (sizeof (ACPI_EVALUATE_INFO));
    if (!Info)
    {
        return_ACPI_STATUS (AE_NO_MEMORY);
    }

    /* Convert and validate the device handle */

    Info->PrefixNode = AcpiNsValidateHandle (Handle);
    if (!Info->PrefixNode)
    {
        Status = AE_BAD_PARAMETER;
        goto Cleanup;
    }

    /*
     * Get the actual namespace node for the target object.
     * Handles these cases:
     *
     * 1) Null node, valid pathname from root (absolute path)
     * 2) Node and valid pathname (path relative to Node)
     * 3) Node, Null pathname
     */
    if ((Pathname) &&
        (ACPI_IS_ROOT_PREFIX (Pathname[0])))
    {
        /* The path is fully qualified, just evaluate by name */

        Info->PrefixNode = NULL;
    }
    else if (!Handle)
    {
        /*
         * A handle is optional iff a fully qualified pathname is specified.
         * Since we've already handled fully qualified names above, this is
         * an error.
         */
        if (!Pathname)
        {
            ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
                "Both Handle and Pathname are NULL"));
        }
        else
        {
            ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
                "Null Handle with relative pathname [%s]", Pathname));
        }

        Status = AE_BAD_PARAMETER;
        goto Cleanup;
    }

    Info->RelativePathname = Pathname;

    /*
     * Convert all external objects passed as arguments to the
     * internal version(s).
     */
    if (ExternalParams && ExternalParams->Count)
    {
        Info->ParamCount = (UINT16) ExternalParams->Count;

        /* Warn on impossible argument count */

        if (Info->ParamCount > ACPI_METHOD_NUM_ARGS)
        {
            ACPI_WARN_PREDEFINED ((AE_INFO, Pathname, ACPI_WARN_ALWAYS,
                "Excess arguments (%u) - using only %u",
                Info->ParamCount, ACPI_METHOD_NUM_ARGS));

            Info->ParamCount = ACPI_METHOD_NUM_ARGS;
        }

        /*
         * Allocate a new parameter block for the internal objects
         * Add 1 to count to allow for null terminated internal list
         */
        Info->Parameters = ACPI_ALLOCATE_ZEROED (
            ((ACPI_SIZE) Info->ParamCount + 1) * sizeof (void *));
        if (!Info->Parameters)
        {
            Status = AE_NO_MEMORY;
//.........這裏部分代碼省略.........

ACPI_STATUS
AcpiNsGetNodeUnlocked (
    ACPI_NAMESPACE_NODE     *PrefixNode,
    const char              *Pathname,
    UINT32                  Flags,
    ACPI_NAMESPACE_NODE     **ReturnNode)
{
    ACPI_GENERIC_STATE      ScopeInfo;
    ACPI_STATUS             Status;
    char                    *InternalPath;


    ACPI_FUNCTION_TRACE_PTR (NsGetNodeUnlocked, ACPI_CAST_PTR (char, Pathname));


    /* Simplest case is a null pathname */

    if (!Pathname)
    {
        *ReturnNode = PrefixNode;
        if (!PrefixNode)
        {
            *ReturnNode = AcpiGbl_RootNode;
        }

        return_ACPI_STATUS (AE_OK);
    }

    /* Quick check for a reference to the root */

    if (ACPI_IS_ROOT_PREFIX (Pathname[0]) && (!Pathname[1]))
    {
        *ReturnNode = AcpiGbl_RootNode;
        return_ACPI_STATUS (AE_OK);
    }

    /* Convert path to internal representation */

    Status = AcpiNsInternalizeName (Pathname, &InternalPath);
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    /* Setup lookup scope (search starting point) */

    ScopeInfo.Scope.Node = PrefixNode;

    /* Lookup the name in the namespace */

    Status = AcpiNsLookup (&ScopeInfo, InternalPath, ACPI_TYPE_ANY,
        ACPI_IMODE_EXECUTE, (Flags | ACPI_NS_DONT_OPEN_SCOPE),
        NULL, ReturnNode);
    if (ACPI_FAILURE (Status))
    {
        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "%s, %s\n",
            Pathname, AcpiFormatException (Status)));
    }

    ACPI_FREE (InternalPath);
    return_ACPI_STATUS (Status);
}

void
AcpiNsGetInternalNameLength (
    ACPI_NAMESTRING_INFO    *Info)
{
    const char              *NextExternalChar;
    UINT32                  i;


    ACPI_FUNCTION_ENTRY ();


    NextExternalChar = Info->ExternalName;
    Info->NumCarats = 0;
    Info->NumSegments = 0;
    Info->FullyQualified = FALSE;

    /*
     * For the internal name, the required length is 4 bytes per segment,
     * plus 1 each for RootPrefix, MultiNamePrefixOp, segment count,
     * trailing null (which is not really needed, but no there's harm in
     * putting it there)
     *
     * strlen() + 1 covers the first NameSeg, which has no path separator
     */
    if (ACPI_IS_ROOT_PREFIX (*NextExternalChar))
    {
        Info->FullyQualified = TRUE;
        NextExternalChar++;

        /* Skip redundant RootPrefix, like \\_SB.PCI0.SBRG.EC0 */

        while (ACPI_IS_ROOT_PREFIX (*NextExternalChar))
        {
            NextExternalChar++;
        }
    }
    else
    {
        /* Handle Carat prefixes */

        while (ACPI_IS_PARENT_PREFIX (*NextExternalChar))
        {
            Info->NumCarats++;
            NextExternalChar++;
        }
    }

    /*
     * Determine the number of ACPI name "segments" by counting the number of
     * path separators within the string. Start with one segment since the
     * segment count is [(# separators) + 1], and zero separators is ok.
     */
    if (*NextExternalChar)
    {
        Info->NumSegments = 1;
        for (i = 0; NextExternalChar[i]; i++)
        {
            if (ACPI_IS_PATH_SEPARATOR (NextExternalChar[i]))
            {
                Info->NumSegments++;
            }
        }
    }

    Info->Length = (ACPI_NAME_SIZE * Info->NumSegments) +
        4 + Info->NumCarats;

    Info->NextExternalChar = NextExternalChar;
}

void
AcpiDmDisplayPath (
    ACPI_PARSE_OBJECT       *Op)
{
    ACPI_PARSE_OBJECT       *Prev;
    ACPI_PARSE_OBJECT       *Search;
    UINT32                  Name;
    BOOLEAN                 DoDot = FALSE;
    ACPI_PARSE_OBJECT       *NamePath;
    const ACPI_OPCODE_INFO  *OpInfo;


    /* We are only interested in named objects */

    OpInfo = AcpiPsGetOpcodeInfo (Op->Common.AmlOpcode);
    if (!(OpInfo->Flags & AML_NSNODE))
    {
        return;
    }

    if (OpInfo->Flags & AML_CREATE)
    {
        /* Field creation - check for a fully qualified namepath */

        if (Op->Common.AmlOpcode == AML_CREATE_FIELD_OP)
        {
            NamePath = AcpiPsGetArg (Op, 3);
        }
        else
        {
            NamePath = AcpiPsGetArg (Op, 2);
        }

        if ((NamePath) &&
            (NamePath->Common.Value.String) &&
            (ACPI_IS_ROOT_PREFIX (NamePath->Common.Value.String[0])))
        {
            AcpiDmNamestring (NamePath->Common.Value.String);
            return;
        }
    }

    Prev = NULL;            /* Start with Root Node */

    while (Prev != Op)
    {
        /* Search upwards in the tree to find scope with "prev" as its parent */

        Search = Op;
        for (; ;)
        {
            if (Search->Common.Parent == Prev)
            {
                break;
            }

            /* Go up one level */

            Search = Search->Common.Parent;
        }

        if (Prev)
        {
            OpInfo = AcpiPsGetOpcodeInfo (Search->Common.AmlOpcode);
            if (!(OpInfo->Flags & AML_FIELD))
            {
                /* Below root scope, append scope name */

                if (DoDot)
                {
                    /* Append dot */

                    AcpiOsPrintf (".");
                }

                if (OpInfo->Flags & AML_CREATE)
                {
                    if (Op->Common.AmlOpcode == AML_CREATE_FIELD_OP)
                    {
                        NamePath = AcpiPsGetArg (Op, 3);
                    }
                    else
                    {
                        NamePath = AcpiPsGetArg (Op, 2);
                    }

                    if ((NamePath) &&
                        (NamePath->Common.Value.String))
                    {
                        AcpiDmDumpName (NamePath->Common.Value.String);
                    }
                }
                else
                {
                    Name = AcpiPsGetName (Search);
                    AcpiDmDumpName ((char *) &Name);
                }

                DoDot = TRUE;
            }
//.........這裏部分代碼省略.........

static ACPI_STATUS
OptOptimizeNameDeclaration (
    ACPI_PARSE_OBJECT       *Op,
    ACPI_WALK_STATE         *WalkState,
    ACPI_NAMESPACE_NODE     *CurrentNode,
    ACPI_NAMESPACE_NODE     *TargetNode,
    char                    *AmlNameString,
    char                    **NewPath)
{
    ACPI_STATUS             Status;
    char                    *NewPathExternal;
    ACPI_NAMESPACE_NODE     *Node;


    ACPI_FUNCTION_TRACE (OptOptimizeNameDeclaration);


    if (((CurrentNode == AcpiGbl_RootNode) ||
        (Op->Common.Parent->Asl.ParseOpcode == PARSEOP_DEFINITION_BLOCK)) &&
            (ACPI_IS_ROOT_PREFIX (AmlNameString[0])))
    {
        /*
         * The current scope is the root, and the namepath has a root prefix
         * that is therefore extraneous. Remove it.
         */
        *NewPath = &AmlNameString[1];

        /* Debug output */

        Status = AcpiNsExternalizeName (ACPI_UINT32_MAX, *NewPath,
            NULL, &NewPathExternal);
        if (ACPI_FAILURE (Status))
        {
            AslCoreSubsystemError (Op, Status, "Externalizing NamePath",
                ASL_NO_ABORT);
            return (Status);
        }

        /*
         * Check to make sure that the optimization finds the node we are
         * looking for. This is simply a sanity check on the new
         * path that has been created.
         *
         * We know that we are at the root, so NULL is used for the scope.
         */
        Status = AcpiNsLookup (NULL, *NewPath,
            ACPI_TYPE_ANY, ACPI_IMODE_EXECUTE,
            ACPI_NS_DONT_OPEN_SCOPE, WalkState, &(Node));
        if (ACPI_SUCCESS (Status))
        {
            /* Found the namepath, but make sure the node is correct */

            if (Node == TargetNode)
            {
                /* The lookup matched the node, accept this optimization */

                AslError (ASL_OPTIMIZATION, ASL_MSG_NAME_OPTIMIZATION,
                    Op, NewPathExternal);

                ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
                    "AT ROOT:   %-24s", NewPathExternal));
            }
            else
            {
                /* Node is not correct, do not use this optimization */

                Status = AE_NOT_FOUND;
                ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
                    " ***** WRONG NODE"));
                AslError (ASL_WARNING, ASL_MSG_COMPILER_INTERNAL, Op,
                    "Not using optimized name - found wrong node");
            }
        }
        else
        {
            /* The lookup failed, we obviously cannot use this optimization */

            ACPI_DEBUG_PRINT_RAW ((ACPI_DB_OPTIMIZATIONS,
                " ***** NOT FOUND"));
            AslError (ASL_WARNING, ASL_MSG_COMPILER_INTERNAL, Op,
                "Not using optimized name - did not find node");
        }

        ACPI_FREE (NewPathExternal);
        return (Status);
    }

    /* Could not optimize */

    return (AE_NOT_FOUND);
}