452 lines
15 KiB
C
452 lines
15 KiB
C
/*******************************************************************************
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*
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* Module Name: utmath - Integer math support routines
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*
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******************************************************************************/
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/******************************************************************************
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*
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* 1. Copyright Notice
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*
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* Some or all of this work - Copyright (c) 1999 - 2011, Intel Corp.
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* All rights reserved.
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*
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* 2. License
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*
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* 2.1. This is your license from Intel Corp. under its intellectual property
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* rights. You may have additional license terms from the party that provided
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* you this software, covering your right to use that party's intellectual
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* property rights.
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*
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* 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
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* copy of the source code appearing in this file ("Covered Code") an
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* irrevocable, perpetual, worldwide license under Intel's copyrights in the
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* base code distributed originally by Intel ("Original Intel Code") to copy,
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* make derivatives, distribute, use and display any portion of the Covered
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* Code in any form, with the right to sublicense such rights; and
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*
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* 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
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* license (with the right to sublicense), under only those claims of Intel
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* patents that are infringed by the Original Intel Code, to make, use, sell,
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* offer to sell, and import the Covered Code and derivative works thereof
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* solely to the minimum extent necessary to exercise the above copyright
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* license, and in no event shall the patent license extend to any additions
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* to or modifications of the Original Intel Code. No other license or right
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* is granted directly or by implication, estoppel or otherwise;
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*
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* The above copyright and patent license is granted only if the following
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* conditions are met:
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*
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* 3. Conditions
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*
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* 3.1. Redistribution of Source with Rights to Further Distribute Source.
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* Redistribution of source code of any substantial portion of the Covered
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* Code or modification with rights to further distribute source must include
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* the above Copyright Notice, the above License, this list of Conditions,
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* and the following Disclaimer and Export Compliance provision. In addition,
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* Licensee must cause all Covered Code to which Licensee contributes to
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* contain a file documenting the changes Licensee made to create that Covered
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* Code and the date of any change. Licensee must include in that file the
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* documentation of any changes made by any predecessor Licensee. Licensee
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* must include a prominent statement that the modification is derived,
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* directly or indirectly, from Original Intel Code.
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*
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* 3.2. Redistribution of Source with no Rights to Further Distribute Source.
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* Redistribution of source code of any substantial portion of the Covered
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* Code or modification without rights to further distribute source must
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* include the following Disclaimer and Export Compliance provision in the
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* documentation and/or other materials provided with distribution. In
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* addition, Licensee may not authorize further sublicense of source of any
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* portion of the Covered Code, and must include terms to the effect that the
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* license from Licensee to its licensee is limited to the intellectual
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* property embodied in the software Licensee provides to its licensee, and
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* not to intellectual property embodied in modifications its licensee may
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* make.
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*
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* 3.3. Redistribution of Executable. Redistribution in executable form of any
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* substantial portion of the Covered Code or modification must reproduce the
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* above Copyright Notice, and the following Disclaimer and Export Compliance
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* provision in the documentation and/or other materials provided with the
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* distribution.
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*
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* 3.4. Intel retains all right, title, and interest in and to the Original
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* Intel Code.
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*
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* 3.5. Neither the name Intel nor any other trademark owned or controlled by
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* Intel shall be used in advertising or otherwise to promote the sale, use or
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* other dealings in products derived from or relating to the Covered Code
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* without prior written authorization from Intel.
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*
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* 4. Disclaimer and Export Compliance
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*
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* 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
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* HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
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* IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
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* INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
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* UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
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* IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
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* PARTICULAR PURPOSE.
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*
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* 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
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* OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
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* COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
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* SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
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* CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
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* HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
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* SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
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* LIMITED REMEDY.
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*
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* 4.3. Licensee shall not export, either directly or indirectly, any of this
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* software or system incorporating such software without first obtaining any
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* required license or other approval from the U. S. Department of Commerce or
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* any other agency or department of the United States Government. In the
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* event Licensee exports any such software from the United States or
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* re-exports any such software from a foreign destination, Licensee shall
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* ensure that the distribution and export/re-export of the software is in
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* compliance with all laws, regulations, orders, or other restrictions of the
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* U.S. Export Administration Regulations. Licensee agrees that neither it nor
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* any of its subsidiaries will export/re-export any technical data, process,
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* software, or service, directly or indirectly, to any country for which the
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* United States government or any agency thereof requires an export license,
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* other governmental approval, or letter of assurance, without first obtaining
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* such license, approval or letter.
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*
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*****************************************************************************/
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#define __UTMATH_C__
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#include "acpi.h"
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#include "accommon.h"
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#define _COMPONENT ACPI_UTILITIES
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ACPI_MODULE_NAME ("utmath")
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/*
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* Optional support for 64-bit double-precision integer divide. This code
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* is configurable and is implemented in order to support 32-bit kernel
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* environments where a 64-bit double-precision math library is not available.
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*
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* Support for a more normal 64-bit divide/modulo (with check for a divide-
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* by-zero) appears after this optional section of code.
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*/
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#ifndef ACPI_USE_NATIVE_DIVIDE
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/* Structures used only for 64-bit divide */
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typedef struct uint64_struct
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{
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UINT32 Lo;
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UINT32 Hi;
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} UINT64_STRUCT;
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typedef union uint64_overlay
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{
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UINT64 Full;
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UINT64_STRUCT Part;
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} UINT64_OVERLAY;
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/*******************************************************************************
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*
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* FUNCTION: AcpiUtShortDivide
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*
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* PARAMETERS: Dividend - 64-bit dividend
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* Divisor - 32-bit divisor
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* OutQuotient - Pointer to where the quotient is returned
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* OutRemainder - Pointer to where the remainder is returned
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*
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* RETURN: Status (Checks for divide-by-zero)
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*
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* DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits)
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* divide and modulo. The result is a 64-bit quotient and a
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* 32-bit remainder.
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*
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******************************************************************************/
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ACPI_STATUS
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AcpiUtShortDivide (
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UINT64 Dividend,
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UINT32 Divisor,
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UINT64 *OutQuotient,
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UINT32 *OutRemainder)
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{
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UINT64_OVERLAY DividendOvl;
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UINT64_OVERLAY Quotient;
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UINT32 Remainder32;
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ACPI_FUNCTION_TRACE (UtShortDivide);
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/* Always check for a zero divisor */
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if (Divisor == 0)
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{
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ACPI_ERROR ((AE_INFO, "Divide by zero"));
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return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
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}
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DividendOvl.Full = Dividend;
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/*
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* The quotient is 64 bits, the remainder is always 32 bits,
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* and is generated by the second divide.
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*/
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ACPI_DIV_64_BY_32 (0, DividendOvl.Part.Hi, Divisor,
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Quotient.Part.Hi, Remainder32);
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ACPI_DIV_64_BY_32 (Remainder32, DividendOvl.Part.Lo, Divisor,
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Quotient.Part.Lo, Remainder32);
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/* Return only what was requested */
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if (OutQuotient)
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{
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*OutQuotient = Quotient.Full;
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}
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if (OutRemainder)
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{
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*OutRemainder = Remainder32;
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}
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return_ACPI_STATUS (AE_OK);
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}
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/*******************************************************************************
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*
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* FUNCTION: AcpiUtDivide
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*
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* PARAMETERS: InDividend - Dividend
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* InDivisor - Divisor
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* OutQuotient - Pointer to where the quotient is returned
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* OutRemainder - Pointer to where the remainder is returned
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*
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* RETURN: Status (Checks for divide-by-zero)
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*
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* DESCRIPTION: Perform a divide and modulo.
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*
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******************************************************************************/
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ACPI_STATUS
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AcpiUtDivide (
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UINT64 InDividend,
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UINT64 InDivisor,
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UINT64 *OutQuotient,
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UINT64 *OutRemainder)
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{
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UINT64_OVERLAY Dividend;
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UINT64_OVERLAY Divisor;
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UINT64_OVERLAY Quotient;
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UINT64_OVERLAY Remainder;
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UINT64_OVERLAY NormalizedDividend;
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UINT64_OVERLAY NormalizedDivisor;
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UINT32 Partial1;
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UINT64_OVERLAY Partial2;
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UINT64_OVERLAY Partial3;
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ACPI_FUNCTION_TRACE (UtDivide);
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/* Always check for a zero divisor */
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if (InDivisor == 0)
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{
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ACPI_ERROR ((AE_INFO, "Divide by zero"));
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return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
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}
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Divisor.Full = InDivisor;
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Dividend.Full = InDividend;
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if (Divisor.Part.Hi == 0)
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{
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/*
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* 1) Simplest case is where the divisor is 32 bits, we can
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* just do two divides
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*/
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Remainder.Part.Hi = 0;
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/*
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* The quotient is 64 bits, the remainder is always 32 bits,
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* and is generated by the second divide.
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*/
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ACPI_DIV_64_BY_32 (0, Dividend.Part.Hi, Divisor.Part.Lo,
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Quotient.Part.Hi, Partial1);
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ACPI_DIV_64_BY_32 (Partial1, Dividend.Part.Lo, Divisor.Part.Lo,
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Quotient.Part.Lo, Remainder.Part.Lo);
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}
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else
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{
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/*
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* 2) The general case where the divisor is a full 64 bits
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* is more difficult
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*/
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Quotient.Part.Hi = 0;
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NormalizedDividend = Dividend;
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NormalizedDivisor = Divisor;
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/* Normalize the operands (shift until the divisor is < 32 bits) */
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do
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{
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ACPI_SHIFT_RIGHT_64 (NormalizedDivisor.Part.Hi,
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NormalizedDivisor.Part.Lo);
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ACPI_SHIFT_RIGHT_64 (NormalizedDividend.Part.Hi,
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NormalizedDividend.Part.Lo);
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} while (NormalizedDivisor.Part.Hi != 0);
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/* Partial divide */
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ACPI_DIV_64_BY_32 (NormalizedDividend.Part.Hi,
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NormalizedDividend.Part.Lo,
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NormalizedDivisor.Part.Lo,
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Quotient.Part.Lo, Partial1);
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/*
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* The quotient is always 32 bits, and simply requires adjustment.
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* The 64-bit remainder must be generated.
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*/
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Partial1 = Quotient.Part.Lo * Divisor.Part.Hi;
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Partial2.Full = (UINT64) Quotient.Part.Lo * Divisor.Part.Lo;
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Partial3.Full = (UINT64) Partial2.Part.Hi + Partial1;
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Remainder.Part.Hi = Partial3.Part.Lo;
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Remainder.Part.Lo = Partial2.Part.Lo;
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if (Partial3.Part.Hi == 0)
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{
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if (Partial3.Part.Lo >= Dividend.Part.Hi)
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{
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if (Partial3.Part.Lo == Dividend.Part.Hi)
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{
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if (Partial2.Part.Lo > Dividend.Part.Lo)
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{
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Quotient.Part.Lo--;
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Remainder.Full -= Divisor.Full;
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}
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}
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else
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{
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Quotient.Part.Lo--;
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Remainder.Full -= Divisor.Full;
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}
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}
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Remainder.Full = Remainder.Full - Dividend.Full;
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Remainder.Part.Hi = (UINT32) -((INT32) Remainder.Part.Hi);
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Remainder.Part.Lo = (UINT32) -((INT32) Remainder.Part.Lo);
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if (Remainder.Part.Lo)
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{
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Remainder.Part.Hi--;
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}
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}
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}
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/* Return only what was requested */
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if (OutQuotient)
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{
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*OutQuotient = Quotient.Full;
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}
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if (OutRemainder)
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{
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*OutRemainder = Remainder.Full;
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}
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return_ACPI_STATUS (AE_OK);
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}
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#else
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/*******************************************************************************
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*
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* FUNCTION: AcpiUtShortDivide, AcpiUtDivide
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*
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* PARAMETERS: See function headers above
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*
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* DESCRIPTION: Native versions of the UtDivide functions. Use these if either
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* 1) The target is a 64-bit platform and therefore 64-bit
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* integer math is supported directly by the machine.
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* 2) The target is a 32-bit or 16-bit platform, and the
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* double-precision integer math library is available to
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* perform the divide.
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*
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******************************************************************************/
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ACPI_STATUS
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AcpiUtShortDivide (
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UINT64 InDividend,
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UINT32 Divisor,
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UINT64 *OutQuotient,
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UINT32 *OutRemainder)
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{
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ACPI_FUNCTION_TRACE (UtShortDivide);
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/* Always check for a zero divisor */
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if (Divisor == 0)
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{
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ACPI_ERROR ((AE_INFO, "Divide by zero"));
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return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
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}
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/* Return only what was requested */
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if (OutQuotient)
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{
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*OutQuotient = InDividend / Divisor;
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}
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if (OutRemainder)
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{
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*OutRemainder = (UINT32) (InDividend % Divisor);
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}
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return_ACPI_STATUS (AE_OK);
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}
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ACPI_STATUS
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AcpiUtDivide (
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UINT64 InDividend,
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UINT64 InDivisor,
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UINT64 *OutQuotient,
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UINT64 *OutRemainder)
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{
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ACPI_FUNCTION_TRACE (UtDivide);
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/* Always check for a zero divisor */
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if (InDivisor == 0)
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{
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ACPI_ERROR ((AE_INFO, "Divide by zero"));
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return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
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}
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/* Return only what was requested */
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if (OutQuotient)
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{
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*OutQuotient = InDividend / InDivisor;
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}
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if (OutRemainder)
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{
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*OutRemainder = InDividend % InDivisor;
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}
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return_ACPI_STATUS (AE_OK);
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}
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#endif
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