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/*******************************************************************************

 *

 * Module Name: utmath - Integer math support routines

 *

 ******************************************************************************/

/******************************************************************************

 *

 * 1. Copyright Notice

 *

 * Some or all of this work - Copyright (c) 1999 - 2011, Intel Corp.

 * All rights reserved.

 *

 * 2. License

 *

 * 2.1. This is your license from Intel Corp. under its intellectual property

 * rights.  You may have additional license terms from the party that provided

 * you this software, covering your right to use that party's intellectual

 * property rights.

 *

 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a

 * copy of the source code appearing in this file ("Covered Code") an

 * irrevocable, perpetual, worldwide license under Intel's copyrights in the

 * base code distributed originally by Intel ("Original Intel Code") to copy,

 * make derivatives, distribute, use and display any portion of the Covered

 * Code in any form, with the right to sublicense such rights; and

 *

 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent

 * license (with the right to sublicense), under only those claims of Intel

 * patents that are infringed by the Original Intel Code, to make, use, sell,

 * offer to sell, and import the Covered Code and derivative works thereof

 * solely to the minimum extent necessary to exercise the above copyright

 * license, and in no event shall the patent license extend to any additions

 * to or modifications of the Original Intel Code.  No other license or right

 * is granted directly or by implication, estoppel or otherwise;

 *

 * The above copyright and patent license is granted only if the following

 * conditions are met:

 *

 * 3. Conditions

 *

 * 3.1. Redistribution of Source with Rights to Further Distribute Source.

 * Redistribution of source code of any substantial portion of the Covered

 * Code or modification with rights to further distribute source must include

 * the above Copyright Notice, the above License, this list of Conditions,

 * and the following Disclaimer and Export Compliance provision.  In addition,

 * Licensee must cause all Covered Code to which Licensee contributes to

 * contain a file documenting the changes Licensee made to create that Covered

 * Code and the date of any change.  Licensee must include in that file the

 * documentation of any changes made by any predecessor Licensee.  Licensee

 * must include a prominent statement that the modification is derived,

 * directly or indirectly, from Original Intel Code.

 *

 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.

 * Redistribution of source code of any substantial portion of the Covered

 * Code or modification without rights to further distribute source must

 * include the following Disclaimer and Export Compliance provision in the

 * documentation and/or other materials provided with distribution.  In

 * addition, Licensee may not authorize further sublicense of source of any

 * portion of the Covered Code, and must include terms to the effect that the

 * license from Licensee to its licensee is limited to the intellectual

 * property embodied in the software Licensee provides to its licensee, and

 * not to intellectual property embodied in modifications its licensee may

 * make.

 *

 * 3.3. Redistribution of Executable. Redistribution in executable form of any

 * substantial portion of the Covered Code or modification must reproduce the

 * above Copyright Notice, and the following Disclaimer and Export Compliance

 * provision in the documentation and/or other materials provided with the

 * distribution.

 *

 * 3.4. Intel retains all right, title, and interest in and to the Original

 * Intel Code.

 *

 * 3.5. Neither the name Intel nor any other trademark owned or controlled by

 * Intel shall be used in advertising or otherwise to promote the sale, use or

 * other dealings in products derived from or relating to the Covered Code

 * without prior written authorization from Intel.

 *

 * 4. Disclaimer and Export Compliance

 *

 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED

 * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE

 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,

 * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY

 * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY

 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A

 * PARTICULAR PURPOSE.

 *

 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES

 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR

 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,

 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY

 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL

 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS

 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY

 * LIMITED REMEDY.

 *

 * 4.3. Licensee shall not export, either directly or indirectly, any of this

 * software or system incorporating such software without first obtaining any

 * required license or other approval from the U. S. Department of Commerce or

 * any other agency or department of the United States Government.  In the

 * event Licensee exports any such software from the United States or

 * re-exports any such software from a foreign destination, Licensee shall

 * ensure that the distribution and export/re-export of the software is in

 * compliance with all laws, regulations, orders, or other restrictions of the

 * U.S. Export Administration Regulations. Licensee agrees that neither it nor

 * any of its subsidiaries will export/re-export any technical data, process,

 * software, or service, directly or indirectly, to any country for which the

 * United States government or any agency thereof requires an export license,

 * other governmental approval, or letter of assurance, without first obtaining

 * such license, approval or letter.

 *

 *****************************************************************************/

#define __UTMATH_C__

#include "acpi.h"

#include "accommon.h"

#define _COMPONENT          ACPI_UTILITIES

        ACPI_MODULE_NAME    ("utmath")

/*

 * Optional support for 64-bit double-precision integer divide. This code

 * is configurable and is implemented in order to support 32-bit kernel

 * environments where a 64-bit double-precision math library is not available.

 *

 * Support for a more normal 64-bit divide/modulo (with check for a divide-

 * by-zero) appears after this optional section of code.

 */

#ifndef ACPI_USE_NATIVE_DIVIDE

/* Structures used only for 64-bit divide */

typedef struct uint64_struct

{

    UINT32                          Lo;

    UINT32                          Hi;

} UINT64_STRUCT;

typedef union uint64_overlay

{

    UINT64                          Full;

    UINT64_STRUCT                   Part;

} UINT64_OVERLAY;

/*******************************************************************************

 *

 * FUNCTION:    AcpiUtShortDivide

 *

 * PARAMETERS:  Dividend            - 64-bit dividend

 *              Divisor             - 32-bit divisor

 *              OutQuotient         - Pointer to where the quotient is returned

 *              OutRemainder        - Pointer to where the remainder is returned

 *

 * RETURN:      Status (Checks for divide-by-zero)

 *

 * DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits)

 *              divide and modulo.  The result is a 64-bit quotient and a

 *              32-bit remainder.

 *

 ******************************************************************************/

ACPI_STATUS

AcpiUtShortDivide (

    UINT64                  Dividend,

    UINT32                  Divisor,

    UINT64                  *OutQuotient,

    UINT32                  *OutRemainder)

{

    UINT64_OVERLAY          DividendOvl;

    UINT64_OVERLAY          Quotient;

    UINT32                  Remainder32;

    ACPI_FUNCTION_TRACE (UtShortDivide);

    /* Always check for a zero divisor */

    if (Divisor == 0)

    {

        ACPI_ERROR ((AE_INFO, "Divide by zero"));

        return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);

    }

    DividendOvl.Full = Dividend;

    /*

     * The quotient is 64 bits, the remainder is always 32 bits,

     * and is generated by the second divide.

     */

    ACPI_DIV_64_BY_32 (0, DividendOvl.Part.Hi, Divisor,

                       Quotient.Part.Hi, Remainder32);

    ACPI_DIV_64_BY_32 (Remainder32, DividendOvl.Part.Lo, Divisor,

                       Quotient.Part.Lo, Remainder32);

    /* Return only what was requested */

    if (OutQuotient)

    {

        *OutQuotient = Quotient.Full;

    }

    if (OutRemainder)

    {

        *OutRemainder = Remainder32;

    }

    return_ACPI_STATUS (AE_OK);

}

/*******************************************************************************

 *

 * FUNCTION:    AcpiUtDivide

 *

 * PARAMETERS:  InDividend          - Dividend

 *              InDivisor           - Divisor

 *              OutQuotient         - Pointer to where the quotient is returned

 *              OutRemainder        - Pointer to where the remainder is returned

 *

 * RETURN:      Status (Checks for divide-by-zero)

 *

 * DESCRIPTION: Perform a divide and modulo.

 *

 ******************************************************************************/

ACPI_STATUS

AcpiUtDivide (

    UINT64                  InDividend,

    UINT64                  InDivisor,

    UINT64                  *OutQuotient,

    UINT64                  *OutRemainder)

{

    UINT64_OVERLAY          Dividend;

    UINT64_OVERLAY          Divisor;

    UINT64_OVERLAY          Quotient;

    UINT64_OVERLAY          Remainder;

    UINT64_OVERLAY          NormalizedDividend;

    UINT64_OVERLAY          NormalizedDivisor;

    UINT32                  Partial1;

    UINT64_OVERLAY          Partial2;

    UINT64_OVERLAY          Partial3;

    ACPI_FUNCTION_TRACE (UtDivide);

    /* Always check for a zero divisor */

    if (InDivisor == 0)

    {

        ACPI_ERROR ((AE_INFO, "Divide by zero"));

        return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);

    }

    Divisor.Full  = InDivisor;

    Dividend.Full = InDividend;

    if (Divisor.Part.Hi == 0)

    {

        /*

         * 1) Simplest case is where the divisor is 32 bits, we can

         * just do two divides

         */

        Remainder.Part.Hi = 0;

        /*

         * The quotient is 64 bits, the remainder is always 32 bits,

         * and is generated by the second divide.

         */

        ACPI_DIV_64_BY_32 (0, Dividend.Part.Hi, Divisor.Part.Lo,

                           Quotient.Part.Hi, Partial1);

        ACPI_DIV_64_BY_32 (Partial1, Dividend.Part.Lo, Divisor.Part.Lo,

                           Quotient.Part.Lo, Remainder.Part.Lo);

    }

    else

    {

        /*

         * 2) The general case where the divisor is a full 64 bits

         * is more difficult

         */

        Quotient.Part.Hi   = 0;

        NormalizedDividend = Dividend;

        NormalizedDivisor  = Divisor;

        /* Normalize the operands (shift until the divisor is < 32 bits) */

        do

        {

            ACPI_SHIFT_RIGHT_64 (NormalizedDivisor.Part.Hi,

                                 NormalizedDivisor.Part.Lo);

            ACPI_SHIFT_RIGHT_64 (NormalizedDividend.Part.Hi,

                                 NormalizedDividend.Part.Lo);

        } while (NormalizedDivisor.Part.Hi != 0);

        /* Partial divide */

        ACPI_DIV_64_BY_32 (NormalizedDividend.Part.Hi,

                           NormalizedDividend.Part.Lo,

                           NormalizedDivisor.Part.Lo,

                           Quotient.Part.Lo, Partial1);

        /*

         * The quotient is always 32 bits, and simply requires adjustment.

         * The 64-bit remainder must be generated.

         */

        Partial1      = Quotient.Part.Lo * Divisor.Part.Hi;

        Partial2.Full = (UINT64) Quotient.Part.Lo * Divisor.Part.Lo;

        Partial3.Full = (UINT64) Partial2.Part.Hi + Partial1;

        Remainder.Part.Hi = Partial3.Part.Lo;

        Remainder.Part.Lo = Partial2.Part.Lo;

        if (Partial3.Part.Hi == 0)

        {

            if (Partial3.Part.Lo >= Dividend.Part.Hi)

            {

                if (Partial3.Part.Lo == Dividend.Part.Hi)

                {

                    if (Partial2.Part.Lo > Dividend.Part.Lo)

                    {

                        Quotient.Part.Lo--;

                        Remainder.Full -= Divisor.Full;

                    }

                }

                else

                {

                    Quotient.Part.Lo--;

                    Remainder.Full -= Divisor.Full;

                }

            }

            Remainder.Full    = Remainder.Full - Dividend.Full;

            Remainder.Part.Hi = (UINT32) -((INT32) Remainder.Part.Hi);

            Remainder.Part.Lo = (UINT32) -((INT32) Remainder.Part.Lo);

            if (Remainder.Part.Lo)

            {

                Remainder.Part.Hi--;

            }

        }

    }

    /* Return only what was requested */

    if (OutQuotient)

    {

        *OutQuotient = Quotient.Full;

    }

    if (OutRemainder)

    {

        *OutRemainder = Remainder.Full;

    }

    return_ACPI_STATUS (AE_OK);

}

#else

/*******************************************************************************

 *

 * FUNCTION:    AcpiUtShortDivide, AcpiUtDivide

 *

 * PARAMETERS:  See function headers above

 *

 * DESCRIPTION: Native versions of the UtDivide functions. Use these if either

 *              1) The target is a 64-bit platform and therefore 64-bit

 *                 integer math is supported directly by the machine.

 *              2) The target is a 32-bit or 16-bit platform, and the

 *                 double-precision integer math library is available to

 *                 perform the divide.

 *

 ******************************************************************************/

ACPI_STATUS

AcpiUtShortDivide (

    UINT64                  InDividend,

    UINT32                  Divisor,

    UINT64                  *OutQuotient,

    UINT32                  *OutRemainder)

{

    ACPI_FUNCTION_TRACE (UtShortDivide);

    /* Always check for a zero divisor */

    if (Divisor == 0)

    {

        ACPI_ERROR ((AE_INFO, "Divide by zero"));

        return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);

    }

    /* Return only what was requested */

    if (OutQuotient)

    {

        *OutQuotient = InDividend / Divisor;

    }

    if (OutRemainder)

    {

        *OutRemainder = (UINT32) (InDividend % Divisor);

    }

    return_ACPI_STATUS (AE_OK);

}

ACPI_STATUS

AcpiUtDivide (

    UINT64                  InDividend,

    UINT64                  InDivisor,

    UINT64                  *OutQuotient,

    UINT64                  *OutRemainder)

{

    ACPI_FUNCTION_TRACE (UtDivide);

    /* Always check for a zero divisor */

    if (InDivisor == 0)

    {

        ACPI_ERROR ((AE_INFO, "Divide by zero"));

        return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);

    }

    /* Return only what was requested */

    if (OutQuotient)

    {

        *OutQuotient = InDividend / InDivisor;

    }

    if (OutRemainder)

    {

        *OutRemainder = InDividend % InDivisor;

    }

    return_ACPI_STATUS (AE_OK);

}

#endif