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

 *

 * Module Name: utmath - Integer math support routines

 *

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

/*

 * Copyright (C) 2000 - 2004, R. Byron Moore

 * All rights reserved.

 *

 * 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.

 *

 * Alternatively, this software may be distributed under the terms of the

 * GNU General Public License ("GPL") version 2 as published by the Free

 * Software Foundation.

 *

 * NO WARRANTY

 * 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 MERCHANTIBILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.

 */

#include <acpi/acpi.h>

#define _COMPONENT          ACPI_UTILITIES

         ACPI_MODULE_NAME    ("utmath")

/*

 * Support for double-precision integer divide.  This code is included here

 * in order to support kernel environments where the double-precision math

 * library is not available.

 */

#ifndef ACPI_USE_NATIVE_DIVIDE

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

 *

 * FUNCTION:    acpi_ut_short_divide

 *

 * PARAMETERS:  in_dividend         - Pointer to the dividend

 *              Divisor             - 32-bit divisor

 *              out_quotient        - Pointer to where the quotient is returned

 *              out_remainder       - 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

acpi_ut_short_divide (

        acpi_integer                    *in_dividend,

        u32                             divisor,

        acpi_integer                    *out_quotient,

        u32                             *out_remainder)

{

        union uint64_overlay            dividend;

        union uint64_overlay            quotient;

        u32                             remainder32;

        ACPI_FUNCTION_TRACE ("ut_short_divide");

        dividend.full = *in_dividend;

        /* Always check for a zero divisor */

        if (divisor == 0) {

                ACPI_REPORT_ERROR (("acpi_ut_short_divide: Divide by zero\n"));

                return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);

        }

        /*

         * 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,

                          quotient.part.hi, remainder32);

        ACPI_DIV_64_BY_32 (remainder32, dividend.part.lo,  divisor,

                          quotient.part.lo, remainder32);

        /* Return only what was requested */

        if (out_quotient) {

                *out_quotient = quotient.full;

        }

        if (out_remainder) {

                *out_remainder = remainder32;

        }

        return_ACPI_STATUS (AE_OK);

}

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

 *

 * FUNCTION:    acpi_ut_divide

 *

 * PARAMETERS:  in_dividend         - Pointer to the dividend

 *              in_divisor          - Pointer to the divisor

 *              out_quotient        - Pointer to where the quotient is returned

 *              out_remainder       - Pointer to where the remainder is returned

 *

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

 *

 * DESCRIPTION: Perform a divide and modulo.

 *

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

acpi_status

acpi_ut_divide (

        acpi_integer                    *in_dividend,

        acpi_integer                    *in_divisor,

        acpi_integer                    *out_quotient,

        acpi_integer                    *out_remainder)

{

        union uint64_overlay            dividend;

        union uint64_overlay            divisor;

        union uint64_overlay            quotient;

        union uint64_overlay            remainder;

        union uint64_overlay            normalized_dividend;

        union uint64_overlay            normalized_divisor;

        u32                             partial1;

        union uint64_overlay            partial2;

        union uint64_overlay            partial3;

        ACPI_FUNCTION_TRACE ("ut_divide");

        /* Always check for a zero divisor */

        if (*in_divisor == 0) {

                ACPI_REPORT_ERROR (("acpi_ut_divide: Divide by zero\n"));

                return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);

        }

        divisor.full  = *in_divisor;

        dividend.full = *in_dividend;

        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;

                normalized_dividend = dividend;

                normalized_divisor = divisor;

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

                do {

                        ACPI_SHIFT_RIGHT_64 (normalized_divisor.part.hi,

                                         normalized_divisor.part.lo);

                        ACPI_SHIFT_RIGHT_64 (normalized_dividend.part.hi,

                                         normalized_dividend.part.lo);

                } while (normalized_divisor.part.hi != 0);

                /* Partial divide */

                ACPI_DIV_64_BY_32 (normalized_dividend.part.hi,

                                  normalized_dividend.part.lo,

                                  normalized_divisor.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 = (acpi_integer) quotient.part.lo * divisor.part.lo;

                partial3.full = (acpi_integer) 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 = (u32) -((s32) remainder.part.hi);

                        remainder.part.lo = (u32) -((s32) remainder.part.lo);

                        if (remainder.part.lo) {

                                remainder.part.hi--;

                        }

                }

        }

        /* Return only what was requested */

        if (out_quotient) {

                *out_quotient = quotient.full;

        }

        if (out_remainder) {

                *out_remainder = remainder.full;

        }

        return_ACPI_STATUS (AE_OK);

}

#else

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

 *

 * FUNCTION:    acpi_ut_short_divide, acpi_ut_divide

 *

 * DESCRIPTION: Native versions of the ut_divide 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

acpi_ut_short_divide (

        acpi_integer                    *in_dividend,

        u32                             divisor,

        acpi_integer                    *out_quotient,

        u32                             *out_remainder)

{

        ACPI_FUNCTION_TRACE ("ut_short_divide");

        /* Always check for a zero divisor */

        if (divisor == 0) {

                ACPI_REPORT_ERROR (("acpi_ut_short_divide: Divide by zero\n"));

                return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);

        }

        /* Return only what was requested */

        if (out_quotient) {

                *out_quotient = *in_dividend / divisor;

        }

        if (out_remainder) {

                *out_remainder = (u32) *in_dividend % divisor;

        }

        return_ACPI_STATUS (AE_OK);

}

acpi_status

acpi_ut_divide (

        acpi_integer                    *in_dividend,

        acpi_integer                    *in_divisor,

        acpi_integer                    *out_quotient,

        acpi_integer                    *out_remainder)

{

        ACPI_FUNCTION_TRACE ("ut_divide");

        /* Always check for a zero divisor */

        if (*in_divisor == 0) {

                ACPI_REPORT_ERROR (("acpi_ut_divide: Divide by zero\n"));

                return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);

        }

        /* Return only what was requested */

        if (out_quotient) {

                *out_quotient = *in_dividend / *in_divisor;

        }

        if (out_remainder) {

                *out_remainder = *in_dividend % *in_divisor;

        }

        return_ACPI_STATUS (AE_OK);

}

#endif