drivers/acpica/utmath.c

0001 /*******************************************************************************
0002  *
0003  * Module Name: utmath - Integer math support routines
0004  *
0005  ******************************************************************************/
0006
0007 /******************************************************************************
0008  *
0009  * 1. Copyright Notice
0010  *
0011  * Some or all of this work - Copyright (c) 1999 - 2009, Intel Corp.
0012  * All rights reserved.
0013  *
0014  * 2. License
0015  *
0016  * 2.1. This is your license from Intel Corp. under its intellectual property
0017  * rights.  You may have additional license terms from the party that provided
0018  * you this software, covering your right to use that party's intellectual
0019  * property rights.
0020  *
0021  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
0022  * copy of the source code appearing in this file ("Covered Code") an
0023  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
0024  * base code distributed originally by Intel ("Original Intel Code") to copy,
0025  * make derivatives, distribute, use and display any portion of the Covered
0026  * Code in any form, with the right to sublicense such rights; and
0027  *
0028  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
0029  * license (with the right to sublicense), under only those claims of Intel
0030  * patents that are infringed by the Original Intel Code, to make, use, sell,
0031  * offer to sell, and import the Covered Code and derivative works thereof
0032  * solely to the minimum extent necessary to exercise the above copyright
0033  * license, and in no event shall the patent license extend to any additions
0034  * to or modifications of the Original Intel Code.  No other license or right
0035  * is granted directly or by implication, estoppel or otherwise;
0036  *
0037  * The above copyright and patent license is granted only if the following
0038  * conditions are met:
0039  *
0040  * 3. Conditions
0041  *
0042  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
0043  * Redistribution of source code of any substantial portion of the Covered
0044  * Code or modification with rights to further distribute source must include
0045  * the above Copyright Notice, the above License, this list of Conditions,
0046  * and the following Disclaimer and Export Compliance provision.  In addition,
0047  * Licensee must cause all Covered Code to which Licensee contributes to
0048  * contain a file documenting the changes Licensee made to create that Covered
0049  * Code and the date of any change.  Licensee must include in that file the
0050  * documentation of any changes made by any predecessor Licensee.  Licensee
0051  * must include a prominent statement that the modification is derived,
0052  * directly or indirectly, from Original Intel Code.
0053  *
0054  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
0055  * Redistribution of source code of any substantial portion of the Covered
0056  * Code or modification without rights to further distribute source must
0057  * include the following Disclaimer and Export Compliance provision in the
0058  * documentation and/or other materials provided with distribution.  In
0059  * addition, Licensee may not authorize further sublicense of source of any
0060  * portion of the Covered Code, and must include terms to the effect that the
0061  * license from Licensee to its licensee is limited to the intellectual
0062  * property embodied in the software Licensee provides to its licensee, and
0063  * not to intellectual property embodied in modifications its licensee may
0064  * make.
0065  *
0066  * 3.3. Redistribution of Executable. Redistribution in executable form of any
0067  * substantial portion of the Covered Code or modification must reproduce the
0068  * above Copyright Notice, and the following Disclaimer and Export Compliance
0069  * provision in the documentation and/or other materials provided with the
0070  * distribution.
0071  *
0072  * 3.4. Intel retains all right, title, and interest in and to the Original
0073  * Intel Code.
0074  *
0075  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
0076  * Intel shall be used in advertising or otherwise to promote the sale, use or
0077  * other dealings in products derived from or relating to the Covered Code
0078  * without prior written authorization from Intel.
0079  *
0080  * 4. Disclaimer and Export Compliance
0081  *
0082  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
0083  * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
0084  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
0085  * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
0086  * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
0087  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
0088  * PARTICULAR PURPOSE.
0089  *
0090  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
0091  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
0092  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
0093  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
0094  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
0095  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
0096  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
0097  * LIMITED REMEDY.
0098  *
0099  * 4.3. Licensee shall not export, either directly or indirectly, any of this
0100  * software or system incorporating such software without first obtaining any
0101  * required license or other approval from the U. S. Department of Commerce or
0102  * any other agency or department of the United States Government.  In the
0103  * event Licensee exports any such software from the United States or
0104  * re-exports any such software from a foreign destination, Licensee shall
0105  * ensure that the distribution and export/re-export of the software is in
0106  * compliance with all laws, regulations, orders, or other restrictions of the
0107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
0108  * any of its subsidiaries will export/re-export any technical data, process,
0109  * software, or service, directly or indirectly, to any country for which the
0110  * United States government or any agency thereof requires an export license,
0111  * other governmental approval, or letter of assurance, without first obtaining
0112  * such license, approval or letter.
0113  *
0114  *****************************************************************************/
0115
0116
0117 #define __UTMATH_C__
0118
0119 #include "acpi.h"
0120 #include "accommon.h"
0121
0122
0123 #define _COMPONENT          ACPI_UTILITIES
0124         ACPI_MODULE_NAME    ("utmath")
0125
0126 /*
0127  * Support for double-precision integer divide.  This code is included here
0128  * in order to support kernel environments where the double-precision math
0129  * library is not available.
0130  */
0131
0132 #ifndef ACPI_USE_NATIVE_DIVIDE
0133 /*******************************************************************************
0134  *
0135  * FUNCTION:    AcpiUtShortDivide
0136  *
0137  * PARAMETERS:  Dividend            - 64-bit dividend
0138  *              Divisor             - 32-bit divisor
0139  *              OutQuotient         - Pointer to where the quotient is returned
0140  *              OutRemainder        - Pointer to where the remainder is returned
0141  *
0142  * RETURN:      Status (Checks for divide-by-zero)
0143  *
0144  * DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits)
0145  *              divide and modulo.  The result is a 64-bit quotient and a
0146  *              32-bit remainder.
0147  *
0148  ******************************************************************************/
0149
0150 ACPI_STATUS
0151 AcpiUtShortDivide (
0152     ACPI_INTEGER            Dividend,
0153     UINT32                  Divisor,
0154     ACPI_INTEGER            *OutQuotient,
0155     UINT32                  *OutRemainder)
0156 {
0157     UINT64_OVERLAY          DividendOvl;
0158     UINT64_OVERLAY          Quotient;
0159     UINT32                  Remainder32;
0160
0161
0162     ACPI_FUNCTION_TRACE (UtShortDivide);
0163
0164
0165     /* Always check for a zero divisor */
0166
0167     if (Divisor == 0)
0168     {
0169         ACPI_ERROR ((AE_INFO, "Divide by zero"));
0170         return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
0171     }
0172
0173     DividendOvl.Full = Dividend;
0174
0175     /*
0176      * The quotient is 64 bits, the remainder is always 32 bits,
0177      * and is generated by the second divide.
0178      */
0179     ACPI_DIV_64_BY_32 (0, DividendOvl.Part.Hi, Divisor,
0180                        Quotient.Part.Hi, Remainder32);
0181     ACPI_DIV_64_BY_32 (Remainder32, DividendOvl.Part.Lo, Divisor,
0182                        Quotient.Part.Lo, Remainder32);
0183
0184     /* Return only what was requested */
0185
0186     if (OutQuotient)
0187     {
0188         *OutQuotient = Quotient.Full;
0189     }
0190     if (OutRemainder)
0191     {
0192         *OutRemainder = Remainder32;
0193     }
0194
0195     return_ACPI_STATUS (AE_OK);
0196 }
0197
0198
0199 /*******************************************************************************
0200  *
0201  * FUNCTION:    AcpiUtDivide
0202  *
0203  * PARAMETERS:  InDividend          - Dividend
0204  *              InDivisor           - Divisor
0205  *              OutQuotient         - Pointer to where the quotient is returned
0206  *              OutRemainder        - Pointer to where the remainder is returned
0207  *
0208  * RETURN:      Status (Checks for divide-by-zero)
0209  *
0210  * DESCRIPTION: Perform a divide and modulo.
0211  *
0212  ******************************************************************************/
0213
0214 ACPI_STATUS
0215 AcpiUtDivide (
0216     ACPI_INTEGER            InDividend,
0217     ACPI_INTEGER            InDivisor,
0218     ACPI_INTEGER            *OutQuotient,
0219     ACPI_INTEGER            *OutRemainder)
0220 {
0221     UINT64_OVERLAY          Dividend;
0222     UINT64_OVERLAY          Divisor;
0223     UINT64_OVERLAY          Quotient;
0224     UINT64_OVERLAY          Remainder;
0225     UINT64_OVERLAY          NormalizedDividend;
0226     UINT64_OVERLAY          NormalizedDivisor;
0227     UINT32                  Partial1;
0228     UINT64_OVERLAY          Partial2;
0229     UINT64_OVERLAY          Partial3;
0230
0231
0232     ACPI_FUNCTION_TRACE (UtDivide);
0233
0234
0235     /* Always check for a zero divisor */
0236
0237     if (InDivisor == 0)
0238     {
0239         ACPI_ERROR ((AE_INFO, "Divide by zero"));
0240         return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
0241     }
0242
0243     Divisor.Full  = InDivisor;
0244     Dividend.Full = InDividend;
0245     if (Divisor.Part.Hi == 0)
0246     {
0247         /*
0248          * 1) Simplest case is where the divisor is 32 bits, we can
0249          * just do two divides
0250          */
0251         Remainder.Part.Hi = 0;
0252
0253         /*
0254          * The quotient is 64 bits, the remainder is always 32 bits,
0255          * and is generated by the second divide.
0256          */
0257         ACPI_DIV_64_BY_32 (0, Dividend.Part.Hi, Divisor.Part.Lo,
0258                            Quotient.Part.Hi, Partial1);
0259         ACPI_DIV_64_BY_32 (Partial1, Dividend.Part.Lo, Divisor.Part.Lo,
0260                            Quotient.Part.Lo, Remainder.Part.Lo);
0261     }
0262
0263     else
0264     {
0265         /*
0266          * 2) The general case where the divisor is a full 64 bits
0267          * is more difficult
0268          */
0269         Quotient.Part.Hi   = 0;
0270         NormalizedDividend = Dividend;
0271         NormalizedDivisor  = Divisor;
0272
0273         /* Normalize the operands (shift until the divisor is < 32 bits) */
0274
0275         do
0276         {
0277             ACPI_SHIFT_RIGHT_64 (NormalizedDivisor.Part.Hi,
0278                                  NormalizedDivisor.Part.Lo);
0279             ACPI_SHIFT_RIGHT_64 (NormalizedDividend.Part.Hi,
0280                                  NormalizedDividend.Part.Lo);
0281
0282         } while (NormalizedDivisor.Part.Hi != 0);
0283
0284         /* Partial divide */
0285
0286         ACPI_DIV_64_BY_32 (NormalizedDividend.Part.Hi,
0287                            NormalizedDividend.Part.Lo,
0288                            NormalizedDivisor.Part.Lo,
0289                            Quotient.Part.Lo, Partial1);
0290
0291         /*
0292          * The quotient is always 32 bits, and simply requires adjustment.
0293          * The 64-bit remainder must be generated.
0294          */
0295         Partial1      = Quotient.Part.Lo * Divisor.Part.Hi;
0296         Partial2.Full = (ACPI_INTEGER) Quotient.Part.Lo * Divisor.Part.Lo;
0297         Partial3.Full = (ACPI_INTEGER) Partial2.Part.Hi + Partial1;
0298
0299         Remainder.Part.Hi = Partial3.Part.Lo;
0300         Remainder.Part.Lo = Partial2.Part.Lo;
0301
0302         if (Partial3.Part.Hi == 0)
0303         {
0304             if (Partial3.Part.Lo >= Dividend.Part.Hi)
0305             {
0306                 if (Partial3.Part.Lo == Dividend.Part.Hi)
0307                 {
0308                     if (Partial2.Part.Lo > Dividend.Part.Lo)
0309                     {
0310                         Quotient.Part.Lo--;
0311                         Remainder.Full -= Divisor.Full;
0312                     }
0313                 }
0314                 else
0315                 {
0316                     Quotient.Part.Lo--;
0317                     Remainder.Full -= Divisor.Full;
0318                 }
0319             }
0320
0321             Remainder.Full    = Remainder.Full - Dividend.Full;
0322             Remainder.Part.Hi = (UINT32) -((INT32) Remainder.Part.Hi);
0323             Remainder.Part.Lo = (UINT32) -((INT32) Remainder.Part.Lo);
0324
0325             if (Remainder.Part.Lo)
0326             {
0327                 Remainder.Part.Hi--;
0328             }
0329         }
0330     }
0331
0332     /* Return only what was requested */
0333
0334     if (OutQuotient)
0335     {
0336         *OutQuotient = Quotient.Full;
0337     }
0338     if (OutRemainder)
0339     {
0340         *OutRemainder = Remainder.Full;
0341     }
0342
0343     return_ACPI_STATUS (AE_OK);
0344 }
0345
0346 #else
0347
0348 /*******************************************************************************
0349  *
0350  * FUNCTION:    AcpiUtShortDivide, AcpiUtDivide
0351  *
0352  * PARAMETERS:  See function headers above
0353  *
0354  * DESCRIPTION: Native versions of the UtDivide functions. Use these if either
0355  *              1) The target is a 64-bit platform and therefore 64-bit
0356  *                 integer math is supported directly by the machine.
0357  *              2) The target is a 32-bit or 16-bit platform, and the
0358  *                 double-precision integer math library is available to
0359  *                 perform the divide.
0360  *
0361  ******************************************************************************/
0362
0363 ACPI_STATUS
0364 AcpiUtShortDivide (
0365     ACPI_INTEGER            InDividend,
0366     UINT32                  Divisor,
0367     ACPI_INTEGER            *OutQuotient,
0368     UINT32                  *OutRemainder)
0369 {
0370
0371     ACPI_FUNCTION_TRACE (UtShortDivide);
0372
0373
0374     /* Always check for a zero divisor */
0375
0376     if (Divisor == 0)
0377     {
0378         ACPI_ERROR ((AE_INFO, "Divide by zero"));
0379         return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
0380     }
0381
0382     /* Return only what was requested */
0383
0384     if (OutQuotient)
0385     {
0386         *OutQuotient = InDividend / Divisor;
0387     }
0388     if (OutRemainder)
0389     {
0390         *OutRemainder = (UINT32) (InDividend % Divisor);
0391     }
0392
0393     return_ACPI_STATUS (AE_OK);
0394 }
0395
0396 ACPI_STATUS
0397 AcpiUtDivide (
0398     ACPI_INTEGER            InDividend,
0399     ACPI_INTEGER            InDivisor,
0400     ACPI_INTEGER            *OutQuotient,
0401     ACPI_INTEGER            *OutRemainder)
0402 {
0403     ACPI_FUNCTION_TRACE (UtDivide);
0404
0405
0406     /* Always check for a zero divisor */
0407
0408     if (InDivisor == 0)
0409     {
0410         ACPI_ERROR ((AE_INFO, "Divide by zero"));
0411         return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
0412     }
0413
0414
0415     /* Return only what was requested */
0416
0417     if (OutQuotient)
0418     {
0419         *OutQuotient = InDividend / InDivisor;
0420     }
0421     if (OutRemainder)
0422     {
0423         *OutRemainder = InDividend % InDivisor;
0424     }
0425
0426     return_ACPI_STATUS (AE_OK);
0427 }
0428
0429 #endif
0430
0431