drivers/acpi/utilities/utmath.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: utmath - Integer math support routines
   4  *
   5  ******************************************************************************/
   6
   7 /******************************************************************************
   8  *
   9  * 1. Copyright Notice
  10  *
  11  * Some or all of this work - Copyright (c) 1999 - 2010, Intel Corp.
  12  * All rights reserved.
  13  *
  14  * 2. License
  15  *
  16  * 2.1. This is your license from Intel Corp. under its intellectual property
  17  * rights.  You may have additional license terms from the party that provided
  18  * you this software, covering your right to use that party's intellectual
  19  * property rights.
  20  *
  21  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
  22  * copy of the source code appearing in this file ("Covered Code") an
  23  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
  24  * base code distributed originally by Intel ("Original Intel Code") to copy,
  25  * make derivatives, distribute, use and display any portion of the Covered
  26  * Code in any form, with the right to sublicense such rights; and
  27  *
  28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
  29  * license (with the right to sublicense), under only those claims of Intel
  30  * patents that are infringed by the Original Intel Code, to make, use, sell,
  31  * offer to sell, and import the Covered Code and derivative works thereof
  32  * solely to the minimum extent necessary to exercise the above copyright
  33  * license, and in no event shall the patent license extend to any additions
  34  * to or modifications of the Original Intel Code.  No other license or right
  35  * is granted directly or by implication, estoppel or otherwise;
  36  *
  37  * The above copyright and patent license is granted only if the following
  38  * conditions are met:
  39  *
  40  * 3. Conditions
  41  *
  42  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
  43  * Redistribution of source code of any substantial portion of the Covered
  44  * Code or modification with rights to further distribute source must include
  45  * the above Copyright Notice, the above License, this list of Conditions,
  46  * and the following Disclaimer and Export Compliance provision.  In addition,
  47  * Licensee must cause all Covered Code to which Licensee contributes to
  48  * contain a file documenting the changes Licensee made to create that Covered
  49  * Code and the date of any change.  Licensee must include in that file the
  50  * documentation of any changes made by any predecessor Licensee.  Licensee
  51  * must include a prominent statement that the modification is derived,
  52  * directly or indirectly, from Original Intel Code.
  53  *
  54  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
  55  * Redistribution of source code of any substantial portion of the Covered
  56  * Code or modification without rights to further distribute source must
  57  * include the following Disclaimer and Export Compliance provision in the
  58  * documentation and/or other materials provided with distribution.  In
  59  * addition, Licensee may not authorize further sublicense of source of any
  60  * portion of the Covered Code, and must include terms to the effect that the
  61  * license from Licensee to its licensee is limited to the intellectual
  62  * property embodied in the software Licensee provides to its licensee, and
  63  * not to intellectual property embodied in modifications its licensee may
  64  * make.
  65  *
  66  * 3.3. Redistribution of Executable. Redistribution in executable form of any
  67  * substantial portion of the Covered Code or modification must reproduce the
  68  * above Copyright Notice, and the following Disclaimer and Export Compliance
  69  * provision in the documentation and/or other materials provided with the
  70  * distribution.
  71  *
  72  * 3.4. Intel retains all right, title, and interest in and to the Original
  73  * Intel Code.
  74  *
  75  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
  76  * Intel shall be used in advertising or otherwise to promote the sale, use or
  77  * other dealings in products derived from or relating to the Covered Code
  78  * without prior written authorization from Intel.
  79  *
  80  * 4. Disclaimer and Export Compliance
  81  *
  82  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
  83  * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
  84  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
  85  * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
  86  * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
  87  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
  88  * PARTICULAR PURPOSE.
  89  *
  90  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
  91  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
  92  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
  93  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
  94  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
  95  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
  96  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
  97  * LIMITED REMEDY.
  98  *
  99  * 4.3. Licensee shall not export, either directly or indirectly, any of this
 100  * software or system incorporating such software without first obtaining any
 101  * required license or other approval from the U. S. Department of Commerce or
 102  * any other agency or department of the United States Government.  In the
 103  * event Licensee exports any such software from the United States or
 104  * re-exports any such software from a foreign destination, Licensee shall
 105  * ensure that the distribution and export/re-export of the software is in
 106  * compliance with all laws, regulations, orders, or other restrictions of the
 107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
 108  * any of its subsidiaries will export/re-export any technical data, process,
 109  * software, or service, directly or indirectly, to any country for which the
 110  * United States government or any agency thereof requires an export license,
 111  * other governmental approval, or letter of assurance, without first obtaining
 112  * such license, approval or letter.
 113  *
 114  *****************************************************************************/
 115
 116
 117 #define __UTMATH_C__
 118
 119 #include "acpi.h"
 120 #include "accommon.h"
 121
 122
 123 #define _COMPONENT          ACPI_UTILITIES
 124         ACPI_MODULE_NAME    ("utmath")
 125
 126 /*
 127  * Support for double-precision integer divide.  This code is included here
 128  * in order to support kernel environments where the double-precision math
 129  * library is not available.
 130  */
 131
 132 #ifndef ACPI_USE_NATIVE_DIVIDE
 133 /*******************************************************************************
 134  *
 135  * FUNCTION:    AcpiUtShortDivide
 136  *
 137  * PARAMETERS:  Dividend            - 64-bit dividend
 138  *              Divisor             - 32-bit divisor
 139  *              OutQuotient         - Pointer to where the quotient is returned
 140  *              OutRemainder        - Pointer to where the remainder is returned
 141  *
 142  * RETURN:      Status (Checks for divide-by-zero)
 143  *
 144  * DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits)
 145  *              divide and modulo.  The result is a 64-bit quotient and a
 146  *              32-bit remainder.
 147  *
 148  ******************************************************************************/
 149
 150 ACPI_STATUS
 151 AcpiUtShortDivide (
 152     UINT64                  Dividend,
 153     UINT32                  Divisor,
 154     UINT64                  *OutQuotient,
 155     UINT32                  *OutRemainder)
 156 {
 157     UINT64_OVERLAY          DividendOvl;
 158     UINT64_OVERLAY          Quotient;
 159     UINT32                  Remainder32;
 160
 161
 162     ACPI_FUNCTION_TRACE (UtShortDivide);
 163
 164
 165     /* Always check for a zero divisor */
 166
 167     if (Divisor == 0)
 168     {
 169         ACPI_ERROR ((AE_INFO, "Divide by zero"));
 170         return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
 171     }
 172
 173     DividendOvl.Full = Dividend;
 174
 175     /*
 176      * The quotient is 64 bits, the remainder is always 32 bits,
 177      * and is generated by the second divide.
 178      */
 179     ACPI_DIV_64_BY_32 (0, DividendOvl.Part.Hi, Divisor,
 180                        Quotient.Part.Hi, Remainder32);
 181     ACPI_DIV_64_BY_32 (Remainder32, DividendOvl.Part.Lo, Divisor,
 182                        Quotient.Part.Lo, Remainder32);
 183
 184     /* Return only what was requested */
 185
 186     if (OutQuotient)
 187     {
 188         *OutQuotient = Quotient.Full;
 189     }
 190     if (OutRemainder)
 191     {
 192         *OutRemainder = Remainder32;
 193     }
 194
 195     return_ACPI_STATUS (AE_OK);
 196 }
 197
 198
 199 /*******************************************************************************
 200  *
 201  * FUNCTION:    AcpiUtDivide
 202  *
 203  * PARAMETERS:  InDividend          - Dividend
 204  *              InDivisor           - Divisor
 205  *              OutQuotient         - Pointer to where the quotient is returned
 206  *              OutRemainder        - Pointer to where the remainder is returned
 207  *
 208  * RETURN:      Status (Checks for divide-by-zero)
 209  *
 210  * DESCRIPTION: Perform a divide and modulo.
 211  *
 212  ******************************************************************************/
 213
 214 ACPI_STATUS
 215 AcpiUtDivide (
 216     UINT64                  InDividend,
 217     UINT64                  InDivisor,
 218     UINT64                  *OutQuotient,
 219     UINT64                  *OutRemainder)
 220 {
 221     UINT64_OVERLAY          Dividend;
 222     UINT64_OVERLAY          Divisor;
 223     UINT64_OVERLAY          Quotient;
 224     UINT64_OVERLAY          Remainder;
 225     UINT64_OVERLAY          NormalizedDividend;
 226     UINT64_OVERLAY          NormalizedDivisor;
 227     UINT32                  Partial1;
 228     UINT64_OVERLAY          Partial2;
 229     UINT64_OVERLAY          Partial3;
 230
 231
 232     ACPI_FUNCTION_TRACE (UtDivide);
 233
 234
 235     /* Always check for a zero divisor */
 236
 237     if (InDivisor == 0)
 238     {
 239         ACPI_ERROR ((AE_INFO, "Divide by zero"));
 240         return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
 241     }
 242
 243     Divisor.Full  = InDivisor;
 244     Dividend.Full = InDividend;
 245     if (Divisor.Part.Hi == 0)
 246     {
 247         /*
 248          * 1) Simplest case is where the divisor is 32 bits, we can
 249          * just do two divides
 250          */
 251         Remainder.Part.Hi = 0;
 252
 253         /*
 254          * The quotient is 64 bits, the remainder is always 32 bits,
 255          * and is generated by the second divide.
 256          */
 257         ACPI_DIV_64_BY_32 (0, Dividend.Part.Hi, Divisor.Part.Lo,
 258                            Quotient.Part.Hi, Partial1);
 259         ACPI_DIV_64_BY_32 (Partial1, Dividend.Part.Lo, Divisor.Part.Lo,
 260                            Quotient.Part.Lo, Remainder.Part.Lo);
 261     }
 262
 263     else
 264     {
 265         /*
 266          * 2) The general case where the divisor is a full 64 bits
 267          * is more difficult
 268          */
 269         Quotient.Part.Hi   = 0;
 270         NormalizedDividend = Dividend;
 271         NormalizedDivisor  = Divisor;
 272
 273         /* Normalize the operands (shift until the divisor is < 32 bits) */
 274
 275         do
 276         {
 277             ACPI_SHIFT_RIGHT_64 (NormalizedDivisor.Part.Hi,
 278                                  NormalizedDivisor.Part.Lo);
 279             ACPI_SHIFT_RIGHT_64 (NormalizedDividend.Part.Hi,
 280                                  NormalizedDividend.Part.Lo);
 281
 282         } while (NormalizedDivisor.Part.Hi != 0);
 283
 284         /* Partial divide */
 285
 286         ACPI_DIV_64_BY_32 (NormalizedDividend.Part.Hi,
 287                            NormalizedDividend.Part.Lo,
 288                            NormalizedDivisor.Part.Lo,
 289                            Quotient.Part.Lo, Partial1);
 290
 291         /*
 292          * The quotient is always 32 bits, and simply requires adjustment.
 293          * The 64-bit remainder must be generated.
 294          */
 295         Partial1      = Quotient.Part.Lo * Divisor.Part.Hi;
 296         Partial2.Full = (UINT64) Quotient.Part.Lo * Divisor.Part.Lo;
 297         Partial3.Full = (UINT64) Partial2.Part.Hi + Partial1;
 298
 299         Remainder.Part.Hi = Partial3.Part.Lo;
 300         Remainder.Part.Lo = Partial2.Part.Lo;
 301
 302         if (Partial3.Part.Hi == 0)
 303         {
 304             if (Partial3.Part.Lo >= Dividend.Part.Hi)
 305             {
 306                 if (Partial3.Part.Lo == Dividend.Part.Hi)
 307                 {
 308                     if (Partial2.Part.Lo > Dividend.Part.Lo)
 309                     {
 310                         Quotient.Part.Lo--;
 311                         Remainder.Full -= Divisor.Full;
 312                     }
 313                 }
 314                 else
 315                 {
 316                     Quotient.Part.Lo--;
 317                     Remainder.Full -= Divisor.Full;
 318                 }
 319             }
 320
 321             Remainder.Full    = Remainder.Full - Dividend.Full;
 322             Remainder.Part.Hi = (UINT32) -((INT32) Remainder.Part.Hi);
 323             Remainder.Part.Lo = (UINT32) -((INT32) Remainder.Part.Lo);
 324
 325             if (Remainder.Part.Lo)
 326             {
 327                 Remainder.Part.Hi--;
 328             }
 329         }
 330     }
 331
 332     /* Return only what was requested */
 333
 334     if (OutQuotient)
 335     {
 336         *OutQuotient = Quotient.Full;
 337     }
 338     if (OutRemainder)
 339     {
 340         *OutRemainder = Remainder.Full;
 341     }
 342
 343     return_ACPI_STATUS (AE_OK);
 344 }
 345
 346 #else
 347
 348 /*******************************************************************************
 349  *
 350  * FUNCTION:    AcpiUtShortDivide, AcpiUtDivide
 351  *
 352  * PARAMETERS:  See function headers above
 353  *
 354  * DESCRIPTION: Native versions of the UtDivide functions. Use these if either
 355  *              1) The target is a 64-bit platform and therefore 64-bit
 356  *                 integer math is supported directly by the machine.
 357  *              2) The target is a 32-bit or 16-bit platform, and the
 358  *                 double-precision integer math library is available to
 359  *                 perform the divide.
 360  *
 361  ******************************************************************************/
 362
 363 ACPI_STATUS
 364 AcpiUtShortDivide (
 365     UINT64                  InDividend,
 366     UINT32                  Divisor,
 367     UINT64                  *OutQuotient,
 368     UINT32                  *OutRemainder)
 369 {
 370
 371     ACPI_FUNCTION_TRACE (UtShortDivide);
 372
 373
 374     /* Always check for a zero divisor */
 375
 376     if (Divisor == 0)
 377     {
 378         ACPI_ERROR ((AE_INFO, "Divide by zero"));
 379         return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
 380     }
 381
 382     /* Return only what was requested */
 383
 384     if (OutQuotient)
 385     {
 386         *OutQuotient = InDividend / Divisor;
 387     }
 388     if (OutRemainder)
 389     {
 390         *OutRemainder = (UINT32) (InDividend % Divisor);
 391     }
 392
 393     return_ACPI_STATUS (AE_OK);
 394 }
 395
 396 ACPI_STATUS
 397 AcpiUtDivide (
 398     UINT64                  InDividend,
 399     UINT64                  InDivisor,
 400     UINT64                  *OutQuotient,
 401     UINT64                  *OutRemainder)
 402 {
 403     ACPI_FUNCTION_TRACE (UtDivide);
 404
 405
 406     /* Always check for a zero divisor */
 407
 408     if (InDivisor == 0)
 409     {
 410         ACPI_ERROR ((AE_INFO, "Divide by zero"));
 411         return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
 412     }
 413
 414
 415     /* Return only what was requested */
 416
 417     if (OutQuotient)
 418     {
 419         *OutQuotient = InDividend / InDivisor;
 420     }
 421     if (OutRemainder)
 422     {
 423         *OutRemainder = InDividend % InDivisor;
 424     }
 425
 426     return_ACPI_STATUS (AE_OK);
 427 }
 428
 429 #endif
 430
 431