1 /*******************************************************************************
3 * Module Name: utmath - Integer math support routines
5 ******************************************************************************/
7 /******************************************************************************
11 * Some or all of this work - Copyright (c) 1999 - 2015, Intel Corp.
12 * All rights reserved.
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
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
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;
37 * The above copyright and patent license is granted only if the following
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.
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
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
72 * 3.4. Intel retains all right, title, and interest in and to the Original
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.
80 * 4. Disclaimer and Export Compliance
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
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
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.
114 *****************************************************************************/
117 #include "accommon.h"
120 #define _COMPONENT ACPI_UTILITIES
121 ACPI_MODULE_NAME ("utmath")
124 * Optional support for 64-bit double-precision integer divide. This code
125 * is configurable and is implemented in order to support 32-bit kernel
126 * environments where a 64-bit double-precision math library is not available.
128 * Support for a more normal 64-bit divide/modulo (with check for a divide-
129 * by-zero) appears after this optional section of code.
131 #ifndef ACPI_USE_NATIVE_DIVIDE
133 /* Structures used only for 64-bit divide */
135 typedef struct uint64_struct
142 typedef union uint64_overlay
150 /*******************************************************************************
152 * FUNCTION: AcpiUtShortDivide
154 * PARAMETERS: Dividend - 64-bit dividend
155 * Divisor - 32-bit divisor
156 * OutQuotient - Pointer to where the quotient is returned
157 * OutRemainder - Pointer to where the remainder is returned
159 * RETURN: Status (Checks for divide-by-zero)
161 * DESCRIPTION: Perform a short (maximum 64 bits divided by 32 bits)
162 * divide and modulo. The result is a 64-bit quotient and a
165 ******************************************************************************/
172 UINT32 *OutRemainder)
174 UINT64_OVERLAY DividendOvl;
175 UINT64_OVERLAY Quotient;
179 ACPI_FUNCTION_TRACE (UtShortDivide);
182 /* Always check for a zero divisor */
186 ACPI_ERROR ((AE_INFO, "Divide by zero"));
187 return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
190 DividendOvl.Full = Dividend;
193 * The quotient is 64 bits, the remainder is always 32 bits,
194 * and is generated by the second divide.
196 ACPI_DIV_64_BY_32 (0, DividendOvl.Part.Hi, Divisor,
197 Quotient.Part.Hi, Remainder32);
198 ACPI_DIV_64_BY_32 (Remainder32, DividendOvl.Part.Lo, Divisor,
199 Quotient.Part.Lo, Remainder32);
201 /* Return only what was requested */
205 *OutQuotient = Quotient.Full;
209 *OutRemainder = Remainder32;
212 return_ACPI_STATUS (AE_OK);
216 /*******************************************************************************
218 * FUNCTION: AcpiUtDivide
220 * PARAMETERS: InDividend - Dividend
221 * InDivisor - Divisor
222 * OutQuotient - Pointer to where the quotient is returned
223 * OutRemainder - Pointer to where the remainder is returned
225 * RETURN: Status (Checks for divide-by-zero)
227 * DESCRIPTION: Perform a divide and modulo.
229 ******************************************************************************/
236 UINT64 *OutRemainder)
238 UINT64_OVERLAY Dividend;
239 UINT64_OVERLAY Divisor;
240 UINT64_OVERLAY Quotient;
241 UINT64_OVERLAY Remainder;
242 UINT64_OVERLAY NormalizedDividend;
243 UINT64_OVERLAY NormalizedDivisor;
245 UINT64_OVERLAY Partial2;
246 UINT64_OVERLAY Partial3;
249 ACPI_FUNCTION_TRACE (UtDivide);
252 /* Always check for a zero divisor */
256 ACPI_ERROR ((AE_INFO, "Divide by zero"));
257 return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
260 Divisor.Full = InDivisor;
261 Dividend.Full = InDividend;
262 if (Divisor.Part.Hi == 0)
265 * 1) Simplest case is where the divisor is 32 bits, we can
266 * just do two divides
268 Remainder.Part.Hi = 0;
271 * The quotient is 64 bits, the remainder is always 32 bits,
272 * and is generated by the second divide.
274 ACPI_DIV_64_BY_32 (0, Dividend.Part.Hi, Divisor.Part.Lo,
275 Quotient.Part.Hi, Partial1);
276 ACPI_DIV_64_BY_32 (Partial1, Dividend.Part.Lo, Divisor.Part.Lo,
277 Quotient.Part.Lo, Remainder.Part.Lo);
283 * 2) The general case where the divisor is a full 64 bits
286 Quotient.Part.Hi = 0;
287 NormalizedDividend = Dividend;
288 NormalizedDivisor = Divisor;
290 /* Normalize the operands (shift until the divisor is < 32 bits) */
294 ACPI_SHIFT_RIGHT_64 (NormalizedDivisor.Part.Hi,
295 NormalizedDivisor.Part.Lo);
296 ACPI_SHIFT_RIGHT_64 (NormalizedDividend.Part.Hi,
297 NormalizedDividend.Part.Lo);
299 } while (NormalizedDivisor.Part.Hi != 0);
303 ACPI_DIV_64_BY_32 (NormalizedDividend.Part.Hi,
304 NormalizedDividend.Part.Lo,
305 NormalizedDivisor.Part.Lo,
306 Quotient.Part.Lo, Partial1);
309 * The quotient is always 32 bits, and simply requires adjustment.
310 * The 64-bit remainder must be generated.
312 Partial1 = Quotient.Part.Lo * Divisor.Part.Hi;
313 Partial2.Full = (UINT64) Quotient.Part.Lo * Divisor.Part.Lo;
314 Partial3.Full = (UINT64) Partial2.Part.Hi + Partial1;
316 Remainder.Part.Hi = Partial3.Part.Lo;
317 Remainder.Part.Lo = Partial2.Part.Lo;
319 if (Partial3.Part.Hi == 0)
321 if (Partial3.Part.Lo >= Dividend.Part.Hi)
323 if (Partial3.Part.Lo == Dividend.Part.Hi)
325 if (Partial2.Part.Lo > Dividend.Part.Lo)
328 Remainder.Full -= Divisor.Full;
334 Remainder.Full -= Divisor.Full;
338 Remainder.Full = Remainder.Full - Dividend.Full;
339 Remainder.Part.Hi = (UINT32) -((INT32) Remainder.Part.Hi);
340 Remainder.Part.Lo = (UINT32) -((INT32) Remainder.Part.Lo);
342 if (Remainder.Part.Lo)
349 /* Return only what was requested */
353 *OutQuotient = Quotient.Full;
357 *OutRemainder = Remainder.Full;
360 return_ACPI_STATUS (AE_OK);
365 /*******************************************************************************
367 * FUNCTION: AcpiUtShortDivide, AcpiUtDivide
369 * PARAMETERS: See function headers above
371 * DESCRIPTION: Native versions of the UtDivide functions. Use these if either
372 * 1) The target is a 64-bit platform and therefore 64-bit
373 * integer math is supported directly by the machine.
374 * 2) The target is a 32-bit or 16-bit platform, and the
375 * double-precision integer math library is available to
376 * perform the divide.
378 ******************************************************************************/
385 UINT32 *OutRemainder)
388 ACPI_FUNCTION_TRACE (UtShortDivide);
391 /* Always check for a zero divisor */
395 ACPI_ERROR ((AE_INFO, "Divide by zero"));
396 return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
399 /* Return only what was requested */
403 *OutQuotient = InDividend / Divisor;
407 *OutRemainder = (UINT32) (InDividend % Divisor);
410 return_ACPI_STATUS (AE_OK);
418 UINT64 *OutRemainder)
420 ACPI_FUNCTION_TRACE (UtDivide);
423 /* Always check for a zero divisor */
427 ACPI_ERROR ((AE_INFO, "Divide by zero"));
428 return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO);
432 /* Return only what was requested */
436 *OutQuotient = InDividend / InDivisor;
440 *OutRemainder = InDividend % InDivisor;
443 return_ACPI_STATUS (AE_OK);