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 - 2016, 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 #include "acpi.h" 117 #include "accommon.h" 118 119 120 #define _COMPONENT ACPI_UTILITIES 121 ACPI_MODULE_NAME ("utmath") 122 123 /* 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. 127 * 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. 130 */ 131 #ifndef ACPI_USE_NATIVE_DIVIDE 132 133 /* Structures used only for 64-bit divide */ 134 135 typedef struct uint64_struct 136 { 137 UINT32 Lo; 138 UINT32 Hi; 139 140 } UINT64_STRUCT; 141 142 typedef union uint64_overlay 143 { 144 UINT64 Full; 145 UINT64_STRUCT Part; 146 147 } UINT64_OVERLAY; 148 149 150 /******************************************************************************* 151 * 152 * FUNCTION: AcpiUtShortDivide 153 * 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 158 * 159 * RETURN: Status (Checks for divide-by-zero) 160 * 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 163 * 32-bit remainder. 164 * 165 ******************************************************************************/ 166 167 ACPI_STATUS 168 AcpiUtShortDivide ( 169 UINT64 Dividend, 170 UINT32 Divisor, 171 UINT64 *OutQuotient, 172 UINT32 *OutRemainder) 173 { 174 UINT64_OVERLAY DividendOvl; 175 UINT64_OVERLAY Quotient; 176 UINT32 Remainder32; 177 178 179 ACPI_FUNCTION_TRACE (UtShortDivide); 180 181 182 /* Always check for a zero divisor */ 183 184 if (Divisor == 0) 185 { 186 ACPI_ERROR ((AE_INFO, "Divide by zero")); 187 return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO); 188 } 189 190 DividendOvl.Full = Dividend; 191 192 /* 193 * The quotient is 64 bits, the remainder is always 32 bits, 194 * and is generated by the second divide. 195 */ 196 ACPI_DIV_64_BY_32 (0, DividendOvl.Part.Hi, Divisor, 197 Quotient.Part.Hi, Remainder32); 198 199 ACPI_DIV_64_BY_32 (Remainder32, DividendOvl.Part.Lo, Divisor, 200 Quotient.Part.Lo, Remainder32); 201 202 /* Return only what was requested */ 203 204 if (OutQuotient) 205 { 206 *OutQuotient = Quotient.Full; 207 } 208 if (OutRemainder) 209 { 210 *OutRemainder = Remainder32; 211 } 212 213 return_ACPI_STATUS (AE_OK); 214 } 215 216 217 /******************************************************************************* 218 * 219 * FUNCTION: AcpiUtDivide 220 * 221 * PARAMETERS: InDividend - Dividend 222 * InDivisor - Divisor 223 * OutQuotient - Pointer to where the quotient is returned 224 * OutRemainder - Pointer to where the remainder is returned 225 * 226 * RETURN: Status (Checks for divide-by-zero) 227 * 228 * DESCRIPTION: Perform a divide and modulo. 229 * 230 ******************************************************************************/ 231 232 ACPI_STATUS 233 AcpiUtDivide ( 234 UINT64 InDividend, 235 UINT64 InDivisor, 236 UINT64 *OutQuotient, 237 UINT64 *OutRemainder) 238 { 239 UINT64_OVERLAY Dividend; 240 UINT64_OVERLAY Divisor; 241 UINT64_OVERLAY Quotient; 242 UINT64_OVERLAY Remainder; 243 UINT64_OVERLAY NormalizedDividend; 244 UINT64_OVERLAY NormalizedDivisor; 245 UINT32 Partial1; 246 UINT64_OVERLAY Partial2; 247 UINT64_OVERLAY Partial3; 248 249 250 ACPI_FUNCTION_TRACE (UtDivide); 251 252 253 /* Always check for a zero divisor */ 254 255 if (InDivisor == 0) 256 { 257 ACPI_ERROR ((AE_INFO, "Divide by zero")); 258 return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO); 259 } 260 261 Divisor.Full = InDivisor; 262 Dividend.Full = InDividend; 263 if (Divisor.Part.Hi == 0) 264 { 265 /* 266 * 1) Simplest case is where the divisor is 32 bits, we can 267 * just do two divides 268 */ 269 Remainder.Part.Hi = 0; 270 271 /* 272 * The quotient is 64 bits, the remainder is always 32 bits, 273 * and is generated by the second divide. 274 */ 275 ACPI_DIV_64_BY_32 (0, Dividend.Part.Hi, Divisor.Part.Lo, 276 Quotient.Part.Hi, Partial1); 277 278 ACPI_DIV_64_BY_32 (Partial1, Dividend.Part.Lo, Divisor.Part.Lo, 279 Quotient.Part.Lo, Remainder.Part.Lo); 280 } 281 282 else 283 { 284 /* 285 * 2) The general case where the divisor is a full 64 bits 286 * is more difficult 287 */ 288 Quotient.Part.Hi = 0; 289 NormalizedDividend = Dividend; 290 NormalizedDivisor = Divisor; 291 292 /* Normalize the operands (shift until the divisor is < 32 bits) */ 293 294 do 295 { 296 ACPI_SHIFT_RIGHT_64 ( 297 NormalizedDivisor.Part.Hi, NormalizedDivisor.Part.Lo); 298 ACPI_SHIFT_RIGHT_64 ( 299 NormalizedDividend.Part.Hi, NormalizedDividend.Part.Lo); 300 301 } while (NormalizedDivisor.Part.Hi != 0); 302 303 /* Partial divide */ 304 305 ACPI_DIV_64_BY_32 ( 306 NormalizedDividend.Part.Hi, NormalizedDividend.Part.Lo, 307 NormalizedDivisor.Part.Lo, Quotient.Part.Lo, Partial1); 308 309 /* 310 * The quotient is always 32 bits, and simply requires 311 * adjustment. The 64-bit remainder must be generated. 312 */ 313 Partial1 = Quotient.Part.Lo * Divisor.Part.Hi; 314 Partial2.Full = (UINT64) Quotient.Part.Lo * Divisor.Part.Lo; 315 Partial3.Full = (UINT64) Partial2.Part.Hi + Partial1; 316 317 Remainder.Part.Hi = Partial3.Part.Lo; 318 Remainder.Part.Lo = Partial2.Part.Lo; 319 320 if (Partial3.Part.Hi == 0) 321 { 322 if (Partial3.Part.Lo >= Dividend.Part.Hi) 323 { 324 if (Partial3.Part.Lo == Dividend.Part.Hi) 325 { 326 if (Partial2.Part.Lo > Dividend.Part.Lo) 327 { 328 Quotient.Part.Lo--; 329 Remainder.Full -= Divisor.Full; 330 } 331 } 332 else 333 { 334 Quotient.Part.Lo--; 335 Remainder.Full -= Divisor.Full; 336 } 337 } 338 339 Remainder.Full = Remainder.Full - Dividend.Full; 340 Remainder.Part.Hi = (UINT32) -((INT32) Remainder.Part.Hi); 341 Remainder.Part.Lo = (UINT32) -((INT32) Remainder.Part.Lo); 342 343 if (Remainder.Part.Lo) 344 { 345 Remainder.Part.Hi--; 346 } 347 } 348 } 349 350 /* Return only what was requested */ 351 352 if (OutQuotient) 353 { 354 *OutQuotient = Quotient.Full; 355 } 356 if (OutRemainder) 357 { 358 *OutRemainder = Remainder.Full; 359 } 360 361 return_ACPI_STATUS (AE_OK); 362 } 363 364 #else 365 366 /******************************************************************************* 367 * 368 * FUNCTION: AcpiUtShortDivide, AcpiUtDivide 369 * 370 * PARAMETERS: See function headers above 371 * 372 * DESCRIPTION: Native versions of the UtDivide functions. Use these if either 373 * 1) The target is a 64-bit platform and therefore 64-bit 374 * integer math is supported directly by the machine. 375 * 2) The target is a 32-bit or 16-bit platform, and the 376 * double-precision integer math library is available to 377 * perform the divide. 378 * 379 ******************************************************************************/ 380 381 ACPI_STATUS 382 AcpiUtShortDivide ( 383 UINT64 InDividend, 384 UINT32 Divisor, 385 UINT64 *OutQuotient, 386 UINT32 *OutRemainder) 387 { 388 389 ACPI_FUNCTION_TRACE (UtShortDivide); 390 391 392 /* Always check for a zero divisor */ 393 394 if (Divisor == 0) 395 { 396 ACPI_ERROR ((AE_INFO, "Divide by zero")); 397 return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO); 398 } 399 400 /* Return only what was requested */ 401 402 if (OutQuotient) 403 { 404 *OutQuotient = InDividend / Divisor; 405 } 406 if (OutRemainder) 407 { 408 *OutRemainder = (UINT32) (InDividend % Divisor); 409 } 410 411 return_ACPI_STATUS (AE_OK); 412 } 413 414 ACPI_STATUS 415 AcpiUtDivide ( 416 UINT64 InDividend, 417 UINT64 InDivisor, 418 UINT64 *OutQuotient, 419 UINT64 *OutRemainder) 420 { 421 ACPI_FUNCTION_TRACE (UtDivide); 422 423 424 /* Always check for a zero divisor */ 425 426 if (InDivisor == 0) 427 { 428 ACPI_ERROR ((AE_INFO, "Divide by zero")); 429 return_ACPI_STATUS (AE_AML_DIVIDE_BY_ZERO); 430 } 431 432 433 /* Return only what was requested */ 434 435 if (OutQuotient) 436 { 437 *OutQuotient = InDividend / InDivisor; 438 } 439 if (OutRemainder) 440 { 441 *OutRemainder = InDividend % InDivisor; 442 } 443 444 return_ACPI_STATUS (AE_OK); 445 } 446 447 #endif 448