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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 | // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 /******************************************************************************* * * Module Name: utmath - Integer math support routines * ******************************************************************************/ #include <acpi/acpi.h> #include "accommon.h" #define _COMPONENT ACPI_UTILITIES ACPI_MODULE_NAME("utmath") /* Structures used only for 64-bit divide */ typedef struct uint64_struct { u32 lo; u32 hi; } uint64_struct; typedef union uint64_overlay { u64 full; struct uint64_struct part; } uint64_overlay; /* * Optional support for 64-bit double-precision integer multiply and shift. * This code is configurable and is implemented in order to support 32-bit * kernel environments where a 64-bit double-precision math library is not * available. */ #ifndef ACPI_USE_NATIVE_MATH64 /******************************************************************************* * * FUNCTION: acpi_ut_short_multiply * * PARAMETERS: multiplicand - 64-bit multiplicand * multiplier - 32-bit multiplier * out_product - Pointer to where the product is returned * * DESCRIPTION: Perform a short multiply. * ******************************************************************************/ acpi_status acpi_ut_short_multiply(u64 multiplicand, u32 multiplier, u64 *out_product) { union uint64_overlay multiplicand_ovl; union uint64_overlay product; u32 carry32; ACPI_FUNCTION_TRACE(ut_short_multiply); multiplicand_ovl.full = multiplicand; /* * The Product is 64 bits, the carry is always 32 bits, * and is generated by the second multiply. */ ACPI_MUL_64_BY_32(0, multiplicand_ovl.part.hi, multiplier, product.part.hi, carry32); ACPI_MUL_64_BY_32(0, multiplicand_ovl.part.lo, multiplier, product.part.lo, carry32); product.part.hi += carry32; /* Return only what was requested */ if (out_product) { *out_product = product.full; } return_ACPI_STATUS(AE_OK); } /******************************************************************************* * * FUNCTION: acpi_ut_short_shift_left * * PARAMETERS: operand - 64-bit shift operand * count - 32-bit shift count * out_result - Pointer to where the result is returned * * DESCRIPTION: Perform a short left shift. * ******************************************************************************/ acpi_status acpi_ut_short_shift_left(u64 operand, u32 count, u64 *out_result) { union uint64_overlay operand_ovl; ACPI_FUNCTION_TRACE(ut_short_shift_left); operand_ovl.full = operand; if ((count & 63) >= 32) { operand_ovl.part.hi = operand_ovl.part.lo; operand_ovl.part.lo = 0; count = (count & 63) - 32; } ACPI_SHIFT_LEFT_64_BY_32(operand_ovl.part.hi, operand_ovl.part.lo, count); /* Return only what was requested */ if (out_result) { *out_result = operand_ovl.full; } return_ACPI_STATUS(AE_OK); } /******************************************************************************* * * FUNCTION: acpi_ut_short_shift_right * * PARAMETERS: operand - 64-bit shift operand * count - 32-bit shift count * out_result - Pointer to where the result is returned * * DESCRIPTION: Perform a short right shift. * ******************************************************************************/ acpi_status acpi_ut_short_shift_right(u64 operand, u32 count, u64 *out_result) { union uint64_overlay operand_ovl; ACPI_FUNCTION_TRACE(ut_short_shift_right); operand_ovl.full = operand; if ((count & 63) >= 32) { operand_ovl.part.lo = operand_ovl.part.hi; operand_ovl.part.hi = 0; count = (count & 63) - 32; } ACPI_SHIFT_RIGHT_64_BY_32(operand_ovl.part.hi, operand_ovl.part.lo, count); /* Return only what was requested */ if (out_result) { *out_result = operand_ovl.full; } return_ACPI_STATUS(AE_OK); } #else /******************************************************************************* * * FUNCTION: acpi_ut_short_multiply * * PARAMETERS: See function headers above * * DESCRIPTION: Native version of the ut_short_multiply function. * ******************************************************************************/ acpi_status acpi_ut_short_multiply(u64 multiplicand, u32 multiplier, u64 *out_product) { ACPI_FUNCTION_TRACE(ut_short_multiply); /* Return only what was requested */ if (out_product) { *out_product = multiplicand * multiplier; } return_ACPI_STATUS(AE_OK); } /******************************************************************************* * * FUNCTION: acpi_ut_short_shift_left * * PARAMETERS: See function headers above * * DESCRIPTION: Native version of the ut_short_shift_left function. * ******************************************************************************/ acpi_status acpi_ut_short_shift_left(u64 operand, u32 count, u64 *out_result) { ACPI_FUNCTION_TRACE(ut_short_shift_left); /* Return only what was requested */ if (out_result) { *out_result = operand << count; } return_ACPI_STATUS(AE_OK); } /******************************************************************************* * * FUNCTION: acpi_ut_short_shift_right * * PARAMETERS: See function headers above * * DESCRIPTION: Native version of the ut_short_shift_right function. * ******************************************************************************/ acpi_status acpi_ut_short_shift_right(u64 operand, u32 count, u64 *out_result) { ACPI_FUNCTION_TRACE(ut_short_shift_right); /* Return only what was requested */ if (out_result) { *out_result = operand >> count; } return_ACPI_STATUS(AE_OK); } #endif /* * Optional support for 64-bit double-precision integer divide. This code * is configurable and is implemented in order to support 32-bit kernel * environments where a 64-bit double-precision math library is not available. * * Support for a more normal 64-bit divide/modulo (with check for a divide- * by-zero) appears after this optional section of code. */ #ifndef ACPI_USE_NATIVE_DIVIDE /******************************************************************************* * * FUNCTION: acpi_ut_short_divide * * PARAMETERS: dividend - 64-bit 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(u64 dividend, u32 divisor, u64 *out_quotient, u32 *out_remainder) { union uint64_overlay dividend_ovl; union uint64_overlay quotient; u32 remainder32; ACPI_FUNCTION_TRACE(ut_short_divide); /* Always check for a zero divisor */ if (divisor == 0) { ACPI_ERROR((AE_INFO, "Divide by zero")); return_ACPI_STATUS(AE_AML_DIVIDE_BY_ZERO); } dividend_ovl.full = dividend; /* * 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_ovl.part.hi, divisor, quotient.part.hi, remainder32); ACPI_DIV_64_BY_32(remainder32, dividend_ovl.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 - Dividend * in_divisor - 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(u64 in_dividend, u64 in_divisor, u64 *out_quotient, u64 *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_ERROR((AE_INFO, "Divide by zero")); 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 = (u64) quotient.part.lo * divisor.part.lo; partial3.full = (u64) 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 * * PARAMETERS: See function headers above * * 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(u64 in_dividend, u32 divisor, u64 *out_quotient, u32 *out_remainder) { ACPI_FUNCTION_TRACE(ut_short_divide); /* Always check for a zero divisor */ if (divisor == 0) { ACPI_ERROR((AE_INFO, "Divide by zero")); 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(u64 in_dividend, u64 in_divisor, u64 *out_quotient, u64 *out_remainder) { ACPI_FUNCTION_TRACE(ut_divide); /* Always check for a zero divisor */ if (in_divisor == 0) { ACPI_ERROR((AE_INFO, "Divide by zero")); 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 |