1 /* Fixed-point arithmetic support. 2 Copyright (C) 2006-2022 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify it under 7 the terms of the GNU General Public License as published by the Free 8 Software Foundation; either version 3, or (at your option) any later 9 version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GCC; see the file COPYING3. If not see 18 <http://www.gnu.org/licenses/>. */ 19 20 #include "config.h" 21 #include "system.h" 22 #include "coretypes.h" 23 #include "tm.h" 24 #include "tree.h" 25 #include "diagnostic-core.h" 26 27 /* Compare two fixed objects for bitwise identity. */ 28 29 bool 30 fixed_identical (const FIXED_VALUE_TYPE *a, const FIXED_VALUE_TYPE *b) 31 { 32 return (a->mode == b->mode 33 && a->data.high == b->data.high 34 && a->data.low == b->data.low); 35 } 36 37 /* Calculate a hash value. */ 38 39 unsigned int 40 fixed_hash (const FIXED_VALUE_TYPE *f) 41 { 42 return (unsigned int) (f->data.low ^ f->data.high); 43 } 44 45 /* Define the enum code for the range of the fixed-point value. */ 46 enum fixed_value_range_code { 47 FIXED_OK, /* The value is within the range. */ 48 FIXED_UNDERFLOW, /* The value is less than the minimum. */ 49 FIXED_GT_MAX_EPS, /* The value is greater than the maximum, but not equal 50 to the maximum plus the epsilon. */ 51 FIXED_MAX_EPS /* The value equals the maximum plus the epsilon. */ 52 }; 53 54 /* Check REAL_VALUE against the range of the fixed-point mode. 55 Return FIXED_OK, if it is within the range. 56 FIXED_UNDERFLOW, if it is less than the minimum. 57 FIXED_GT_MAX_EPS, if it is greater than the maximum, but not equal to 58 the maximum plus the epsilon. 59 FIXED_MAX_EPS, if it is equal to the maximum plus the epsilon. */ 60 61 static enum fixed_value_range_code 62 check_real_for_fixed_mode (REAL_VALUE_TYPE *real_value, machine_mode mode) 63 { 64 REAL_VALUE_TYPE max_value, min_value, epsilon_value; 65 66 real_2expN (&max_value, GET_MODE_IBIT (mode), VOIDmode); 67 real_2expN (&epsilon_value, -GET_MODE_FBIT (mode), VOIDmode); 68 69 if (SIGNED_FIXED_POINT_MODE_P (mode)) 70 min_value = real_value_negate (&max_value); 71 else 72 real_from_string (&min_value, "0.0"); 73 74 if (real_compare (LT_EXPR, real_value, &min_value)) 75 return FIXED_UNDERFLOW; 76 if (real_compare (EQ_EXPR, real_value, &max_value)) 77 return FIXED_MAX_EPS; 78 real_arithmetic (&max_value, MINUS_EXPR, &max_value, &epsilon_value); 79 if (real_compare (GT_EXPR, real_value, &max_value)) 80 return FIXED_GT_MAX_EPS; 81 return FIXED_OK; 82 } 83 84 85 /* Construct a CONST_FIXED from a bit payload and machine mode MODE. 86 The bits in PAYLOAD are sign-extended/zero-extended according to MODE. */ 87 88 FIXED_VALUE_TYPE 89 fixed_from_double_int (double_int payload, scalar_mode mode) 90 { 91 FIXED_VALUE_TYPE value; 92 93 gcc_assert (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_DOUBLE_INT); 94 95 if (SIGNED_SCALAR_FIXED_POINT_MODE_P (mode)) 96 value.data = payload.sext (1 + GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode)); 97 else if (UNSIGNED_SCALAR_FIXED_POINT_MODE_P (mode)) 98 value.data = payload.zext (GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode)); 99 else 100 gcc_unreachable (); 101 102 value.mode = mode; 103 104 return value; 105 } 106 107 108 /* Initialize from a decimal or hexadecimal string. */ 109 110 void 111 fixed_from_string (FIXED_VALUE_TYPE *f, const char *str, scalar_mode mode) 112 { 113 REAL_VALUE_TYPE real_value, fixed_value, base_value; 114 unsigned int fbit; 115 enum fixed_value_range_code temp; 116 bool fail; 117 118 f->mode = mode; 119 fbit = GET_MODE_FBIT (mode); 120 121 real_from_string (&real_value, str); 122 temp = check_real_for_fixed_mode (&real_value, f->mode); 123 /* We don't want to warn the case when the _Fract value is 1.0. */ 124 if (temp == FIXED_UNDERFLOW 125 || temp == FIXED_GT_MAX_EPS 126 || (temp == FIXED_MAX_EPS && ALL_ACCUM_MODE_P (f->mode))) 127 warning (OPT_Woverflow, 128 "large fixed-point constant implicitly truncated to fixed-point type"); 129 real_2expN (&base_value, fbit, VOIDmode); 130 real_arithmetic (&fixed_value, MULT_EXPR, &real_value, &base_value); 131 wide_int w = real_to_integer (&fixed_value, &fail, 132 GET_MODE_PRECISION (mode)); 133 f->data.low = w.ulow (); 134 f->data.high = w.elt (1); 135 136 if (temp == FIXED_MAX_EPS && ALL_FRACT_MODE_P (f->mode)) 137 { 138 /* From the spec, we need to evaluate 1 to the maximal value. */ 139 f->data.low = -1; 140 f->data.high = -1; 141 f->data = f->data.zext (GET_MODE_FBIT (f->mode) 142 + GET_MODE_IBIT (f->mode)); 143 } 144 else 145 f->data = f->data.ext (SIGNED_FIXED_POINT_MODE_P (f->mode) 146 + GET_MODE_FBIT (f->mode) 147 + GET_MODE_IBIT (f->mode), 148 UNSIGNED_FIXED_POINT_MODE_P (f->mode)); 149 } 150 151 /* Render F as a decimal floating point constant. */ 152 153 void 154 fixed_to_decimal (char *str, const FIXED_VALUE_TYPE *f_orig, 155 size_t buf_size) 156 { 157 REAL_VALUE_TYPE real_value, base_value, fixed_value; 158 159 signop sgn = UNSIGNED_FIXED_POINT_MODE_P (f_orig->mode) ? UNSIGNED : SIGNED; 160 real_2expN (&base_value, GET_MODE_FBIT (f_orig->mode), VOIDmode); 161 real_from_integer (&real_value, VOIDmode, 162 wide_int::from (f_orig->data, 163 GET_MODE_PRECISION (f_orig->mode), sgn), 164 sgn); 165 real_arithmetic (&fixed_value, RDIV_EXPR, &real_value, &base_value); 166 real_to_decimal (str, &fixed_value, buf_size, 0, 1); 167 } 168 169 /* If SAT_P, saturate A to the maximum or the minimum, and save to *F based on 170 the machine mode MODE. 171 Do not modify *F otherwise. 172 This function assumes the width of double_int is greater than the width 173 of the fixed-point value (the sum of a possible sign bit, possible ibits, 174 and fbits). 175 Return true, if !SAT_P and overflow. */ 176 177 static bool 178 fixed_saturate1 (machine_mode mode, double_int a, double_int *f, 179 bool sat_p) 180 { 181 bool overflow_p = false; 182 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (mode); 183 int i_f_bits = GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode); 184 185 if (unsigned_p) /* Unsigned type. */ 186 { 187 double_int max; 188 max.low = -1; 189 max.high = -1; 190 max = max.zext (i_f_bits); 191 if (a.ugt (max)) 192 { 193 if (sat_p) 194 *f = max; 195 else 196 overflow_p = true; 197 } 198 } 199 else /* Signed type. */ 200 { 201 double_int max, min; 202 max.high = -1; 203 max.low = -1; 204 max = max.zext (i_f_bits); 205 min.high = 0; 206 min.low = 1; 207 min = min.alshift (i_f_bits, HOST_BITS_PER_DOUBLE_INT); 208 min = min.sext (1 + i_f_bits); 209 if (a.sgt (max)) 210 { 211 if (sat_p) 212 *f = max; 213 else 214 overflow_p = true; 215 } 216 else if (a.slt (min)) 217 { 218 if (sat_p) 219 *f = min; 220 else 221 overflow_p = true; 222 } 223 } 224 return overflow_p; 225 } 226 227 /* If SAT_P, saturate {A_HIGH, A_LOW} to the maximum or the minimum, and 228 save to *F based on the machine mode MODE. 229 Do not modify *F otherwise. 230 This function assumes the width of two double_int is greater than the width 231 of the fixed-point value (the sum of a possible sign bit, possible ibits, 232 and fbits). 233 Return true, if !SAT_P and overflow. */ 234 235 static bool 236 fixed_saturate2 (machine_mode mode, double_int a_high, double_int a_low, 237 double_int *f, bool sat_p) 238 { 239 bool overflow_p = false; 240 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (mode); 241 int i_f_bits = GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode); 242 243 if (unsigned_p) /* Unsigned type. */ 244 { 245 double_int max_r, max_s; 246 max_r.high = 0; 247 max_r.low = 0; 248 max_s.high = -1; 249 max_s.low = -1; 250 max_s = max_s.zext (i_f_bits); 251 if (a_high.ugt (max_r) 252 || (a_high == max_r && 253 a_low.ugt (max_s))) 254 { 255 if (sat_p) 256 *f = max_s; 257 else 258 overflow_p = true; 259 } 260 } 261 else /* Signed type. */ 262 { 263 double_int max_r, max_s, min_r, min_s; 264 max_r.high = 0; 265 max_r.low = 0; 266 max_s.high = -1; 267 max_s.low = -1; 268 max_s = max_s.zext (i_f_bits); 269 min_r.high = -1; 270 min_r.low = -1; 271 min_s.high = 0; 272 min_s.low = 1; 273 min_s = min_s.alshift (i_f_bits, HOST_BITS_PER_DOUBLE_INT); 274 min_s = min_s.sext (1 + i_f_bits); 275 if (a_high.sgt (max_r) 276 || (a_high == max_r && 277 a_low.ugt (max_s))) 278 { 279 if (sat_p) 280 *f = max_s; 281 else 282 overflow_p = true; 283 } 284 else if (a_high.slt (min_r) 285 || (a_high == min_r && 286 a_low.ult (min_s))) 287 { 288 if (sat_p) 289 *f = min_s; 290 else 291 overflow_p = true; 292 } 293 } 294 return overflow_p; 295 } 296 297 /* Return the sign bit based on I_F_BITS. */ 298 299 static inline int 300 get_fixed_sign_bit (double_int a, int i_f_bits) 301 { 302 if (i_f_bits < HOST_BITS_PER_WIDE_INT) 303 return (a.low >> i_f_bits) & 1; 304 else 305 return (a.high >> (i_f_bits - HOST_BITS_PER_WIDE_INT)) & 1; 306 } 307 308 /* Calculate F = A + (SUBTRACT_P ? -B : B). 309 If SAT_P, saturate the result to the max or the min. 310 Return true, if !SAT_P and overflow. */ 311 312 static bool 313 do_fixed_add (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, 314 const FIXED_VALUE_TYPE *b, bool subtract_p, bool sat_p) 315 { 316 bool overflow_p = false; 317 bool unsigned_p; 318 double_int temp; 319 int i_f_bits; 320 321 /* This was a conditional expression but it triggered a bug in 322 Sun C 5.5. */ 323 if (subtract_p) 324 temp = -b->data; 325 else 326 temp = b->data; 327 328 unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode); 329 i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode); 330 f->mode = a->mode; 331 f->data = a->data + temp; 332 if (unsigned_p) /* Unsigned type. */ 333 { 334 if (subtract_p) /* Unsigned subtraction. */ 335 { 336 if (a->data.ult (b->data)) 337 { 338 if (sat_p) 339 { 340 f->data.high = 0; 341 f->data.low = 0; 342 } 343 else 344 overflow_p = true; 345 } 346 } 347 else /* Unsigned addition. */ 348 { 349 f->data = f->data.zext (i_f_bits); 350 if (f->data.ult (a->data) 351 || f->data.ult (b->data)) 352 { 353 if (sat_p) 354 { 355 f->data.high = -1; 356 f->data.low = -1; 357 } 358 else 359 overflow_p = true; 360 } 361 } 362 } 363 else /* Signed type. */ 364 { 365 if ((!subtract_p 366 && (get_fixed_sign_bit (a->data, i_f_bits) 367 == get_fixed_sign_bit (b->data, i_f_bits)) 368 && (get_fixed_sign_bit (a->data, i_f_bits) 369 != get_fixed_sign_bit (f->data, i_f_bits))) 370 || (subtract_p 371 && (get_fixed_sign_bit (a->data, i_f_bits) 372 != get_fixed_sign_bit (b->data, i_f_bits)) 373 && (get_fixed_sign_bit (a->data, i_f_bits) 374 != get_fixed_sign_bit (f->data, i_f_bits)))) 375 { 376 if (sat_p) 377 { 378 f->data.low = 1; 379 f->data.high = 0; 380 f->data = f->data.alshift (i_f_bits, HOST_BITS_PER_DOUBLE_INT); 381 if (get_fixed_sign_bit (a->data, i_f_bits) == 0) 382 { 383 --f->data; 384 } 385 } 386 else 387 overflow_p = true; 388 } 389 } 390 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 391 return overflow_p; 392 } 393 394 /* Calculate F = A * B. 395 If SAT_P, saturate the result to the max or the min. 396 Return true, if !SAT_P and overflow. */ 397 398 static bool 399 do_fixed_multiply (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, 400 const FIXED_VALUE_TYPE *b, bool sat_p) 401 { 402 bool overflow_p = false; 403 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode); 404 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode); 405 f->mode = a->mode; 406 if (GET_MODE_PRECISION (f->mode) <= HOST_BITS_PER_WIDE_INT) 407 { 408 f->data = a->data * b->data; 409 f->data = f->data.lshift (-GET_MODE_FBIT (f->mode), 410 HOST_BITS_PER_DOUBLE_INT, !unsigned_p); 411 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p); 412 } 413 else 414 { 415 /* The result of multiplication expands to two double_int. */ 416 double_int a_high, a_low, b_high, b_low; 417 double_int high_high, high_low, low_high, low_low; 418 double_int r, s, temp1, temp2; 419 int carry = 0; 420 421 /* Decompose a and b to four double_int. */ 422 a_high.low = a->data.high; 423 a_high.high = 0; 424 a_low.low = a->data.low; 425 a_low.high = 0; 426 b_high.low = b->data.high; 427 b_high.high = 0; 428 b_low.low = b->data.low; 429 b_low.high = 0; 430 431 /* Perform four multiplications. */ 432 low_low = a_low * b_low; 433 low_high = a_low * b_high; 434 high_low = a_high * b_low; 435 high_high = a_high * b_high; 436 437 /* Accumulate four results to {r, s}. */ 438 temp1.high = high_low.low; 439 temp1.low = 0; 440 s = low_low + temp1; 441 if (s.ult (low_low) 442 || s.ult (temp1)) 443 carry ++; /* Carry */ 444 temp1.high = s.high; 445 temp1.low = s.low; 446 temp2.high = low_high.low; 447 temp2.low = 0; 448 s = temp1 + temp2; 449 if (s.ult (temp1) 450 || s.ult (temp2)) 451 carry ++; /* Carry */ 452 453 temp1.low = high_low.high; 454 temp1.high = 0; 455 r = high_high + temp1; 456 temp1.low = low_high.high; 457 temp1.high = 0; 458 r += temp1; 459 temp1.low = carry; 460 temp1.high = 0; 461 r += temp1; 462 463 /* We need to subtract b from r, if a < 0. */ 464 if (!unsigned_p && a->data.high < 0) 465 r -= b->data; 466 /* We need to subtract a from r, if b < 0. */ 467 if (!unsigned_p && b->data.high < 0) 468 r -= a->data; 469 470 /* Shift right the result by FBIT. */ 471 if (GET_MODE_FBIT (f->mode) == HOST_BITS_PER_DOUBLE_INT) 472 { 473 s.low = r.low; 474 s.high = r.high; 475 if (unsigned_p) 476 { 477 r.low = 0; 478 r.high = 0; 479 } 480 else 481 { 482 r.low = -1; 483 r.high = -1; 484 } 485 f->data.low = s.low; 486 f->data.high = s.high; 487 } 488 else 489 { 490 s = s.llshift ((-GET_MODE_FBIT (f->mode)), HOST_BITS_PER_DOUBLE_INT); 491 f->data = r.llshift ((HOST_BITS_PER_DOUBLE_INT 492 - GET_MODE_FBIT (f->mode)), 493 HOST_BITS_PER_DOUBLE_INT); 494 f->data.low = f->data.low | s.low; 495 f->data.high = f->data.high | s.high; 496 s.low = f->data.low; 497 s.high = f->data.high; 498 r = r.lshift (-GET_MODE_FBIT (f->mode), 499 HOST_BITS_PER_DOUBLE_INT, !unsigned_p); 500 } 501 502 overflow_p = fixed_saturate2 (f->mode, r, s, &f->data, sat_p); 503 } 504 505 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 506 return overflow_p; 507 } 508 509 /* Calculate F = A / B. 510 If SAT_P, saturate the result to the max or the min. 511 Return true, if !SAT_P and overflow. */ 512 513 static bool 514 do_fixed_divide (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, 515 const FIXED_VALUE_TYPE *b, bool sat_p) 516 { 517 bool overflow_p = false; 518 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode); 519 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode); 520 f->mode = a->mode; 521 if (GET_MODE_PRECISION (f->mode) <= HOST_BITS_PER_WIDE_INT) 522 { 523 f->data = a->data.lshift (GET_MODE_FBIT (f->mode), 524 HOST_BITS_PER_DOUBLE_INT, !unsigned_p); 525 f->data = f->data.div (b->data, unsigned_p, TRUNC_DIV_EXPR); 526 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p); 527 } 528 else 529 { 530 double_int pos_a, pos_b, r, s; 531 double_int quo_r, quo_s, mod, temp; 532 int num_of_neg = 0; 533 int i; 534 535 /* If a < 0, negate a. */ 536 if (!unsigned_p && a->data.high < 0) 537 { 538 pos_a = -a->data; 539 num_of_neg ++; 540 } 541 else 542 pos_a = a->data; 543 544 /* If b < 0, negate b. */ 545 if (!unsigned_p && b->data.high < 0) 546 { 547 pos_b = -b->data; 548 num_of_neg ++; 549 } 550 else 551 pos_b = b->data; 552 553 /* Left shift pos_a to {r, s} by FBIT. */ 554 if (GET_MODE_FBIT (f->mode) == HOST_BITS_PER_DOUBLE_INT) 555 { 556 r = pos_a; 557 s.high = 0; 558 s.low = 0; 559 } 560 else 561 { 562 s = pos_a.llshift (GET_MODE_FBIT (f->mode), HOST_BITS_PER_DOUBLE_INT); 563 r = pos_a.llshift (- (HOST_BITS_PER_DOUBLE_INT 564 - GET_MODE_FBIT (f->mode)), 565 HOST_BITS_PER_DOUBLE_INT); 566 } 567 568 /* Divide r by pos_b to quo_r. The remainder is in mod. */ 569 quo_r = r.divmod (pos_b, 1, TRUNC_DIV_EXPR, &mod); 570 quo_s = double_int_zero; 571 572 for (i = 0; i < HOST_BITS_PER_DOUBLE_INT; i++) 573 { 574 /* Record the leftmost bit of mod. */ 575 int leftmost_mod = (mod.high < 0); 576 577 /* Shift left mod by 1 bit. */ 578 mod = mod.lshift (1); 579 580 /* Test the leftmost bit of s to add to mod. */ 581 if (s.high < 0) 582 mod.low += 1; 583 584 /* Shift left quo_s by 1 bit. */ 585 quo_s = quo_s.lshift (1); 586 587 /* Try to calculate (mod - pos_b). */ 588 temp = mod - pos_b; 589 590 if (leftmost_mod == 1 || mod.ucmp (pos_b) != -1) 591 { 592 quo_s.low += 1; 593 mod = temp; 594 } 595 596 /* Shift left s by 1 bit. */ 597 s = s.lshift (1); 598 599 } 600 601 if (num_of_neg == 1) 602 { 603 quo_s = -quo_s; 604 if (quo_s.high == 0 && quo_s.low == 0) 605 quo_r = -quo_r; 606 else 607 { 608 quo_r.low = ~quo_r.low; 609 quo_r.high = ~quo_r.high; 610 } 611 } 612 613 f->data = quo_s; 614 overflow_p = fixed_saturate2 (f->mode, quo_r, quo_s, &f->data, sat_p); 615 } 616 617 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 618 return overflow_p; 619 } 620 621 /* Calculate F = A << B if LEFT_P. Otherwise, F = A >> B. 622 If SAT_P, saturate the result to the max or the min. 623 Return true, if !SAT_P and overflow. */ 624 625 static bool 626 do_fixed_shift (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, 627 const FIXED_VALUE_TYPE *b, bool left_p, bool sat_p) 628 { 629 bool overflow_p = false; 630 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode); 631 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode); 632 f->mode = a->mode; 633 634 if (b->data.low == 0) 635 { 636 f->data = a->data; 637 return overflow_p; 638 } 639 640 if (GET_MODE_PRECISION (f->mode) <= HOST_BITS_PER_WIDE_INT || (!left_p)) 641 { 642 f->data = a->data.lshift (left_p ? b->data.low : -b->data.low, 643 HOST_BITS_PER_DOUBLE_INT, !unsigned_p); 644 if (left_p) /* Only left shift saturates. */ 645 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p); 646 } 647 else /* We need two double_int to store the left-shift result. */ 648 { 649 double_int temp_high, temp_low; 650 if (b->data.low == HOST_BITS_PER_DOUBLE_INT) 651 { 652 temp_high = a->data; 653 temp_low.high = 0; 654 temp_low.low = 0; 655 } 656 else 657 { 658 temp_low = a->data.lshift (b->data.low, 659 HOST_BITS_PER_DOUBLE_INT, !unsigned_p); 660 /* Logical shift right to temp_high. */ 661 temp_high = a->data.llshift (b->data.low - HOST_BITS_PER_DOUBLE_INT, 662 HOST_BITS_PER_DOUBLE_INT); 663 } 664 if (!unsigned_p && a->data.high < 0) /* Signed-extend temp_high. */ 665 temp_high = temp_high.ext (b->data.low, unsigned_p); 666 f->data = temp_low; 667 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, &f->data, 668 sat_p); 669 } 670 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 671 return overflow_p; 672 } 673 674 /* Calculate F = -A. 675 If SAT_P, saturate the result to the max or the min. 676 Return true, if !SAT_P and overflow. */ 677 678 static bool 679 do_fixed_neg (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, bool sat_p) 680 { 681 bool overflow_p = false; 682 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode); 683 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode); 684 f->mode = a->mode; 685 f->data = -a->data; 686 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 687 688 if (unsigned_p) /* Unsigned type. */ 689 { 690 if (f->data.low != 0 || f->data.high != 0) 691 { 692 if (sat_p) 693 { 694 f->data.low = 0; 695 f->data.high = 0; 696 } 697 else 698 overflow_p = true; 699 } 700 } 701 else /* Signed type. */ 702 { 703 if (!(f->data.high == 0 && f->data.low == 0) 704 && f->data.high == a->data.high && f->data.low == a->data.low ) 705 { 706 if (sat_p) 707 { 708 /* Saturate to the maximum by subtracting f->data by one. */ 709 f->data.low = -1; 710 f->data.high = -1; 711 f->data = f->data.zext (i_f_bits); 712 } 713 else 714 overflow_p = true; 715 } 716 } 717 return overflow_p; 718 } 719 720 /* Perform the binary or unary operation described by CODE. 721 Note that OP0 and OP1 must have the same mode for binary operators. 722 For a unary operation, leave OP1 NULL. 723 Return true, if !SAT_P and overflow. */ 724 725 bool 726 fixed_arithmetic (FIXED_VALUE_TYPE *f, int icode, const FIXED_VALUE_TYPE *op0, 727 const FIXED_VALUE_TYPE *op1, bool sat_p) 728 { 729 switch (icode) 730 { 731 case NEGATE_EXPR: 732 return do_fixed_neg (f, op0, sat_p); 733 734 case PLUS_EXPR: 735 gcc_assert (op0->mode == op1->mode); 736 return do_fixed_add (f, op0, op1, false, sat_p); 737 738 case MINUS_EXPR: 739 gcc_assert (op0->mode == op1->mode); 740 return do_fixed_add (f, op0, op1, true, sat_p); 741 742 case MULT_EXPR: 743 gcc_assert (op0->mode == op1->mode); 744 return do_fixed_multiply (f, op0, op1, sat_p); 745 746 case TRUNC_DIV_EXPR: 747 gcc_assert (op0->mode == op1->mode); 748 return do_fixed_divide (f, op0, op1, sat_p); 749 750 case LSHIFT_EXPR: 751 return do_fixed_shift (f, op0, op1, true, sat_p); 752 753 case RSHIFT_EXPR: 754 return do_fixed_shift (f, op0, op1, false, sat_p); 755 756 default: 757 gcc_unreachable (); 758 } 759 } 760 761 /* Compare fixed-point values by tree_code. 762 Note that OP0 and OP1 must have the same mode. */ 763 764 bool 765 fixed_compare (int icode, const FIXED_VALUE_TYPE *op0, 766 const FIXED_VALUE_TYPE *op1) 767 { 768 enum tree_code code = (enum tree_code) icode; 769 gcc_assert (op0->mode == op1->mode); 770 771 switch (code) 772 { 773 case NE_EXPR: 774 return op0->data != op1->data; 775 776 case EQ_EXPR: 777 return op0->data == op1->data; 778 779 case LT_EXPR: 780 return op0->data.cmp (op1->data, 781 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) == -1; 782 783 case LE_EXPR: 784 return op0->data.cmp (op1->data, 785 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) != 1; 786 787 case GT_EXPR: 788 return op0->data.cmp (op1->data, 789 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) == 1; 790 791 case GE_EXPR: 792 return op0->data.cmp (op1->data, 793 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) != -1; 794 795 default: 796 gcc_unreachable (); 797 } 798 } 799 800 /* Extend or truncate to a new mode. 801 If SAT_P, saturate the result to the max or the min. 802 Return true, if !SAT_P and overflow. */ 803 804 bool 805 fixed_convert (FIXED_VALUE_TYPE *f, scalar_mode mode, 806 const FIXED_VALUE_TYPE *a, bool sat_p) 807 { 808 bool overflow_p = false; 809 if (mode == a->mode) 810 { 811 *f = *a; 812 return overflow_p; 813 } 814 815 if (GET_MODE_FBIT (mode) > GET_MODE_FBIT (a->mode)) 816 { 817 /* Left shift a to temp_high, temp_low based on a->mode. */ 818 double_int temp_high, temp_low; 819 int amount = GET_MODE_FBIT (mode) - GET_MODE_FBIT (a->mode); 820 temp_low = a->data.lshift (amount, 821 HOST_BITS_PER_DOUBLE_INT, 822 SIGNED_FIXED_POINT_MODE_P (a->mode)); 823 /* Logical shift right to temp_high. */ 824 temp_high = a->data.llshift (amount - HOST_BITS_PER_DOUBLE_INT, 825 HOST_BITS_PER_DOUBLE_INT); 826 if (SIGNED_FIXED_POINT_MODE_P (a->mode) 827 && a->data.high < 0) /* Signed-extend temp_high. */ 828 temp_high = temp_high.sext (amount); 829 f->mode = mode; 830 f->data = temp_low; 831 if (SIGNED_FIXED_POINT_MODE_P (a->mode) == 832 SIGNED_FIXED_POINT_MODE_P (f->mode)) 833 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, &f->data, 834 sat_p); 835 else 836 { 837 /* Take care of the cases when converting between signed and 838 unsigned. */ 839 if (SIGNED_FIXED_POINT_MODE_P (a->mode)) 840 { 841 /* Signed -> Unsigned. */ 842 if (a->data.high < 0) 843 { 844 if (sat_p) 845 { 846 f->data.low = 0; /* Set to zero. */ 847 f->data.high = 0; /* Set to zero. */ 848 } 849 else 850 overflow_p = true; 851 } 852 else 853 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, 854 &f->data, sat_p); 855 } 856 else 857 { 858 /* Unsigned -> Signed. */ 859 if (temp_high.high < 0) 860 { 861 if (sat_p) 862 { 863 /* Set to maximum. */ 864 f->data.low = -1; /* Set to all ones. */ 865 f->data.high = -1; /* Set to all ones. */ 866 f->data = f->data.zext (GET_MODE_FBIT (f->mode) 867 + GET_MODE_IBIT (f->mode)); 868 /* Clear the sign. */ 869 } 870 else 871 overflow_p = true; 872 } 873 else 874 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, 875 &f->data, sat_p); 876 } 877 } 878 } 879 else 880 { 881 /* Right shift a to temp based on a->mode. */ 882 double_int temp; 883 temp = a->data.lshift (GET_MODE_FBIT (mode) - GET_MODE_FBIT (a->mode), 884 HOST_BITS_PER_DOUBLE_INT, 885 SIGNED_FIXED_POINT_MODE_P (a->mode)); 886 f->mode = mode; 887 f->data = temp; 888 if (SIGNED_FIXED_POINT_MODE_P (a->mode) == 889 SIGNED_FIXED_POINT_MODE_P (f->mode)) 890 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p); 891 else 892 { 893 /* Take care of the cases when converting between signed and 894 unsigned. */ 895 if (SIGNED_FIXED_POINT_MODE_P (a->mode)) 896 { 897 /* Signed -> Unsigned. */ 898 if (a->data.high < 0) 899 { 900 if (sat_p) 901 { 902 f->data.low = 0; /* Set to zero. */ 903 f->data.high = 0; /* Set to zero. */ 904 } 905 else 906 overflow_p = true; 907 } 908 else 909 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, 910 sat_p); 911 } 912 else 913 { 914 /* Unsigned -> Signed. */ 915 if (temp.high < 0) 916 { 917 if (sat_p) 918 { 919 /* Set to maximum. */ 920 f->data.low = -1; /* Set to all ones. */ 921 f->data.high = -1; /* Set to all ones. */ 922 f->data = f->data.zext (GET_MODE_FBIT (f->mode) 923 + GET_MODE_IBIT (f->mode)); 924 /* Clear the sign. */ 925 } 926 else 927 overflow_p = true; 928 } 929 else 930 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, 931 sat_p); 932 } 933 } 934 } 935 936 f->data = f->data.ext (SIGNED_FIXED_POINT_MODE_P (f->mode) 937 + GET_MODE_FBIT (f->mode) 938 + GET_MODE_IBIT (f->mode), 939 UNSIGNED_FIXED_POINT_MODE_P (f->mode)); 940 return overflow_p; 941 } 942 943 /* Convert to a new fixed-point mode from an integer. 944 If UNSIGNED_P, this integer is unsigned. 945 If SAT_P, saturate the result to the max or the min. 946 Return true, if !SAT_P and overflow. */ 947 948 bool 949 fixed_convert_from_int (FIXED_VALUE_TYPE *f, scalar_mode mode, 950 double_int a, bool unsigned_p, bool sat_p) 951 { 952 bool overflow_p = false; 953 /* Left shift a to temp_high, temp_low. */ 954 double_int temp_high, temp_low; 955 int amount = GET_MODE_FBIT (mode); 956 if (amount == HOST_BITS_PER_DOUBLE_INT) 957 { 958 temp_high = a; 959 temp_low.low = 0; 960 temp_low.high = 0; 961 } 962 else 963 { 964 temp_low = a.llshift (amount, HOST_BITS_PER_DOUBLE_INT); 965 966 /* Logical shift right to temp_high. */ 967 temp_high = a.llshift (amount - HOST_BITS_PER_DOUBLE_INT, 968 HOST_BITS_PER_DOUBLE_INT); 969 } 970 if (!unsigned_p && a.high < 0) /* Signed-extend temp_high. */ 971 temp_high = temp_high.sext (amount); 972 973 f->mode = mode; 974 f->data = temp_low; 975 976 if (unsigned_p == UNSIGNED_FIXED_POINT_MODE_P (f->mode)) 977 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, &f->data, 978 sat_p); 979 else 980 { 981 /* Take care of the cases when converting between signed and unsigned. */ 982 if (!unsigned_p) 983 { 984 /* Signed -> Unsigned. */ 985 if (a.high < 0) 986 { 987 if (sat_p) 988 { 989 f->data.low = 0; /* Set to zero. */ 990 f->data.high = 0; /* Set to zero. */ 991 } 992 else 993 overflow_p = true; 994 } 995 else 996 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, 997 &f->data, sat_p); 998 } 999 else 1000 { 1001 /* Unsigned -> Signed. */ 1002 if (temp_high.high < 0) 1003 { 1004 if (sat_p) 1005 { 1006 /* Set to maximum. */ 1007 f->data.low = -1; /* Set to all ones. */ 1008 f->data.high = -1; /* Set to all ones. */ 1009 f->data = f->data.zext (GET_MODE_FBIT (f->mode) 1010 + GET_MODE_IBIT (f->mode)); 1011 /* Clear the sign. */ 1012 } 1013 else 1014 overflow_p = true; 1015 } 1016 else 1017 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, 1018 &f->data, sat_p); 1019 } 1020 } 1021 f->data = f->data.ext (SIGNED_FIXED_POINT_MODE_P (f->mode) 1022 + GET_MODE_FBIT (f->mode) 1023 + GET_MODE_IBIT (f->mode), 1024 UNSIGNED_FIXED_POINT_MODE_P (f->mode)); 1025 return overflow_p; 1026 } 1027 1028 /* Convert to a new fixed-point mode from a real. 1029 If SAT_P, saturate the result to the max or the min. 1030 Return true, if !SAT_P and overflow. */ 1031 1032 bool 1033 fixed_convert_from_real (FIXED_VALUE_TYPE *f, scalar_mode mode, 1034 const REAL_VALUE_TYPE *a, bool sat_p) 1035 { 1036 bool overflow_p = false; 1037 REAL_VALUE_TYPE real_value, fixed_value, base_value; 1038 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (mode); 1039 int i_f_bits = GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode); 1040 unsigned int fbit = GET_MODE_FBIT (mode); 1041 enum fixed_value_range_code temp; 1042 bool fail; 1043 1044 real_value = *a; 1045 f->mode = mode; 1046 real_2expN (&base_value, fbit, VOIDmode); 1047 real_arithmetic (&fixed_value, MULT_EXPR, &real_value, &base_value); 1048 1049 wide_int w = real_to_integer (&fixed_value, &fail, 1050 GET_MODE_PRECISION (mode)); 1051 f->data.low = w.ulow (); 1052 f->data.high = w.elt (1); 1053 temp = check_real_for_fixed_mode (&real_value, mode); 1054 if (temp == FIXED_UNDERFLOW) /* Minimum. */ 1055 { 1056 if (sat_p) 1057 { 1058 if (unsigned_p) 1059 { 1060 f->data.low = 0; 1061 f->data.high = 0; 1062 } 1063 else 1064 { 1065 f->data.low = 1; 1066 f->data.high = 0; 1067 f->data = f->data.alshift (i_f_bits, HOST_BITS_PER_DOUBLE_INT); 1068 f->data = f->data.sext (1 + i_f_bits); 1069 } 1070 } 1071 else 1072 overflow_p = true; 1073 } 1074 else if (temp == FIXED_GT_MAX_EPS || temp == FIXED_MAX_EPS) /* Maximum. */ 1075 { 1076 if (sat_p) 1077 { 1078 f->data.low = -1; 1079 f->data.high = -1; 1080 f->data = f->data.zext (i_f_bits); 1081 } 1082 else 1083 overflow_p = true; 1084 } 1085 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 1086 return overflow_p; 1087 } 1088 1089 /* Convert to a new real mode from a fixed-point. */ 1090 1091 void 1092 real_convert_from_fixed (REAL_VALUE_TYPE *r, scalar_mode mode, 1093 const FIXED_VALUE_TYPE *f) 1094 { 1095 REAL_VALUE_TYPE base_value, fixed_value, real_value; 1096 1097 signop sgn = UNSIGNED_FIXED_POINT_MODE_P (f->mode) ? UNSIGNED : SIGNED; 1098 real_2expN (&base_value, GET_MODE_FBIT (f->mode), VOIDmode); 1099 real_from_integer (&fixed_value, VOIDmode, 1100 wide_int::from (f->data, GET_MODE_PRECISION (f->mode), 1101 sgn), sgn); 1102 real_arithmetic (&real_value, RDIV_EXPR, &fixed_value, &base_value); 1103 real_convert (r, mode, &real_value); 1104 } 1105 1106 /* Determine whether a fixed-point value F is negative. */ 1107 1108 bool 1109 fixed_isneg (const FIXED_VALUE_TYPE *f) 1110 { 1111 if (SIGNED_FIXED_POINT_MODE_P (f->mode)) 1112 { 1113 int i_f_bits = GET_MODE_IBIT (f->mode) + GET_MODE_FBIT (f->mode); 1114 int sign_bit = get_fixed_sign_bit (f->data, i_f_bits); 1115 if (sign_bit == 1) 1116 return true; 1117 } 1118 1119 return false; 1120 } 1121
Indexes created Tue Feb 24 01:34:59 UTC 2026