1 /* Fixed-point arithmetic support. 2 Copyright (C) 2006-2013 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, enum machine_mode mode) 63 { 64 REAL_VALUE_TYPE max_value, min_value, epsilon_value; 65 66 real_2expN (&max_value, GET_MODE_IBIT (mode), mode); 67 real_2expN (&epsilon_value, -GET_MODE_FBIT (mode), mode); 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, enum machine_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, enum machine_mode mode) 112 { 113 REAL_VALUE_TYPE real_value, fixed_value, base_value; 114 unsigned int fbit; 115 enum fixed_value_range_code temp; 116 117 f->mode = mode; 118 fbit = GET_MODE_FBIT (mode); 119 120 real_from_string (&real_value, str); 121 temp = check_real_for_fixed_mode (&real_value, f->mode); 122 /* We don't want to warn the case when the _Fract value is 1.0. */ 123 if (temp == FIXED_UNDERFLOW 124 || temp == FIXED_GT_MAX_EPS 125 || (temp == FIXED_MAX_EPS && ALL_ACCUM_MODE_P (f->mode))) 126 warning (OPT_Woverflow, 127 "large fixed-point constant implicitly truncated to fixed-point type"); 128 real_2expN (&base_value, fbit, mode); 129 real_arithmetic (&fixed_value, MULT_EXPR, &real_value, &base_value); 130 real_to_integer2 ((HOST_WIDE_INT *)&f->data.low, &f->data.high, 131 &fixed_value); 132 133 if (temp == FIXED_MAX_EPS && ALL_FRACT_MODE_P (f->mode)) 134 { 135 /* From the spec, we need to evaluate 1 to the maximal value. */ 136 f->data.low = -1; 137 f->data.high = -1; 138 f->data = f->data.zext (GET_MODE_FBIT (f->mode) 139 + GET_MODE_IBIT (f->mode)); 140 } 141 else 142 f->data = f->data.ext (SIGNED_FIXED_POINT_MODE_P (f->mode) 143 + GET_MODE_FBIT (f->mode) 144 + GET_MODE_IBIT (f->mode), 145 UNSIGNED_FIXED_POINT_MODE_P (f->mode)); 146 } 147 148 /* Render F as a decimal floating point constant. */ 149 150 void 151 fixed_to_decimal (char *str, const FIXED_VALUE_TYPE *f_orig, 152 size_t buf_size) 153 { 154 REAL_VALUE_TYPE real_value, base_value, fixed_value; 155 156 real_2expN (&base_value, GET_MODE_FBIT (f_orig->mode), f_orig->mode); 157 real_from_integer (&real_value, VOIDmode, f_orig->data.low, f_orig->data.high, 158 UNSIGNED_FIXED_POINT_MODE_P (f_orig->mode)); 159 real_arithmetic (&fixed_value, RDIV_EXPR, &real_value, &base_value); 160 real_to_decimal (str, &fixed_value, buf_size, 0, 1); 161 } 162 163 /* If SAT_P, saturate A to the maximum or the minimum, and save to *F based on 164 the machine mode MODE. 165 Do not modify *F otherwise. 166 This function assumes the width of double_int is greater than the width 167 of the fixed-point value (the sum of a possible sign bit, possible ibits, 168 and fbits). 169 Return true, if !SAT_P and overflow. */ 170 171 static bool 172 fixed_saturate1 (enum machine_mode mode, double_int a, double_int *f, 173 bool sat_p) 174 { 175 bool overflow_p = false; 176 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (mode); 177 int i_f_bits = GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode); 178 179 if (unsigned_p) /* Unsigned type. */ 180 { 181 double_int max; 182 max.low = -1; 183 max.high = -1; 184 max = max.zext (i_f_bits); 185 if (a.ugt (max)) 186 { 187 if (sat_p) 188 *f = max; 189 else 190 overflow_p = true; 191 } 192 } 193 else /* Signed type. */ 194 { 195 double_int max, min; 196 max.high = -1; 197 max.low = -1; 198 max = max.zext (i_f_bits); 199 min.high = 0; 200 min.low = 1; 201 min = min.alshift (i_f_bits, HOST_BITS_PER_DOUBLE_INT); 202 min = min.sext (1 + i_f_bits); 203 if (a.sgt (max)) 204 { 205 if (sat_p) 206 *f = max; 207 else 208 overflow_p = true; 209 } 210 else if (a.slt (min)) 211 { 212 if (sat_p) 213 *f = min; 214 else 215 overflow_p = true; 216 } 217 } 218 return overflow_p; 219 } 220 221 /* If SAT_P, saturate {A_HIGH, A_LOW} to the maximum or the minimum, and 222 save to *F based on the machine mode MODE. 223 Do not modify *F otherwise. 224 This function assumes the width of two double_int is greater than the width 225 of the fixed-point value (the sum of a possible sign bit, possible ibits, 226 and fbits). 227 Return true, if !SAT_P and overflow. */ 228 229 static bool 230 fixed_saturate2 (enum machine_mode mode, double_int a_high, double_int a_low, 231 double_int *f, bool sat_p) 232 { 233 bool overflow_p = false; 234 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (mode); 235 int i_f_bits = GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode); 236 237 if (unsigned_p) /* Unsigned type. */ 238 { 239 double_int max_r, max_s; 240 max_r.high = 0; 241 max_r.low = 0; 242 max_s.high = -1; 243 max_s.low = -1; 244 max_s = max_s.zext (i_f_bits); 245 if (a_high.ugt (max_r) 246 || (a_high == max_r && 247 a_low.ugt (max_s))) 248 { 249 if (sat_p) 250 *f = max_s; 251 else 252 overflow_p = true; 253 } 254 } 255 else /* Signed type. */ 256 { 257 double_int max_r, max_s, min_r, min_s; 258 max_r.high = 0; 259 max_r.low = 0; 260 max_s.high = -1; 261 max_s.low = -1; 262 max_s = max_s.zext (i_f_bits); 263 min_r.high = -1; 264 min_r.low = -1; 265 min_s.high = 0; 266 min_s.low = 1; 267 min_s = min_s.alshift (i_f_bits, HOST_BITS_PER_DOUBLE_INT); 268 min_s = min_s.sext (1 + i_f_bits); 269 if (a_high.sgt (max_r) 270 || (a_high == max_r && 271 a_low.ugt (max_s))) 272 { 273 if (sat_p) 274 *f = max_s; 275 else 276 overflow_p = true; 277 } 278 else if (a_high.slt (min_r) 279 || (a_high == min_r && 280 a_low.ult (min_s))) 281 { 282 if (sat_p) 283 *f = min_s; 284 else 285 overflow_p = true; 286 } 287 } 288 return overflow_p; 289 } 290 291 /* Return the sign bit based on I_F_BITS. */ 292 293 static inline int 294 get_fixed_sign_bit (double_int a, int i_f_bits) 295 { 296 if (i_f_bits < HOST_BITS_PER_WIDE_INT) 297 return (a.low >> i_f_bits) & 1; 298 else 299 return (a.high >> (i_f_bits - HOST_BITS_PER_WIDE_INT)) & 1; 300 } 301 302 /* Calculate F = A + (SUBTRACT_P ? -B : B). 303 If SAT_P, saturate the result to the max or the min. 304 Return true, if !SAT_P and overflow. */ 305 306 static bool 307 do_fixed_add (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, 308 const FIXED_VALUE_TYPE *b, bool subtract_p, bool sat_p) 309 { 310 bool overflow_p = false; 311 bool unsigned_p; 312 double_int temp; 313 int i_f_bits; 314 315 /* This was a conditional expression but it triggered a bug in 316 Sun C 5.5. */ 317 if (subtract_p) 318 temp = -b->data; 319 else 320 temp = b->data; 321 322 unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode); 323 i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode); 324 f->mode = a->mode; 325 f->data = a->data + temp; 326 if (unsigned_p) /* Unsigned type. */ 327 { 328 if (subtract_p) /* Unsigned subtraction. */ 329 { 330 if (a->data.ult (b->data)) 331 { 332 if (sat_p) 333 { 334 f->data.high = 0; 335 f->data.low = 0; 336 } 337 else 338 overflow_p = true; 339 } 340 } 341 else /* Unsigned addition. */ 342 { 343 f->data = f->data.zext (i_f_bits); 344 if (f->data.ult (a->data) 345 || f->data.ult (b->data)) 346 { 347 if (sat_p) 348 { 349 f->data.high = -1; 350 f->data.low = -1; 351 } 352 else 353 overflow_p = true; 354 } 355 } 356 } 357 else /* Signed type. */ 358 { 359 if ((!subtract_p 360 && (get_fixed_sign_bit (a->data, i_f_bits) 361 == get_fixed_sign_bit (b->data, i_f_bits)) 362 && (get_fixed_sign_bit (a->data, i_f_bits) 363 != get_fixed_sign_bit (f->data, i_f_bits))) 364 || (subtract_p 365 && (get_fixed_sign_bit (a->data, i_f_bits) 366 != get_fixed_sign_bit (b->data, i_f_bits)) 367 && (get_fixed_sign_bit (a->data, i_f_bits) 368 != get_fixed_sign_bit (f->data, i_f_bits)))) 369 { 370 if (sat_p) 371 { 372 f->data.low = 1; 373 f->data.high = 0; 374 f->data = f->data.alshift (i_f_bits, HOST_BITS_PER_DOUBLE_INT); 375 if (get_fixed_sign_bit (a->data, i_f_bits) == 0) 376 { 377 --f->data; 378 } 379 } 380 else 381 overflow_p = true; 382 } 383 } 384 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 385 return overflow_p; 386 } 387 388 /* Calculate F = A * B. 389 If SAT_P, saturate the result to the max or the min. 390 Return true, if !SAT_P and overflow. */ 391 392 static bool 393 do_fixed_multiply (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, 394 const FIXED_VALUE_TYPE *b, bool sat_p) 395 { 396 bool overflow_p = false; 397 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode); 398 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode); 399 f->mode = a->mode; 400 if (GET_MODE_PRECISION (f->mode) <= HOST_BITS_PER_WIDE_INT) 401 { 402 f->data = a->data * b->data; 403 f->data = f->data.lshift (-GET_MODE_FBIT (f->mode), 404 HOST_BITS_PER_DOUBLE_INT, !unsigned_p); 405 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p); 406 } 407 else 408 { 409 /* The result of multiplication expands to two double_int. */ 410 double_int a_high, a_low, b_high, b_low; 411 double_int high_high, high_low, low_high, low_low; 412 double_int r, s, temp1, temp2; 413 int carry = 0; 414 415 /* Decompose a and b to four double_int. */ 416 a_high.low = a->data.high; 417 a_high.high = 0; 418 a_low.low = a->data.low; 419 a_low.high = 0; 420 b_high.low = b->data.high; 421 b_high.high = 0; 422 b_low.low = b->data.low; 423 b_low.high = 0; 424 425 /* Perform four multiplications. */ 426 low_low = a_low * b_low; 427 low_high = a_low * b_high; 428 high_low = a_high * b_low; 429 high_high = a_high * b_high; 430 431 /* Accumulate four results to {r, s}. */ 432 temp1.high = high_low.low; 433 temp1.low = 0; 434 s = low_low + temp1; 435 if (s.ult (low_low) 436 || s.ult (temp1)) 437 carry ++; /* Carry */ 438 temp1.high = s.high; 439 temp1.low = s.low; 440 temp2.high = low_high.low; 441 temp2.low = 0; 442 s = temp1 + temp2; 443 if (s.ult (temp1) 444 || s.ult (temp2)) 445 carry ++; /* Carry */ 446 447 temp1.low = high_low.high; 448 temp1.high = 0; 449 r = high_high + temp1; 450 temp1.low = low_high.high; 451 temp1.high = 0; 452 r += temp1; 453 temp1.low = carry; 454 temp1.high = 0; 455 r += temp1; 456 457 /* We need to subtract b from r, if a < 0. */ 458 if (!unsigned_p && a->data.high < 0) 459 r -= b->data; 460 /* We need to subtract a from r, if b < 0. */ 461 if (!unsigned_p && b->data.high < 0) 462 r -= a->data; 463 464 /* Shift right the result by FBIT. */ 465 if (GET_MODE_FBIT (f->mode) == HOST_BITS_PER_DOUBLE_INT) 466 { 467 s.low = r.low; 468 s.high = r.high; 469 if (unsigned_p) 470 { 471 r.low = 0; 472 r.high = 0; 473 } 474 else 475 { 476 r.low = -1; 477 r.high = -1; 478 } 479 f->data.low = s.low; 480 f->data.high = s.high; 481 } 482 else 483 { 484 s = s.llshift ((-GET_MODE_FBIT (f->mode)), HOST_BITS_PER_DOUBLE_INT); 485 f->data = r.llshift ((HOST_BITS_PER_DOUBLE_INT 486 - GET_MODE_FBIT (f->mode)), 487 HOST_BITS_PER_DOUBLE_INT); 488 f->data.low = f->data.low | s.low; 489 f->data.high = f->data.high | s.high; 490 s.low = f->data.low; 491 s.high = f->data.high; 492 r = r.lshift (-GET_MODE_FBIT (f->mode), 493 HOST_BITS_PER_DOUBLE_INT, !unsigned_p); 494 } 495 496 overflow_p = fixed_saturate2 (f->mode, r, s, &f->data, sat_p); 497 } 498 499 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 500 return overflow_p; 501 } 502 503 /* Calculate F = A / B. 504 If SAT_P, saturate the result to the max or the min. 505 Return true, if !SAT_P and overflow. */ 506 507 static bool 508 do_fixed_divide (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, 509 const FIXED_VALUE_TYPE *b, bool sat_p) 510 { 511 bool overflow_p = false; 512 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode); 513 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode); 514 f->mode = a->mode; 515 if (GET_MODE_PRECISION (f->mode) <= HOST_BITS_PER_WIDE_INT) 516 { 517 f->data = a->data.lshift (GET_MODE_FBIT (f->mode), 518 HOST_BITS_PER_DOUBLE_INT, !unsigned_p); 519 f->data = f->data.div (b->data, unsigned_p, TRUNC_DIV_EXPR); 520 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p); 521 } 522 else 523 { 524 double_int pos_a, pos_b, r, s; 525 double_int quo_r, quo_s, mod, temp; 526 int num_of_neg = 0; 527 int i; 528 529 /* If a < 0, negate a. */ 530 if (!unsigned_p && a->data.high < 0) 531 { 532 pos_a = -a->data; 533 num_of_neg ++; 534 } 535 else 536 pos_a = a->data; 537 538 /* If b < 0, negate b. */ 539 if (!unsigned_p && b->data.high < 0) 540 { 541 pos_b = -b->data; 542 num_of_neg ++; 543 } 544 else 545 pos_b = b->data; 546 547 /* Left shift pos_a to {r, s} by FBIT. */ 548 if (GET_MODE_FBIT (f->mode) == HOST_BITS_PER_DOUBLE_INT) 549 { 550 r = pos_a; 551 s.high = 0; 552 s.low = 0; 553 } 554 else 555 { 556 s = pos_a.llshift (GET_MODE_FBIT (f->mode), HOST_BITS_PER_DOUBLE_INT); 557 r = pos_a.llshift (- (HOST_BITS_PER_DOUBLE_INT 558 - GET_MODE_FBIT (f->mode)), 559 HOST_BITS_PER_DOUBLE_INT); 560 } 561 562 /* Divide r by pos_b to quo_r. The remainder is in mod. */ 563 quo_r = r.divmod (pos_b, 1, TRUNC_DIV_EXPR, &mod); 564 quo_s = double_int_zero; 565 566 for (i = 0; i < HOST_BITS_PER_DOUBLE_INT; i++) 567 { 568 /* Record the leftmost bit of mod. */ 569 int leftmost_mod = (mod.high < 0); 570 571 /* Shift left mod by 1 bit. */ 572 mod = mod.llshift (1, HOST_BITS_PER_DOUBLE_INT); 573 574 /* Test the leftmost bit of s to add to mod. */ 575 if (s.high < 0) 576 mod.low += 1; 577 578 /* Shift left quo_s by 1 bit. */ 579 quo_s = quo_s.llshift (1, HOST_BITS_PER_DOUBLE_INT); 580 581 /* Try to calculate (mod - pos_b). */ 582 temp = mod - pos_b; 583 584 if (leftmost_mod == 1 || mod.ucmp (pos_b) != -1) 585 { 586 quo_s.low += 1; 587 mod = temp; 588 } 589 590 /* Shift left s by 1 bit. */ 591 s = s.llshift (1, HOST_BITS_PER_DOUBLE_INT); 592 593 } 594 595 if (num_of_neg == 1) 596 { 597 quo_s = -quo_s; 598 if (quo_s.high == 0 && quo_s.low == 0) 599 quo_r = -quo_r; 600 else 601 { 602 quo_r.low = ~quo_r.low; 603 quo_r.high = ~quo_r.high; 604 } 605 } 606 607 f->data = quo_s; 608 overflow_p = fixed_saturate2 (f->mode, quo_r, quo_s, &f->data, sat_p); 609 } 610 611 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 612 return overflow_p; 613 } 614 615 /* Calculate F = A << B if LEFT_P. Otherwise, F = A >> B. 616 If SAT_P, saturate the result to the max or the min. 617 Return true, if !SAT_P and overflow. */ 618 619 static bool 620 do_fixed_shift (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, 621 const FIXED_VALUE_TYPE *b, bool left_p, bool sat_p) 622 { 623 bool overflow_p = false; 624 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode); 625 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode); 626 f->mode = a->mode; 627 628 if (b->data.low == 0) 629 { 630 f->data = a->data; 631 return overflow_p; 632 } 633 634 if (GET_MODE_PRECISION (f->mode) <= HOST_BITS_PER_WIDE_INT || (!left_p)) 635 { 636 f->data = a->data.lshift (left_p ? b->data.low : -b->data.low, 637 HOST_BITS_PER_DOUBLE_INT, !unsigned_p); 638 if (left_p) /* Only left shift saturates. */ 639 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p); 640 } 641 else /* We need two double_int to store the left-shift result. */ 642 { 643 double_int temp_high, temp_low; 644 if (b->data.low == HOST_BITS_PER_DOUBLE_INT) 645 { 646 temp_high = a->data; 647 temp_low.high = 0; 648 temp_low.low = 0; 649 } 650 else 651 { 652 temp_low = a->data.lshift (b->data.low, 653 HOST_BITS_PER_DOUBLE_INT, !unsigned_p); 654 /* Logical shift right to temp_high. */ 655 temp_high = a->data.llshift (b->data.low - HOST_BITS_PER_DOUBLE_INT, 656 HOST_BITS_PER_DOUBLE_INT); 657 } 658 if (!unsigned_p && a->data.high < 0) /* Signed-extend temp_high. */ 659 temp_high = temp_high.ext (b->data.low, unsigned_p); 660 f->data = temp_low; 661 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, &f->data, 662 sat_p); 663 } 664 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 665 return overflow_p; 666 } 667 668 /* Calculate F = -A. 669 If SAT_P, saturate the result to the max or the min. 670 Return true, if !SAT_P and overflow. */ 671 672 static bool 673 do_fixed_neg (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, bool sat_p) 674 { 675 bool overflow_p = false; 676 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode); 677 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode); 678 f->mode = a->mode; 679 f->data = -a->data; 680 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 681 682 if (unsigned_p) /* Unsigned type. */ 683 { 684 if (f->data.low != 0 || f->data.high != 0) 685 { 686 if (sat_p) 687 { 688 f->data.low = 0; 689 f->data.high = 0; 690 } 691 else 692 overflow_p = true; 693 } 694 } 695 else /* Signed type. */ 696 { 697 if (!(f->data.high == 0 && f->data.low == 0) 698 && f->data.high == a->data.high && f->data.low == a->data.low ) 699 { 700 if (sat_p) 701 { 702 /* Saturate to the maximum by subtracting f->data by one. */ 703 f->data.low = -1; 704 f->data.high = -1; 705 f->data = f->data.zext (i_f_bits); 706 } 707 else 708 overflow_p = true; 709 } 710 } 711 return overflow_p; 712 } 713 714 /* Perform the binary or unary operation described by CODE. 715 Note that OP0 and OP1 must have the same mode for binary operators. 716 For a unary operation, leave OP1 NULL. 717 Return true, if !SAT_P and overflow. */ 718 719 bool 720 fixed_arithmetic (FIXED_VALUE_TYPE *f, int icode, const FIXED_VALUE_TYPE *op0, 721 const FIXED_VALUE_TYPE *op1, bool sat_p) 722 { 723 switch (icode) 724 { 725 case NEGATE_EXPR: 726 return do_fixed_neg (f, op0, sat_p); 727 break; 728 729 case PLUS_EXPR: 730 gcc_assert (op0->mode == op1->mode); 731 return do_fixed_add (f, op0, op1, false, sat_p); 732 break; 733 734 case MINUS_EXPR: 735 gcc_assert (op0->mode == op1->mode); 736 return do_fixed_add (f, op0, op1, true, sat_p); 737 break; 738 739 case MULT_EXPR: 740 gcc_assert (op0->mode == op1->mode); 741 return do_fixed_multiply (f, op0, op1, sat_p); 742 break; 743 744 case TRUNC_DIV_EXPR: 745 gcc_assert (op0->mode == op1->mode); 746 return do_fixed_divide (f, op0, op1, sat_p); 747 break; 748 749 case LSHIFT_EXPR: 750 return do_fixed_shift (f, op0, op1, true, sat_p); 751 break; 752 753 case RSHIFT_EXPR: 754 return do_fixed_shift (f, op0, op1, false, sat_p); 755 break; 756 757 default: 758 gcc_unreachable (); 759 } 760 return false; 761 } 762 763 /* Compare fixed-point values by tree_code. 764 Note that OP0 and OP1 must have the same mode. */ 765 766 bool 767 fixed_compare (int icode, const FIXED_VALUE_TYPE *op0, 768 const FIXED_VALUE_TYPE *op1) 769 { 770 enum tree_code code = (enum tree_code) icode; 771 gcc_assert (op0->mode == op1->mode); 772 773 switch (code) 774 { 775 case NE_EXPR: 776 return op0->data != op1->data; 777 778 case EQ_EXPR: 779 return op0->data == op1->data; 780 781 case LT_EXPR: 782 return op0->data.cmp (op1->data, 783 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) == -1; 784 785 case LE_EXPR: 786 return op0->data.cmp (op1->data, 787 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) != 1; 788 789 case GT_EXPR: 790 return op0->data.cmp (op1->data, 791 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) == 1; 792 793 case GE_EXPR: 794 return op0->data.cmp (op1->data, 795 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) != -1; 796 797 default: 798 gcc_unreachable (); 799 } 800 } 801 802 /* Extend or truncate to a new mode. 803 If SAT_P, saturate the result to the max or the min. 804 Return true, if !SAT_P and overflow. */ 805 806 bool 807 fixed_convert (FIXED_VALUE_TYPE *f, enum machine_mode mode, 808 const FIXED_VALUE_TYPE *a, bool sat_p) 809 { 810 bool overflow_p = false; 811 if (mode == a->mode) 812 { 813 *f = *a; 814 return overflow_p; 815 } 816 817 if (GET_MODE_FBIT (mode) > GET_MODE_FBIT (a->mode)) 818 { 819 /* Left shift a to temp_high, temp_low based on a->mode. */ 820 double_int temp_high, temp_low; 821 int amount = GET_MODE_FBIT (mode) - GET_MODE_FBIT (a->mode); 822 temp_low = a->data.lshift (amount, 823 HOST_BITS_PER_DOUBLE_INT, 824 SIGNED_FIXED_POINT_MODE_P (a->mode)); 825 /* Logical shift right to temp_high. */ 826 temp_high = a->data.llshift (amount - HOST_BITS_PER_DOUBLE_INT, 827 HOST_BITS_PER_DOUBLE_INT); 828 if (SIGNED_FIXED_POINT_MODE_P (a->mode) 829 && a->data.high < 0) /* Signed-extend temp_high. */ 830 temp_high = temp_high.sext (amount); 831 f->mode = mode; 832 f->data = temp_low; 833 if (SIGNED_FIXED_POINT_MODE_P (a->mode) == 834 SIGNED_FIXED_POINT_MODE_P (f->mode)) 835 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, &f->data, 836 sat_p); 837 else 838 { 839 /* Take care of the cases when converting between signed and 840 unsigned. */ 841 if (SIGNED_FIXED_POINT_MODE_P (a->mode)) 842 { 843 /* Signed -> Unsigned. */ 844 if (a->data.high < 0) 845 { 846 if (sat_p) 847 { 848 f->data.low = 0; /* Set to zero. */ 849 f->data.high = 0; /* Set to zero. */ 850 } 851 else 852 overflow_p = true; 853 } 854 else 855 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, 856 &f->data, sat_p); 857 } 858 else 859 { 860 /* Unsigned -> Signed. */ 861 if (temp_high.high < 0) 862 { 863 if (sat_p) 864 { 865 /* Set to maximum. */ 866 f->data.low = -1; /* Set to all ones. */ 867 f->data.high = -1; /* Set to all ones. */ 868 f->data = f->data.zext (GET_MODE_FBIT (f->mode) 869 + GET_MODE_IBIT (f->mode)); 870 /* Clear the sign. */ 871 } 872 else 873 overflow_p = true; 874 } 875 else 876 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, 877 &f->data, sat_p); 878 } 879 } 880 } 881 else 882 { 883 /* Right shift a to temp based on a->mode. */ 884 double_int temp; 885 temp = a->data.lshift (GET_MODE_FBIT (mode) - GET_MODE_FBIT (a->mode), 886 HOST_BITS_PER_DOUBLE_INT, 887 SIGNED_FIXED_POINT_MODE_P (a->mode)); 888 f->mode = mode; 889 f->data = temp; 890 if (SIGNED_FIXED_POINT_MODE_P (a->mode) == 891 SIGNED_FIXED_POINT_MODE_P (f->mode)) 892 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p); 893 else 894 { 895 /* Take care of the cases when converting between signed and 896 unsigned. */ 897 if (SIGNED_FIXED_POINT_MODE_P (a->mode)) 898 { 899 /* Signed -> Unsigned. */ 900 if (a->data.high < 0) 901 { 902 if (sat_p) 903 { 904 f->data.low = 0; /* Set to zero. */ 905 f->data.high = 0; /* Set to zero. */ 906 } 907 else 908 overflow_p = true; 909 } 910 else 911 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, 912 sat_p); 913 } 914 else 915 { 916 /* Unsigned -> Signed. */ 917 if (temp.high < 0) 918 { 919 if (sat_p) 920 { 921 /* Set to maximum. */ 922 f->data.low = -1; /* Set to all ones. */ 923 f->data.high = -1; /* Set to all ones. */ 924 f->data = f->data.zext (GET_MODE_FBIT (f->mode) 925 + GET_MODE_IBIT (f->mode)); 926 /* Clear the sign. */ 927 } 928 else 929 overflow_p = true; 930 } 931 else 932 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, 933 sat_p); 934 } 935 } 936 } 937 938 f->data = f->data.ext (SIGNED_FIXED_POINT_MODE_P (f->mode) 939 + GET_MODE_FBIT (f->mode) 940 + GET_MODE_IBIT (f->mode), 941 UNSIGNED_FIXED_POINT_MODE_P (f->mode)); 942 return overflow_p; 943 } 944 945 /* Convert to a new fixed-point mode from an integer. 946 If UNSIGNED_P, this integer is unsigned. 947 If SAT_P, saturate the result to the max or the min. 948 Return true, if !SAT_P and overflow. */ 949 950 bool 951 fixed_convert_from_int (FIXED_VALUE_TYPE *f, enum machine_mode mode, 952 double_int a, bool unsigned_p, bool sat_p) 953 { 954 bool overflow_p = false; 955 /* Left shift a to temp_high, temp_low. */ 956 double_int temp_high, temp_low; 957 int amount = GET_MODE_FBIT (mode); 958 if (amount == HOST_BITS_PER_DOUBLE_INT) 959 { 960 temp_high = a; 961 temp_low.low = 0; 962 temp_low.high = 0; 963 } 964 else 965 { 966 temp_low = a.llshift (amount, HOST_BITS_PER_DOUBLE_INT); 967 968 /* Logical shift right to temp_high. */ 969 temp_high = a.llshift (amount - HOST_BITS_PER_DOUBLE_INT, 970 HOST_BITS_PER_DOUBLE_INT); 971 } 972 if (!unsigned_p && a.high < 0) /* Signed-extend temp_high. */ 973 temp_high = temp_high.sext (amount); 974 975 f->mode = mode; 976 f->data = temp_low; 977 978 if (unsigned_p == UNSIGNED_FIXED_POINT_MODE_P (f->mode)) 979 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, &f->data, 980 sat_p); 981 else 982 { 983 /* Take care of the cases when converting between signed and unsigned. */ 984 if (!unsigned_p) 985 { 986 /* Signed -> Unsigned. */ 987 if (a.high < 0) 988 { 989 if (sat_p) 990 { 991 f->data.low = 0; /* Set to zero. */ 992 f->data.high = 0; /* Set to zero. */ 993 } 994 else 995 overflow_p = true; 996 } 997 else 998 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, 999 &f->data, sat_p); 1000 } 1001 else 1002 { 1003 /* Unsigned -> Signed. */ 1004 if (temp_high.high < 0) 1005 { 1006 if (sat_p) 1007 { 1008 /* Set to maximum. */ 1009 f->data.low = -1; /* Set to all ones. */ 1010 f->data.high = -1; /* Set to all ones. */ 1011 f->data = f->data.zext (GET_MODE_FBIT (f->mode) 1012 + GET_MODE_IBIT (f->mode)); 1013 /* Clear the sign. */ 1014 } 1015 else 1016 overflow_p = true; 1017 } 1018 else 1019 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, 1020 &f->data, sat_p); 1021 } 1022 } 1023 f->data = f->data.ext (SIGNED_FIXED_POINT_MODE_P (f->mode) 1024 + GET_MODE_FBIT (f->mode) 1025 + GET_MODE_IBIT (f->mode), 1026 UNSIGNED_FIXED_POINT_MODE_P (f->mode)); 1027 return overflow_p; 1028 } 1029 1030 /* Convert to a new fixed-point mode from a real. 1031 If SAT_P, saturate the result to the max or the min. 1032 Return true, if !SAT_P and overflow. */ 1033 1034 bool 1035 fixed_convert_from_real (FIXED_VALUE_TYPE *f, enum machine_mode mode, 1036 const REAL_VALUE_TYPE *a, bool sat_p) 1037 { 1038 bool overflow_p = false; 1039 REAL_VALUE_TYPE real_value, fixed_value, base_value; 1040 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (mode); 1041 int i_f_bits = GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode); 1042 unsigned int fbit = GET_MODE_FBIT (mode); 1043 enum fixed_value_range_code temp; 1044 1045 real_value = *a; 1046 f->mode = mode; 1047 real_2expN (&base_value, fbit, mode); 1048 real_arithmetic (&fixed_value, MULT_EXPR, &real_value, &base_value); 1049 real_to_integer2 ((HOST_WIDE_INT *)&f->data.low, &f->data.high, &fixed_value); 1050 temp = check_real_for_fixed_mode (&real_value, mode); 1051 if (temp == FIXED_UNDERFLOW) /* Minimum. */ 1052 { 1053 if (sat_p) 1054 { 1055 if (unsigned_p) 1056 { 1057 f->data.low = 0; 1058 f->data.high = 0; 1059 } 1060 else 1061 { 1062 f->data.low = 1; 1063 f->data.high = 0; 1064 f->data = f->data.alshift (i_f_bits, HOST_BITS_PER_DOUBLE_INT); 1065 f->data = f->data.sext (1 + i_f_bits); 1066 } 1067 } 1068 else 1069 overflow_p = true; 1070 } 1071 else if (temp == FIXED_GT_MAX_EPS || temp == FIXED_MAX_EPS) /* Maximum. */ 1072 { 1073 if (sat_p) 1074 { 1075 f->data.low = -1; 1076 f->data.high = -1; 1077 f->data = f->data.zext (i_f_bits); 1078 } 1079 else 1080 overflow_p = true; 1081 } 1082 f->data = f->data.ext ((!unsigned_p) + i_f_bits, unsigned_p); 1083 return overflow_p; 1084 } 1085 1086 /* Convert to a new real mode from a fixed-point. */ 1087 1088 void 1089 real_convert_from_fixed (REAL_VALUE_TYPE *r, enum machine_mode mode, 1090 const FIXED_VALUE_TYPE *f) 1091 { 1092 REAL_VALUE_TYPE base_value, fixed_value, real_value; 1093 1094 real_2expN (&base_value, GET_MODE_FBIT (f->mode), f->mode); 1095 real_from_integer (&fixed_value, VOIDmode, f->data.low, f->data.high, 1096 UNSIGNED_FIXED_POINT_MODE_P (f->mode)); 1097 real_arithmetic (&real_value, RDIV_EXPR, &fixed_value, &base_value); 1098 real_convert (r, mode, &real_value); 1099 } 1100 1101 /* Determine whether a fixed-point value F is negative. */ 1102 1103 bool 1104 fixed_isneg (const FIXED_VALUE_TYPE *f) 1105 { 1106 if (SIGNED_FIXED_POINT_MODE_P (f->mode)) 1107 { 1108 int i_f_bits = GET_MODE_IBIT (f->mode) + GET_MODE_FBIT (f->mode); 1109 int sign_bit = get_fixed_sign_bit (f->data, i_f_bits); 1110 if (sign_bit == 1) 1111 return true; 1112 } 1113 1114 return false; 1115 } 1116