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
fixed_identical(const FIXED_VALUE_TYPE * a,const FIXED_VALUE_TYPE * b)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
fixed_hash(const FIXED_VALUE_TYPE * f)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
check_real_for_fixed_mode(REAL_VALUE_TYPE * real_value,machine_mode mode)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
fixed_from_double_int(double_int payload,scalar_mode mode)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
fixed_from_string(FIXED_VALUE_TYPE * f,const char * str,scalar_mode mode)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
fixed_to_decimal(char * str,const FIXED_VALUE_TYPE * f_orig,size_t buf_size)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
fixed_saturate1(machine_mode mode,double_int a,double_int * f,bool sat_p)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
fixed_saturate2(machine_mode mode,double_int a_high,double_int a_low,double_int * f,bool sat_p)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
get_fixed_sign_bit(double_int a,int i_f_bits)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
do_fixed_add(FIXED_VALUE_TYPE * f,const FIXED_VALUE_TYPE * a,const FIXED_VALUE_TYPE * b,bool subtract_p,bool sat_p)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
do_fixed_multiply(FIXED_VALUE_TYPE * f,const FIXED_VALUE_TYPE * a,const FIXED_VALUE_TYPE * b,bool sat_p)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
do_fixed_divide(FIXED_VALUE_TYPE * f,const FIXED_VALUE_TYPE * a,const FIXED_VALUE_TYPE * b,bool sat_p)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
do_fixed_shift(FIXED_VALUE_TYPE * f,const FIXED_VALUE_TYPE * a,const FIXED_VALUE_TYPE * b,bool left_p,bool sat_p)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
do_fixed_neg(FIXED_VALUE_TYPE * f,const FIXED_VALUE_TYPE * a,bool sat_p)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
fixed_arithmetic(FIXED_VALUE_TYPE * f,int icode,const FIXED_VALUE_TYPE * op0,const FIXED_VALUE_TYPE * op1,bool sat_p)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
fixed_compare(int icode,const FIXED_VALUE_TYPE * op0,const FIXED_VALUE_TYPE * op1)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
fixed_convert(FIXED_VALUE_TYPE * f,scalar_mode mode,const FIXED_VALUE_TYPE * a,bool sat_p)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
fixed_convert_from_int(FIXED_VALUE_TYPE * f,scalar_mode mode,double_int a,bool unsigned_p,bool sat_p)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
fixed_convert_from_real(FIXED_VALUE_TYPE * f,scalar_mode mode,const REAL_VALUE_TYPE * a,bool sat_p)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
real_convert_from_fixed(REAL_VALUE_TYPE * r,scalar_mode mode,const FIXED_VALUE_TYPE * f)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
fixed_isneg(const FIXED_VALUE_TYPE * f)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