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author kent <kent@cr.ie.u-ryukyu.ac.jp>
date Fri, 17 Jul 2009 14:47:48 +0900
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1 /* Fixed-point arithmetic support.
2 Copyright (C) 2006, 2007, 2008 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 "toplev.h"
26 #include "fixed-value.h"
27
28 /* Compare two fixed objects for bitwise identity. */
29
30 bool
31 fixed_identical (const FIXED_VALUE_TYPE *a, const FIXED_VALUE_TYPE *b)
32 {
33 return (a->mode == b->mode
34 && a->data.high == b->data.high
35 && a->data.low == b->data.low);
36 }
37
38 /* Calculate a hash value. */
39
40 unsigned int
41 fixed_hash (const FIXED_VALUE_TYPE *f)
42 {
43 return (unsigned int) (f->data.low ^ f->data.high);
44 }
45
46 /* Define the enum code for the range of the fixed-point value. */
47 enum fixed_value_range_code {
48 FIXED_OK, /* The value is within the range. */
49 FIXED_UNDERFLOW, /* The value is less than the minimum. */
50 FIXED_GT_MAX_EPS, /* The value is greater than the maximum, but not equal
51 to the maximum plus the epsilon. */
52 FIXED_MAX_EPS /* The value equals the maximum plus the epsilon. */
53 };
54
55 /* Check REAL_VALUE against the range of the fixed-point mode.
56 Return FIXED_OK, if it is within the range.
57 FIXED_UNDERFLOW, if it is less than the minimum.
58 FIXED_GT_MAX_EPS, if it is greater than the maximum, but not equal to
59 the maximum plus the epsilon.
60 FIXED_MAX_EPS, if it is equal to the maximum plus the epsilon. */
61
62 static enum fixed_value_range_code
63 check_real_for_fixed_mode (REAL_VALUE_TYPE *real_value, enum machine_mode mode)
64 {
65 REAL_VALUE_TYPE max_value, min_value, epsilon_value;
66
67 real_2expN (&max_value, GET_MODE_IBIT (mode), mode);
68 real_2expN (&epsilon_value, -GET_MODE_FBIT (mode), mode);
69
70 if (SIGNED_FIXED_POINT_MODE_P (mode))
71 min_value = REAL_VALUE_NEGATE (max_value);
72 else
73 real_from_string (&min_value, "0.0");
74
75 if (real_compare (LT_EXPR, real_value, &min_value))
76 return FIXED_UNDERFLOW;
77 if (real_compare (EQ_EXPR, real_value, &max_value))
78 return FIXED_MAX_EPS;
79 real_arithmetic (&max_value, MINUS_EXPR, &max_value, &epsilon_value);
80 if (real_compare (GT_EXPR, real_value, &max_value))
81 return FIXED_GT_MAX_EPS;
82 return FIXED_OK;
83 }
84
85 /* Initialize from a decimal or hexadecimal string. */
86
87 void
88 fixed_from_string (FIXED_VALUE_TYPE *f, const char *str, enum machine_mode mode)
89 {
90 REAL_VALUE_TYPE real_value, fixed_value, base_value;
91 unsigned int fbit;
92 enum fixed_value_range_code temp;
93
94 f->mode = mode;
95 fbit = GET_MODE_FBIT (mode);
96
97 real_from_string (&real_value, str);
98 temp = check_real_for_fixed_mode (&real_value, f->mode);
99 /* We don't want to warn the case when the _Fract value is 1.0. */
100 if (temp == FIXED_UNDERFLOW
101 || temp == FIXED_GT_MAX_EPS
102 || (temp == FIXED_MAX_EPS && ALL_ACCUM_MODE_P (f->mode)))
103 warning (OPT_Woverflow,
104 "large fixed-point constant implicitly truncated to fixed-point type");
105 real_2expN (&base_value, fbit, mode);
106 real_arithmetic (&fixed_value, MULT_EXPR, &real_value, &base_value);
107 real_to_integer2 ((HOST_WIDE_INT *)&f->data.low, &f->data.high,
108 &fixed_value);
109
110 if (temp == FIXED_MAX_EPS && ALL_FRACT_MODE_P (f->mode))
111 {
112 /* From the spec, we need to evaluate 1 to the maximal value. */
113 f->data.low = -1;
114 f->data.high = -1;
115 f->data = double_int_ext (f->data,
116 GET_MODE_FBIT (f->mode)
117 + GET_MODE_IBIT (f->mode), 1);
118 }
119 else
120 f->data = double_int_ext (f->data,
121 SIGNED_FIXED_POINT_MODE_P (f->mode)
122 + GET_MODE_FBIT (f->mode)
123 + GET_MODE_IBIT (f->mode),
124 UNSIGNED_FIXED_POINT_MODE_P (f->mode));
125 }
126
127 /* Render F as a decimal floating point constant. */
128
129 void
130 fixed_to_decimal (char *str, const FIXED_VALUE_TYPE *f_orig,
131 size_t buf_size)
132 {
133 REAL_VALUE_TYPE real_value, base_value, fixed_value;
134
135 real_2expN (&base_value, GET_MODE_FBIT (f_orig->mode), f_orig->mode);
136 real_from_integer (&real_value, VOIDmode, f_orig->data.low, f_orig->data.high,
137 UNSIGNED_FIXED_POINT_MODE_P (f_orig->mode));
138 real_arithmetic (&fixed_value, RDIV_EXPR, &real_value, &base_value);
139 real_to_decimal (str, &fixed_value, buf_size, 0, 1);
140 }
141
142 /* If SAT_P, saturate A to the maximum or the minimum, and save to *F based on
143 the machine mode MODE.
144 Do not modify *F otherwise.
145 This function assumes the width of double_int is greater than the width
146 of the fixed-point value (the sum of a possible sign bit, possible ibits,
147 and fbits).
148 Return true, if !SAT_P and overflow. */
149
150 static bool
151 fixed_saturate1 (enum machine_mode mode, double_int a, double_int *f,
152 bool sat_p)
153 {
154 bool overflow_p = false;
155 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (mode);
156 int i_f_bits = GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode);
157
158 if (unsigned_p) /* Unsigned type. */
159 {
160 double_int max;
161 max.low = -1;
162 max.high = -1;
163 max = double_int_ext (max, i_f_bits, 1);
164 if (double_int_cmp (a, max, 1) == 1)
165 {
166 if (sat_p)
167 *f = max;
168 else
169 overflow_p = true;
170 }
171 }
172 else /* Signed type. */
173 {
174 double_int max, min;
175 max.high = -1;
176 max.low = -1;
177 max = double_int_ext (max, i_f_bits, 1);
178 min.high = 0;
179 min.low = 1;
180 lshift_double (min.low, min.high, i_f_bits,
181 2 * HOST_BITS_PER_WIDE_INT,
182 &min.low, &min.high, 1);
183 min = double_int_ext (min, 1 + i_f_bits, 0);
184 if (double_int_cmp (a, max, 0) == 1)
185 {
186 if (sat_p)
187 *f = max;
188 else
189 overflow_p = true;
190 }
191 else if (double_int_cmp (a, min, 0) == -1)
192 {
193 if (sat_p)
194 *f = min;
195 else
196 overflow_p = true;
197 }
198 }
199 return overflow_p;
200 }
201
202 /* If SAT_P, saturate {A_HIGH, A_LOW} to the maximum or the minimum, and
203 save to *F based on the machine mode MODE.
204 Do not modify *F otherwise.
205 This function assumes the width of two double_int is greater than the width
206 of the fixed-point value (the sum of a possible sign bit, possible ibits,
207 and fbits).
208 Return true, if !SAT_P and overflow. */
209
210 static bool
211 fixed_saturate2 (enum machine_mode mode, double_int a_high, double_int a_low,
212 double_int *f, bool sat_p)
213 {
214 bool overflow_p = false;
215 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (mode);
216 int i_f_bits = GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode);
217
218 if (unsigned_p) /* Unsigned type. */
219 {
220 double_int max_r, max_s;
221 max_r.high = 0;
222 max_r.low = 0;
223 max_s.high = -1;
224 max_s.low = -1;
225 max_s = double_int_ext (max_s, i_f_bits, 1);
226 if (double_int_cmp (a_high, max_r, 1) == 1
227 || (double_int_equal_p (a_high, max_r) &&
228 double_int_cmp (a_low, max_s, 1) == 1))
229 {
230 if (sat_p)
231 *f = max_s;
232 else
233 overflow_p = true;
234 }
235 }
236 else /* Signed type. */
237 {
238 double_int max_r, max_s, min_r, min_s;
239 max_r.high = 0;
240 max_r.low = 0;
241 max_s.high = -1;
242 max_s.low = -1;
243 max_s = double_int_ext (max_s, i_f_bits, 1);
244 min_r.high = -1;
245 min_r.low = -1;
246 min_s.high = 0;
247 min_s.low = 1;
248 lshift_double (min_s.low, min_s.high, i_f_bits,
249 2 * HOST_BITS_PER_WIDE_INT,
250 &min_s.low, &min_s.high, 1);
251 min_s = double_int_ext (min_s, 1 + i_f_bits, 0);
252 if (double_int_cmp (a_high, max_r, 0) == 1
253 || (double_int_equal_p (a_high, max_r) &&
254 double_int_cmp (a_low, max_s, 1) == 1))
255 {
256 if (sat_p)
257 *f = max_s;
258 else
259 overflow_p = true;
260 }
261 else if (double_int_cmp (a_high, min_r, 0) == -1
262 || (double_int_equal_p (a_high, min_r) &&
263 double_int_cmp (a_low, min_s, 1) == -1))
264 {
265 if (sat_p)
266 *f = min_s;
267 else
268 overflow_p = true;
269 }
270 }
271 return overflow_p;
272 }
273
274 /* Return the sign bit based on I_F_BITS. */
275
276 static inline int
277 get_fixed_sign_bit (double_int a, int i_f_bits)
278 {
279 if (i_f_bits < HOST_BITS_PER_WIDE_INT)
280 return (a.low >> i_f_bits) & 1;
281 else
282 return (a.high >> (i_f_bits - HOST_BITS_PER_WIDE_INT)) & 1;
283 }
284
285 /* Calculate F = A + (SUBTRACT_P ? -B : B).
286 If SAT_P, saturate the result to the max or the min.
287 Return true, if !SAT_P and overflow. */
288
289 static bool
290 do_fixed_add (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a,
291 const FIXED_VALUE_TYPE *b, bool subtract_p, bool sat_p)
292 {
293 bool overflow_p = false;
294 bool unsigned_p;
295 double_int temp;
296 int i_f_bits;
297
298 /* This was a conditional expression but it triggered a bug in
299 Sun C 5.5. */
300 if (subtract_p)
301 temp = double_int_neg (b->data);
302 else
303 temp = b->data;
304
305 unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode);
306 i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode);
307 f->mode = a->mode;
308 f->data = double_int_add (a->data, temp);
309 if (unsigned_p) /* Unsigned type. */
310 {
311 if (subtract_p) /* Unsigned subtraction. */
312 {
313 if (double_int_cmp (a->data, b->data, 1) == -1)
314 {
315 if (sat_p)
316 {
317 f->data.high = 0;
318 f->data.low = 0;
319 }
320 else
321 overflow_p = true;
322 }
323 }
324 else /* Unsigned addition. */
325 {
326 f->data = double_int_ext (f->data, i_f_bits, 1);
327 if (double_int_cmp (f->data, a->data, 1) == -1
328 || double_int_cmp (f->data, b->data, 1) == -1)
329 {
330 if (sat_p)
331 {
332 f->data.high = -1;
333 f->data.low = -1;
334 }
335 else
336 overflow_p = true;
337 }
338 }
339 }
340 else /* Signed type. */
341 {
342 if ((!subtract_p
343 && (get_fixed_sign_bit (a->data, i_f_bits)
344 == get_fixed_sign_bit (b->data, i_f_bits))
345 && (get_fixed_sign_bit (a->data, i_f_bits)
346 != get_fixed_sign_bit (f->data, i_f_bits)))
347 || (subtract_p
348 && (get_fixed_sign_bit (a->data, i_f_bits)
349 != get_fixed_sign_bit (b->data, i_f_bits))
350 && (get_fixed_sign_bit (a->data, i_f_bits)
351 != get_fixed_sign_bit (f->data, i_f_bits))))
352 {
353 if (sat_p)
354 {
355 f->data.low = 1;
356 f->data.high = 0;
357 lshift_double (f->data.low, f->data.high, i_f_bits,
358 2 * HOST_BITS_PER_WIDE_INT,
359 &f->data.low, &f->data.high, 1);
360 if (get_fixed_sign_bit (a->data, i_f_bits) == 0)
361 {
362 double_int one;
363 one.low = 1;
364 one.high = 0;
365 f->data = double_int_add (f->data, double_int_neg (one));
366 }
367 }
368 else
369 overflow_p = true;
370 }
371 }
372 f->data = double_int_ext (f->data, (!unsigned_p) + i_f_bits, unsigned_p);
373 return overflow_p;
374 }
375
376 /* Calculate F = A * B.
377 If SAT_P, saturate the result to the max or the min.
378 Return true, if !SAT_P and overflow. */
379
380 static bool
381 do_fixed_multiply (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a,
382 const FIXED_VALUE_TYPE *b, bool sat_p)
383 {
384 bool overflow_p = false;
385 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode);
386 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode);
387 f->mode = a->mode;
388 if (GET_MODE_PRECISION (f->mode) <= HOST_BITS_PER_WIDE_INT)
389 {
390 f->data = double_int_mul (a->data, b->data);
391 lshift_double (f->data.low, f->data.high,
392 (-GET_MODE_FBIT (f->mode)),
393 2 * HOST_BITS_PER_WIDE_INT,
394 &f->data.low, &f->data.high, !unsigned_p);
395 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p);
396 }
397 else
398 {
399 /* The result of multiplication expands to two double_int. */
400 double_int a_high, a_low, b_high, b_low;
401 double_int high_high, high_low, low_high, low_low;
402 double_int r, s, temp1, temp2;
403 int carry = 0;
404
405 /* Decompose a and b to four double_int. */
406 a_high.low = a->data.high;
407 a_high.high = 0;
408 a_low.low = a->data.low;
409 a_low.high = 0;
410 b_high.low = b->data.high;
411 b_high.high = 0;
412 b_low.low = b->data.low;
413 b_low.high = 0;
414
415 /* Perform four multiplications. */
416 low_low = double_int_mul (a_low, b_low);
417 low_high = double_int_mul (a_low, b_high);
418 high_low = double_int_mul (a_high, b_low);
419 high_high = double_int_mul (a_high, b_high);
420
421 /* Accumulate four results to {r, s}. */
422 temp1.high = high_low.low;
423 temp1.low = 0;
424 s = double_int_add (low_low, temp1);
425 if (double_int_cmp (s, low_low, 1) == -1
426 || double_int_cmp (s, temp1, 1) == -1)
427 carry ++; /* Carry */
428 temp1.high = s.high;
429 temp1.low = s.low;
430 temp2.high = low_high.low;
431 temp2.low = 0;
432 s = double_int_add (temp1, temp2);
433 if (double_int_cmp (s, temp1, 1) == -1
434 || double_int_cmp (s, temp2, 1) == -1)
435 carry ++; /* Carry */
436
437 temp1.low = high_low.high;
438 temp1.high = 0;
439 r = double_int_add (high_high, temp1);
440 temp1.low = low_high.high;
441 temp1.high = 0;
442 r = double_int_add (r, temp1);
443 temp1.low = carry;
444 temp1.high = 0;
445 r = double_int_add (r, temp1);
446
447 /* We need to add neg(b) to r, if a < 0. */
448 if (!unsigned_p && a->data.high < 0)
449 r = double_int_add (r, double_int_neg (b->data));
450 /* We need to add neg(a) to r, if b < 0. */
451 if (!unsigned_p && b->data.high < 0)
452 r = double_int_add (r, double_int_neg (a->data));
453
454 /* Shift right the result by FBIT. */
455 if (GET_MODE_FBIT (f->mode) == 2 * HOST_BITS_PER_WIDE_INT)
456 {
457 s.low = r.low;
458 s.high = r.high;
459 if (unsigned_p)
460 {
461 r.low = 0;
462 r.high = 0;
463 }
464 else
465 {
466 r.low = -1;
467 r.high = -1;
468 }
469 f->data.low = s.low;
470 f->data.high = s.high;
471 }
472 else
473 {
474 lshift_double (s.low, s.high,
475 (-GET_MODE_FBIT (f->mode)),
476 2 * HOST_BITS_PER_WIDE_INT,
477 &s.low, &s.high, 0);
478 lshift_double (r.low, r.high,
479 (2 * HOST_BITS_PER_WIDE_INT
480 - GET_MODE_FBIT (f->mode)),
481 2 * HOST_BITS_PER_WIDE_INT,
482 &f->data.low, &f->data.high, 0);
483 f->data.low = f->data.low | s.low;
484 f->data.high = f->data.high | s.high;
485 s.low = f->data.low;
486 s.high = f->data.high;
487 lshift_double (r.low, r.high,
488 (-GET_MODE_FBIT (f->mode)),
489 2 * HOST_BITS_PER_WIDE_INT,
490 &r.low, &r.high, !unsigned_p);
491 }
492
493 overflow_p = fixed_saturate2 (f->mode, r, s, &f->data, sat_p);
494 }
495
496 f->data = double_int_ext (f->data, (!unsigned_p) + i_f_bits, unsigned_p);
497 return overflow_p;
498 }
499
500 /* Calculate F = A / B.
501 If SAT_P, saturate the result to the max or the min.
502 Return true, if !SAT_P and overflow. */
503
504 static bool
505 do_fixed_divide (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a,
506 const FIXED_VALUE_TYPE *b, bool sat_p)
507 {
508 bool overflow_p = false;
509 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode);
510 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode);
511 f->mode = a->mode;
512 if (GET_MODE_PRECISION (f->mode) <= HOST_BITS_PER_WIDE_INT)
513 {
514 lshift_double (a->data.low, a->data.high,
515 GET_MODE_FBIT (f->mode),
516 2 * HOST_BITS_PER_WIDE_INT,
517 &f->data.low, &f->data.high, !unsigned_p);
518 f->data = double_int_div (f->data, b->data, unsigned_p, TRUNC_DIV_EXPR);
519 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p);
520 }
521 else
522 {
523 double_int pos_a, pos_b, r, s;
524 double_int quo_r, quo_s, mod, temp;
525 int num_of_neg = 0;
526 int i;
527
528 /* If a < 0, negate a. */
529 if (!unsigned_p && a->data.high < 0)
530 {
531 pos_a = double_int_neg (a->data);
532 num_of_neg ++;
533 }
534 else
535 pos_a = a->data;
536
537 /* If b < 0, negate b. */
538 if (!unsigned_p && b->data.high < 0)
539 {
540 pos_b = double_int_neg (b->data);
541 num_of_neg ++;
542 }
543 else
544 pos_b = b->data;
545
546 /* Left shift pos_a to {r, s} by FBIT. */
547 if (GET_MODE_FBIT (f->mode) == 2 * HOST_BITS_PER_WIDE_INT)
548 {
549 r = pos_a;
550 s.high = 0;
551 s.low = 0;
552 }
553 else
554 {
555 lshift_double (pos_a.low, pos_a.high,
556 GET_MODE_FBIT (f->mode),
557 2 * HOST_BITS_PER_WIDE_INT,
558 &s.low, &s.high, 0);
559 lshift_double (pos_a.low, pos_a.high,
560 - (2 * HOST_BITS_PER_WIDE_INT
561 - GET_MODE_FBIT (f->mode)),
562 2 * HOST_BITS_PER_WIDE_INT,
563 &r.low, &r.high, 0);
564 }
565
566 /* Divide r by pos_b to quo_r. The remainder is in mod. */
567 div_and_round_double (TRUNC_DIV_EXPR, 1, r.low, r.high, pos_b.low,
568 pos_b.high, &quo_r.low, &quo_r.high, &mod.low,
569 &mod.high);
570
571 quo_s.high = 0;
572 quo_s.low = 0;
573
574 for (i = 0; i < 2 * HOST_BITS_PER_WIDE_INT; i++)
575 {
576 /* Record the leftmost bit of mod. */
577 int leftmost_mod = (mod.high < 0);
578
579 /* Shift left mod by 1 bit. */
580 lshift_double (mod.low, mod.high, 1, 2 * HOST_BITS_PER_WIDE_INT,
581 &mod.low, &mod.high, 0);
582
583 /* Test the leftmost bit of s to add to mod. */
584 if (s.high < 0)
585 mod.low += 1;
586
587 /* Shift left quo_s by 1 bit. */
588 lshift_double (quo_s.low, quo_s.high, 1, 2 * HOST_BITS_PER_WIDE_INT,
589 &quo_s.low, &quo_s.high, 0);
590
591 /* Try to calculate (mod - pos_b). */
592 temp = double_int_add (mod, double_int_neg (pos_b));
593
594 if (leftmost_mod == 1 || double_int_cmp (mod, pos_b, 1) != -1)
595 {
596 quo_s.low += 1;
597 mod = temp;
598 }
599
600 /* Shift left s by 1 bit. */
601 lshift_double (s.low, s.high, 1, 2 * HOST_BITS_PER_WIDE_INT,
602 &s.low, &s.high, 0);
603
604 }
605
606 if (num_of_neg == 1)
607 {
608 quo_s = double_int_neg (quo_s);
609 if (quo_s.high == 0 && quo_s.low == 0)
610 quo_r = double_int_neg (quo_r);
611 else
612 {
613 quo_r.low = ~quo_r.low;
614 quo_r.high = ~quo_r.high;
615 }
616 }
617
618 f->data = quo_s;
619 overflow_p = fixed_saturate2 (f->mode, quo_r, quo_s, &f->data, sat_p);
620 }
621
622 f->data = double_int_ext (f->data, (!unsigned_p) + i_f_bits, unsigned_p);
623 return overflow_p;
624 }
625
626 /* Calculate F = A << B if LEFT_P. Otherwise, F = A >> B.
627 If SAT_P, saturate the result to the max or the min.
628 Return true, if !SAT_P and overflow. */
629
630 static bool
631 do_fixed_shift (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a,
632 const FIXED_VALUE_TYPE *b, bool left_p, bool sat_p)
633 {
634 bool overflow_p = false;
635 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode);
636 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode);
637 f->mode = a->mode;
638
639 if (b->data.low == 0)
640 {
641 f->data = a->data;
642 return overflow_p;
643 }
644
645 if (GET_MODE_PRECISION (f->mode) <= HOST_BITS_PER_WIDE_INT || (!left_p))
646 {
647 lshift_double (a->data.low, a->data.high,
648 left_p ? b->data.low : (-b->data.low),
649 2 * HOST_BITS_PER_WIDE_INT,
650 &f->data.low, &f->data.high, !unsigned_p);
651 if (left_p) /* Only left shift saturates. */
652 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p);
653 }
654 else /* We need two double_int to store the left-shift result. */
655 {
656 double_int temp_high, temp_low;
657 if (b->data.low == 2 * HOST_BITS_PER_WIDE_INT)
658 {
659 temp_high = a->data;
660 temp_low.high = 0;
661 temp_low.low = 0;
662 }
663 else
664 {
665 lshift_double (a->data.low, a->data.high,
666 b->data.low,
667 2 * HOST_BITS_PER_WIDE_INT,
668 &temp_low.low, &temp_low.high, !unsigned_p);
669 /* Logical shift right to temp_high. */
670 lshift_double (a->data.low, a->data.high,
671 b->data.low - 2 * HOST_BITS_PER_WIDE_INT,
672 2 * HOST_BITS_PER_WIDE_INT,
673 &temp_high.low, &temp_high.high, 0);
674 }
675 if (!unsigned_p && a->data.high < 0) /* Signed-extend temp_high. */
676 temp_high = double_int_ext (temp_high, b->data.low, unsigned_p);
677 f->data = temp_low;
678 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, &f->data,
679 sat_p);
680 }
681 f->data = double_int_ext (f->data, (!unsigned_p) + i_f_bits, unsigned_p);
682 return overflow_p;
683 }
684
685 /* Calculate F = -A.
686 If SAT_P, saturate the result to the max or the min.
687 Return true, if !SAT_P and overflow. */
688
689 static bool
690 do_fixed_neg (FIXED_VALUE_TYPE *f, const FIXED_VALUE_TYPE *a, bool sat_p)
691 {
692 bool overflow_p = false;
693 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (a->mode);
694 int i_f_bits = GET_MODE_IBIT (a->mode) + GET_MODE_FBIT (a->mode);
695 f->mode = a->mode;
696 f->data = double_int_neg (a->data);
697 f->data = double_int_ext (f->data, (!unsigned_p) + i_f_bits, unsigned_p);
698
699 if (unsigned_p) /* Unsigned type. */
700 {
701 if (f->data.low != 0 || f->data.high != 0)
702 {
703 if (sat_p)
704 {
705 f->data.low = 0;
706 f->data.high = 0;
707 }
708 else
709 overflow_p = true;
710 }
711 }
712 else /* Signed type. */
713 {
714 if (!(f->data.high == 0 && f->data.low == 0)
715 && f->data.high == a->data.high && f->data.low == a->data.low )
716 {
717 if (sat_p)
718 {
719 /* Saturate to the maximum by subtracting f->data by one. */
720 f->data.low = -1;
721 f->data.high = -1;
722 f->data = double_int_ext (f->data, i_f_bits, 1);
723 }
724 else
725 overflow_p = true;
726 }
727 }
728 return overflow_p;
729 }
730
731 /* Perform the binary or unary operation described by CODE.
732 Note that OP0 and OP1 must have the same mode for binary operators.
733 For a unary operation, leave OP1 NULL.
734 Return true, if !SAT_P and overflow. */
735
736 bool
737 fixed_arithmetic (FIXED_VALUE_TYPE *f, int icode, const FIXED_VALUE_TYPE *op0,
738 const FIXED_VALUE_TYPE *op1, bool sat_p)
739 {
740 switch (icode)
741 {
742 case NEGATE_EXPR:
743 return do_fixed_neg (f, op0, sat_p);
744 break;
745
746 case PLUS_EXPR:
747 gcc_assert (op0->mode == op1->mode);
748 return do_fixed_add (f, op0, op1, false, sat_p);
749 break;
750
751 case MINUS_EXPR:
752 gcc_assert (op0->mode == op1->mode);
753 return do_fixed_add (f, op0, op1, true, sat_p);
754 break;
755
756 case MULT_EXPR:
757 gcc_assert (op0->mode == op1->mode);
758 return do_fixed_multiply (f, op0, op1, sat_p);
759 break;
760
761 case TRUNC_DIV_EXPR:
762 gcc_assert (op0->mode == op1->mode);
763 return do_fixed_divide (f, op0, op1, sat_p);
764 break;
765
766 case LSHIFT_EXPR:
767 return do_fixed_shift (f, op0, op1, true, sat_p);
768 break;
769
770 case RSHIFT_EXPR:
771 return do_fixed_shift (f, op0, op1, false, sat_p);
772 break;
773
774 default:
775 gcc_unreachable ();
776 }
777 return false;
778 }
779
780 /* Compare fixed-point values by tree_code.
781 Note that OP0 and OP1 must have the same mode. */
782
783 bool
784 fixed_compare (int icode, const FIXED_VALUE_TYPE *op0,
785 const FIXED_VALUE_TYPE *op1)
786 {
787 enum tree_code code = icode;
788 gcc_assert (op0->mode == op1->mode);
789
790 switch (code)
791 {
792 case NE_EXPR:
793 return !double_int_equal_p (op0->data, op1->data);
794
795 case EQ_EXPR:
796 return double_int_equal_p (op0->data, op1->data);
797
798 case LT_EXPR:
799 return double_int_cmp (op0->data, op1->data,
800 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) == -1;
801
802 case LE_EXPR:
803 return double_int_cmp (op0->data, op1->data,
804 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) != 1;
805
806 case GT_EXPR:
807 return double_int_cmp (op0->data, op1->data,
808 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) == 1;
809
810 case GE_EXPR:
811 return double_int_cmp (op0->data, op1->data,
812 UNSIGNED_FIXED_POINT_MODE_P (op0->mode)) != -1;
813
814 default:
815 gcc_unreachable ();
816 }
817 }
818
819 /* Extend or truncate to a new mode.
820 If SAT_P, saturate the result to the max or the min.
821 Return true, if !SAT_P and overflow. */
822
823 bool
824 fixed_convert (FIXED_VALUE_TYPE *f, enum machine_mode mode,
825 const FIXED_VALUE_TYPE *a, bool sat_p)
826 {
827 bool overflow_p = false;
828 if (mode == a->mode)
829 {
830 *f = *a;
831 return overflow_p;
832 }
833
834 if (GET_MODE_FBIT (mode) > GET_MODE_FBIT (a->mode))
835 {
836 /* Left shift a to temp_high, temp_low based on a->mode. */
837 double_int temp_high, temp_low;
838 int amount = GET_MODE_FBIT (mode) - GET_MODE_FBIT (a->mode);
839 lshift_double (a->data.low, a->data.high,
840 amount,
841 2 * HOST_BITS_PER_WIDE_INT,
842 &temp_low.low, &temp_low.high,
843 SIGNED_FIXED_POINT_MODE_P (a->mode));
844 /* Logical shift right to temp_high. */
845 lshift_double (a->data.low, a->data.high,
846 amount - 2 * HOST_BITS_PER_WIDE_INT,
847 2 * HOST_BITS_PER_WIDE_INT,
848 &temp_high.low, &temp_high.high, 0);
849 if (SIGNED_FIXED_POINT_MODE_P (a->mode)
850 && a->data.high < 0) /* Signed-extend temp_high. */
851 temp_high = double_int_ext (temp_high, amount, 0);
852 f->mode = mode;
853 f->data = temp_low;
854 if (SIGNED_FIXED_POINT_MODE_P (a->mode) ==
855 SIGNED_FIXED_POINT_MODE_P (f->mode))
856 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, &f->data,
857 sat_p);
858 else
859 {
860 /* Take care of the cases when converting between signed and
861 unsigned. */
862 if (SIGNED_FIXED_POINT_MODE_P (a->mode))
863 {
864 /* Signed -> Unsigned. */
865 if (a->data.high < 0)
866 {
867 if (sat_p)
868 {
869 f->data.low = 0; /* Set to zero. */
870 f->data.high = 0; /* Set to zero. */
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 else
880 {
881 /* Unsigned -> Signed. */
882 if (temp_high.high < 0)
883 {
884 if (sat_p)
885 {
886 /* Set to maximum. */
887 f->data.low = -1; /* Set to all ones. */
888 f->data.high = -1; /* Set to all ones. */
889 f->data = double_int_ext (f->data,
890 GET_MODE_FBIT (f->mode)
891 + GET_MODE_IBIT (f->mode),
892 1); /* Clear the sign. */
893 }
894 else
895 overflow_p = true;
896 }
897 else
898 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low,
899 &f->data, sat_p);
900 }
901 }
902 }
903 else
904 {
905 /* Right shift a to temp based on a->mode. */
906 double_int temp;
907 lshift_double (a->data.low, a->data.high,
908 GET_MODE_FBIT (mode) - GET_MODE_FBIT (a->mode),
909 2 * HOST_BITS_PER_WIDE_INT,
910 &temp.low, &temp.high,
911 SIGNED_FIXED_POINT_MODE_P (a->mode));
912 f->mode = mode;
913 f->data = temp;
914 if (SIGNED_FIXED_POINT_MODE_P (a->mode) ==
915 SIGNED_FIXED_POINT_MODE_P (f->mode))
916 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data, sat_p);
917 else
918 {
919 /* Take care of the cases when converting between signed and
920 unsigned. */
921 if (SIGNED_FIXED_POINT_MODE_P (a->mode))
922 {
923 /* Signed -> Unsigned. */
924 if (a->data.high < 0)
925 {
926 if (sat_p)
927 {
928 f->data.low = 0; /* Set to zero. */
929 f->data.high = 0; /* Set to zero. */
930 }
931 else
932 overflow_p = true;
933 }
934 else
935 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data,
936 sat_p);
937 }
938 else
939 {
940 /* Unsigned -> Signed. */
941 if (temp.high < 0)
942 {
943 if (sat_p)
944 {
945 /* Set to maximum. */
946 f->data.low = -1; /* Set to all ones. */
947 f->data.high = -1; /* Set to all ones. */
948 f->data = double_int_ext (f->data,
949 GET_MODE_FBIT (f->mode)
950 + GET_MODE_IBIT (f->mode),
951 1); /* Clear the sign. */
952 }
953 else
954 overflow_p = true;
955 }
956 else
957 overflow_p = fixed_saturate1 (f->mode, f->data, &f->data,
958 sat_p);
959 }
960 }
961 }
962
963 f->data = double_int_ext (f->data,
964 SIGNED_FIXED_POINT_MODE_P (f->mode)
965 + GET_MODE_FBIT (f->mode)
966 + GET_MODE_IBIT (f->mode),
967 UNSIGNED_FIXED_POINT_MODE_P (f->mode));
968 return overflow_p;
969 }
970
971 /* Convert to a new fixed-point mode from an integer.
972 If UNSIGNED_P, this integer is unsigned.
973 If SAT_P, saturate the result to the max or the min.
974 Return true, if !SAT_P and overflow. */
975
976 bool
977 fixed_convert_from_int (FIXED_VALUE_TYPE *f, enum machine_mode mode,
978 double_int a, bool unsigned_p, bool sat_p)
979 {
980 bool overflow_p = false;
981 /* Left shift a to temp_high, temp_low. */
982 double_int temp_high, temp_low;
983 int amount = GET_MODE_FBIT (mode);
984 if (amount == 2 * HOST_BITS_PER_WIDE_INT)
985 {
986 temp_high = a;
987 temp_low.low = 0;
988 temp_low.high = 0;
989 }
990 else
991 {
992 lshift_double (a.low, a.high,
993 amount,
994 2 * HOST_BITS_PER_WIDE_INT,
995 &temp_low.low, &temp_low.high, 0);
996
997 /* Logical shift right to temp_high. */
998 lshift_double (a.low, a.high,
999 amount - 2 * HOST_BITS_PER_WIDE_INT,
1000 2 * HOST_BITS_PER_WIDE_INT,
1001 &temp_high.low, &temp_high.high, 0);
1002 }
1003 if (!unsigned_p && a.high < 0) /* Signed-extend temp_high. */
1004 temp_high = double_int_ext (temp_high, amount, 0);
1005
1006 f->mode = mode;
1007 f->data = temp_low;
1008
1009 if (unsigned_p == UNSIGNED_FIXED_POINT_MODE_P (f->mode))
1010 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low, &f->data,
1011 sat_p);
1012 else
1013 {
1014 /* Take care of the cases when converting between signed and unsigned. */
1015 if (!unsigned_p)
1016 {
1017 /* Signed -> Unsigned. */
1018 if (a.high < 0)
1019 {
1020 if (sat_p)
1021 {
1022 f->data.low = 0; /* Set to zero. */
1023 f->data.high = 0; /* Set to zero. */
1024 }
1025 else
1026 overflow_p = true;
1027 }
1028 else
1029 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low,
1030 &f->data, sat_p);
1031 }
1032 else
1033 {
1034 /* Unsigned -> Signed. */
1035 if (temp_high.high < 0)
1036 {
1037 if (sat_p)
1038 {
1039 /* Set to maximum. */
1040 f->data.low = -1; /* Set to all ones. */
1041 f->data.high = -1; /* Set to all ones. */
1042 f->data = double_int_ext (f->data,
1043 GET_MODE_FBIT (f->mode)
1044 + GET_MODE_IBIT (f->mode),
1045 1); /* Clear the sign. */
1046 }
1047 else
1048 overflow_p = true;
1049 }
1050 else
1051 overflow_p = fixed_saturate2 (f->mode, temp_high, temp_low,
1052 &f->data, sat_p);
1053 }
1054 }
1055 f->data = double_int_ext (f->data,
1056 SIGNED_FIXED_POINT_MODE_P (f->mode)
1057 + GET_MODE_FBIT (f->mode)
1058 + GET_MODE_IBIT (f->mode),
1059 UNSIGNED_FIXED_POINT_MODE_P (f->mode));
1060 return overflow_p;
1061 }
1062
1063 /* Convert to a new fixed-point mode from a real.
1064 If SAT_P, saturate the result to the max or the min.
1065 Return true, if !SAT_P and overflow. */
1066
1067 bool
1068 fixed_convert_from_real (FIXED_VALUE_TYPE *f, enum machine_mode mode,
1069 const REAL_VALUE_TYPE *a, bool sat_p)
1070 {
1071 bool overflow_p = false;
1072 REAL_VALUE_TYPE real_value, fixed_value, base_value;
1073 bool unsigned_p = UNSIGNED_FIXED_POINT_MODE_P (mode);
1074 int i_f_bits = GET_MODE_IBIT (mode) + GET_MODE_FBIT (mode);
1075 unsigned int fbit = GET_MODE_FBIT (mode);
1076 enum fixed_value_range_code temp;
1077
1078 real_value = *a;
1079 f->mode = mode;
1080 real_2expN (&base_value, fbit, mode);
1081 real_arithmetic (&fixed_value, MULT_EXPR, &real_value, &base_value);
1082 real_to_integer2 ((HOST_WIDE_INT *)&f->data.low, &f->data.high, &fixed_value);
1083 temp = check_real_for_fixed_mode (&real_value, mode);
1084 if (temp == FIXED_UNDERFLOW) /* Minimum. */
1085 {
1086 if (sat_p)
1087 {
1088 if (unsigned_p)
1089 {
1090 f->data.low = 0;
1091 f->data.high = 0;
1092 }
1093 else
1094 {
1095 f->data.low = 1;
1096 f->data.high = 0;
1097 lshift_double (f->data.low, f->data.high, i_f_bits,
1098 2 * HOST_BITS_PER_WIDE_INT,
1099 &f->data.low, &f->data.high, 1);
1100 f->data = double_int_ext (f->data, 1 + i_f_bits, 0);
1101 }
1102 }
1103 else
1104 overflow_p = true;
1105 }
1106 else if (temp == FIXED_GT_MAX_EPS || temp == FIXED_MAX_EPS) /* Maximum. */
1107 {
1108 if (sat_p)
1109 {
1110 f->data.low = -1;
1111 f->data.high = -1;
1112 f->data = double_int_ext (f->data, i_f_bits, 1);
1113 }
1114 else
1115 overflow_p = true;
1116 }
1117 f->data = double_int_ext (f->data, (!unsigned_p) + i_f_bits, unsigned_p);
1118 return overflow_p;
1119 }
1120
1121 /* Convert to a new real mode from a fixed-point. */
1122
1123 void
1124 real_convert_from_fixed (REAL_VALUE_TYPE *r, enum machine_mode mode,
1125 const FIXED_VALUE_TYPE *f)
1126 {
1127 REAL_VALUE_TYPE base_value, fixed_value, real_value;
1128
1129 real_2expN (&base_value, GET_MODE_FBIT (f->mode), f->mode);
1130 real_from_integer (&fixed_value, VOIDmode, f->data.low, f->data.high,
1131 UNSIGNED_FIXED_POINT_MODE_P (f->mode));
1132 real_arithmetic (&real_value, RDIV_EXPR, &fixed_value, &base_value);
1133 real_convert (r, mode, &real_value);
1134 }
1135
1136 /* Determine whether a fixed-point value F is negative. */
1137
1138 bool
1139 fixed_isneg (const FIXED_VALUE_TYPE *f)
1140 {
1141 if (SIGNED_FIXED_POINT_MODE_P (f->mode))
1142 {
1143 int i_f_bits = GET_MODE_IBIT (f->mode) + GET_MODE_FBIT (f->mode);
1144 int sign_bit = get_fixed_sign_bit (f->data, i_f_bits);
1145 if (sign_bit == 1)
1146 return true;
1147 }
1148
1149 return false;
1150 }