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[iverilog.git] / eval_tree.cc
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1 /*
2 * Copyright (c) 1999-2003 Stephen Williams (steve@icarus.com)
3 *
4 * This source code is free software; you can redistribute it
5 * and/or modify it in source code form under the terms of the GNU
6 * General Public License as published by the Free Software
7 * Foundation; either version 2 of the License, or (at your option)
8 * any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
18 */
19
20 # include "config.h"
21 # include "compiler.h"
22
23 # include <iostream>
24
25 # include "netlist.h"
26 # include "ivl_assert.h"
27
28 NetExpr* NetExpr::eval_tree(int prune_to_width)
29 {
30 return 0;
31 }
32
33 /*
34 * Some of the derived classes can be evaluated by the compiler, this
35 * method provides the common aid of evaluating the parameter
36 * expressions.
37 */
38 void NetEBinary::eval_sub_tree_()
39 {
40 NetExpr*tmp = left_->eval_tree();
41 if (tmp) {
42 delete left_;
43 left_ = tmp;
44 }
45 tmp = right_->eval_tree();
46 if (tmp){
47 delete right_;
48 right_ = tmp;
49 }
50 }
51
52 bool NetEBinary::get_real_arguments_(verireal&lval, verireal&rval)
53 {
54 switch (left_->expr_type()) {
55 case IVL_VT_REAL: {
56 NetECReal*lc = dynamic_cast<NetECReal*> (left_);
57 if (lc == 0) return false;
58 lval = lc->value();
59 break;
60 }
61
62 case IVL_VT_BOOL:
63 case IVL_VT_LOGIC: {
64 NetEConst*lc = dynamic_cast<NetEConst*>(left_);
65 if (lc == 0) return false;
66 verinum tmp = lc->value();
67 lval = verireal(tmp.as_long());
68 break;
69 }
70
71 default:
72 assert(0);
73 }
74
75 switch (right_->expr_type()) {
76 case IVL_VT_REAL: {
77 NetECReal*rc = dynamic_cast<NetECReal*> (right_);
78 if (rc == 0) return 0;
79 rval = rc->value();
80 break;
81 }
82
83 case IVL_VT_BOOL:
84 case IVL_VT_LOGIC: {
85 NetEConst*rc = dynamic_cast<NetEConst*>(right_);
86 if (rc == 0) return 0;
87 verinum tmp = rc->value();
88 rval = verireal(tmp.as_long());
89 break;
90 }
91
92 default:
93 assert(0);
94 }
95
96
97 return true;
98 }
99
100 NetExpr* NetEBAdd::eval_tree(int prune_to_width)
101 {
102 eval_sub_tree_();
103
104 if (left_->expr_type() == IVL_VT_REAL || right_->expr_type()==IVL_VT_REAL)
105 return eval_tree_real_();
106
107 NetEConst*lc = dynamic_cast<NetEConst*>(left_);
108 NetEConst*rc = dynamic_cast<NetEConst*>(right_);
109
110 /* If both operands are constant, then replace the entire
111 expression with a constant value. */
112 if (lc != 0 && rc != 0) {
113 verinum lval = lc->value();
114 verinum rval = rc->value();
115
116 verinum val;
117 switch (op_) {
118 case '+':
119 val = lval + rval;
120 break;
121 case '-':
122 val = lval - rval;
123 break;
124 default:
125 return 0;
126 }
127
128 /* Result might have known width. */
129 if (has_width()) {
130 if (debug_eval_tree) {
131 cerr << get_line() << ": debug: Evaluate expr=" << *this
132 << " --- prune=" << prune_to_width << endl;
133 }
134 unsigned lwid = lc->expr_width();
135 unsigned rwid = rc->expr_width();
136 unsigned wid = (rwid > lwid) ? rwid : lwid;
137 if (prune_to_width < 0)
138 wid += 1;
139 verinum val2=verinum(val,wid);
140 val=val2;
141 }
142
143 return new NetEConst(val);
144 }
145
146 /* Try to combine a right constant value with the right
147 constant value of a sub-expression add. For example, the
148 expression (a + 2) - 1 can be rewritten as a + 1. */
149
150 NetEBAdd*se = dynamic_cast<NetEBAdd*>(left_);
151 lc = se? dynamic_cast<NetEConst*>(se->right_) : 0;
152
153 if (lc != 0 && rc != 0) {
154 assert(se != 0);
155 verinum lval = lc->value();
156 verinum rval = rc->value();
157
158 verinum val;
159 if (op_ == se->op_) {
160 /* (a + lval) + rval --> a + (rval+lval) */
161 /* (a - lval) - rval --> a - (rval+lval) */
162 val = rval + lval;
163 } else {
164 /* (a - lval) + rval --> a + (rval-lval) */
165 /* (a + lval) - rval --> a - (rval-lval) */
166 val = rval - lval;
167 }
168
169 NetEConst*tmp = new NetEConst(val);
170 left_ = se->left_->dup_expr();
171 delete se;
172 delete right_;
173 right_ = tmp;
174 /* We've changed the subexpression, but the result is
175 still not constant, so return nil here anyhow. */
176 return 0;
177 }
178
179 /* Nothing more to be done, the value is not constant. */
180 return 0;
181 }
182
183 NetECReal* NetEBAdd::eval_tree_real_()
184 {
185 verireal lval;
186 verireal rval;
187 bool flag = get_real_arguments_(lval, rval);
188 if (!flag) return 0;
189
190 verireal res_val;
191
192 switch (op()) {
193 case '+':
194 res_val = lval + rval;
195 break;
196 case '-':
197 res_val = lval - rval;
198 break;
199 default:
200 ivl_assert(*this, 0);
201 }
202
203 NetECReal*res = new NetECReal( res_val );
204 res->set_line(*this);
205 return res;
206 }
207
208 NetEConst* NetEBBits::eval_tree(int prune_to_width)
209 {
210 eval_sub_tree_();
211
212 NetEConst*lc = dynamic_cast<NetEConst*>(left_);
213 NetEConst*rc = dynamic_cast<NetEConst*>(right_);
214
215 /* Notice the special case where one of the operands is 0 and
216 this is a bitwise &. If this happens, then the result is
217 known to be 0. */
218 if ((op() == '&') && lc && (lc->value() == verinum(0))) {
219 verinum res (verinum::V0, expr_width());
220 return new NetEConst(res);
221 }
222
223 if ((op() == '&') && rc && (rc->value() == verinum(0))) {
224 verinum res (verinum::V0, expr_width());
225 return new NetEConst(res);
226 }
227
228 if (lc == 0) return 0;
229 if (rc == 0) return 0;
230
231 verinum lval = lc->value();
232 verinum rval = rc->value();
233
234 unsigned lwid = lc->expr_width();
235 if (lwid == 0) lwid = lval.len();
236
237 unsigned rwid = rc->expr_width();
238 if (rwid == 0) rwid = rval.len();
239
240 unsigned wid = expr_width();
241 if (wid == 0)
242 wid = (rwid > lwid)? rwid : lwid;
243
244 verinum res (verinum::V0, wid);
245
246 if (lwid > wid)
247 lwid = wid;
248 if (rwid > wid)
249 rwid = wid;
250
251 switch (op()) {
252
253 case '|': {
254 unsigned cnt = lwid;
255 if (cnt > wid) cnt = wid;
256 if (cnt > rwid) cnt = rwid;
257 for (unsigned idx = 0 ; idx < cnt ; idx += 1)
258 res.set(idx, lval.get(idx) | rval.get(idx));
259
260 if (lwid < rwid)
261 for (unsigned idx = lwid ; idx < rwid ; idx += 1)
262 res.set(idx, rval.get(idx));
263
264 if (rwid < lwid)
265 for (unsigned idx = rwid ; idx < lwid ; idx += 1)
266 res.set(idx, lval.get(idx));
267
268 break;
269 }
270
271 case '&': {
272 unsigned cnt = lwid;
273 if (cnt > wid) cnt = wid;
274 if (cnt > rwid) cnt = rwid;
275 for (unsigned idx = 0 ; idx < cnt ; idx += 1)
276 res.set(idx, lval.get(idx) & rval.get(idx));
277
278 break;
279 }
280
281 case '^': {
282 unsigned cnt = lwid;
283 if (cnt > wid) cnt = wid;
284 if (cnt > rwid) cnt = rwid;
285 for (unsigned idx = 0 ; idx < cnt ; idx += 1)
286 res.set(idx, lval.get(idx) ^ rval.get(idx));
287
288 if (lwid < rwid)
289 for (unsigned idx = lwid ; idx < rwid ; idx += 1)
290 res.set(idx, rval.get(idx));
291
292 if (rwid < lwid)
293 for (unsigned idx = rwid ; idx < lwid ; idx += 1)
294 res.set(idx, lval.get(idx));
295
296 break;
297 }
298
299 default:
300 return 0;
301 }
302
303 return new NetEConst(res);
304 }
305
306
307 NetEConst* NetEBComp::eval_less_()
308 {
309 NetEConst*r = dynamic_cast<NetEConst*>(right_);
310 if (r == 0) return 0;
311
312 verinum rv = r->value();
313 if (! rv.is_defined()) {
314 verinum result(verinum::Vx, 1);
315 return new NetEConst(result);
316 }
317
318
319 /* Detect the case where the right side is greater than or
320 equal to the largest value the left side can possibly
321 have. Use the width of the left expression as all 1's to
322 calculate the maximum possible width for the left_
323 expression. This test only works of the compare is
324 unsigned. */
325 if (! (rv.has_sign() || left_->has_sign())) {
326
327 assert(left_->expr_width() > 0);
328 verinum lv (verinum::V1, left_->expr_width());
329 if (lv < rv) {
330 verinum result(verinum::V1, 1);
331 return new NetEConst(result);
332 }
333 }
334
335 /* Now go on to the normal test of the values. */
336 NetEConst*l = dynamic_cast<NetEConst*>(left_);
337 if (l == 0) return 0;
338 verinum lv = l->value();
339 if (! lv.is_defined()) {
340 verinum result(verinum::Vx, 1);
341 return new NetEConst(result);
342 }
343
344 if (lv.has_sign() && rv.has_sign()) {
345 if (lv.as_long() < rv.as_long()) {
346 verinum result(verinum::V1, 1);
347 return new NetEConst(result);
348 }
349 } else {
350 if (lv.as_ulong() < rv.as_ulong()) {
351 verinum result(verinum::V1, 1);
352 return new NetEConst(result);
353 }
354 }
355
356 verinum result(verinum::V0, 1);
357 return new NetEConst(result);
358 }
359
360 NetEConst* NetEBComp::eval_leeq_real_()
361 {
362 NetEConst*vtmp;
363 NetECReal*rtmp;
364 double lv, rv;
365
366 switch (left_->expr_type()) {
367 case IVL_VT_REAL:
368 rtmp = dynamic_cast<NetECReal*> (left_);
369 if (rtmp == 0)
370 return 0;
371
372 lv = rtmp->value().as_double();
373 break;
374
375 case IVL_VT_LOGIC:
376 vtmp = dynamic_cast<NetEConst*> (left_);
377 if (vtmp == 0)
378 return 0;
379
380 lv = vtmp->value().as_long();
381 break;
382
383 default:
384 assert(0);
385 }
386
387
388 switch (right_->expr_type()) {
389 case IVL_VT_REAL:
390 rtmp = dynamic_cast<NetECReal*> (right_);
391 if (rtmp == 0)
392 return 0;
393
394 rv = rtmp->value().as_double();
395 break;
396
397 case IVL_VT_LOGIC:
398 vtmp = dynamic_cast<NetEConst*> (right_);
399 if (vtmp == 0)
400 return 0;
401
402 rv = vtmp->value().as_long();
403 break;
404
405 default:
406 assert(0);
407 }
408
409 verinum result((lv <= rv)? verinum::V1 : verinum::V0, 1);
410 vtmp = new NetEConst(result);
411 vtmp->set_line(*this);
412
413 return vtmp;
414 }
415
416 NetEConst* NetEBComp::eval_leeq_()
417 {
418 if (right_->expr_type() == IVL_VT_REAL)
419 return eval_leeq_real_();
420 if (left_->expr_type() == IVL_VT_REAL)
421 return eval_leeq_real_();
422
423 NetEConst*r = dynamic_cast<NetEConst*>(right_);
424 if (r == 0) return 0;
425
426 verinum rv = r->value();
427 if (! rv.is_defined()) {
428 verinum result(verinum::Vx, 1);
429 return new NetEConst(result);
430 }
431
432 if (left_->expr_width() == 0) {
433 cerr << get_line() << ": internal error: Something wrong "
434 << "with the left side width of <= ?" << endl;
435 cerr << get_line() << ": : " << *this << endl;
436 }
437
438 /* Detect the case where the right side is greater that or
439 equal to the largest value the left side can possibly
440 have. */
441 assert(left_->expr_width() > 0);
442 verinum lv (verinum::V1, left_->expr_width());
443 if (lv <= rv) {
444 verinum result(verinum::V1, 1);
445 return new NetEConst(result);
446 }
447
448 /* Now go on to the normal test of the values. */
449 NetEConst*l = dynamic_cast<NetEConst*>(left_);
450 if (l == 0) return 0;
451 lv = l->value();
452 if (! lv.is_defined()) {
453 verinum result(verinum::Vx, 1);
454 return new NetEConst(result);
455 }
456
457 if (lv.has_sign() && rv.has_sign()) {
458 if (lv.as_long() <= rv.as_long()) {
459 verinum result(verinum::V1, 1);
460 return new NetEConst(result);
461 }
462 } else {
463 if (lv.as_ulong() <= rv.as_ulong()) {
464 verinum result(verinum::V1, 1);
465 return new NetEConst(result);
466 }
467 }
468
469 verinum result(verinum::V0, 1);
470 return new NetEConst(result);
471 }
472
473 NetEConst* NetEBComp::eval_gt_()
474 {
475 if ((left_->expr_type() == IVL_VT_REAL)
476 && (right_->expr_type() == IVL_VT_REAL)) {
477
478 NetECReal*tmpl = dynamic_cast<NetECReal*>(left_);
479 if (tmpl == 0)
480 return 0;
481
482 NetECReal*tmpr = dynamic_cast<NetECReal*>(right_);
483 if (tmpr == 0)
484 return 0;
485
486 double ll = tmpl->value().as_double();
487 double rr = tmpr->value().as_double();
488
489 verinum result ((ll > rr)? verinum::V1 : verinum::V0, 1, true);
490 return new NetEConst(result);
491 }
492
493 NetEConst*l = dynamic_cast<NetEConst*>(left_);
494 if (l == 0) return 0;
495
496 verinum lv = l->value();
497 if (! lv.is_defined()) {
498 verinum result(verinum::Vx, 1);
499 return new NetEConst(result);
500 }
501
502 /* Check for the special case where we know, simply by the
503 limited width of the right expression, that it cannot
504 possibly be false. */
505 if (right_->expr_width() > 0) {
506 verinum rv (verinum::V1, right_->expr_width());
507 if (lv > rv) {
508 verinum result(verinum::V1, 1);
509 return new NetEConst(result);
510 }
511 }
512
513 /* Compare with a real value. Do it as double precision. */
514 if (right_->expr_type() == IVL_VT_REAL) {
515 NetECReal*tmp = dynamic_cast<NetECReal*>(right_);
516 if (tmp == 0)
517 return 0;
518
519 double rr = tmp->value().as_double();
520 double ll = lv.has_sign()? lv.as_long() : lv.as_ulong();
521
522 verinum result ((ll > rr)? verinum::V1 : verinum::V0, 1, true);
523 return new NetEConst(result);
524 }
525
526 /* Now go on to the normal test of the values. */
527 NetEConst*r = dynamic_cast<NetEConst*>(right_);
528 if (r == 0) return 0;
529 verinum rv = r->value();
530 if (! rv.is_defined()) {
531 verinum result(verinum::Vx, 1);
532 return new NetEConst(result);
533 }
534
535 if (lv.has_sign() && rv.has_sign() && (lv.as_long() > rv.as_long())) {
536 verinum result(verinum::V1, 1);
537 return new NetEConst(result);
538 }
539
540 if (lv.as_ulong() > rv.as_ulong()) {
541 verinum result(verinum::V1, 1);
542 return new NetEConst(result);
543 }
544
545 verinum result(verinum::V0, 1);
546 return new NetEConst(result);
547 }
548
549 NetEConst* NetEBComp::eval_gteq_()
550 {
551 if ((left_->expr_type() == IVL_VT_REAL)
552 && (right_->expr_type() == IVL_VT_REAL)) {
553
554 NetECReal*tmpl = dynamic_cast<NetECReal*>(left_);
555 if (tmpl == 0)
556 return 0;
557
558 NetECReal*tmpr = dynamic_cast<NetECReal*>(right_);
559 if (tmpr == 0)
560 return 0;
561
562 double ll = tmpl->value().as_double();
563 double rr = tmpr->value().as_double();
564
565 verinum result ((ll >= rr)? verinum::V1 : verinum::V0, 1, true);
566 return new NetEConst(result);
567 }
568
569 NetEConst*l = dynamic_cast<NetEConst*>(left_);
570 if (l == 0) return 0;
571
572 verinum lv = l->value();
573 if (! lv.is_defined()) {
574 verinum result(verinum::Vx, 1);
575 return new NetEConst(result);
576 }
577
578 /* Detect the case where the left side is greater than the
579 largest value the right side can possibly have. */
580 if (right_->expr_type() == IVL_VT_LOGIC) {
581 assert(right_->expr_width() > 0);
582 verinum rv (verinum::V1, right_->expr_width());
583 if (lv >= rv) {
584 verinum result(verinum::V1, 1);
585 return new NetEConst(result);
586 }
587 }
588
589 /* Compare with a real value. Do it as double precision. */
590 if (right_->expr_type() == IVL_VT_REAL) {
591 NetECReal*tmp = dynamic_cast<NetECReal*>(right_);
592 if (tmp == 0)
593 return 0;
594
595 double rr = tmp->value().as_double();
596 double ll = lv.has_sign()? lv.as_long() : lv.as_ulong();
597
598 verinum result ((ll >= rr)? verinum::V1 : verinum::V0, 1, true);
599 return new NetEConst(result);
600 }
601
602 /* Now go on to the normal test of the values. */
603 NetEConst*r = dynamic_cast<NetEConst*>(right_);
604 if (r == 0) return 0;
605 verinum rv = r->value();
606 if (! rv.is_defined()) {
607 verinum result(verinum::Vx, 1);
608 return new NetEConst(result);
609 }
610
611 if (lv.has_sign() && rv.has_sign()) {
612
613 if (lv.as_long() >= rv.as_long()) {
614 verinum result(verinum::V1, 1);
615 return new NetEConst(result);
616 }
617 } else {
618
619 if (lv.as_ulong() >= rv.as_ulong()) {
620 verinum result(verinum::V1, 1);
621 return new NetEConst(result);
622 }
623 }
624
625 verinum result(verinum::V0, 1);
626 return new NetEConst(result);
627 }
628
629 NetEConst* NetEBComp::eval_eqeq_(bool ne_flag)
630 {
631 NetEConst*l = dynamic_cast<NetEConst*>(left_);
632 if (l == 0) return 0;
633 NetEConst*r = dynamic_cast<NetEConst*>(right_);
634 if (r == 0) return 0;
635
636 const verinum&lv = l->value();
637 const verinum&rv = r->value();
638
639 const verinum::V eq_res = ne_flag? verinum::V0 : verinum::V1;
640 const verinum::V ne_res = ne_flag? verinum::V1 : verinum::V0;
641
642 verinum::V res = eq_res;
643 unsigned top = lv.len();
644 if (rv.len() < top)
645 top = rv.len();
646
647 for (unsigned idx = 0 ; idx < top ; idx += 1) {
648
649 switch (lv.get(idx)) {
650
651 case verinum::Vx:
652 case verinum::Vz:
653 res = verinum::Vx;
654 break;
655
656 default:
657 break;
658 }
659
660 switch (rv.get(idx)) {
661
662 case verinum::Vx:
663 case verinum::Vz:
664 res = verinum::Vx;
665 break;
666
667 default:
668 break;
669 }
670
671 if (res == verinum::Vx)
672 break;
673
674 if (rv.get(idx) != lv.get(idx))
675 res = ne_res;
676 }
677
678 if (res != verinum::Vx) {
679 verinum::V lpad = verinum::V0;
680 verinum::V rpad = verinum::V0;
681
682 if (lv.has_sign() && lv.get(lv.len()-1) == verinum::V1)
683 lpad = verinum::V1;
684 if (rv.has_sign() && rv.get(rv.len()-1) == verinum::V1)
685 rpad = verinum::V1;
686
687 for (unsigned idx = top ; idx < lv.len() ; idx += 1)
688 switch (lv.get(idx)) {
689
690 case verinum::Vx:
691 case verinum::Vz:
692 res = verinum::Vx;
693 break;
694
695 case verinum::V0:
696 if (res != verinum::Vx && rpad != verinum::V0)
697 res = ne_res;
698 break;
699
700 case verinum::V1:
701 if (res != verinum::Vx && rpad != verinum::V1)
702 res = ne_res;
703 break;
704
705 default:
706 break;
707 }
708
709 for (unsigned idx = top ; idx < rv.len() ; idx += 1)
710 switch (rv.get(idx)) {
711
712 case verinum::Vx:
713 case verinum::Vz:
714 res = verinum::Vx;
715 break;
716
717 case verinum::V0:
718 if (res != verinum::Vx && lpad != verinum::V0)
719 res = ne_res;
720 break;
721
722 case verinum::V1:
723 if (res != verinum::Vx && lpad != verinum::V1)
724 res = ne_res;
725 break;
726
727 default:
728 break;
729 }
730 }
731
732 return new NetEConst(verinum(res));
733 }
734
735 NetEConst* NetEBComp::eval_eqeqeq_()
736 {
737 NetEConst*l = dynamic_cast<NetEConst*>(left_);
738 if (l == 0) return 0;
739 NetEConst*r = dynamic_cast<NetEConst*>(right_);
740 if (r == 0) return 0;
741
742 const verinum&lv = l->value();
743 const verinum&rv = r->value();
744
745 verinum::V res = verinum::V1;
746
747 unsigned cnt = lv.len();
748 if (cnt > rv.len())
749 cnt = rv.len();
750
751 for (unsigned idx = 0 ; idx < cnt ; idx += 1)
752 if (lv.get(idx) != rv.get(idx))
753 res = verinum::V0;
754
755 for (unsigned idx = cnt ; idx < lv.len() ; idx += 1)
756 if (lv.get(idx) != verinum::V0)
757 res = verinum::V0;
758
759 for (unsigned idx = cnt ; idx < rv.len() ; idx += 1)
760 if (rv.get(idx) != verinum::V0)
761 res = verinum::V0;
762
763 return new NetEConst(verinum(res, 1));
764 }
765
766 NetEConst* NetEBComp::eval_neeqeq_()
767 {
768 NetEConst*tmp = eval_eqeqeq_();
769 if (tmp == 0)
770 return 0;
771
772 NetEConst*res;
773
774 if (tmp->value().get(0) == verinum::V0)
775 res = new NetEConst(verinum(verinum::V1,1));
776 else
777 res = new NetEConst(verinum(verinum::V0,1));
778
779 delete tmp;
780 return res;
781 }
782
783 NetEConst* NetEBComp::eval_tree(int prune_to_width)
784 {
785 eval_sub_tree_();
786
787 switch (op_) {
788 case 'E': // Case equality (===)
789 return eval_eqeqeq_();
790
791 case 'e': // Equality (==)
792 return eval_eqeq_(false);
793
794 case 'G': // >=
795 return eval_gteq_();
796
797 case 'L': // <=
798 return eval_leeq_();
799
800 case 'N': // Case inequality (!==)
801 return eval_neeqeq_();
802
803 case 'n': // not-equal (!=)
804 return eval_eqeq_(true);
805
806 case '<': // Less than
807 return eval_less_();
808
809 case '>': // Greater then
810 return eval_gt_();
811
812 default:
813 return 0;
814 }
815 }
816
817 /*
818 * The NetEBDiv operator includes the / and % operators. First evaluate
819 * the sub-expressions, then perform the required operation.
820 */
821 NetExpr* NetEBDiv::eval_tree(int prune_to_width)
822 {
823 eval_sub_tree_();
824
825 if (expr_type() == IVL_VT_REAL) {
826 NetECReal*lc = dynamic_cast<NetECReal*>(left_);
827 if (lc == 0) return 0;
828
829 verireal lval = lc->value();
830
831 if (NetECReal*rc = dynamic_cast<NetECReal*>(right_)) {
832 NetECReal*tmp = 0;
833 verireal rval = rc->value();
834
835 switch (op_) {
836 case '/':
837 tmp = new NetECReal(lval / rval);
838 break;
839
840 case '%':
841 tmp = new NetECReal(lval % rval);
842 }
843
844 assert(tmp);
845 tmp->set_line(*this);
846 return tmp;
847
848 } else if (NetEConst*rc = dynamic_cast<NetEConst*>(right_)) {
849
850 NetECReal*tmp = 0;
851 verinum rval = rc->value();
852
853 switch (op_) {
854 case '/':
855 tmp = new NetECReal(lval / rval);
856 break;
857
858 case '%':
859 tmp = new NetECReal(lval % rval);
860 }
861
862 assert(tmp);
863 tmp->set_line(*this);
864 return tmp;
865
866 }
867
868
869 } else {
870 assert(expr_type() == IVL_VT_LOGIC);
871 NetEConst*lc = dynamic_cast<NetEConst*>(left_);
872 if (lc == 0) return 0;
873 NetEConst*rc = dynamic_cast<NetEConst*>(right_);
874 if (rc == 0) return 0;
875
876 verinum lval = lc->value();
877 verinum rval = rc->value();
878
879 switch (op_) {
880 case '/':
881 return new NetEConst(lval / rval);
882
883 case '%':
884 return new NetEConst(lval % rval);
885 }
886 }
887
888 return 0;
889 }
890
891 NetEConst* NetEBLogic::eval_tree(int prune_to_width)
892 {
893 eval_sub_tree_();
894 NetEConst*lc = dynamic_cast<NetEConst*>(left_);
895 if (lc == 0) return 0;
896 NetEConst*rc = dynamic_cast<NetEConst*>(right_);
897 if (rc == 0) return 0;
898
899 verinum::V lv = verinum::V0;
900 verinum::V rv = verinum::V0;
901
902 verinum v = lc->value();
903 for (unsigned idx = 0 ; idx < v.len() ; idx += 1)
904 if (v.get(idx) == verinum::V1)
905 lv = verinum::V1;
906
907 if (lv == verinum::V0)
908 for (unsigned idx = 0 ; idx < v.len() ; idx += 1)
909 if (v.get(idx) != verinum::V0)
910 lv = verinum::Vx;
911
912 v = rc->value();
913 for (unsigned idx = 0 ; idx < v.len() ; idx += 1)
914 if (v.get(idx) == verinum::V1)
915 rv = verinum::V1;
916
917 if (rv == verinum::V0)
918 for (unsigned idx = 0 ; idx < v.len() ; idx += 1)
919 if (v.get(idx) != verinum::V0)
920 rv = verinum::Vx;
921
922 verinum::V res;
923 switch (op_) {
924 case 'a': { // Logical AND (&&)
925 if ((lv == verinum::V0) || (rv == verinum::V0))
926 res = verinum::V0;
927
928 else if ((lv == verinum::V1) && (rv == verinum::V1))
929 res = verinum::V1;
930
931 else
932 res = verinum::Vx;
933
934 break;
935 }
936
937 case 'o': { // Logical OR (||)
938 if ((lv == verinum::V1) || (rv == verinum::V1))
939 res = verinum::V1;
940
941 else if ((lv == verinum::V0) && (rv == verinum::V0))
942 res = verinum::V0;
943
944 else
945 res = verinum::Vx;
946
947 break;
948 }
949
950 default:
951 return 0;
952 }
953
954 return new NetEConst(verinum(res, 1));
955 }
956
957
958 NetExpr* NetEBMult::eval_tree_real_()
959 {
960 verireal lval;
961 verireal rval;
962
963 bool flag = get_real_arguments_(lval, rval);
964 if (! flag) return 0;
965
966
967 NetECReal*res = new NetECReal(lval * rval);
968 res->set_line(*this);
969 return res;
970 }
971
972 NetExpr* NetEBMult::eval_tree(int prune_to_width)
973 {
974 eval_sub_tree_();
975
976 if (expr_type() == IVL_VT_REAL)
977 return eval_tree_real_();
978
979 assert(expr_type() == IVL_VT_LOGIC);
980
981 NetEConst*lc = dynamic_cast<NetEConst*>(left_);
982 if (lc == 0) return 0;
983 NetEConst*rc = dynamic_cast<NetEConst*>(right_);
984 if (rc == 0) return 0;
985
986 verinum lval = lc->value();
987 verinum rval = rc->value();
988
989 return new NetEConst(lval * rval);
990 }
991
992 NetExpr* NetEBPow::eval_tree_real_()
993 {
994 verireal lval;
995 verireal rval;
996
997 bool flag = get_real_arguments_(lval, rval);
998 if (! flag) return 0;
999
1000 NetECReal*res = new NetECReal( pow(lval,rval) );
1001 res->set_line(*this);
1002 return res;
1003 }
1004
1005 NetExpr* NetEBPow::eval_tree(int prune_to_width)
1006 {
1007 eval_sub_tree_();
1008
1009 if (expr_type() == IVL_VT_REAL)
1010 return eval_tree_real_();
1011
1012 assert(expr_type() == IVL_VT_LOGIC);
1013
1014 NetEConst*lc = dynamic_cast<NetEConst*>(left_);
1015 if (lc == 0) return 0;
1016 NetEConst*rc = dynamic_cast<NetEConst*>(right_);
1017 if (rc == 0) return 0;
1018
1019 verinum lval = lc->value();
1020 verinum rval = rc->value();
1021
1022 return new NetEConst( pow(lval,rval) );
1023
1024 }
1025
1026 /*
1027 * Evaluate the shift operator if possible. For this to work, both
1028 * operands must be constant.
1029 */
1030 NetEConst* NetEBShift::eval_tree(int prune_to_width)
1031 {
1032 eval_sub_tree_();
1033 NetEConst*re = dynamic_cast<NetEConst*>(right_);
1034 if (re == 0)
1035 return 0;
1036
1037 NetEConst*le = dynamic_cast<NetEConst*>(left_);
1038 if (le == 0)
1039 return 0;
1040
1041 NetEConst*res;
1042
1043 verinum rv = re->value();
1044 verinum lv = le->value();
1045
1046 /* Make an early estimate of the expression width. */
1047 unsigned wid = expr_width();
1048
1049 if (rv.is_defined()) {
1050
1051 unsigned shift = rv.as_ulong();
1052
1053 if (debug_eval_tree) {
1054 cerr << get_line() << ": debug: "
1055 << "Evaluate " << lv << "<<" << op() << ">> "
1056 << rv << ", wid=" << wid << ", shift=" << shift
1057 << ", lv.has_len()=" << lv.has_len() << endl;
1058 }
1059
1060 if ((wid == 0) || ! lv.has_len()) {
1061 /* If the caller doesn't care what the width is,
1062 then calcuate a width from the trimmed left
1063 expression, plus the shift. This avoids
1064 data loss. */
1065 lv = trim_vnum(lv);
1066 wid = lv.len();
1067 if (op() == 'l')
1068 wid = lv.len() + shift;
1069 }
1070
1071 if (prune_to_width > 0 && wid > (unsigned)prune_to_width)
1072 wid = prune_to_width;
1073
1074 assert(wid);
1075 verinum::V pad = verinum::V0;
1076 if (op() == 'R' && has_sign()) {
1077 pad = lv[lv.len()-1];
1078 }
1079 verinum nv (pad, wid, lv.has_len());
1080
1081 if (op() == 'r' || op() == 'R') {
1082 unsigned cnt = wid;
1083 if (cnt > nv.len())
1084 cnt = nv.len();
1085 if (shift >= lv.len())
1086 cnt = 0;
1087 else if (cnt > (lv.len()-shift))
1088 cnt = (lv.len()-shift);
1089 for (unsigned idx = 0 ; idx < cnt ; idx += 1)
1090 nv.set(idx, lv[idx+shift]);
1091
1092 } else {
1093 unsigned cnt = wid;
1094 if (cnt > lv.len())
1095 cnt = lv.len();
1096 if (shift >= nv.len())
1097 cnt = 0;
1098 else if (cnt > (nv.len()-shift))
1099 cnt = nv.len() - shift;
1100
1101 for (unsigned idx = 0 ; idx < cnt ; idx += 1)
1102 nv.set(idx+shift, lv[idx]);
1103 }
1104
1105 res = new NetEConst(nv);
1106
1107 } else {
1108 if (wid == 0)
1109 wid = left_->expr_width();
1110
1111 verinum nv (verinum::Vx, wid);
1112 res = new NetEConst(nv);
1113 }
1114
1115 return res;
1116 }
1117
1118 NetEConst* NetEConcat::eval_tree(int prune_to_width)
1119 {
1120 unsigned repeat_val = repeat();
1121 unsigned local_errors = 0;
1122
1123 if (debug_eval_tree) {
1124 cerr << get_line() << ": debug: Evaluate expr=" << *this
1125 << ", prune_to_width=" << prune_to_width << endl;
1126 }
1127
1128 unsigned gap = 0;
1129 for (unsigned idx = 0 ; idx < parms_.count() ; idx += 1) {
1130
1131 // Parameter not here? This is an error, but presumably
1132 // already caught and we are here just to catch more.
1133 if (parms_[idx] == 0)
1134 continue;
1135
1136
1137 // If this parameter is already a constant, all is well
1138 // so go on.
1139 if (dynamic_cast<NetEConst*>(parms_[idx])) {
1140 gap += parms_[idx]->expr_width();
1141 continue;
1142 }
1143
1144 // Finally, try to evaluate the parameter expression
1145 // that is here. If I succeed, reset the parameter to
1146 // the evaluated value.
1147 assert(parms_[idx]);
1148 NetExpr*expr = parms_[idx]->eval_tree(0);
1149 if (expr) {
1150 delete parms_[idx];
1151 parms_[idx] = expr;
1152
1153 if (! expr->has_width()) {
1154 cerr << get_line() << ": error: concatenation "
1155 << "operand has indefinite width: "
1156 << *parms_[idx] << endl;
1157 local_errors += 1;
1158 } else if (expr->expr_width() == 0) {
1159 cerr << expr->get_line() << ": internal error: "
1160 << "Operand of concatenation has no width: "
1161 << *expr << endl;
1162 local_errors += 1;
1163 }
1164
1165 gap += expr->expr_width();
1166 }
1167
1168 }
1169
1170 if (local_errors > 0)
1171 return 0;
1172
1173 // Handle the special case that the repeat expression is
1174 // zero. In this case, just return a 0 value with the expected
1175 // width.
1176 if (repeat_val == 0) {
1177 verinum val (verinum::V0, expr_width());
1178 NetEConst*res = new NetEConst(val);
1179 res->set_width(val.len());
1180 return res;
1181 }
1182
1183 // At this point, the "gap" is the width of a single repeat of
1184 // the concatenation. The total width of the result is the gap
1185 // times the repeat count.
1186 verinum val (verinum::Vx, repeat_val * gap);
1187
1188 // build up the result from least significant to most.
1189
1190 unsigned cur = 0;
1191 bool is_string_flag = true;
1192 for (unsigned idx = parms_.count() ; idx > 0 ; idx -= 1) {
1193 NetEConst*expr = dynamic_cast<NetEConst*>(parms_[idx-1]);
1194 if (expr == 0)
1195 return 0;
1196
1197 verinum tmp = expr->value();
1198 for (unsigned bit = 0; bit < tmp.len(); bit += 1, cur += 1)
1199 for (unsigned rep = 0 ; rep < repeat_val ; rep += 1)
1200 val.set(rep*gap+cur, tmp[bit]);
1201
1202 is_string_flag = is_string_flag && tmp.is_string();
1203 }
1204
1205 /* If all the values were strings, then re-stringify this
1206 constant. This might be useful information in the code
1207 generator or other optimizer steps. */
1208 if (is_string_flag) {
1209 val = verinum(val.as_string());
1210 }
1211
1212 NetEConst*res = new NetEConst(val);
1213 res->set_width(val.len());
1214 return res;
1215 }
1216
1217 NetExpr* NetEParam::eval_tree(int prune_to_width)
1218 {
1219 if (des_ == 0) {
1220 assert(scope_ == 0);
1221 return 0;
1222 }
1223
1224 if (debug_elaborate) {
1225 cerr << get_line() << ": debug: evaluating expression: "
1226 << *this << endl;
1227 }
1228
1229 assert(scope_);
1230 const NetExpr*expr_msb;
1231 const NetExpr*expr_lsb;
1232 const NetExpr*expr = scope_->get_parameter(name_, expr_msb, expr_lsb);
1233 if (expr == 0) {
1234 cerr << get_line() << ": internal error: Unable to match "
1235 << "parameter " << name_ << " in scope "
1236 << scope_path(scope_) << endl;
1237 return 0;
1238 }
1239
1240 assert(expr);
1241
1242 NetExpr*nexpr = expr->dup_expr();
1243 assert(nexpr);
1244
1245 // If the parameter that I refer to is already evaluated, then
1246 // return the constant value.
1247 if (NetEConst*tmp = dynamic_cast<NetEConst*>(nexpr)) {
1248 verinum val = tmp->value();
1249 NetEConstParam*ptmp = new NetEConstParam(scope_, name_, val);
1250 ptmp->set_line(*this);
1251 delete nexpr;
1252 return ptmp;
1253 }
1254
1255 if (NetECReal*tmp = dynamic_cast<NetECReal*>(nexpr)) {
1256 verireal val = tmp->value();
1257 NetECRealParam*ptmp = new NetECRealParam(scope_, name_, val);
1258 ptmp->set_line(*this);
1259 delete nexpr;
1260 return ptmp;
1261 }
1262
1263 // Try to evaluate the expression. If I cannot, then the
1264 // expression is not a constant expression and I fail here.
1265 NetExpr*res = nexpr->eval_tree();
1266 if (res == 0) {
1267 cerr << get_line() << ": internal error: Unable to evaluate "
1268 << "parameter " << name_ << " expression: "
1269 << *nexpr << endl;
1270 delete nexpr;
1271 return 0;
1272 }
1273
1274 // The result can be saved as the value of the parameter for
1275 // future reference, and return a copy to the caller.
1276 scope_->replace_parameter(name_, res);
1277
1278 /* Return as a result a NetEConstParam or NetECRealParam
1279 object, depending on the type of the expression. */
1280
1281 switch (res->expr_type()) {
1282
1283 case IVL_VT_BOOL:
1284 case IVL_VT_LOGIC:
1285 { NetEConst*tmp = dynamic_cast<NetEConst*>(res);
1286 if (tmp == 0) {
1287 cerr << get_line() << ": internal error: parameter "
1288 << name_ << " evaluates to incomprehensible "
1289 << *res << "." << endl;
1290 return 0;
1291 }
1292
1293 assert(tmp);
1294
1295 verinum val = tmp->value();
1296 NetEConstParam*ptmp = new NetEConstParam(scope_, name_, val);
1297
1298 return ptmp;
1299 }
1300
1301 case IVL_VT_REAL:
1302 { NetECReal*tmp = dynamic_cast<NetECReal*>(res);
1303 if (tmp == 0) {
1304 cerr << get_line() << ": internal error: parameter "
1305 << name_ << " evaluates to incomprehensible "
1306 << *res << "." << endl;
1307 return 0;
1308 }
1309
1310 assert(tmp);
1311
1312 verireal val = tmp->value();
1313 NetECRealParam*ptmp = new NetECRealParam(scope_, name_, val);
1314
1315 return ptmp;
1316 }
1317
1318 default:
1319 assert(0);
1320 return 0;
1321 }
1322 }
1323
1324 NetEConst* NetESelect::eval_tree(int prune_to_width)
1325 {
1326 NetEConst*expr = dynamic_cast<NetEConst*>(expr_);
1327 if (expr == 0) {
1328 NetExpr*tmp = expr_->eval_tree();
1329 if (tmp != 0) {
1330 delete expr_;
1331 expr_ = tmp;
1332 }
1333
1334 expr = dynamic_cast<NetEConst*>(expr_);
1335 }
1336
1337 long bval = 0;
1338 if (base_) {
1339 NetEConst*base = dynamic_cast<NetEConst*>(base_);
1340 if (base == 0) {
1341 NetExpr*tmp = base_->eval_tree();
1342 if (tmp != 0) {
1343 delete base_;
1344 base_ = tmp;
1345 }
1346
1347 base = dynamic_cast<NetEConst*>(base_);
1348 }
1349
1350 if (base == 0)
1351 return 0;
1352
1353 bval = base->value().as_long();
1354 }
1355
1356 if (expr == 0)
1357 return 0;
1358
1359 verinum eval = expr->value();
1360 verinum oval (verinum::V0, expr_width(), true);
1361
1362 verinum::V pad_bit = verinum::Vx;
1363 if (base_ == 0) {
1364
1365 /* If the base is NULL (different from 0) the this
1366 select is here for sign extension. So calculate a
1367 proper pad bit. Extend x or z or 0, and sign extend 1
1368 if this is signed. */
1369 unsigned top = expr->expr_width()-1;
1370
1371 pad_bit = eval.get(top);
1372 if (pad_bit==verinum::V1 && !has_sign())
1373 pad_bit = verinum::V0;
1374 }
1375
1376 for (unsigned long idx = 0 ; idx < expr_width() ; idx += 1) {
1377 if ((bval >= 0) && ((unsigned long) bval < eval.len()))
1378 oval.set(idx, eval.get(bval));
1379 else
1380 oval.set(idx, pad_bit);
1381
1382 bval += 1;
1383 }
1384
1385 NetEConst*res = new NetEConst(oval);
1386 return res;
1387 }
1388
1389
1390 /*
1391 * A ternary expression evaluation is controlled by the condition
1392 * expression. If the condition evaluates to true or false, then
1393 * return the evaluated true or false expression. If the condition
1394 * evaluates to x or z, then merge the constant bits of the true and
1395 * false expressions.
1396 */
1397 NetExpr* NetETernary::eval_tree(int prune_to_width)
1398 {
1399 NetExpr*tmp;
1400
1401 assert(cond_);
1402 if (0 == dynamic_cast<NetEConst*>(cond_)) {
1403 tmp = cond_->eval_tree();
1404 if (tmp != 0) {
1405 delete cond_;
1406 cond_ = tmp;
1407 }
1408 }
1409
1410 assert(true_val_);
1411 if (0 == dynamic_cast<NetEConst*>(true_val_)) {
1412 tmp = true_val_->eval_tree();
1413 if (tmp != 0) {
1414 delete true_val_;
1415 true_val_ = tmp;
1416 }
1417 }
1418
1419 assert(false_val_);
1420 if (0 == dynamic_cast<NetEConst*>(false_val_)) {
1421 tmp = false_val_->eval_tree();
1422 if (tmp != 0) {
1423 delete false_val_;
1424 false_val_ = tmp;
1425 }
1426 }
1427
1428
1429 NetEConst*c = dynamic_cast<NetEConst*>(cond_);
1430 if (c == 0)
1431 return 0;
1432
1433 /* Check the boolean value of the constant condition
1434 expression. Note that the X case is handled explicitly, so
1435 we must differentiate. */
1436
1437 verinum cond_value = c->value();
1438 bool true_flag = false;
1439 bool x_flag = false;
1440
1441 for (unsigned idx = 0 ; idx < cond_value.len() ; idx += 1) {
1442 switch (cond_value.get(idx)) {
1443 case verinum::V1:
1444 true_flag = true;
1445 break;
1446 case verinum::V0:
1447 break;
1448 default:
1449 x_flag = true;
1450 }
1451 }
1452
1453
1454 /* If the condition is 1 or 0, return the true or false
1455 expression. Try to evaluate the expression down as far as
1456 we can. */
1457
1458 if (true_flag) {
1459 if (debug_eval_tree) {
1460 cerr << get_line() << ": debug: Evaluate ternary with "
1461 << "constant condition value: " << c->value() << endl;
1462 cerr << get_line() << ": : Selecting true case: "
1463 << *true_val_ << endl;
1464 }
1465 return true_val_->dup_expr();
1466 }
1467
1468 if (! x_flag) {
1469 if (debug_eval_tree) {
1470 cerr << get_line() << ": debug: Evaluate ternary with "
1471 << "constant condition value: " << c->value() << endl;
1472 cerr << get_line() << ": : Selecting false case: "
1473 << *true_val_ << endl;
1474 }
1475 return false_val_->dup_expr();
1476 }
1477
1478 /* Here we have a more complex case. We need to evaluate both
1479 expressions down to constants then compare the values to
1480 build up a constant result. */
1481
1482 NetEConst*t = dynamic_cast<NetEConst*>(true_val_);
1483 if (t == 0)
1484 return 0;
1485
1486
1487 NetEConst*f = dynamic_cast<NetEConst*>(false_val_);
1488 if (f == 0)
1489 return 0;
1490
1491
1492 unsigned tsize = t->expr_width();
1493 unsigned fsize = f->expr_width();
1494 /* Size of the result is the size of the widest operand. */
1495 unsigned rsize = tsize > fsize? tsize : fsize;
1496
1497 verinum val (verinum::V0, rsize);
1498 for (unsigned idx = 0 ; idx < rsize ; idx += 1) {
1499 verinum::V tv = idx < tsize? t->value().get(idx) : verinum::V0;
1500 verinum::V fv = idx < rsize? f->value().get(idx) : verinum::V0;
1501
1502 if (tv == fv)
1503 val.set(idx, tv);
1504 else
1505 val.set(idx, verinum::Vx);
1506 }
1507
1508 if (debug_eval_tree) {
1509 cerr << get_line() << ": debug: Evaluate ternary with "
1510 << "constant condition value: " << c->value() << endl;
1511 cerr << get_line() << ": : Blending cases to get "
1512 << val << endl;
1513 }
1514
1515 NetEConst*rc = new NetEConst(val);
1516 rc->set_line(*this);
1517 return rc;
1518 }
1519
1520 void NetEUnary::eval_expr_()
1521 {
1522 assert(expr_);
1523 if (dynamic_cast<NetEConst*>(expr_))
1524 return;
1525
1526 NetExpr*oper = expr_->eval_tree();
1527 if (oper == 0)
1528 return;
1529
1530 delete expr_;
1531 expr_ = oper;
1532 }
1533
1534 NetEConst* NetEUnary::eval_tree(int prune_to_width)
1535 {
1536 eval_expr_();
1537 NetEConst*rval = dynamic_cast<NetEConst*>(expr_);
1538 if (rval == 0)
1539 return 0;
1540
1541 verinum val = rval->value();
1542
1543 switch (op_) {
1544
1545 case '+':
1546 /* Unary + is a no-op. */
1547 return new NetEConst(val);
1548
1549 case '-': {
1550 if (val.is_defined()) {
1551
1552 verinum tmp (verinum::V0, val.len());
1553 tmp.has_sign(val.has_sign());
1554 val = tmp - val;
1555
1556 } else {
1557 for (unsigned idx = 0 ; idx < val.len() ; idx += 1)
1558 val.set(idx, verinum::Vx);
1559 }
1560
1561 return new NetEConst(val);
1562 }
1563
1564 case '~': {
1565 /* Bitwise not is even simpler then logical
1566 not. Just invert all the bits of the operand and
1567 make the new value with the same dimensions. */
1568 for (unsigned idx = 0 ; idx < val.len() ; idx += 1)
1569 switch (val.get(idx)) {
1570 case verinum::V0:
1571 val.set(idx, verinum::V1);
1572 break;
1573 case verinum::V1:
1574 val.set(idx, verinum::V0);
1575 break;
1576 default:
1577 val.set(idx, verinum::Vx);
1578 }
1579
1580 return new NetEConst(val);
1581 }
1582
1583 case '!':
1584 assert(0);
1585 default:
1586 return 0;
1587 }
1588 }
1589
1590
1591 NetEConst* NetEUBits::eval_tree(int prune_to_width)
1592 {
1593 return NetEUnary::eval_tree(prune_to_width);
1594 }
1595
1596 NetEConst* NetEUReduce::eval_tree(int prune_to_width)
1597 {
1598 eval_expr_();
1599 NetEConst*rval = dynamic_cast<NetEConst*>(expr_);
1600 if (rval == 0)
1601 return 0;
1602
1603 verinum val = rval->value();
1604 verinum::V res;
1605
1606 switch (op_) {
1607
1608 case '!': {
1609 /* Evaluate the unary logical not by first scanning
1610 the operand value for V1 and Vx bits. If we find
1611 any V1 bits we know that the value is TRUE, so
1612 the result of ! is V0. If there are no V1 bits
1613 but there are some Vx/Vz bits, the result is
1614 unknown. Otherwise, the result is V1. */
1615 unsigned v1 = 0, vx = 0;
1616 for (unsigned idx = 0 ; idx < val.len() ; idx += 1) {
1617 switch (val.get(idx)) {
1618 case verinum::V0:
1619 break;
1620 case verinum::V1:
1621 v1 += 1;
1622 break;
1623 default:
1624 vx += 1;
1625 break;
1626 }
1627 }
1628
1629 res = v1? verinum::V0 : (vx? verinum::Vx : verinum::V1);
1630 break;
1631 }
1632
1633 case '&': {
1634 res = verinum::V1;
1635 for (unsigned idx = 0 ; idx < val.len() ; idx += 1)
1636 res = res & val.get(idx);
1637 break;
1638 }
1639
1640 case '|': {
1641 res = verinum::V0;
1642 for (unsigned idx = 0 ; idx < val.len() ; idx += 1)
1643 res = res | val.get(idx);
1644 break;
1645 }
1646
1647 case '^': {
1648 /* Reduction XOR. */
1649 unsigned ones = 0, unknown = 0;
1650 for (unsigned idx = 0 ; idx < val.len() ; idx += 1)
1651 switch (val.get(idx)) {
1652 case verinum::V0:
1653 break;
1654 case verinum::V1:
1655 ones += 1;
1656 break;
1657 default:
1658 unknown += 1;
1659 break;
1660 }
1661
1662 if (unknown)
1663 return new NetEConst(verinum(verinum::Vx,1,true));
1664 if (ones%2)
1665 return new NetEConst(verinum(verinum::V1,1,true));
1666 return new NetEConst(verinum(verinum::V0,1,true));
1667 }
1668
1669 default:
1670 return 0;
1671 }
1672
1673 return new NetEConst(verinum(res, 1));
1674 }
1675
Icarus Verilog