1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
|
/**CFile****************************************************************
FileName [ivyDfs.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [And-Inverter Graph package.]
Synopsis [DFS collection procedures.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - May 11, 2006.]
Revision [$Id: ivyDfs.c,v 1.00 2006/05/11 00:00:00 alanmi Exp $]
***********************************************************************/
#include "ivy.h"
ABC_NAMESPACE_IMPL_START
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Collects nodes in the DFS order.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_ManDfs_rec( Ivy_Man_t * p, Ivy_Obj_t * pObj, Vec_Int_t * vNodes )
{
if ( Ivy_ObjIsMarkA(pObj) )
return;
Ivy_ObjSetMarkA(pObj);
if ( Ivy_ObjIsConst1(pObj) || Ivy_ObjIsCi(pObj) )
{
if ( p->pHaig == NULL && pObj->pEquiv )
Ivy_ManDfs_rec( p, Ivy_Regular(pObj->pEquiv), vNodes );
return;
}
//printf( "visiting node %d\n", pObj->Id );
/*
if ( pObj->Id == 87 || pObj->Id == 90 )
{
int y = 0;
}
*/
assert( Ivy_ObjIsBuf(pObj) || Ivy_ObjIsAnd(pObj) || Ivy_ObjIsExor(pObj) );
Ivy_ManDfs_rec( p, Ivy_ObjFanin0(pObj), vNodes );
if ( !Ivy_ObjIsBuf(pObj) )
Ivy_ManDfs_rec( p, Ivy_ObjFanin1(pObj), vNodes );
if ( p->pHaig == NULL && pObj->pEquiv )
Ivy_ManDfs_rec( p, Ivy_Regular(pObj->pEquiv), vNodes );
Vec_IntPush( vNodes, pObj->Id );
//printf( "adding node %d with fanins %d and %d and equiv %d (refs = %d)\n",
// pObj->Id, Ivy_ObjFanin0(pObj)->Id, Ivy_ObjFanin1(pObj)->Id,
// pObj->pEquiv? Ivy_Regular(pObj->pEquiv)->Id: -1, Ivy_ObjRefs(pObj) );
}
/**Function*************************************************************
Synopsis [Collects AND/EXOR nodes in the DFS order from CIs to COs.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Ivy_ManDfs( Ivy_Man_t * p )
{
Vec_Int_t * vNodes;
Ivy_Obj_t * pObj;
int i;
assert( Ivy_ManLatchNum(p) == 0 );
// make sure the nodes are not marked
Ivy_ManForEachObj( p, pObj, i )
assert( !pObj->fMarkA && !pObj->fMarkB );
// collect the nodes
vNodes = Vec_IntAlloc( Ivy_ManNodeNum(p) );
Ivy_ManForEachPo( p, pObj, i )
Ivy_ManDfs_rec( p, Ivy_ObjFanin0(pObj), vNodes );
// unmark the collected nodes
// Ivy_ManForEachNodeVec( p, vNodes, pObj, i )
// Ivy_ObjClearMarkA(pObj);
Ivy_ManForEachObj( p, pObj, i )
Ivy_ObjClearMarkA(pObj);
// make sure network does not have dangling nodes
assert( Vec_IntSize(vNodes) == Ivy_ManNodeNum(p) + Ivy_ManBufNum(p) );
return vNodes;
}
/**Function*************************************************************
Synopsis [Collects AND/EXOR nodes in the DFS order from CIs to COs.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Ivy_ManDfsSeq( Ivy_Man_t * p, Vec_Int_t ** pvLatches )
{
Vec_Int_t * vNodes, * vLatches;
Ivy_Obj_t * pObj;
int i;
// assert( Ivy_ManLatchNum(p) > 0 );
// make sure the nodes are not marked
Ivy_ManForEachObj( p, pObj, i )
assert( !pObj->fMarkA && !pObj->fMarkB );
// collect the latches
vLatches = Vec_IntAlloc( Ivy_ManLatchNum(p) );
Ivy_ManForEachLatch( p, pObj, i )
Vec_IntPush( vLatches, pObj->Id );
// collect the nodes
vNodes = Vec_IntAlloc( Ivy_ManNodeNum(p) );
Ivy_ManForEachPo( p, pObj, i )
Ivy_ManDfs_rec( p, Ivy_ObjFanin0(pObj), vNodes );
Ivy_ManForEachNodeVec( p, vLatches, pObj, i )
Ivy_ManDfs_rec( p, Ivy_ObjFanin0(pObj), vNodes );
// unmark the collected nodes
// Ivy_ManForEachNodeVec( p, vNodes, pObj, i )
// Ivy_ObjClearMarkA(pObj);
Ivy_ManForEachObj( p, pObj, i )
Ivy_ObjClearMarkA(pObj);
// make sure network does not have dangling nodes
// assert( Vec_IntSize(vNodes) == Ivy_ManNodeNum(p) + Ivy_ManBufNum(p) );
// temporary!!!
if ( pvLatches == NULL )
Vec_IntFree( vLatches );
else
*pvLatches = vLatches;
return vNodes;
}
/**Function*************************************************************
Synopsis [Collects nodes in the cone.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_ManCollectCone_rec( Ivy_Obj_t * pObj, Vec_Ptr_t * vCone )
{
if ( pObj->fMarkA )
return;
if ( Ivy_ObjIsBuf(pObj) )
{
Ivy_ManCollectCone_rec( Ivy_ObjFanin0(pObj), vCone );
Vec_PtrPush( vCone, pObj );
return;
}
assert( Ivy_ObjIsNode(pObj) );
Ivy_ManCollectCone_rec( Ivy_ObjFanin0(pObj), vCone );
Ivy_ManCollectCone_rec( Ivy_ObjFanin1(pObj), vCone );
Vec_PtrPushUnique( vCone, pObj );
}
/**Function*************************************************************
Synopsis [Collects nodes in the cone.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_ManCollectCone( Ivy_Obj_t * pObj, Vec_Ptr_t * vFront, Vec_Ptr_t * vCone )
{
Ivy_Obj_t * pTemp;
int i;
assert( !Ivy_IsComplement(pObj) );
assert( Ivy_ObjIsNode(pObj) );
// mark the nodes
Vec_PtrForEachEntry( Ivy_Obj_t *, vFront, pTemp, i )
Ivy_Regular(pTemp)->fMarkA = 1;
assert( pObj->fMarkA == 0 );
// collect the cone
Vec_PtrClear( vCone );
Ivy_ManCollectCone_rec( pObj, vCone );
// unmark the nodes
Vec_PtrForEachEntry( Ivy_Obj_t *, vFront, pTemp, i )
Ivy_Regular(pTemp)->fMarkA = 0;
}
/**Function*************************************************************
Synopsis [Returns the nodes by level.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Vec_t * Ivy_ManLevelize( Ivy_Man_t * p )
{
Vec_Vec_t * vNodes;
Ivy_Obj_t * pObj;
int i;
vNodes = Vec_VecAlloc( 100 );
Ivy_ManForEachObj( p, pObj, i )
{
assert( !Ivy_ObjIsBuf(pObj) );
if ( Ivy_ObjIsNode(pObj) )
Vec_VecPush( vNodes, pObj->Level, pObj );
}
return vNodes;
}
/**Function*************************************************************
Synopsis [Computes required levels for each node.]
Description [Assumes topological ordering of the nodes.]
SideEffects []
SeeAlso []
***********************************************************************/
Vec_Int_t * Ivy_ManRequiredLevels( Ivy_Man_t * p )
{
Ivy_Obj_t * pObj;
Vec_Int_t * vLevelsR;
Vec_Vec_t * vNodes;
int i, k, Level, LevelMax;
assert( p->vRequired == NULL );
// start the required times
vLevelsR = Vec_IntStart( Ivy_ManObjIdMax(p) + 1 );
// iterate through the nodes in the reverse order
vNodes = Ivy_ManLevelize( p );
Vec_VecForEachEntryReverseReverse( Ivy_Obj_t *, vNodes, pObj, i, k )
{
Level = Vec_IntEntry( vLevelsR, pObj->Id ) + 1 + Ivy_ObjIsExor(pObj);
if ( Vec_IntEntry( vLevelsR, Ivy_ObjFaninId0(pObj) ) < Level )
Vec_IntWriteEntry( vLevelsR, Ivy_ObjFaninId0(pObj), Level );
if ( Vec_IntEntry( vLevelsR, Ivy_ObjFaninId1(pObj) ) < Level )
Vec_IntWriteEntry( vLevelsR, Ivy_ObjFaninId1(pObj), Level );
}
Vec_VecFree( vNodes );
// convert it into the required times
LevelMax = Ivy_ManLevels( p );
//printf( "max %5d\n",LevelMax );
Ivy_ManForEachObj( p, pObj, i )
{
Level = Vec_IntEntry( vLevelsR, pObj->Id );
Vec_IntWriteEntry( vLevelsR, pObj->Id, LevelMax - Level );
//printf( "%5d : %5d %5d\n", pObj->Id, Level, LevelMax - Level );
}
p->vRequired = vLevelsR;
return vLevelsR;
}
/**Function*************************************************************
Synopsis [Recursively detects combinational loops.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManIsAcyclic_rec( Ivy_Man_t * p, Ivy_Obj_t * pObj )
{
// skip the node if it is already visited
if ( Ivy_ObjIsTravIdPrevious(p, pObj) )
return 1;
// check if the node is part of the combinational loop
if ( Ivy_ObjIsTravIdCurrent(p, pObj) )
{
fprintf( stdout, "Manager contains combinational loop!\n" );
fprintf( stdout, "Node \"%d\" is encountered twice on the following path:\n", Ivy_ObjId(pObj) );
fprintf( stdout, " %d", Ivy_ObjId(pObj) );
return 0;
}
// mark this node as a node on the current path
Ivy_ObjSetTravIdCurrent( p, pObj );
// explore equivalent nodes if pObj is the main node
if ( p->pHaig == NULL && pObj->pEquiv && Ivy_ObjRefs(pObj) > 0 )
{
Ivy_Obj_t * pTemp;
assert( !Ivy_IsComplement(pObj->pEquiv) );
for ( pTemp = pObj->pEquiv; pTemp != pObj; pTemp = Ivy_Regular(pTemp->pEquiv) )
{
// traverse the fanin's cone searching for the loop
if ( !Ivy_ManIsAcyclic_rec(p, pTemp) )
{
// return as soon as the loop is detected
fprintf( stdout, " -> (%d", Ivy_ObjId(pObj) );
for ( pTemp = pObj->pEquiv; pTemp != pObj; pTemp = Ivy_Regular(pTemp->pEquiv) )
fprintf( stdout, " %d", Ivy_ObjId(pTemp) );
fprintf( stdout, ")" );
return 0;
}
}
}
// quite if it is a CI node
if ( Ivy_ObjIsCi(pObj) || Ivy_ObjIsConst1(pObj) )
{
// mark this node as a visited node
Ivy_ObjSetTravIdPrevious( p, pObj );
return 1;
}
assert( Ivy_ObjIsNode(pObj) || Ivy_ObjIsBuf(pObj) );
// traverse the fanin's cone searching for the loop
if ( !Ivy_ManIsAcyclic_rec(p, Ivy_ObjFanin0(pObj)) )
{
// return as soon as the loop is detected
fprintf( stdout, " -> %d", Ivy_ObjId(pObj) );
return 0;
}
// traverse the fanin's cone searching for the loop
if ( Ivy_ObjIsNode(pObj) && !Ivy_ManIsAcyclic_rec(p, Ivy_ObjFanin1(pObj)) )
{
// return as soon as the loop is detected
fprintf( stdout, " -> %d", Ivy_ObjId(pObj) );
return 0;
}
// mark this node as a visited node
Ivy_ObjSetTravIdPrevious( p, pObj );
return 1;
}
/**Function*************************************************************
Synopsis [Detects combinational loops.]
Description [This procedure is based on the idea suggested by Donald Chai.
As we traverse the network and visit the nodes, we need to distinquish
three types of nodes: (1) those that are visited for the first time,
(2) those that have been visited in this traversal but are currently not
on the traversal path, (3) those that have been visited and are currently
on the travesal path. When the node of type (3) is encountered, it means
that there is a combinational loop. To mark the three types of nodes,
two new values of the traversal IDs are used.]
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManIsAcyclic( Ivy_Man_t * p )
{
Ivy_Obj_t * pObj;
int fAcyclic, i;
// set the traversal ID for this DFS ordering
Ivy_ManIncrementTravId( p );
Ivy_ManIncrementTravId( p );
// pObj->TravId == pNet->nTravIds means "pObj is on the path"
// pObj->TravId == pNet->nTravIds - 1 means "pObj is visited but is not on the path"
// pObj->TravId < pNet->nTravIds - 1 means "pObj is not visited"
// traverse the network to detect cycles
fAcyclic = 1;
Ivy_ManForEachCo( p, pObj, i )
{
// traverse the output logic cone
if ( (fAcyclic = Ivy_ManIsAcyclic_rec(p, Ivy_ObjFanin0(pObj))) )
continue;
// stop as soon as the first loop is detected
fprintf( stdout, " (cone of %s \"%d\")\n", Ivy_ObjIsLatch(pObj)? "latch" : "PO", Ivy_ObjId(pObj) );
break;
}
return fAcyclic;
}
/**Function*************************************************************
Synopsis [Sets the levels of the nodes.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManSetLevels_rec( Ivy_Obj_t * pObj, int fHaig )
{
// quit if the node is visited
if ( Ivy_ObjIsMarkA(pObj) )
return pObj->Level;
Ivy_ObjSetMarkA(pObj);
// quit if this is a CI
if ( Ivy_ObjIsConst1(pObj) || Ivy_ObjIsCi(pObj) )
return 0;
assert( Ivy_ObjIsBuf(pObj) || Ivy_ObjIsAnd(pObj) || Ivy_ObjIsExor(pObj) );
// get levels of the fanins
Ivy_ManSetLevels_rec( Ivy_ObjFanin0(pObj), fHaig );
if ( !Ivy_ObjIsBuf(pObj) )
Ivy_ManSetLevels_rec( Ivy_ObjFanin1(pObj), fHaig );
// get level of the node
if ( Ivy_ObjIsBuf(pObj) )
pObj->Level = 1 + Ivy_ObjFanin0(pObj)->Level;
else if ( Ivy_ObjIsNode(pObj) )
pObj->Level = Ivy_ObjLevelNew( pObj );
else assert( 0 );
// get level of other choices
if ( fHaig && pObj->pEquiv && Ivy_ObjRefs(pObj) > 0 )
{
Ivy_Obj_t * pTemp;
unsigned LevelMax = pObj->Level;
for ( pTemp = pObj->pEquiv; pTemp != pObj; pTemp = Ivy_Regular(pTemp->pEquiv) )
{
Ivy_ManSetLevels_rec( pTemp, fHaig );
LevelMax = IVY_MAX( LevelMax, pTemp->Level );
}
// get this level
pObj->Level = LevelMax;
for ( pTemp = pObj->pEquiv; pTemp != pObj; pTemp = Ivy_Regular(pTemp->pEquiv) )
pTemp->Level = LevelMax;
}
return pObj->Level;
}
/**Function*************************************************************
Synopsis [Sets the levels of the nodes.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_ManSetLevels( Ivy_Man_t * p, int fHaig )
{
Ivy_Obj_t * pObj;
int i, LevelMax;
// check if CIs have choices
if ( fHaig )
{
Ivy_ManForEachCi( p, pObj, i )
if ( pObj->pEquiv )
printf( "CI %d has a choice, which will not be visualized.\n", pObj->Id );
}
// clean the levels
Ivy_ManForEachObj( p, pObj, i )
pObj->Level = 0;
// compute the levels
LevelMax = 0;
Ivy_ManForEachCo( p, pObj, i )
{
Ivy_ManSetLevels_rec( Ivy_ObjFanin0(pObj), fHaig );
LevelMax = IVY_MAX( LevelMax, (int)Ivy_ObjFanin0(pObj)->Level );
}
// compute levels of nodes without fanout
Ivy_ManForEachObj( p, pObj, i )
if ( (Ivy_ObjIsNode(pObj) || Ivy_ObjIsBuf(pObj)) && Ivy_ObjRefs(pObj) == 0 )
{
Ivy_ManSetLevels_rec( pObj, fHaig );
LevelMax = IVY_MAX( LevelMax, (int)pObj->Level );
}
// clean the marks
Ivy_ManForEachObj( p, pObj, i )
Ivy_ObjClearMarkA(pObj);
return LevelMax;
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
ABC_NAMESPACE_IMPL_END
|
