1 /**CFile****************************************************************
2
3 FileName [mfsDiv.c]
4
5 SystemName [ABC: Logic synthesis and verification system.]
6
7 PackageName [The good old minimization with complete don't-cares.]
8
9 Synopsis [Procedures to compute candidate divisors.]
10
11 Author [Alan Mishchenko]
12
13 Affiliation [UC Berkeley]
14
15 Date [Ver. 1.0. Started - June 20, 2005.]
16
17 Revision [$Id: mfsDiv.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]
18
19 ***********************************************************************/
20
21 #include "mfsInt.h"
22
23 ABC_NAMESPACE_IMPL_START
24
25
26 ////////////////////////////////////////////////////////////////////////
27 /// DECLARATIONS ///
28 ////////////////////////////////////////////////////////////////////////
29
30 ////////////////////////////////////////////////////////////////////////
31 /// FUNCTION DEFINITIONS ///
32 ////////////////////////////////////////////////////////////////////////
33
34 /**Function*************************************************************
35
36 Synopsis [Marks and collects the TFI cone of the node.]
37
38 Description []
39
40 SideEffects []
41
42 SeeAlso []
43
44 ***********************************************************************/
Abc_MfsWinMarkTfi_rec(Abc_Obj_t * pObj,Vec_Ptr_t * vCone)45 void Abc_MfsWinMarkTfi_rec( Abc_Obj_t * pObj, Vec_Ptr_t * vCone )
46 {
47 Abc_Obj_t * pFanin;
48 int i;
49 if ( Abc_NodeIsTravIdCurrent(pObj) )
50 return;
51 Abc_NodeSetTravIdCurrent( pObj );
52 if ( Abc_ObjIsCi(pObj) )
53 {
54 Vec_PtrPush( vCone, pObj );
55 return;
56 }
57 assert( Abc_ObjIsNode(pObj) );
58 // visit the fanins of the node
59 Abc_ObjForEachFanin( pObj, pFanin, i )
60 Abc_MfsWinMarkTfi_rec( pFanin, vCone );
61 Vec_PtrPush( vCone, pObj );
62 }
63
64 /**Function*************************************************************
65
66 Synopsis [Marks and collects the TFI cone of the node.]
67
68 Description []
69
70 SideEffects []
71
72 SeeAlso []
73
74 ***********************************************************************/
Abc_MfsWinMarkTfi(Abc_Obj_t * pNode)75 Vec_Ptr_t * Abc_MfsWinMarkTfi( Abc_Obj_t * pNode )
76 {
77 Vec_Ptr_t * vCone;
78 vCone = Vec_PtrAlloc( 100 );
79 Abc_MfsWinMarkTfi_rec( pNode, vCone );
80 return vCone;
81 }
82
83 /**Function*************************************************************
84
85 Synopsis [Marks the TFO of the collected nodes up to the given level.]
86
87 Description []
88
89 SideEffects []
90
91 SeeAlso []
92
93 ***********************************************************************/
Abc_MfsWinSweepLeafTfo_rec(Abc_Obj_t * pObj,int nLevelLimit)94 void Abc_MfsWinSweepLeafTfo_rec( Abc_Obj_t * pObj, int nLevelLimit )
95 {
96 Abc_Obj_t * pFanout;
97 int i;
98 if ( Abc_ObjIsCo(pObj) || (int)pObj->Level > nLevelLimit )
99 return;
100 if ( Abc_NodeIsTravIdCurrent(pObj) )
101 return;
102 Abc_NodeSetTravIdCurrent( pObj );
103 Abc_ObjForEachFanout( pObj, pFanout, i )
104 Abc_MfsWinSweepLeafTfo_rec( pFanout, nLevelLimit );
105 }
106
107 /**Function*************************************************************
108
109 Synopsis [Dereferences the node's MFFC.]
110
111 Description []
112
113 SideEffects []
114
115 SeeAlso []
116
117 ***********************************************************************/
Abc_MfsNodeDeref_rec(Abc_Obj_t * pNode)118 int Abc_MfsNodeDeref_rec( Abc_Obj_t * pNode )
119 {
120 Abc_Obj_t * pFanin;
121 int i, Counter = 1;
122 if ( Abc_ObjIsCi(pNode) )
123 return 0;
124 Abc_NodeSetTravIdCurrent( pNode );
125 Abc_ObjForEachFanin( pNode, pFanin, i )
126 {
127 assert( pFanin->vFanouts.nSize > 0 );
128 if ( --pFanin->vFanouts.nSize == 0 )
129 Counter += Abc_MfsNodeDeref_rec( pFanin );
130 }
131 return Counter;
132 }
133
134 /**Function*************************************************************
135
136 Synopsis [References the node's MFFC.]
137
138 Description []
139
140 SideEffects []
141
142 SeeAlso []
143
144 ***********************************************************************/
Abc_MfsNodeRef_rec(Abc_Obj_t * pNode)145 int Abc_MfsNodeRef_rec( Abc_Obj_t * pNode )
146 {
147 Abc_Obj_t * pFanin;
148 int i, Counter = 1;
149 if ( Abc_ObjIsCi(pNode) )
150 return 0;
151 Abc_ObjForEachFanin( pNode, pFanin, i )
152 {
153 if ( pFanin->vFanouts.nSize++ == 0 )
154 Counter += Abc_MfsNodeRef_rec( pFanin );
155 }
156 return Counter;
157 }
158
159 /**Function*************************************************************
160
161 Synopsis [Labels MFFC of the node with the current trav ID.]
162
163 Description []
164
165 SideEffects []
166
167 SeeAlso []
168
169 ***********************************************************************/
Abc_MfsWinVisitMffc(Abc_Obj_t * pNode)170 int Abc_MfsWinVisitMffc( Abc_Obj_t * pNode )
171 {
172 int Count1, Count2;
173 assert( Abc_ObjIsNode(pNode) );
174 // dereference the node (mark with the current trav ID)
175 Count1 = Abc_MfsNodeDeref_rec( pNode );
176 // reference it back
177 Count2 = Abc_MfsNodeRef_rec( pNode );
178 assert( Count1 == Count2 );
179 return Count1;
180 }
181
182 /**Function*************************************************************
183
184 Synopsis [Computes divisors and add them to nodes in the window.]
185
186 Description []
187
188 SideEffects []
189
190 SeeAlso []
191
192 ***********************************************************************/
Abc_MfsComputeDivisors(Mfs_Man_t * p,Abc_Obj_t * pNode,int nLevDivMax)193 Vec_Ptr_t * Abc_MfsComputeDivisors( Mfs_Man_t * p, Abc_Obj_t * pNode, int nLevDivMax )
194 {
195 Vec_Ptr_t * vCone, * vDivs;
196 Abc_Obj_t * pObj, * pFanout, * pFanin;
197 int k, f, m;
198 int nDivsPlus = 0, nTrueSupp;
199 assert( p->vDivs == NULL );
200
201 // mark the TFI with the current trav ID
202 Abc_NtkIncrementTravId( pNode->pNtk );
203 vCone = Abc_MfsWinMarkTfi( pNode );
204
205 // count the number of PIs
206 nTrueSupp = 0;
207 Vec_PtrForEachEntry( Abc_Obj_t *, vCone, pObj, k )
208 nTrueSupp += Abc_ObjIsCi(pObj);
209 // printf( "%d(%d) ", Vec_PtrSize(p->vSupp), m );
210
211 // mark with the current trav ID those nodes that should not be divisors:
212 // (1) the node and its TFO
213 // (2) the MFFC of the node
214 // (3) the node's fanins (these are treated as a special case)
215 Abc_NtkIncrementTravId( pNode->pNtk );
216 Abc_MfsWinSweepLeafTfo_rec( pNode, nLevDivMax );
217 // Abc_MfsWinVisitMffc( pNode );
218 Abc_ObjForEachFanin( pNode, pObj, k )
219 Abc_NodeSetTravIdCurrent( pObj );
220
221 // at this point the nodes are marked with two trav IDs:
222 // nodes to be collected as divisors are marked with previous trav ID
223 // nodes to be avoided as divisors are marked with current trav ID
224
225 // start collecting the divisors
226 vDivs = Vec_PtrAlloc( p->pPars->nWinMax );
227 Vec_PtrForEachEntry( Abc_Obj_t *, vCone, pObj, k )
228 {
229 if ( !Abc_NodeIsTravIdPrevious(pObj) )
230 continue;
231 if ( (int)pObj->Level > nLevDivMax )
232 continue;
233 Vec_PtrPush( vDivs, pObj );
234 if ( Vec_PtrSize(vDivs) >= p->pPars->nWinMax )
235 break;
236 }
237 Vec_PtrFree( vCone );
238
239 // explore the fanouts of already collected divisors
240 if ( Vec_PtrSize(vDivs) < p->pPars->nWinMax )
241 Vec_PtrForEachEntry( Abc_Obj_t *, vDivs, pObj, k )
242 {
243 // consider fanouts of this node
244 Abc_ObjForEachFanout( pObj, pFanout, f )
245 {
246 // stop if there are too many fanouts
247 if ( p->pPars->nFanoutsMax && f > p->pPars->nFanoutsMax )
248 break;
249 // skip nodes that are already added
250 if ( Abc_NodeIsTravIdPrevious(pFanout) )
251 continue;
252 // skip nodes in the TFO or in the MFFC of node
253 if ( Abc_NodeIsTravIdCurrent(pFanout) )
254 continue;
255 // skip COs
256 if ( !Abc_ObjIsNode(pFanout) )
257 continue;
258 // skip nodes with large level
259 if ( (int)pFanout->Level > nLevDivMax )
260 continue;
261 // skip nodes whose fanins are not divisors -- here we skip more than we need to skip!!! (revise later) August 7, 2009
262 Abc_ObjForEachFanin( pFanout, pFanin, m )
263 if ( !Abc_NodeIsTravIdPrevious(pFanin) )
264 break;
265 if ( m < Abc_ObjFaninNum(pFanout) )
266 continue;
267 // make sure this divisor in not among the nodes
268 // Vec_PtrForEachEntry( Abc_Obj_t *, p->vNodes, pFanin, m )
269 // assert( pFanout != pFanin );
270 // add the node to the divisors
271 Vec_PtrPush( vDivs, pFanout );
272 // Vec_PtrPush( p->vNodes, pFanout );
273 Vec_PtrPushUnique( p->vNodes, pFanout );
274 Abc_NodeSetTravIdPrevious( pFanout );
275 nDivsPlus++;
276 if ( Vec_PtrSize(vDivs) >= p->pPars->nWinMax )
277 break;
278 }
279 if ( Vec_PtrSize(vDivs) >= p->pPars->nWinMax )
280 break;
281 }
282 p->nMaxDivs += (Vec_PtrSize(vDivs) >= p->pPars->nWinMax);
283
284 // sort the divisors by level in the increasing order
285 Vec_PtrSort( vDivs, (int (*)(void))Abc_NodeCompareLevelsIncrease );
286
287 // add the fanins of the node
288 Abc_ObjForEachFanin( pNode, pFanin, k )
289 Vec_PtrPush( vDivs, pFanin );
290
291 /*
292 printf( "Node level = %d. ", Abc_ObjLevel(p->pNode) );
293 Vec_PtrForEachEntryStart( Abc_Obj_t *, vDivs, pObj, k, Vec_PtrSize(vDivs)-p->nDivsPlus )
294 printf( "%d ", Abc_ObjLevel(pObj) );
295 printf( "\n" );
296 */
297 //printf( "%d ", p->nDivsPlus );
298 // printf( "(%d+%d)(%d+%d+%d) ", Vec_PtrSize(p->vSupp), Vec_PtrSize(p->vNodes),
299 // nTrueSupp, Vec_PtrSize(vDivs)-nTrueSupp-nDivsPlus, nDivsPlus );
300 return vDivs;
301 }
302
303 ////////////////////////////////////////////////////////////////////////
304 /// END OF FILE ///
305 ////////////////////////////////////////////////////////////////////////
306
307
308 ABC_NAMESPACE_IMPL_END
309
310