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
|
/**CFile****************************************************************
FileName [ivyMulti.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [And-Inverter Graph package.]
Synopsis [Constructing multi-input AND/EXOR gates.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - May 11, 2006.]
Revision [$Id: ivyMulti.c,v 1.00 2006/05/11 00:00:00 alanmi Exp $]
***********************************************************************/
#include "ivy.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
#define IVY_EVAL_LIMIT 128
typedef struct Ivy_Eva_t_ Ivy_Eva_t;
struct Ivy_Eva_t_
{
Ivy_Obj_t * pArg; // the argument node
unsigned Mask; // the mask of covered nodes
int Weight; // the number of covered nodes
};
static void Ivy_MultiPrint( Ivy_Man_t * p, Ivy_Eva_t * pEvals, int nLeaves, int nEvals );
static int Ivy_MultiCover( Ivy_Man_t * p, Ivy_Eva_t * pEvals, int nLeaves, int nEvals, int nLimit, Vec_Ptr_t * vSols );
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Constructs a balanced tree while taking sharing into account.]
Description [Returns 1 if the implementation exists.]
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_MultiPlus( Ivy_Man_t * p, Vec_Ptr_t * vLeaves, Vec_Ptr_t * vCone, Ivy_Type_t Type, int nLimit, Vec_Ptr_t * vSols )
{
static Ivy_Eva_t pEvals[IVY_EVAL_LIMIT];
Ivy_Eva_t * pEval, * pFan0, * pFan1;
Ivy_Obj_t * pObj, * pTemp;
int nEvals, nEvalsOld, i, k, x, nLeaves;
unsigned uMaskAll;
// consider special cases
nLeaves = Vec_PtrSize(vLeaves);
assert( nLeaves > 2 );
if ( nLeaves > 32 || nLeaves + Vec_PtrSize(vCone) > IVY_EVAL_LIMIT )
return 0;
// if ( nLeaves == 1 )
// return Vec_PtrEntry( vLeaves, 0 );
// if ( nLeaves == 2 )
// return Ivy_Oper( Vec_PtrEntry(vLeaves, 0), Vec_PtrEntry(vLeaves, 1), Type );
// set the leaf entries
uMaskAll = ((1 << nLeaves) - 1);
nEvals = 0;
Vec_PtrForEachEntry( vLeaves, pObj, i )
{
pEval = pEvals + nEvals;
pEval->pArg = pObj;
pEval->Mask = (1 << nEvals);
pEval->Weight = 1;
// mark the leaf
Ivy_Regular(pObj)->TravId = nEvals;
nEvals++;
}
// propagate masks through the cone
Vec_PtrForEachEntry( vCone, pObj, i )
{
pObj->TravId = nEvals + i;
if ( Ivy_ObjIsBuf(pObj) )
pEvals[pObj->TravId].Mask = pEvals[Ivy_ObjFanin0(pObj)->TravId].Mask;
else
pEvals[pObj->TravId].Mask = pEvals[Ivy_ObjFanin0(pObj)->TravId].Mask | pEvals[Ivy_ObjFanin1(pObj)->TravId].Mask;
}
// set the internal entries
Vec_PtrForEachEntry( vCone, pObj, i )
{
if ( i == Vec_PtrSize(vCone) - 1 )
break;
// skip buffers
if ( Ivy_ObjIsBuf(pObj) )
continue;
// skip nodes without external fanout
if ( Ivy_ObjRefs(pObj) == 0 )
continue;
assert( !Ivy_IsComplement(pObj) );
pEval = pEvals + nEvals;
pEval->pArg = pObj;
pEval->Mask = pEvals[pObj->TravId].Mask;
pEval->Weight = Extra_WordCountOnes(pEval->Mask);
// mark the node
pObj->TravId = nEvals;
nEvals++;
}
// find the available nodes
nEvalsOld = nEvals;
for ( i = 1; i < nEvals; i++ )
for ( k = 0; k < i; k++ )
{
pFan0 = pEvals + i;
pFan1 = pEvals + k;
pTemp = Ivy_TableLookup(p, Ivy_ObjCreateGhost(p, pFan0->pArg, pFan1->pArg, Type, IVY_INIT_NONE));
// skip nodes in the cone
if ( pTemp == NULL || pTemp->fMarkB )
continue;
// skip the leaves
for ( x = 0; x < nLeaves; x++ )
if ( pTemp == Ivy_Regular(vLeaves->pArray[x]) )
break;
if ( x < nLeaves )
continue;
pEval = pEvals + nEvals;
pEval->pArg = pTemp;
pEval->Mask = pFan0->Mask | pFan1->Mask;
pEval->Weight = (pFan0->Mask & pFan1->Mask) ? Extra_WordCountOnes(pEval->Mask) : pFan0->Weight + pFan1->Weight;
// save the argument
pObj->TravId = nEvals;
nEvals++;
// quit if the number of entries exceeded the limit
if ( nEvals == IVY_EVAL_LIMIT )
goto Outside;
// quit if we found an acceptable implementation
if ( pEval->Mask == uMaskAll )
goto Outside;
}
Outside:
// Ivy_MultiPrint( pEvals, nLeaves, nEvals );
if ( !Ivy_MultiCover( p, pEvals, nLeaves, nEvals, nLimit, vSols ) )
return 0;
assert( Vec_PtrSize( vSols ) > 0 );
return 1;
}
/**Function*************************************************************
Synopsis [Computes how many uncovered ones this one covers.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void Ivy_MultiPrint( Ivy_Man_t * p, Ivy_Eva_t * pEvals, int nLeaves, int nEvals )
{
Ivy_Eva_t * pEval;
int i, k;
for ( i = nLeaves; i < nEvals; i++ )
{
pEval = pEvals + i;
printf( "%2d (id = %5d) : |", i-nLeaves, Ivy_ObjId(pEval->pArg) );
for ( k = 0; k < nLeaves; k++ )
{
if ( pEval->Mask & (1 << k) )
printf( "+" );
else
printf( " " );
}
printf( "| Lev = %d.\n", Ivy_ObjLevel(pEval->pArg) );
}
}
/**Function*************************************************************
Synopsis [Computes how many uncovered ones this one covers.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
static inline int Ivy_MultiWeight( unsigned uMask, int nMaskOnes, unsigned uFound )
{
assert( uMask & ~uFound );
if ( (uMask & uFound) == 0 )
return nMaskOnes;
return Extra_WordCountOnes( uMask & ~uFound );
}
/**Function*************************************************************
Synopsis [Finds the cover.]
Description [Returns 1 if the cover is found.]
SideEffects []
SeeAlso []
***********************************************************************/
int Ivy_MultiCover( Ivy_Man_t * p, Ivy_Eva_t * pEvals, int nLeaves, int nEvals, int nLimit, Vec_Ptr_t * vSols )
{
int fVerbose = 0;
Ivy_Eva_t * pEval, * pEvalBest;
unsigned uMaskAll, uFound, uTemp;
int i, k, BestK, WeightBest, WeightCur, LevelBest, LevelCur;
uMaskAll = (nLeaves == 32)? (~(unsigned)0) : ((1 << nLeaves) - 1);
uFound = 0;
// solve the covering problem
if ( fVerbose )
printf( "Solution: " );
Vec_PtrClear( vSols );
for ( i = 0; i < nLimit; i++ )
{
BestK = -1;
for ( k = nEvals - 1; k >= 0; k-- )
{
pEval = pEvals + k;
if ( (pEval->Mask & ~uFound) == 0 )
continue;
if ( BestK == -1 )
{
BestK = k;
pEvalBest = pEval;
WeightBest = Ivy_MultiWeight( pEvalBest->Mask, pEvalBest->Weight, uFound );
LevelBest = Ivy_ObjLevel( Ivy_Regular(pEvalBest->pArg) );
continue;
}
// compare BestK and the new one (k)
WeightCur = Ivy_MultiWeight( pEval->Mask, pEval->Weight, uFound );
LevelCur = Ivy_ObjLevel( Ivy_Regular(pEval->pArg) );
if ( WeightBest < WeightCur ||
(WeightBest == WeightCur && LevelBest > LevelCur) )
{
BestK = k;
pEvalBest = pEval;
WeightBest = WeightCur;
LevelBest = LevelCur;
}
}
assert( BestK != -1 );
// if the cost is only 1, take the leaf
if ( WeightBest == 1 && BestK >= nLeaves )
{
uTemp = (pEvalBest->Mask & ~uFound);
for ( k = 0; k < nLeaves; k++ )
if ( uTemp & (1 << k) )
break;
assert( k < nLeaves );
BestK = k;
pEvalBest = pEvals + BestK;
}
if ( fVerbose )
{
if ( BestK < nLeaves )
printf( "L(%d) ", BestK );
else
printf( "%d ", BestK - nLeaves );
}
// update the found set
Vec_PtrPush( vSols, pEvalBest->pArg );
uFound |= pEvalBest->Mask;
if ( uFound == uMaskAll )
break;
}
if ( uFound == uMaskAll )
{
if ( fVerbose )
printf( " Found \n\n" );
return 1;
}
else
{
if ( fVerbose )
printf( " Not found \n\n" );
return 0;
}
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
|
