Computing interpolants as truth tables.

1 files changed, 315 insertions, 0 deletions

diff --git a/src/sat/bsat/satTruth.c b/src/sat/bsat/satTruth.c
new file mode 100644
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+++ b/src/sat/bsat/satTruth.c
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+/**CFile****************************************************************
+
+  FileName    [satTruth.c]
+
+  SystemName  [ABC: Logic synthesis and verification system.]
+
+  PackageName [SAT solver.]
+
+  Synopsis    [Truth table computation package.]
+
+  Author      [Alan Mishchenko]
+  
+  Affiliation [UC Berkeley]
+
+  Date        [Ver. 1.0. Started - June 20, 2005.]
+
+  Revision    [$Id: satTruth.c,v 1.4 2005/09/16 22:55:03 casem Exp $]
+
+***********************************************************************/
+
+#include "satTruth.h"
+#include "vecRec.h"
+
+ABC_NAMESPACE_IMPL_START
+
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////
+///                        DECLARATIONS                              ///
+////////////////////////////////////////////////////////////////////////
+
+struct Tru_Man_t_
+{
+    int              nVars;        // the number of variables
+    int              nWords;       // the number of words in the truth table
+    int              nEntrySize;   // the size of one entry in 'int'
+    int              nTableSize;   // hash table size
+    int *            pTable;       // hash table
+    Vec_Rec_t *      pMem;         // memory for truth tables
+    word *           pZero;        // temporary truth table 
+    int              hIthVars[16]; // variable handles
+    int              nTableLookups;
+};
+
+typedef struct Tru_One_t_ Tru_One_t; // 16 bytes minimum
+struct Tru_One_t_
+{
+    int              Handle;       // support
+    int              Next;         // next one in the table
+    word             pTruth[0];    // truth table
+};
+
+static inline Tru_One_t * Tru_ManReadOne( Tru_Man_t * p, int h ) { return h ? (Tru_One_t *)Vec_RecEntryP(p->pMem, h) : NULL; }
+
+////////////////////////////////////////////////////////////////////////
+///                     FUNCTION DEFINITIONS                         ///
+////////////////////////////////////////////////////////////////////////
+
+/**Function*************************************************************
+
+  Synopsis    [Returns the hash key.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+static inline unsigned Tru_ManHash( word * pTruth, int nWords, int nBins, int * pPrimes )
+{
+    int i;
+    unsigned uHash = 0;
+    for ( i = 0; i < nWords; i++ )
+        uHash ^= pTruth[i] * pPrimes[i & 0x7];
+    return uHash % nBins;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns the given record.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int * Tru_ManLookup( Tru_Man_t * p, word * pTruth )
+{
+    static int s_Primes[10] = { 1291, 1699, 2357, 4177, 5147, 5647, 6343, 7103, 7873, 8147 };
+    Tru_One_t * pEntry;
+    int * pSpot;
+    assert( (pTruth[0] & 1) == 0 );
+    pSpot = p->pTable + Tru_ManHash( pTruth, p->nWords, p->nTableSize, s_Primes );
+    for ( pEntry = Tru_ManReadOne(p, *pSpot); pEntry; pSpot = &pEntry->Next, pEntry = Tru_ManReadOne(p, *pSpot) )
+        if ( Tru_ManEqual(pEntry->pTruth, pTruth, p->nWords) )
+            return pSpot;
+    return pSpot;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns the given record.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Tru_ManResize( Tru_Man_t * p )
+{
+    Tru_One_t * pThis;
+    int * pTableOld, * pSpot;
+    int nTableSizeOld, iNext, Counter, i;
+    assert( p->pTable != NULL );
+    // replace the table
+    pTableOld = p->pTable;
+    nTableSizeOld = p->nTableSize;
+    p->nTableSize = 2 * p->nTableSize + 1; 
+    p->pTable = ABC_CALLOC( int, p->nTableSize );
+    // rehash the entries from the old table
+    Counter = 0;
+    for ( i = 0; i < nTableSizeOld; i++ )
+    for ( pThis = Tru_ManReadOne(p, pTableOld[i]),
+          iNext = (pThis? pThis->Next : 0);  
+          pThis;  pThis = Tru_ManReadOne(p, iNext),   
+          iNext = (pThis? pThis->Next : 0)  )
+    {
+        assert( pThis->Handle );
+        pThis->Next = 0;
+        pSpot = Tru_ManLookup( p, pThis->pTruth );
+        assert( *pSpot == 0 ); // should not be there
+        *pSpot = pThis->Handle;
+        Counter++;
+    }
+    assert( Counter == Vec_RecEntryNum(p->pMem) );
+    ABC_FREE( pTableOld );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Adds entry to the hash table.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Tru_ManInsert( Tru_Man_t * p, word * pTruth )
+{
+    int fCompl, * pSpot;
+    if ( Tru_ManEqual0(pTruth, p->nWords) )
+        return 0;
+    if ( Tru_ManEqual1(pTruth, p->nWords) )
+        return 1;
+    p->nTableLookups++;
+    if ( Vec_RecEntryNum(p->pMem) > 2 * p->nTableSize )
+        Tru_ManResize( p );
+    fCompl = pTruth[0] & 1;
+    if ( fCompl )  
+        Tru_ManNot( pTruth, p->nWords );
+    pSpot = Tru_ManLookup( p, pTruth );
+    if ( *pSpot == 0 )
+    {
+        Tru_One_t * pEntry;
+        *pSpot = Vec_RecAppend( p->pMem, p->nEntrySize );
+        assert( (*pSpot & 1) == 0 );
+        pEntry = Tru_ManReadOne( p, *pSpot );
+        Tru_ManCopy( pEntry->pTruth, pTruth, p->nWords );
+        pEntry->Handle = *pSpot;
+        pEntry->Next = 0;
+    }
+    if ( fCompl )  
+        Tru_ManNot( pTruth, p->nWords );
+    return *pSpot ^ fCompl;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Start the truth table logging.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+Tru_Man_t * Tru_ManAlloc( int nVars )
+{
+    word Masks[6] = 
+    { 
+        0xAAAAAAAAAAAAAAAA, 
+        0xCCCCCCCCCCCCCCCC, 
+        0xF0F0F0F0F0F0F0F0, 
+        0xFF00FF00FF00FF00, 
+        0xFFFF0000FFFF0000, 
+        0xFFFFFFFF00000000 
+    };
+    Tru_Man_t * p;
+    int i, w;
+    assert( nVars > 0 && nVars <= 16 );
+    p = ABC_CALLOC( Tru_Man_t, 1 );
+    p->nVars      = nVars;
+    p->nWords     = (nVars < 6) ? 1 : (1 << (nVars-6));
+    p->nEntrySize = (sizeof(Tru_One_t) + p->nWords * sizeof(word))/sizeof(int);
+    p->nTableSize = 8147;
+    p->pTable     = ABC_CALLOC( int, p->nTableSize );
+    p->pMem       = Vec_RecAlloc();
+    // initialize truth tables
+    p->pZero = ABC_ALLOC( word, p->nWords );
+    for ( i = 0; i < nVars; i++ )
+    {
+        for ( w = 0; w < p->nWords; w++ )
+            if ( i < 6 )
+                p->pZero[w] = Masks[i];
+            else if ( w & (1 << (i-6)) )
+                p->pZero[w] = ~(word)0;
+            else
+                p->pZero[w] = 0;
+        p->hIthVars[i] = Tru_ManInsert( p, p->pZero );
+        assert( !i || p->hIthVars[i] > p->hIthVars[i-1] );
+    }
+    Tru_ManClear( p->pZero, p->nWords );
+    return p;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Stop the truth table logging.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+void Tru_ManFree( Tru_Man_t * p )
+{
+    printf( "Lookups = %d. Entries = %d.\n", p->nTableLookups, Vec_RecEntryNum(p->pMem) );
+    Vec_RecFree( p->pMem );
+    ABC_FREE( p->pZero );
+    ABC_FREE( p->pTable );
+    ABC_FREE( p );
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns elementary variable.]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+word * Tru_ManVar( Tru_Man_t * p, int v )
+{
+    assert( v >= 0 && v < p->nVars );
+    return Tru_ManReadOne( p, p->hIthVars[v] )->pTruth;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns stored truth table]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+word * Tru_ManFunc( Tru_Man_t * p, int h )
+{
+    assert( (h & 1) == 0 );
+    if ( h == 0 )
+        return p->pZero;
+    assert( Vec_RecChunk(h) );
+    return Tru_ManReadOne( p, h )->pTruth;
+}
+
+/**Function*************************************************************
+
+  Synopsis    [Returns stored truth table]
+
+  Description []
+               
+  SideEffects []
+
+  SeeAlso     []
+
+***********************************************************************/
+int Tru_ManHandleMax( Tru_Man_t * p )
+{
+    return p->pMem->hCurrent;
+}
+////////////////////////////////////////////////////////////////////////
+///                       END OF FILE                                ///
+////////////////////////////////////////////////////////////////////////
+
+
+ABC_NAMESPACE_IMPL_END
+