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abc/src/map/if/ifTruth.c

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/**CFile****************************************************************
FileName [ifTruth.c]
SystemName [ABC: Logic synthesis and verification system.]
PackageName [FPGA mapping based on priority cuts.]
Synopsis [Computation of truth tables of the cuts.]
Author [Alan Mishchenko]
Affiliation [UC Berkeley]
Date [Ver. 1.0. Started - November 21, 2006.]
Revision [$Id: ifTruth.c,v 1.00 2006/11/21 00:00:00 alanmi Exp $]
***********************************************************************/
#include "if.h"
////////////////////////////////////////////////////////////////////////
/// DECLARATIONS ///
////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////
/// FUNCTION DEFINITIONS ///
////////////////////////////////////////////////////////////////////////
/**Function*************************************************************
Synopsis [Several simple procedures working with truth tables.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
static inline int If_TruthWordNum( int nVars ) { return nVars <= 5 ? 1 : (1 << (nVars - 5)); }
static inline void If_TruthNot( unsigned * pOut, unsigned * pIn, int nVars )
{
int w;
for ( w = If_TruthWordNum(nVars)-1; w >= 0; w-- )
pOut[w] = ~pIn[w];
}
static inline void If_TruthCopy( unsigned * pOut, unsigned * pIn, int nVars )
{
int w;
for ( w = If_TruthWordNum(nVars)-1; w >= 0; w-- )
pOut[w] = pIn[w];
}
static inline void If_TruthNand( unsigned * pOut, unsigned * pIn0, unsigned * pIn1, int nVars )
{
int w;
for ( w = If_TruthWordNum(nVars)-1; w >= 0; w-- )
pOut[w] = ~(pIn0[w] & pIn1[w]);
}
static inline void If_TruthAnd( unsigned * pOut, unsigned * pIn0, unsigned * pIn1, int nVars )
{
int w;
for ( w = If_TruthWordNum(nVars)-1; w >= 0; w-- )
pOut[w] = pIn0[w] & pIn1[w];
}
/**Function*************************************************************
Synopsis [Swaps two adjacent variables in the truth table.]
Description [Swaps var number Start and var number Start+1 (0-based numbers).
The input truth table is pIn. The output truth table is pOut.]
SideEffects []
SeeAlso []
***********************************************************************/
void If_TruthSwapAdjacentVars( unsigned * pOut, unsigned * pIn, int nVars, int iVar )
{
static unsigned PMasks[4][3] = {
{ 0x99999999, 0x22222222, 0x44444444 },
{ 0xC3C3C3C3, 0x0C0C0C0C, 0x30303030 },
{ 0xF00FF00F, 0x00F000F0, 0x0F000F00 },
{ 0xFF0000FF, 0x0000FF00, 0x00FF0000 }
};
int nWords = If_TruthWordNum( nVars );
int i, k, Step, Shift;
assert( iVar < nVars - 1 );
if ( iVar < 4 )
{
Shift = (1 << iVar);
for ( i = 0; i < nWords; i++ )
pOut[i] = (pIn[i] & PMasks[iVar][0]) | ((pIn[i] & PMasks[iVar][1]) << Shift) | ((pIn[i] & PMasks[iVar][2]) >> Shift);
}
else if ( iVar > 4 )
{
Step = (1 << (iVar - 5));
for ( k = 0; k < nWords; k += 4*Step )
{
for ( i = 0; i < Step; i++ )
pOut[i] = pIn[i];
for ( i = 0; i < Step; i++ )
pOut[Step+i] = pIn[2*Step+i];
for ( i = 0; i < Step; i++ )
pOut[2*Step+i] = pIn[Step+i];
for ( i = 0; i < Step; i++ )
pOut[3*Step+i] = pIn[3*Step+i];
pIn += 4*Step;
pOut += 4*Step;
}
}
else // if ( iVar == 4 )
{
for ( i = 0; i < nWords; i += 2 )
{
pOut[i] = (pIn[i] & 0x0000FFFF) | ((pIn[i+1] & 0x0000FFFF) << 16);
pOut[i+1] = (pIn[i+1] & 0xFFFF0000) | ((pIn[i] & 0xFFFF0000) >> 16);
}
}
}
/**Function*************************************************************
Synopsis [Expands the truth table according to the phase.]
Description [The input and output truth tables are in pIn/pOut. The current number
of variables is nVars. The total number of variables in nVarsAll. The last argument
(Phase) contains shows where the variables should go.]
SideEffects []
SeeAlso []
***********************************************************************/
void If_TruthStretch( unsigned * pOut, unsigned * pIn, int nVars, int nVarsAll, unsigned Phase )
{
unsigned * pTemp;
int i, k, Var = nVars - 1, Counter = 0;
for ( i = nVarsAll - 1; i >= 0; i-- )
if ( Phase & (1 << i) )
{
for ( k = Var; k < i; k++ )
{
If_TruthSwapAdjacentVars( pOut, pIn, nVarsAll, k );
pTemp = pIn; pIn = pOut; pOut = pTemp;
Counter++;
}
Var--;
}
assert( Var == -1 );
// swap if it was moved an even number of times
if ( !(Counter & 1) )
If_TruthCopy( pOut, pIn, nVarsAll );
}
/**Function*************************************************************
Synopsis [Computes the stretching phase of the cut w.r.t. the merged cut.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
static inline unsigned If_CutTruthPhase( If_Cut_t * pCut, If_Cut_t * pCut1 )
{
unsigned uPhase = 0;
int i, k;
for ( i = k = 0; i < (int)pCut->nLeaves; i++ )
{
if ( k == (int)pCut1->nLeaves )
break;
if ( pCut->pLeaves[i] < pCut1->pLeaves[k] )
continue;
assert( pCut->pLeaves[i] == pCut1->pLeaves[k] );
uPhase |= (1 << i);
k++;
}
return uPhase;
}
/**Function*************************************************************
Synopsis [Performs truth table computation.]
Description []
SideEffects []
SeeAlso []
***********************************************************************/
void If_CutComputeTruth( If_Man_t * p, If_Cut_t * pCut, If_Cut_t * pCut0, If_Cut_t * pCut1, int fCompl0, int fCompl1 )
{
extern void Kit_FactorTest( unsigned * pTruth, int nVars );
// permute the first table
if ( fCompl0 ^ pCut0->fCompl )
If_TruthNot( p->puTemp[0], If_CutTruth(pCut0), pCut->nLimit );
else
If_TruthCopy( p->puTemp[0], If_CutTruth(pCut0), pCut->nLimit );
If_TruthStretch( p->puTemp[2], p->puTemp[0], pCut0->nLeaves, pCut->nLimit, If_CutTruthPhase(pCut, pCut0) );
// permute the second table
if ( fCompl1 ^ pCut1->fCompl )
If_TruthNot( p->puTemp[1], If_CutTruth(pCut1), pCut->nLimit );
else
If_TruthCopy( p->puTemp[1], If_CutTruth(pCut1), pCut->nLimit );
If_TruthStretch( p->puTemp[3], p->puTemp[1], pCut1->nLeaves, pCut->nLimit, If_CutTruthPhase(pCut, pCut1) );
// produce the resulting table
assert( pCut->fCompl == 0 );
if ( pCut->fCompl )
If_TruthNand( If_CutTruth(pCut), p->puTemp[2], p->puTemp[3], pCut->nLimit );
else
If_TruthAnd( If_CutTruth(pCut), p->puTemp[2], p->puTemp[3], pCut->nLimit );
// perform
// Kit_FactorTest( If_CutTruth(pCut), pCut->nLimit );
// printf( "%d ", If_CutLeaveNum(pCut) - Kit_TruthSupportSize(If_CutTruth(pCut), If_CutLeaveNum(pCut)) );
}
////////////////////////////////////////////////////////////////////////
/// END OF FILE ///
////////////////////////////////////////////////////////////////////////
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