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author | Alan Mishchenko <alanmi@berkeley.edu> | 2007-10-01 08:01:00 -0700 |
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committer | Alan Mishchenko <alanmi@berkeley.edu> | 2007-10-01 08:01:00 -0700 |
commit | 4812c90424dfc40d26725244723887a2d16ddfd9 (patch) | |
tree | b32ace96e7e2d84d586e09ba605463b6f49c3271 /src/aig/dar/darCut.c | |
parent | e54d9691616b9a0326e2fdb3156bb4eeb8abfcd7 (diff) | |
download | abc-4812c90424dfc40d26725244723887a2d16ddfd9.tar.gz abc-4812c90424dfc40d26725244723887a2d16ddfd9.tar.bz2 abc-4812c90424dfc40d26725244723887a2d16ddfd9.zip |
Version abc71001
Diffstat (limited to 'src/aig/dar/darCut.c')
-rw-r--r-- | src/aig/dar/darCut.c | 698 |
1 files changed, 698 insertions, 0 deletions
diff --git a/src/aig/dar/darCut.c b/src/aig/dar/darCut.c new file mode 100644 index 00000000..08bd77a9 --- /dev/null +++ b/src/aig/dar/darCut.c @@ -0,0 +1,698 @@ +/**CFile**************************************************************** + + FileName [darCut.c] + + SystemName [ABC: Logic synthesis and verification system.] + + PackageName [DAG-aware AIG rewriting.] + + Synopsis [Computation of 4-input cuts.] + + Author [Alan Mishchenko] + + Affiliation [UC Berkeley] + + Date [Ver. 1.0. Started - April 28, 2007.] + + Revision [$Id: darCut.c,v 1.00 2007/04/28 00:00:00 alanmi Exp $] + +***********************************************************************/ + +#include "darInt.h" + +//////////////////////////////////////////////////////////////////////// +/// DECLARATIONS /// +//////////////////////////////////////////////////////////////////////// + +//////////////////////////////////////////////////////////////////////// +/// FUNCTION DEFINITIONS /// +//////////////////////////////////////////////////////////////////////// + +/**Function************************************************************* + + Synopsis [Returns the number of 1s in the machine word.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline int Dar_WordCountOnes( unsigned uWord ) +{ + uWord = (uWord & 0x55555555) + ((uWord>>1) & 0x55555555); + uWord = (uWord & 0x33333333) + ((uWord>>2) & 0x33333333); + uWord = (uWord & 0x0F0F0F0F) + ((uWord>>4) & 0x0F0F0F0F); + uWord = (uWord & 0x00FF00FF) + ((uWord>>8) & 0x00FF00FF); + return (uWord & 0x0000FFFF) + (uWord>>16); +} + +/**Function************************************************************* + + Synopsis [Compute the cost of the cut.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline int Dar_CutFindValue( Dar_Man_t * p, Dar_Cut_t * pCut ) +{ + Aig_Obj_t * pLeaf; + int i, Value, nOnes; + assert( pCut->fUsed ); + Value = 0; + nOnes = 0; + Dar_CutForEachLeaf( p->pAig, pCut, pLeaf, i ) + { + if ( pLeaf == NULL ) + return 0; + assert( pLeaf != NULL ); + Value += pLeaf->nRefs; + nOnes += (pLeaf->nRefs == 1); + } + if ( pCut->nLeaves < 2 ) + return 1001; +// Value = Value * 100 / pCut->nLeaves; + if ( Value > 1000 ) + Value = 1000; + if ( nOnes > 3 ) + Value = 5 - nOnes; + return Value; +} + +/**Function************************************************************* + + Synopsis [Returns the next free cut to use.] + + Description [Uses the cut with the smallest value.] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline Dar_Cut_t * Dar_CutFindFree( Dar_Man_t * p, Aig_Obj_t * pObj ) +{ + Dar_Cut_t * pCut, * pCutMax; + int i; + pCutMax = NULL; + Dar_ObjForEachCutAll( pObj, pCut, i ) + { + if ( pCut->fUsed == 0 ) + return pCut; + if ( pCut->nLeaves < 3 ) + continue; + if ( pCutMax == NULL || pCutMax->Value > pCut->Value ) + pCutMax = pCut; + } + if ( pCutMax == NULL ) + { + Dar_ObjForEachCutAll( pObj, pCut, i ) + { + if ( pCut->nLeaves < 2 ) + continue; + if ( pCutMax == NULL || pCutMax->Value > pCut->Value ) + pCutMax = pCut; + } + } + if ( pCutMax == NULL ) + { + Dar_ObjForEachCutAll( pObj, pCut, i ) + { + if ( pCutMax == NULL || pCutMax->Value > pCut->Value ) + pCutMax = pCut; + } + } + assert( pCutMax != NULL ); + pCutMax->fUsed = 0; + return pCutMax; +} + +/**Function************************************************************* + + Synopsis [Returns 1 if pDom is contained in pCut.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline int Dar_CutCheckDominance( Dar_Cut_t * pDom, Dar_Cut_t * pCut ) +{ + int i, k; + assert( pDom->fUsed && pCut->fUsed ); + for ( i = 0; i < (int)pDom->nLeaves; i++ ) + { + for ( k = 0; k < (int)pCut->nLeaves; k++ ) + if ( pDom->pLeaves[i] == pCut->pLeaves[k] ) + break; + if ( k == (int)pCut->nLeaves ) // node i in pDom is not contained in pCut + return 0; + } + // every node in pDom is contained in pCut + return 1; +} + +/**Function************************************************************* + + Synopsis [Returns 1 if the cut is contained.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline int Dar_CutFilter( Aig_Obj_t * pObj, Dar_Cut_t * pCut ) +{ + Dar_Cut_t * pTemp; + int i; + assert( pCut->fUsed ); + // go through the cuts of the node + Dar_ObjForEachCut( pObj, pTemp, i ) + { + if ( pTemp == pCut ) + continue; + if ( pTemp->nLeaves > pCut->nLeaves ) + { + // skip the non-contained cuts + if ( (pTemp->uSign & pCut->uSign) != pCut->uSign ) + continue; + // check containment seriously + if ( Dar_CutCheckDominance( pCut, pTemp ) ) + { + // remove contained cut + pTemp->fUsed = 0; + } + } + else + { + // skip the non-contained cuts + if ( (pTemp->uSign & pCut->uSign) != pTemp->uSign ) + continue; + // check containment seriously + if ( Dar_CutCheckDominance( pTemp, pCut ) ) + { + // remove the given cut + pCut->fUsed = 0; + return 1; + } + } + } + return 0; +} + +/**Function************************************************************* + + Synopsis [Merges two cuts.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline int Dar_CutMergeOrdered( Dar_Cut_t * pC, Dar_Cut_t * pC0, Dar_Cut_t * pC1 ) +{ + int i, k, c; + assert( pC0->nLeaves >= pC1->nLeaves ); + + // the case of the largest cut sizes + if ( pC0->nLeaves == 4 && pC1->nLeaves == 4 ) + { + if ( pC0->uSign != pC1->uSign ) + return 0; + for ( i = 0; i < (int)pC0->nLeaves; i++ ) + if ( pC0->pLeaves[i] != pC1->pLeaves[i] ) + return 0; + for ( i = 0; i < (int)pC0->nLeaves; i++ ) + pC->pLeaves[i] = pC0->pLeaves[i]; + pC->nLeaves = pC0->nLeaves; + return 1; + } + + // the case when one of the cuts is the largest + if ( pC0->nLeaves == 4 ) + { + if ( (pC0->uSign & pC1->uSign) != pC1->uSign ) + return 0; + for ( i = 0; i < (int)pC1->nLeaves; i++ ) + { + for ( k = (int)pC0->nLeaves - 1; k >= 0; k-- ) + if ( pC0->pLeaves[k] == pC1->pLeaves[i] ) + break; + if ( k == -1 ) // did not find + return 0; + } + for ( i = 0; i < (int)pC0->nLeaves; i++ ) + pC->pLeaves[i] = pC0->pLeaves[i]; + pC->nLeaves = pC0->nLeaves; + return 1; + } + + // compare two cuts with different numbers + i = k = 0; + for ( c = 0; c < 4; c++ ) + { + if ( k == (int)pC1->nLeaves ) + { + if ( i == (int)pC0->nLeaves ) + { + pC->nLeaves = c; + return 1; + } + pC->pLeaves[c] = pC0->pLeaves[i++]; + continue; + } + if ( i == (int)pC0->nLeaves ) + { + if ( k == (int)pC1->nLeaves ) + { + pC->nLeaves = c; + return 1; + } + pC->pLeaves[c] = pC1->pLeaves[k++]; + continue; + } + if ( pC0->pLeaves[i] < pC1->pLeaves[k] ) + { + pC->pLeaves[c] = pC0->pLeaves[i++]; + continue; + } + if ( pC0->pLeaves[i] > pC1->pLeaves[k] ) + { + pC->pLeaves[c] = pC1->pLeaves[k++]; + continue; + } + pC->pLeaves[c] = pC0->pLeaves[i++]; + k++; + } + if ( i < (int)pC0->nLeaves || k < (int)pC1->nLeaves ) + return 0; + pC->nLeaves = c; + return 1; +} + +/**Function************************************************************* + + Synopsis [Prepares the object for FPGA mapping.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline int Dar_CutMerge( Dar_Cut_t * pCut, Dar_Cut_t * pCut0, Dar_Cut_t * pCut1 ) +{ + assert( !pCut->fUsed ); + // merge the nodes + if ( pCut0->nLeaves <= pCut1->nLeaves ) + { + if ( !Dar_CutMergeOrdered( pCut, pCut1, pCut0 ) ) + return 0; + } + else + { + if ( !Dar_CutMergeOrdered( pCut, pCut0, pCut1 ) ) + return 0; + } + pCut->uSign = pCut0->uSign | pCut1->uSign; + pCut->fUsed = 1; + return 1; +} + + +/**Function************************************************************* + + Synopsis [Computes the stretching phase of the cut w.r.t. the merged cut.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline unsigned Dar_CutTruthPhase( Dar_Cut_t * pCut, Dar_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 [Swaps two advancent variables of the truth table.] + + Description [Swaps variable iVar and iVar+1.] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline unsigned Dar_CutTruthSwapAdjacentVars( unsigned uTruth, int iVar ) +{ + assert( iVar >= 0 && iVar <= 2 ); + if ( iVar == 0 ) + return (uTruth & 0x99999999) | ((uTruth & 0x22222222) << 1) | ((uTruth & 0x44444444) >> 1); + if ( iVar == 1 ) + return (uTruth & 0xC3C3C3C3) | ((uTruth & 0x0C0C0C0C) << 2) | ((uTruth & 0x30303030) >> 2); + if ( iVar == 2 ) + return (uTruth & 0xF00FF00F) | ((uTruth & 0x00F000F0) << 4) | ((uTruth & 0x0F000F00) >> 4); + assert( 0 ); + return 0; +} + +/**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 [] + +***********************************************************************/ +static inline unsigned Dar_CutTruthStretch( unsigned uTruth, int nVars, unsigned Phase ) +{ + int i, k, Var = nVars - 1; + for ( i = 3; i >= 0; i-- ) + if ( Phase & (1 << i) ) + { + for ( k = Var; k < i; k++ ) + uTruth = Dar_CutTruthSwapAdjacentVars( uTruth, k ); + Var--; + } + assert( Var == -1 ); + return uTruth; +} + +/**Function************************************************************* + + Synopsis [Shrinks 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 what variables should remain.] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline unsigned Dar_CutTruthShrink( unsigned uTruth, int nVars, unsigned Phase ) +{ + int i, k, Var = 0; + for ( i = 0; i < 4; i++ ) + if ( Phase & (1 << i) ) + { + for ( k = i-1; k >= Var; k-- ) + uTruth = Dar_CutTruthSwapAdjacentVars( uTruth, k ); + Var++; + } + return uTruth; +} + +/**Function************************************************************* + + Synopsis [Performs truth table computation.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline unsigned Dar_CutTruth( Dar_Cut_t * pCut, Dar_Cut_t * pCut0, Dar_Cut_t * pCut1, int fCompl0, int fCompl1 ) +{ + unsigned uTruth0 = fCompl0 ? ~pCut0->uTruth : pCut0->uTruth; + unsigned uTruth1 = fCompl1 ? ~pCut1->uTruth : pCut1->uTruth; + uTruth0 = Dar_CutTruthStretch( uTruth0, pCut0->nLeaves, Dar_CutTruthPhase(pCut, pCut0) ); + uTruth1 = Dar_CutTruthStretch( uTruth1, pCut1->nLeaves, Dar_CutTruthPhase(pCut, pCut1) ); + return uTruth0 & uTruth1; +} + +/**Function************************************************************* + + Synopsis [Minimize support of the cut.] + + Description [Returns 1 if the node's support has changed] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +static inline int Dar_CutSuppMinimize( Dar_Cut_t * pCut ) +{ + unsigned uMasks[4][2] = { + { 0x5555, 0xAAAA }, + { 0x3333, 0xCCCC }, + { 0x0F0F, 0xF0F0 }, + { 0x00FF, 0xFF00 } + }; + unsigned uPhase = 0, uTruth = 0xFFFF & pCut->uTruth; + int i, k, nLeaves; + assert( pCut->fUsed ); + // compute the truth support of the cut's function + nLeaves = pCut->nLeaves; + for ( i = 0; i < (int)pCut->nLeaves; i++ ) + if ( (uTruth & uMasks[i][0]) == ((uTruth & uMasks[i][1]) >> (1 << i)) ) + nLeaves--; + else + uPhase |= (1 << i); + if ( nLeaves == (int)pCut->nLeaves ) + return 0; + // shrink the truth table + uTruth = Dar_CutTruthShrink( uTruth, pCut->nLeaves, uPhase ); + pCut->uTruth = 0xFFFF & uTruth; + // update leaves and signature + pCut->uSign = 0; + for ( i = k = 0; i < (int)pCut->nLeaves; i++ ) + { + if ( !(uPhase & (1 << i)) ) + continue; + pCut->pLeaves[k++] = pCut->pLeaves[i]; + pCut->uSign |= Aig_ObjCutSign( pCut->pLeaves[i] ); + } + assert( k == nLeaves ); + pCut->nLeaves = nLeaves; + return 1; +} + +/**Function************************************************************* + + Synopsis [] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +void Dar_ManCutsFree( Dar_Man_t * p ) +{ + if ( p->pMemCuts == NULL ) + return; + Aig_MmFixedStop( p->pMemCuts, 0 ); + p->pMemCuts = NULL; +// Aig_ManCleanData( p ); +} + +/**Function************************************************************* + + Synopsis [] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +Dar_Cut_t * Dar_ObjPrepareCuts( Dar_Man_t * p, Aig_Obj_t * pObj ) +{ + Dar_Cut_t * pCutSet, * pCut; + int i; + assert( Dar_ObjCuts(pObj) == NULL ); + pObj->nCuts = p->pPars->nCutsMax; + // create the cutset of the node + pCutSet = (Dar_Cut_t *)Aig_MmFixedEntryFetch( p->pMemCuts ); + Dar_ObjSetCuts( pObj, pCutSet ); + Dar_ObjForEachCut( pObj, pCut, i ) + pCut->fUsed = 0; + // add unit cut if needed + pCut = pCutSet; + pCut->fUsed = 1; + if ( Aig_ObjIsConst1(pObj) ) + { + pCut->nLeaves = 0; + pCut->uSign = 0; + pCut->uTruth = 0xFFFF; + } + else + { + pCut->nLeaves = 1; + pCut->pLeaves[0] = pObj->Id; + pCut->uSign = Aig_ObjCutSign( pObj->Id ); + pCut->uTruth = 0xAAAA; + } + pCut->Value = Dar_CutFindValue( p, pCut ); + return pCutSet; +} + +/**Function************************************************************* + + Synopsis [] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +void Dar_ManCutsStart( Dar_Man_t * p ) +{ + Aig_Obj_t * pObj; + int i; + Aig_ManCleanData( p->pAig ); + Aig_MmFixedRestart( p->pMemCuts ); + Dar_ObjPrepareCuts( p, Aig_ManConst1(p->pAig) ); + Aig_ManForEachPi( p->pAig, pObj, i ) + Dar_ObjPrepareCuts( p, pObj ); +} + +/**Function************************************************************* + + Synopsis [] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +Dar_Cut_t * Dar_ObjComputeCuts( Dar_Man_t * p, Aig_Obj_t * pObj ) +{ + Aig_Obj_t * pFanin0 = Aig_ObjReal_rec( Aig_ObjChild0(pObj) ); + Aig_Obj_t * pFanin1 = Aig_ObjReal_rec( Aig_ObjChild1(pObj) ); + Aig_Obj_t * pFaninR0 = Aig_Regular(pFanin0); + Aig_Obj_t * pFaninR1 = Aig_Regular(pFanin1); + Dar_Cut_t * pCutSet, * pCut0, * pCut1, * pCut; + int i, k, RetValue; + + assert( !Aig_IsComplement(pObj) ); + assert( Aig_ObjIsNode(pObj) ); + assert( Dar_ObjCuts(pObj) == NULL ); + assert( Dar_ObjCuts(pFaninR0) != NULL ); + assert( Dar_ObjCuts(pFaninR1) != NULL ); + + // set up the first cut + pCutSet = Dar_ObjPrepareCuts( p, pObj ); + // make sure fanins cuts are computed + Dar_ObjForEachCut( pFaninR0, pCut0, i ) + Dar_ObjForEachCut( pFaninR1, pCut1, k ) + { + p->nCutsAll++; + // make sure K-feasible cut exists + if ( Dar_WordCountOnes(pCut0->uSign | pCut1->uSign) > 4 ) + continue; + // get the next cut of this node + pCut = Dar_CutFindFree( p, pObj ); + // create the new cut + if ( !Dar_CutMerge( pCut, pCut0, pCut1 ) ) + { + assert( !pCut->fUsed ); + continue; + } + p->nCutsTried++; + // check dominance + if ( Dar_CutFilter( pObj, pCut ) ) + { + assert( !pCut->fUsed ); + continue; + } + // compute truth table + pCut->uTruth = 0xFFFF & Dar_CutTruth( pCut, pCut0, pCut1, Aig_IsComplement(pFanin0), Aig_IsComplement(pFanin1) ); + + // minimize support of the cut + if ( Dar_CutSuppMinimize( pCut ) ) + { + RetValue = Dar_CutFilter( pObj, pCut ); + assert( !RetValue ); + } + + // assign the value of the cut + pCut->Value = Dar_CutFindValue( p, pCut ); + // if the cut contains removed node, do not use it + if ( pCut->Value == 0 ) + { + p->nCutsSkipped++; + pCut->fUsed = 0; + } + else if ( pCut->nLeaves < 2 ) + return pCutSet; + } + // count the number of nontrivial cuts cuts + Dar_ObjForEachCut( pObj, pCut, i ) + p->nCutsUsed += pCut->fUsed; + // discount trivial cut + p->nCutsUsed--; + return pCutSet; +} + +/**Function************************************************************* + + Synopsis [] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +Dar_Cut_t * Dar_ObjComputeCuts_rec( Dar_Man_t * p, Aig_Obj_t * pObj ) +{ + if ( Dar_ObjCuts(pObj) ) + return Dar_ObjCuts(pObj); + if ( Aig_ObjIsBuf(pObj) ) + return Dar_ObjComputeCuts_rec( p, Aig_ObjFanin0(pObj) ); + Dar_ObjComputeCuts_rec( p, Aig_ObjFanin0(pObj) ); + Dar_ObjComputeCuts_rec( p, Aig_ObjFanin1(pObj) ); + return Dar_ObjComputeCuts( p, pObj ); +} + +//////////////////////////////////////////////////////////////////////// +/// END OF FILE /// +//////////////////////////////////////////////////////////////////////// + + |