diff options
Diffstat (limited to 'src/base/abcs/abcRetUtil.c')
| -rw-r--r-- | src/base/abcs/abcRetUtil.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/src/base/abcs/abcRetUtil.c b/src/base/abcs/abcRetUtil.c new file mode 100644 index 00000000..52ea6446 --- /dev/null +++ b/src/base/abcs/abcRetUtil.c @@ -0,0 +1,227 @@ +/**CFile**************************************************************** + + FileName [abcRetUtil.c] + + SystemName [ABC: Logic synthesis and verification system.] + + PackageName [Network and node package.] + + Synopsis [Retiming utilities.] + + Author [Alan Mishchenko] + + Affiliation [UC Berkeley] + + Date [Ver. 1.0. Started - June 20, 2005.] + + Revision [$Id: abcRetUtil.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $] + +***********************************************************************/ + +#include "abcs.h" + +//////////////////////////////////////////////////////////////////////// +/// DECLARATIONS /// +//////////////////////////////////////////////////////////////////////// + +//////////////////////////////////////////////////////////////////////// +/// FUNCTION DEFITIONS /// +//////////////////////////////////////////////////////////////////////// + +/**Function************************************************************* + + Synopsis [Performs forward retiming of the sequential AIG.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +Vec_Ptr_t * Abc_NtkUtilRetimingTry( Abc_Ntk_t * pNtk, bool fForward ) +{ + Vec_Ptr_t * vNodes, * vMoves; + Abc_Obj_t * pNode, * pFanout, * pFanin; + int i, k, nLatches; + assert( Abc_NtkIsSeq( pNtk ) ); + // assume that all nodes can be retimed + vNodes = Vec_PtrAlloc( 100 ); + Abc_AigForEachAnd( pNtk, pNode, i ) + { + Vec_PtrPush( vNodes, pNode ); + pNode->fMarkA = 1; + } + // process the nodes + vMoves = Vec_PtrAlloc( 100 ); + Vec_PtrForEachEntry( vNodes, pNode, i ) + { +// printf( "(%d,%d) ", Abc_ObjFaninL0(pNode), Abc_ObjFaninL0(pNode) ); + // unmark the node as processed + pNode->fMarkA = 0; + // get the number of latches to retime + if ( fForward ) + nLatches = Abc_ObjFaninLMin(pNode); + else + nLatches = Abc_ObjFanoutLMin(pNode); + if ( nLatches == 0 ) + continue; + assert( nLatches > 0 ); + // retime the latches forward + if ( fForward ) + Abc_ObjRetimeForwardTry( pNode, nLatches ); + else + Abc_ObjRetimeBackwardTry( pNode, nLatches ); + // write the moves + for ( k = 0; k < nLatches; k++ ) + Vec_PtrPush( vMoves, pNode ); + // schedule fanouts for updating + if ( fForward ) + { + Abc_ObjForEachFanout( pNode, pFanout, k ) + { + if ( Abc_ObjFaninNum(pFanout) != 2 || pFanout->fMarkA ) + continue; + pFanout->fMarkA = 1; + Vec_PtrPush( vNodes, pFanout ); + } + } + else + { + Abc_ObjForEachFanin( pNode, pFanin, k ) + { + if ( Abc_ObjFaninNum(pFanin) != 2 || pFanin->fMarkA ) + continue; + pFanin->fMarkA = 1; + Vec_PtrPush( vNodes, pFanin ); + } + } + } + Vec_PtrFree( vNodes ); + // make sure the marks are clean the the retiming is final + Abc_AigForEachAnd( pNtk, pNode, i ) + { + assert( pNode->fMarkA == 0 ); + if ( fForward ) + assert( Abc_ObjFaninLMin(pNode) == 0 ); + else + assert( Abc_ObjFanoutLMin(pNode) == 0 ); + } + return vMoves; +} + +/**Function************************************************************* + + Synopsis [Translates retiming steps into retiming moves.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +Vec_Ptr_t * Abc_NtkUtilRetimingGetMoves( Abc_Ntk_t * pNtk, Vec_Int_t * vSteps, bool fForward ) +{ + Abc_RetStep_t RetStep; + Vec_Ptr_t * vMoves; + Abc_Obj_t * pNode; + int i, k, iNode, nLatches, Number; + assert( Abc_NtkIsSeq( pNtk ) ); + // process the nodes + vMoves = Vec_PtrAlloc( 100 ); + while ( Vec_IntSize(vSteps) > 0 ) + { + iNode = 0; + Vec_IntForEachEntry( vSteps, Number, i ) + { + // get the retiming step + RetStep = Abc_Int2RetStep( Number ); + // get the node to be retimed + pNode = Abc_NtkObj( pNtk, RetStep.iNode ); + assert( RetStep.nLatches > 0 ); + // get the number of latches that can be retimed + if ( fForward ) + nLatches = Abc_ObjFaninLMin(pNode); + else + nLatches = Abc_ObjFanoutLMin(pNode); + if ( nLatches == 0 ) + { + Vec_IntWriteEntry( vSteps, iNode++, Abc_RetStep2Int(RetStep) ); + continue; + } + assert( nLatches > 0 ); + // get the number of latches to be retimed over this node + nLatches = ABC_MIN( nLatches, (int)RetStep.nLatches ); + // retime the latches forward + if ( fForward ) + Abc_ObjRetimeForwardTry( pNode, nLatches ); + else + Abc_ObjRetimeBackwardTry( pNode, nLatches ); + // write the moves + for ( k = 0; k < nLatches; k++ ) + Vec_PtrPush( vMoves, pNode ); + // subtract the retiming performed + RetStep.nLatches -= nLatches; + // store the node if it is not retimed completely + if ( RetStep.nLatches > 0 ) + Vec_IntWriteEntry( vSteps, iNode++, Abc_RetStep2Int(RetStep) ); + } + // reduce the array + Vec_IntShrink( vSteps, iNode ); + } + // undo the tentative retiming + if ( fForward ) + { + Vec_PtrForEachEntryReverse( vMoves, pNode, i ) + Abc_ObjRetimeBackwardTry( pNode, 1 ); + } + else + { + Vec_PtrForEachEntryReverse( vMoves, pNode, i ) + Abc_ObjRetimeForwardTry( pNode, 1 ); + } + return vMoves; +} + + +/**Function************************************************************* + + Synopsis [Splits retiming into forward and backward.] + + Description [] + + SideEffects [] + + SeeAlso [] + +***********************************************************************/ +Vec_Int_t * Abc_NtkUtilRetimingSplit( Vec_Str_t * vLags, int fForward ) +{ + Vec_Int_t * vNodes; + Abc_RetStep_t RetStep; + int Value, i; + vNodes = Vec_IntAlloc( 100 ); + Vec_StrForEachEntry( vLags, Value, i ) + { + if ( Value < 0 && fForward ) + { + RetStep.iNode = i; + RetStep.nLatches = -Value; + Vec_IntPush( vNodes, Abc_RetStep2Int(RetStep) ); + } + else if ( Value > 0 && !fForward ) + { + RetStep.iNode = i; + RetStep.nLatches = Value; + Vec_IntPush( vNodes, Abc_RetStep2Int(RetStep) ); + } + } + return vNodes; +} + +//////////////////////////////////////////////////////////////////////// +/// END OF FILE /// +//////////////////////////////////////////////////////////////////////// + + |