diff options
Diffstat (limited to 'src/opt/ret/retDelay.c')
| -rw-r--r-- | src/opt/ret/retDelay.c | 305 |
1 files changed, 0 insertions, 305 deletions
diff --git a/src/opt/ret/retDelay.c b/src/opt/ret/retDelay.c deleted file mode 100644 index bcfe3a2e..00000000 --- a/src/opt/ret/retDelay.c +++ /dev/null @@ -1,305 +0,0 @@ -/**CFile**************************************************************** - - FileName [retDelay.c] - - SystemName [ABC: Logic synthesis and verification system.] - - PackageName [Retiming package.] - - Synopsis [Incremental retiming for optimum delay.] - - Author [Alan Mishchenko] - - Affiliation [UC Berkeley] - - Date [Ver. 1.0. Started - Oct 31, 2006.] - - Revision [$Id: retDelay.c,v 1.00 2006/10/31 00:00:00 alanmi Exp $] - -***********************************************************************/ - -#include "retInt.h" - -//////////////////////////////////////////////////////////////////////// -/// DECLARATIONS /// -//////////////////////////////////////////////////////////////////////// - -static int Abc_NtkRetimeMinDelayTry( Abc_Ntk_t * pNtk, int fForward, int fInitial, int nIterLimit, int * pIterBest, int fVerbose ); -static int Abc_NtkRetimeTiming( Abc_Ntk_t * pNtk, int fForward, Vec_Ptr_t * vCritical ); -static int Abc_NtkRetimeTiming_rec( Abc_Obj_t * pObj, int fForward ); - -//////////////////////////////////////////////////////////////////////// -/// FUNCTION DEFINITIONS /// -//////////////////////////////////////////////////////////////////////// - -/**Function************************************************************* - - Synopsis [Retimes incrementally for minimum delay.] - - Description [This procedure cannot be called in the application code - because it assumes that the network is preprocessed by removing LIs/LOs.] - - SideEffects [] - - SeeAlso [] - -***********************************************************************/ -int Abc_NtkRetimeMinDelay( Abc_Ntk_t * pNtk, Abc_Ntk_t * pNtkCopy, int nIterLimit, int fForward, int fVerbose ) -{ - int IterBest, DelayBest; - int IterBest2, DelayBest2; - // try to find the best delay iteration on a copy - DelayBest = Abc_NtkRetimeMinDelayTry( pNtkCopy, fForward, 0, nIterLimit, &IterBest, fVerbose ); - if ( IterBest == 0 ) - return 1; - // perform the given number of iterations on the original network - DelayBest2 = Abc_NtkRetimeMinDelayTry( pNtk, fForward, 1, IterBest, &IterBest2, fVerbose ); - assert( DelayBest == DelayBest2 ); - assert( IterBest == IterBest2 ); - return 1; -} - -/**Function************************************************************* - - Synopsis [Returns the best delay and the number of best iteration.] - - Description [] - - SideEffects [] - - SeeAlso [] - -***********************************************************************/ -int Abc_NtkRetimeMinDelayTry( Abc_Ntk_t * pNtk, int fForward, int fInitial, int nIterLimit, int * pIterBest, int fVerbose ) -{ - Abc_Ntk_t * pNtkNew = NULL; - Vec_Ptr_t * vCritical; - Vec_Int_t * vValues; - Abc_Obj_t * pObj; - int i, k, IterBest, DelayCur, DelayBest, DelayStart, LatchesBest; - // transfer intitial values - if ( fInitial ) - { - if ( fForward ) - Abc_NtkRetimeTranferToCopy( pNtk ); - else - { - // save initial value of the latches - vValues = Abc_NtkRetimeCollectLatchValues( pNtk ); - // start the network for initial value computation - pNtkNew = Abc_NtkRetimeBackwardInitialStart( pNtk ); - } - } - -if ( fVerbose && !fInitial ) - printf( "Performing analysis:\n" ); - // find the best iteration - DelayBest = ABC_INFINITY; IterBest = 0; LatchesBest = Abc_NtkLatchNum(pNtk); - vCritical = Vec_PtrAlloc( 100 ); - for ( i = 0; ; i++ ) - { - // perform moves for the timing-critical nodes - DelayCur = Abc_NtkRetimeTiming( pNtk, fForward, vCritical ); - if ( i == 0 ) - DelayStart = DelayCur; - // record this position if it has the best delay - if ( DelayBest > DelayCur ) - { -if ( fVerbose && !fInitial ) - printf( "%s Iter = %3d. Delay = %3d. Latches = %5d. Delta = %6.2f. Ratio = %4.2f %%\n", - fForward ? "Fwd": "Bwd", i, DelayCur, Abc_NtkLatchNum(pNtk), - 1.0*(Abc_NtkLatchNum(pNtk)-LatchesBest)/(DelayBest-DelayCur), - 100.0*(Abc_NtkLatchNum(pNtk)-LatchesBest)/Abc_NtkLatchNum(pNtk)/(DelayBest-DelayCur) ); - - DelayBest = DelayCur; - IterBest = i; - LatchesBest = Abc_NtkLatchNum(pNtk); - } - // quit after timing analysis - if ( i == nIterLimit ) - break; - // skip if 10 interations did not give improvement - if ( i - IterBest > 20 ) - break; - // try retiming to improve the delay - Vec_PtrForEachEntry( vCritical, pObj, k ) - if ( Abc_NtkRetimeNodeIsEnabled(pObj, fForward) ) - Abc_NtkRetimeNode( pObj, fForward, fInitial ); - // share latches - if ( !fForward ) - Abc_NtkRetimeShareLatches( pNtk, fInitial ); - } - Vec_PtrFree( vCritical ); - // transfer the initial state back to the latches - if ( fInitial ) - { - if ( fForward ) - Abc_NtkRetimeTranferFromCopy( pNtk ); - else - { - Abc_NtkRetimeBackwardInitialFinish( pNtk, pNtkNew, vValues, fVerbose ); - Abc_NtkDelete( pNtkNew ); - Vec_IntFree( vValues ); - } - } -if ( fVerbose && !fInitial ) - printf( "%s : Starting delay = %3d. Final delay = %3d. IterBest = %2d (out of %2d).\n", - fForward? "Forward " : "Backward", DelayStart, DelayBest, IterBest, nIterLimit ); - *pIterBest = (nIterLimit == 1) ? 1 : IterBest; - return DelayBest; -} - -/**Function************************************************************* - - Synopsis [Returns the set of timing-critical nodes.] - - Description [Performs static timing analysis on the network. Uses - unit-delay model.] - - SideEffects [] - - SeeAlso [] - -***********************************************************************/ -int Abc_NtkRetimeTiming( Abc_Ntk_t * pNtk, int fForward, Vec_Ptr_t * vCritical ) -{ - Vec_Ptr_t * vLatches; - Abc_Obj_t * pObj, * pNext; - int i, k, LevelCur, LevelMax = 0; - // mark all objects except nodes - Abc_NtkIncrementTravId(pNtk); - vLatches = Vec_PtrAlloc( Abc_NtkLatchNum(pNtk) ); - Abc_NtkForEachObj( pNtk, pObj, i ) - { - if ( Abc_ObjIsLatch(pObj) ) - Vec_PtrPush( vLatches, pObj ); - if ( Abc_ObjIsNode(pObj) ) - continue; - pObj->Level = 0; - Abc_NodeSetTravIdCurrent( pObj ); - } - // perform analysis from CIs/COs - if ( fForward ) - { - Vec_PtrForEachEntry( vLatches, pObj, i ) - { - Abc_ObjForEachFanout( pObj, pNext, k ) - { - LevelCur = Abc_NtkRetimeTiming_rec( pNext, fForward ); - if ( LevelMax < LevelCur ) - LevelMax = LevelCur; - } - } - Abc_NtkForEachPi( pNtk, pObj, i ) - { - Abc_ObjForEachFanout( pObj, pNext, k ) - { - LevelCur = Abc_NtkRetimeTiming_rec( pNext, fForward ); - if ( LevelMax < LevelCur ) - LevelMax = LevelCur; - } - } - } - else - { - Vec_PtrForEachEntry( vLatches, pObj, i ) - { - LevelCur = Abc_NtkRetimeTiming_rec( Abc_ObjFanin0(pObj), fForward ); - if ( LevelMax < LevelCur ) - LevelMax = LevelCur; - } - Abc_NtkForEachPo( pNtk, pObj, i ) - { - LevelCur = Abc_NtkRetimeTiming_rec( Abc_ObjFanin0(pObj), fForward ); - if ( LevelMax < LevelCur ) - LevelMax = LevelCur; - } - } - // collect timing critical nodes, which should be retimed forward/backward - Vec_PtrClear( vCritical ); - Abc_NtkIncrementTravId(pNtk); - if ( fForward ) - { - Vec_PtrForEachEntry( vLatches, pObj, i ) - { - Abc_ObjForEachFanout( pObj, pNext, k ) - { - if ( Abc_NodeIsTravIdCurrent(pNext) ) - continue; - if ( LevelMax != (int)pNext->Level ) - continue; - // new critical node - Vec_PtrPush( vCritical, pNext ); - Abc_NodeSetTravIdCurrent( pNext ); - } - } - } - else - { - Vec_PtrForEachEntry( vLatches, pObj, i ) - { - Abc_ObjForEachFanin( pObj, pNext, k ) - { - if ( Abc_NodeIsTravIdCurrent(pNext) ) - continue; - if ( LevelMax != (int)pNext->Level ) - continue; - // new critical node - Vec_PtrPush( vCritical, pNext ); - Abc_NodeSetTravIdCurrent( pNext ); - } - } - } - Vec_PtrFree( vLatches ); - return LevelMax; -} - -/**Function************************************************************* - - Synopsis [Recursively performs timing analysis.] - - Description [Performs static timing analysis on the network. Uses - unit-delay model.] - - SideEffects [] - - SeeAlso [] - -***********************************************************************/ -int Abc_NtkRetimeTiming_rec( Abc_Obj_t * pObj, int fForward ) -{ - Abc_Obj_t * pNext; - int i, LevelCur, LevelMax = 0; - // skip visited nodes - if ( Abc_NodeIsTravIdCurrent(pObj) ) - return pObj->Level; - Abc_NodeSetTravIdCurrent(pObj); - // visit the next nodes - if ( fForward ) - { - Abc_ObjForEachFanout( pObj, pNext, i ) - { - LevelCur = Abc_NtkRetimeTiming_rec( pNext, fForward ); - if ( LevelMax < LevelCur ) - LevelMax = LevelCur; - } - } - else - { - Abc_ObjForEachFanin( pObj, pNext, i ) - { - LevelCur = Abc_NtkRetimeTiming_rec( pNext, fForward ); - if ( LevelMax < LevelCur ) - LevelMax = LevelCur; - } - } -// printf( "Node %3d -> Level %3d.\n", pObj->Id, LevelMax + 1 ); - pObj->Level = LevelMax + 1; - return pObj->Level; -} - -//////////////////////////////////////////////////////////////////////// -/// END OF FILE /// -//////////////////////////////////////////////////////////////////////// - - |