Adding new switch to &if to relax the delay.

src/base/abci/abc.c

@@ -29267,7 +29267,7 @@ int Abc_CommandAbc9If( Abc_Frame_t * pAbc, int argc, char ** argv )
     }
     pPars->pLutLib = (If_LibLut_t *)pAbc->pLibLut;
     Extra_UtilGetoptReset();
-    while ( ( c = Extra_UtilGetopt( argc, argv, "KCFAGDEWSqalepmrsdbgyojikfuzvh" ) ) != EOF )
+    while ( ( c = Extra_UtilGetopt( argc, argv, "KCFAGRDEWSqalepmrsdbgyojikfuzvh" ) ) != EOF )
     {
         switch ( c )
         {
@@ -29328,6 +29328,17 @@ int Abc_CommandAbc9If( Abc_Frame_t * pAbc, int argc, char ** argv )
             if ( pPars->nGateSize < 2 )
                 goto usage;
             break;
+        case 'R':
+            if ( globalUtilOptind >= argc )
+            {
+                Abc_Print( 1, "Command line switch \"-R\" should be followed by a floating point number.\n" );
+                return 0;
+            }
+            pPars->nRelaxRatio = (float)atof(argv[globalUtilOptind]);
+            globalUtilOptind++;
+            if ( pPars->nRelaxRatio < 0 ) 
+                goto usage;
+            break;
         case 'D':
             if ( globalUtilOptind >= argc )
             {
@@ -29626,13 +29637,14 @@ usage:
         sprintf(LutSize, "library" );
     else
         sprintf(LutSize, "%d", pPars->nLutSize );
-    Abc_Print( -2, "usage: &if [-KCFAG num] [-DEW float] [-S str] [-qarlepmsdbgyojikfuczvh]\n" );
+    Abc_Print( -2, "usage: &if [-KCFAGR num] [-DEW float] [-S str] [-qarlepmsdbgyojikfuczvh]\n" );
     Abc_Print( -2, "\t           performs FPGA technology mapping of the network\n" );
     Abc_Print( -2, "\t-K num   : the number of LUT inputs (2 < num < %d) [default = %s]\n", IF_MAX_LUTSIZE+1, LutSize );
     Abc_Print( -2, "\t-C num   : the max number of priority cuts (0 < num < 2^12) [default = %d]\n", pPars->nCutsMax );
     Abc_Print( -2, "\t-F num   : the number of area flow recovery iterations (num >= 0) [default = %d]\n", pPars->nFlowIters );
     Abc_Print( -2, "\t-A num   : the number of exact area recovery iterations (num >= 0) [default = %d]\n", pPars->nAreaIters );
     Abc_Print( -2, "\t-G num   : the max AND/OR gate size for mapping (0 = unused) [default = %d]\n", pPars->nGateSize );
+    Abc_Print( -2, "\t-R num   : the delay relaxation ratio (num >= 0) [default = %d]\n", pPars->nRelaxRatio );
     Abc_Print( -2, "\t-D float : sets the delay constraint for the mapping [default = %s]\n", Buffer );
     Abc_Print( -2, "\t-E float : sets epsilon used for tie-breaking [default = %f]\n", pPars->Epsilon );
     Abc_Print( -2, "\t-W float : sets wire delay between adjects LUTs [default = %f]\n", pPars->WireDelay );

src/map/if/if.h

@@ -102,6 +102,7 @@ struct If_Par_t_
     int                nNonDecLimit;  // the max size of non-dec nodes
     float              DelayTarget;   // delay target
     float              Epsilon;       // value used in comparison floating point numbers
+    int                nRelaxRatio;   // delay relaxation ratio
     int                fPreprocess;   // preprossing
     int                fArea;         // area-oriented mapping
     int                fFancy;        // a fancy feature
@@ -141,6 +142,7 @@ struct If_Par_t_
     int                nLatchesCoBox; // the number of white box inputs among the COs
     int                fLiftLeaves;   // shift the leaves for seq mapping
     int                fUseCoAttrs;   // use CO attributes
+    float              DelayTargetNew;// new delay target
     float              FinalDelay;    // final delay after mapping
     If_LibLut_t *      pLutLib;       // the LUT library
     float *            pTimesArr;     // arrival times

src/map/if/ifUtil.c

@@ -182,13 +182,11 @@ void If_ManComputeRequired( If_Man_t * p )
         {
             // get the global required times
             p->RequiredGlo = If_ManDelayMax( p, 0 );
-/*
-            ////////////////////////////////////////
-            // redefine the delay target (positive number means percentage)    
-            if ( p->pPars->DelayTarget > 0 )
-                p->pPars->DelayTarget = p->RequiredGlo * (100.0 + p->pPars->DelayTarget) / 100.0; 
-            ////////////////////////////////////////
-*/
+
+            // find new delay target
+            if ( p->pPars->nRelaxRatio && p->pPars->DelayTargetNew == 0 )
+                p->pPars->DelayTargetNew = p->RequiredGlo * (100.0 + p->pPars->nRelaxRatio) / 100.0; 
+
             // update the required times according to the target
             if ( p->pPars->DelayTarget != -1 )
             {
@@ -210,6 +208,8 @@ void If_ManComputeRequired( If_Man_t * p )
                     p->RequiredGlo = p->pPars->DelayTarget;
                 }
             }
+            else if ( p->pPars->DelayTargetNew > 0 ) // relax the required times 
+                p->RequiredGlo = p->pPars->DelayTargetNew;
             // do not propagate required times if area minimization is requested
             if ( p->pPars->fAreaOnly ) 
                 return;
@@ -239,6 +239,11 @@ void If_ManComputeRequired( If_Man_t * p )
     {
         // get the global required times
         p->RequiredGlo = If_ManDelayMax( p, 0 );
+
+        // find new delay target
+        if ( p->pPars->nRelaxRatio && p->pPars->DelayTargetNew == 0 )
+            p->pPars->DelayTargetNew = p->RequiredGlo * (100.0 + p->pPars->nRelaxRatio) / 100.0; 
+
         // update the required times according to the target
         if ( p->pPars->DelayTarget != -1 )
         {
@@ -260,6 +265,9 @@ void If_ManComputeRequired( If_Man_t * p )
                 p->RequiredGlo = p->pPars->DelayTarget;
             }
         }
+        else if ( p->pPars->DelayTargetNew > 0 ) // relax the required times 
+            p->RequiredGlo = p->pPars->DelayTargetNew;
+
         // do not propagate required times if area minimization is requested
         if ( p->pPars->fAreaOnly ) 
             return;