Update adaptivepow to handle variable block times

src/komodo_bitcoind.h

@@ -1416,6 +1416,29 @@ uint32_t komodo_stakehash(uint256 *hashp,char *address,uint8_t *hashbuf,uint256
     return(addrhash.uints[0]);
 }
 
+arith_uint256 komodo_adaptivepow_target(int32_t height,arith_uint256 bnTarget,uint32_t nTime)
+{
+    arith_uint256 origtarget,easy; int32_t diff,mult; bool fNegative,fOverflow; CBlockIndex *tipindex;
+    if ( height > 10 && (tipindex= komodo_chainactive(height - 1)) != 0 )
+    {
+        diff = (nTime - tipindex->GetMedianTimePast());
+        if ( diff > 20 * ASSETCHAINS_BLOCKTIME )
+        {
+            mult = diff - 19 * ASSETCHAINS_BLOCKTIME;
+            mult = (mult / ASSETCHAINS_BLOCKTIME) * ASSETCHAINS_BLOCKTIME + ASSETCHAINS_BLOCKTIME / 3;
+            origtarget = bnTarget;
+            bnTarget = bnTarget * arith_uint256(mult * mult);
+            easy.SetCompact(KOMODO_MINDIFF_NBITS,&fNegative,&fOverflow);
+            if ( bnTarget < origtarget || bnTarget > easy ) // deal with overflow
+            {
+                bnTarget = easy;
+                fprintf(stderr,"miner overflowed, set to mindiff\n");
+            } else fprintf(stderr,"miner elapsed %d, adjust by factor of %d\n",diff,mult);
+        }
+    }
+    return(bnTarget);
+}
+
 arith_uint256 komodo_PoWtarget(int32_t *percPoSp,arith_uint256 target,int32_t height,int32_t goalperc)
 {
     int32_t oldflag = 0,dispflag = 0;

src/komodo_defs.h

@@ -337,6 +337,7 @@ int32_t komodo_priceget(int64_t *buf64,int32_t ind,int32_t height,int32_t numblo
 uint64_t komodo_accrued_interest(int32_t *txheightp,uint32_t *locktimep,uint256 hash,int32_t n,int32_t checkheight,uint64_t checkvalue,int32_t tipheight);
 int32_t komodo_currentheight();
 int32_t komodo_notarized_bracket(struct notarized_checkpoint *nps[2],int32_t height);
+arith_uint256 komodo_adaptivepow_target(int32_t height,arith_uint256 bnTarget,uint32_t nTime);
 
 uint256 Parseuint256(const char *hexstr);
 

src/miner.cpp

@@ -1448,22 +1448,8 @@ void static BitcoinMiner_noeq()
                 LogPrintf("Block %d : PoS %d%% vs target %d%%\n", Mining_height, percPoS, (int32_t)ASSETCHAINS_STAKED);
             }
             else if ( ASSETCHAINS_ADAPTIVEPOW != 0 && ASSETCHAINS_STAKED == 0 )
-            {
-                arith_uint256 origtarget; bool fNegative,fOverflow;
-                uint32_t elapsed = (pblock->nTime - komodo_heightstamp(Mining_height-1));
-                if ( elapsed > 777 )
-                {
-                    elapsed -= 777;
-                    origtarget = HASHTarget;
-                    HASHTarget_POW = HASHTarget * arith_uint256(elapsed * elapsed);
-                    if ( HASHTarget_POW < origtarget ) // deal with underflow
-                    {
-                        HASHTarget_POW.SetCompact(KOMODO_MINDIFF_NBITS,&fNegative,&fOverflow);
-                        fprintf(stderr,"miner underflowed, set to mindiff\n");
-                    } else fprintf(stderr,"miner elapsed %d, adjust by factor of %d\n",elapsed+777,elapsed*elapsed);
-                }
-            }
-
+                HASHTarget_POW = komodo_adaptivepow_target(height,HASHTarget,pblock->nTime);
+            
             while (true)
             {
                 arith_uint256 arNonce = UintToArith256(pblock->nNonce);

src/pow.cpp

@@ -454,21 +454,7 @@ bool CheckProofOfWork(const CBlockHeader &blkHeader, uint8_t *pubkey33, int32_t
         bnTarget.SetCompact(KOMODO_MINDIFF_NBITS,&fNegative,&fOverflow);
     }
     else if ( ASSETCHAINS_ADAPTIVEPOW != 0 && ASSETCHAINS_STAKED == 0 )
-    {
-        arith_uint256 origtarget;
-        uint32_t elapsed = (blkHeader.nTime - komodo_heightstamp(height-1));
-        if ( elapsed > 777 )
-        {
-            elapsed -= 777;
-            origtarget = bnTarget;
-            bnTarget = bnTarget * arith_uint256(elapsed * elapsed);
-            if ( bnTarget < origtarget ) // deal with underflow
-            {
-                bnTarget.SetCompact(KOMODO_MINDIFF_NBITS,&fNegative,&fOverflow);
-                fprintf(stderr,"underflowed, set to mindiff\n");
-            } else fprintf(stderr,"elapsed %d, adjust by factor of %d\n",elapsed+777,elapsed*elapsed);
-        }
-    }
+        bnTarget = komodo_adaptivepow_target(height,bnTarget,blkHeader.nTime);
     // Check proof of work matches claimed amount
     if ( UintToArith256(hash = blkHeader.GetHash()) > bnTarget && !blkHeader.IsVerusPOSBlock() )
     {