Added Constantinople difficulty bomb delay

header.js

@@ -116,7 +116,7 @@ BlockHeader.prototype.canonicalDifficulty = function (parentBlock) {
  var dif
 
  if (this._common.hardforkGteHardfork(hardfork, 'byzantium')) {
- // max((2 if len(parent.uncles) else 1) - ((timestamp - parent.timestamp) // 9), -99)
+ // max((2 if len(parent.uncles) else 1) - ((timestamp - parent.timestamp) // 9), -99) (EIP100)
  var uncleAddend = parentBlock.header.uncleHash.equals(utils.SHA3_RLP_ARRAY) ? 1 : 2
  a = blockTs.sub(parentTs).idivn(9).ineg().iaddn(uncleAddend)
  cutoff = new BN(-99)
@@ -125,8 +125,16 @@ BlockHeader.prototype.canonicalDifficulty = function (parentBlock) {
  a = cutoff
  }
  dif = parentDif.add(offset.mul(a))
+ }
 
- // Byzantium difficulty bomb delay
+ if (this._common.hardforkGteHardfork(hardfork, 'constantinople')) {
+ // Constantinople difficulty bomb delay (EIP1234)
+ num.isubn(5000000)
+ if (num.ltn(0)) {
+ num = new BN(0)
+ }
+ } else if (this._common.hardforkGteHardfork(hardfork, 'byzantium')) {
+ // Byzantium difficulty bomb delay (EIP649)
  num.isubn(3000000)
  if (num.ltn(0)) {
  num = new BN(0)