implement EIP 1884 stub

nimbus/vm/interpreter/gas_costs.nim

@@ -604,10 +604,17 @@ func spuriousGasFees(previous_fees: GasFeeSchedule): GasFeeSchedule =
   result = previous_fees
   result[GasExpByte]      = 50
 
+func istanbulGasFees(previous_fees: GasFeeSchedule): GasFeeSchedule =
+  # https://eips.ethereum.org/EIPS/eip-1884
+  result[GasSload]        = 800
+  result[GasExtCodeHash]  = 700
+  result[GasBalance]      = 700
+
 const
   HomesteadGasFees = BaseGasFees.homesteadGasFees
   TangerineGasFees = HomesteadGasFees.tangerineGasFees
   SpuriousGasFees = TangerineGasFees.spuriousGasFees
+  IstanbulGasFees = SpuriousGasFees.istanbulGasFees
 
   gasFees*: array[Fork, GasFeeSchedule] = [
     FkFrontier: BaseGasFees,
@@ -618,7 +625,7 @@ const
     FkSpurious: SpuriousGasFees,
     FkByzantium: SpuriousGasFees,
     FkConstantinople: SpuriousGasFees,
-    FkIstanbul: SpuriousGasFees
+    FkIstanbul: IstanbulGasFees
   ]
 
 

nimbus/vm/interpreter/opcode_values.nim

@@ -80,6 +80,7 @@ fill_enum_holes:
       GasLimit =       0x45, # Get the block's gas limit.
 
       ChainID =        0x46, # Get current chain’s EIP-155 unique identifier.
+      SelfBalance =    0x47, # Get current contract's balance.
 
       # 50s: Stack, Memory, Storage and Flow Operations
       Pop =            0x50, # Remove item from stack.

nimbus/vm/interpreter/opcodes_impl.nim

@@ -377,6 +377,11 @@ op chainID, inline = true:
   # TODO: this is a stub
   push: 0
 
+op selfBalance, inline = true:
+  ## 0x47, Get current contract's balance.
+  # TODO: this is a stub
+  push: 0
+
 # ##########################################
 # 50s: Stack, Memory, Storage and Flow Operations
 

nimbus/vm/interpreter_dispatch.nim

@@ -218,6 +218,7 @@ let ConstantinopleOpDispatch {.compileTime.}: array[Op, NimNode] = genConstantin
 proc genIstanbulJumpTable(ops: array[Op, NimNode]): array[Op, NimNode] {.compileTime.} =
   result = ops
   result[ChainID] = newIdentNode "chainID"
+  result[SelfBalance] = newIdentNode "selfBalance"
 
 let IstanbulOpDispatch {.compileTime.}: array[Op, NimNode] = genIstanbulJumpTable(ConstantinopleOpDispatch)