Initial reference implementation of EIP1789

Untested.
Per ethereum-funding/blockrewardsfunding#6.

eth/vm/base.py

@@ -244,6 +244,30 @@ def get_block_reward() -> int:
         """
         raise NotImplementedError("VM classes must implement this method")
 
+    @staticmethod
+    @abstractmethod
+    def get_devfund_reward() -> int:
+        """
+        Return the amount in **wei** that should be given to the dev fund as a reward
+        for this block.
+
+          .. note::
+            This is an abstract method that must be implemented in subclasses
+        """
+        raise NotImplementedError("VM classes must implement this method")
+
+    @staticmethod
+    @abstractmethod
+    def get_devfund_beneficiary() -> Address:
+        """
+        Return the address that should be given to the dev fund reward
+        for this block.
+
+          .. note::
+            This is an abstract method that must be implemented in subclasses
+        """
+        raise NotImplementedError("VM classes must implement this method")
+
     @classmethod
     @abstractmethod
     def get_nephew_reward(cls) -> int:

eth/vm/forks/petersburg/__init__.py

@@ -1,3 +1,7 @@
+from eth_typing import (
+    Address
+)
+
 from typing import (  # noqa: F401
     Type,
 )
@@ -10,7 +14,7 @@
 from eth.vm.state import BaseState  # noqa: F401
 
 from .blocks import PetersburgBlock
-from .constants import EIP1234_BLOCK_REWARD
+from .constants import EIP1234_BLOCK_REWARD, EIP1789_DEVFUND_REWARD, EIP1789_DEVFUND_BENEFICIARY
 from .headers import (
     compute_petersburg_difficulty,
     configure_petersburg_header,
@@ -36,3 +40,30 @@ class PetersburgVM(ByzantiumVM):
     @staticmethod
     def get_block_reward() -> int:
         return EIP1234_BLOCK_REWARD
+
+    @staticmethod
+    def get_devfund_reward() -> int:
+        return EIP1789_DEVFUND_REWARD
+
+    @staticmethod
+    def get_devfund_beneficiary() -> Address:
+        return EIP1789_DEVFUND_BENEFICIARY
+
+    #
+    # Finalization
+    #
+    def finalize_block(self, block: BaseBlock) -> BaseBlock:
+        """
+        Perform any finalization steps like awarding the block mining reward.
+        """
+        devfund_reward = self.get_devfund_reward()
+        devfund_beneficiary = self.get_devfund_beneficiary()
+
+        self.state.account_db.delta_balance(devfund_beneficiary, devfund_reward)
+        self.logger.debug(
+            "DEVDFUND REWARD: %s -> %s",
+            devfund_reward,
+            devfund_beneficiary,
+        )
+
+        return super(block)

eth/vm/forks/petersburg/constants.py

@@ -1,6 +1,13 @@
 from eth_utils import denoms
+from eth_typing import (
+    Address
+)
 
 
 GAS_EXTCODEHASH_EIP1052 = 400
 
 EIP1234_BLOCK_REWARD = 2 * denoms.ether
+
+# Currently no reward is issued.
+EIP1789_DEVFUND_REWARD = 0
+EIP1789_DEVFUND_BENEFICIARY = Address(b'')