Implement EIP-5920

Author: gurukamath

src/ethereum/osaka/utils/address.py

@@ -22,6 +22,9 @@
 from ethereum.utils.byte import left_pad_zero_bytes
 
 from ..fork_types import Address
+from ..vm.exceptions import InvalidParameter
+
+MAX_ADDRESS = Address(b"\xff" * 20)
 
 
 def to_address(data: Union[Uint, U256]) -> Address:
@@ -41,6 +44,31 @@ def to_address(data: Union[Uint, U256]) -> Address:
     return Address(data.to_be_bytes32()[-20:])
 
 
+def to_address_without_mask(data: U256) -> Address:
+    """
+    Convert a Uint or U256 value to a valid address (20 bytes).
+    Raises a `ValueError` if the data is larger than `MAX_ADDRESS
+
+    Parameters
+    ----------
+    data :
+        The string to be converted to bytes.
+
+    Raises
+    ------
+    InvalidParameter
+        If `data` is larger than `MAX_ADDRESS`.
+
+    Returns
+    -------
+    address : `Address`
+        The obtained address.
+    """
+    if data > U256.from_be_bytes(MAX_ADDRESS):
+        raise InvalidParameter("Address is too large")
+    return Address(data.to_be_bytes32()[-20:])
+
+
 def compute_contract_address(address: Address, nonce: Uint) -> Address:
     """
     Computes address of the new account that needs to be created.

src/ethereum/osaka/vm/instructions/__init__.py

@@ -210,6 +210,7 @@ class Ops(enum.Enum):
     DELEGATECALL = 0xF4
     CREATE2 = 0xF5
     STATICCALL = 0xFA
+    PAY = 0xFC
     REVERT = 0xFD
     SELFDESTRUCT = 0xFF
 
@@ -361,6 +362,7 @@ class Ops(enum.Enum):
     Ops.DELEGATECALL: system_instructions.delegatecall,
     Ops.SELFDESTRUCT: system_instructions.selfdestruct,
     Ops.STATICCALL: system_instructions.staticcall,
+    Ops.PAY: system_instructions.pay,
     Ops.REVERT: system_instructions.revert,
     Ops.CREATE2: system_instructions.create2,
 }

src/ethereum/osaka/vm/instructions/system.py

@@ -31,6 +31,7 @@
     compute_contract_address,
     compute_create2_contract_address,
     to_address,
+    to_address_without_mask,
 )
 from ...vm.eoa_delegation import access_delegation
 from .. import (
@@ -742,3 +743,52 @@ def revert(evm: Evm) -> None:
 
     # PROGRAM COUNTER
     pass
+
+
+def pay(evm: Evm) -> None:
+    """
+    Transfer ether to an account.
+
+    Parameters
+    ----------
+    evm :
+        The current EVM frame.
+    """
+    # STACK
+    to = to_address_without_mask(pop(evm.stack))
+    value = pop(evm.stack)
+
+    # GAS
+    if to in evm.accessed_addresses:
+        access_gas_cost = GAS_WARM_ACCESS
+    else:
+        evm.accessed_addresses.add(to)
+        access_gas_cost = GAS_COLD_ACCOUNT_ACCESS
+
+    create_gas_cost = (
+        Uint(0)
+        if is_account_alive(evm.message.block_env.state, to) or value == 0
+        else GAS_NEW_ACCOUNT
+    )
+
+    transfer_gas_cost = Uint(0) if value == U256(0) else GAS_CALL_VALUE
+
+    charge_gas(evm, access_gas_cost + create_gas_cost + transfer_gas_cost)
+
+    # OPERATION
+    if evm.message.is_static:
+        raise WriteInStaticContext("Cannot PAY in static context")
+
+    try:
+        move_ether(
+            evm.message.block_env.state,
+            evm.message.current_target,
+            to,
+            value,
+        )
+        push(evm.stack, U256(1))
+    except AssertionError:
+        push(evm.stack, U256(0))
+
+    # PROGRAM COUNTER
+    evm.pc += Uint(1)