ethereum.forks.amsterdam.vm.interpreter

Ethereum Virtual Machine (EVM) Interpreter.

.. contents:: Table of Contents :backlinks: none :local:

Introduction

A straightforward interpreter that executes EVM code.

STACK_DEPTH_LIMIT

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STACK_DEPTH_LIMIT = Uint(1024)

MAX_CODE_SIZE

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MAX_CODE_SIZE = 0x10000

MAX_INIT_CODE_SIZE

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MAX_INIT_CODE_SIZE = 2 * MAX_CODE_SIZE

MessageCallOutput

Output of a particular message call.

Contains the following:

  1. `gas_left`: remaining gas after execution.
  2. `refund_counter`: gas to refund after execution.
  3. `logs`: list of `Log` generated during execution.
  4. `accounts_to_delete`: Contracts which have self-destructed.
  5. `error`: The error from the execution if any.
  6. `return_data`: The output of the execution.
  7. `regular_gas_used`: Regular gas used during execution.
  8. `state_gas_used`: State gas used during execution.
  9. `state_refund`: State gas refunded by `set_delegation` for
     authorities that already existed in state. Subtracted from
     `tx_state_gas` in block accounting so `block.gas_used`
     matches the receipt `cumulative_gas_used`.
  10. `created_target_alive`: Whether a top-level creation
      transaction targeted an already-existent account.
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@final
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@dataclass
class MessageCallOutput:

gas_left

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    gas_left: Uint

refund_counter

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    refund_counter: U256

logs

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    logs: Tuple[Log, ...]

accounts_to_delete

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    accounts_to_delete: Set[Address]

error

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    error: Optional[EthereumException]

return_data

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    return_data: Bytes

state_gas_left

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    state_gas_left: Uint

regular_gas_used

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    regular_gas_used: Uint

state_gas_used

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    state_gas_used: int

state_refund

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    state_refund: Uint

created_target_alive

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    created_target_alive: bool

process_message_call

If message.target is empty then it creates a smart contract else it executes a call from the message.caller to the message.target.

Parameters

message : Transaction specific items.

Returns

output : MessageCallOutput Output of the message call

def process_message_call(message: Message) -> MessageCallOutput:
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    <snip>
133
    tx_state = message.tx_env.state
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    refund_counter = U256(0)
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    state_refund = Uint(0)
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    target_alive = False
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    if message.target == Bytes0(b""):
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        if account_deployable(tx_state, message.current_target):
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            target_alive = is_account_alive(tx_state, message.current_target)
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            evm = process_create_message(message)
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        else:
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            return MessageCallOutput(
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                gas_left=Uint(0),
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                refund_counter=U256(0),
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                logs=tuple(),
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                accounts_to_delete=set(),
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                error=AddressCollision(),
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                return_data=Bytes(b""),
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                state_gas_left=message.state_gas_reservoir,
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                regular_gas_used=message.gas,
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                state_gas_used=0,
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                state_refund=Uint(0),
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                created_target_alive=False,
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            )
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    else:
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        if message.tx_env.authorizations != ():
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            auth_state_refund, auth_regular_refund = set_delegation(message)
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            state_refund += auth_state_refund
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            refund_counter += U256(auth_regular_refund)
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        delegated_address = get_delegated_code_address(message.code)
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        if delegated_address is not None:
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            message.disable_precompiles = True
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            message.code = get_code(
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                tx_state,
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                get_account(tx_state, delegated_address).code_hash,
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            )
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            message.code_address = delegated_address
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        evm = process_message(message)
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    if evm.error:
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        logs: Tuple[Log, ...] = ()
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        accounts_to_delete = set()
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    else:
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        logs = evm.logs
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        accounts_to_delete = evm.accounts_to_delete
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        refund_counter += U256(evm.refund_counter)
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    tx_end = TransactionEnd(
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        int(message.gas) - int(evm.gas_left), evm.output, evm.error
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    )
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    evm_trace(evm, tx_end)
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    return MessageCallOutput(
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        gas_left=evm.gas_left,
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        refund_counter=refund_counter,
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        logs=logs,
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        accounts_to_delete=accounts_to_delete,
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        error=evm.error,
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        return_data=evm.output,
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        state_gas_left=evm.state_gas_left,
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        regular_gas_used=evm.regular_gas_used,
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        state_gas_used=frame_state_gas_used(evm),
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        state_refund=state_refund,
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        created_target_alive=target_alive,
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    )

process_create_message

Executes a call to create a smart contract.

Parameters

message : Transaction specific items.

Returns

evm: :py:class:~ethereum.forks.amsterdam.vm.Evm Items containing execution specific objects.

def process_create_message(message: Message) -> Evm:
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    <snip>
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    tx_state = message.tx_env.state
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    # take snapshot of state before processing the message
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    snapshot = copy_tx_state(tx_state)
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    # If the address where the account is being created has storage, it is
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    # destroyed. This can only happen in the following highly unlikely
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    # circumstances:
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    # * The address created by a `CREATE` call collides with a subsequent
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    #   `CREATE` or `CREATE2` call.
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    # * The first `CREATE` happened before Spurious Dragon and left empty
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    #   code.
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    destroy_storage(tx_state, message.current_target)
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    # In the previously mentioned edge case the preexisting storage is ignored
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    # for gas refund purposes. In order to do this we must track created
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    # accounts. This tracking is also needed to respect the constraints
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    # added to SELFDESTRUCT by EIP-6780.
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    mark_account_created(tx_state, message.current_target)
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    increment_nonce(tx_state, message.current_target)
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    evm = process_message(message)
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    if not evm.error:
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        contract_code = evm.output
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        try:
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            if len(contract_code) > 0:
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                if contract_code[0] == 0xEF:
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                    raise InvalidContractPrefix
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            if len(contract_code) > MAX_CODE_SIZE:
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                raise OutOfGasError
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            # Hash cost for computing keccak256 of deployed bytecode
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            code_hash_gas = (
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                GasCosts.OPCODE_KECCAK256_PER_WORD
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                * ceil32(ulen(contract_code))
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                // Uint(32)
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            )
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            charge_gas(evm, code_hash_gas)
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            code_deposit_state_gas = (
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                ulen(contract_code) * StateGasCosts.COST_PER_STATE_BYTE
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            )
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            charge_state_gas(evm, code_deposit_state_gas)
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        except ExceptionalHalt as error:
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            restore_tx_state(tx_state, snapshot)
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            refill_frame_state_gas(evm)
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            evm.regular_gas_used += evm.gas_left
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            evm.gas_left = Uint(0)
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            evm.output = b""
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            evm.error = error
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        else:
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            set_code(tx_state, message.current_target, contract_code)
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    else:
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        restore_tx_state(tx_state, snapshot)
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    return evm

process_message

Move ether and execute the relevant code.

Parameters

message : Transaction specific items.

Returns

evm: :py:class:~ethereum.forks.amsterdam.vm.Evm Items containing execution specific objects

def process_message(message: Message) -> Evm:
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    <snip>
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    tx_state = message.tx_env.state
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    if message.depth > STACK_DEPTH_LIMIT:
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        raise StackDepthLimitError("Stack depth limit reached")
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    code = message.code
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    valid_jump_destinations = get_valid_jump_destinations(code)
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    evm = Evm(
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        pc=Uint(0),
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        stack=[],
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        memory=bytearray(),
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        code=code,
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        gas_left=message.gas,
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        state_gas_left=message.state_gas_reservoir,
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        valid_jump_destinations=valid_jump_destinations,
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        logs=(),
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        refund_counter=0,
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        running=True,
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        message=message,
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        output=b"",
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        accounts_to_delete=set(),
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        return_data=b"",
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        error=None,
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        accessed_addresses=message.accessed_addresses,
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        accessed_storage_keys=message.accessed_storage_keys,
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    )
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    snapshot = copy_tx_state(tx_state)
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    # Execute message code and handle errors
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    try:
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        if message.depth == Uint(0) and message.target != Bytes0(b""):
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            recipient = message.current_target
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            if message.value > U256(0) and not is_account_alive(
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                tx_state, recipient
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            ):
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                charge_state_gas(evm, StateGasCosts.NEW_ACCOUNT)
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            recipient_code = get_code(
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                tx_state, get_account(tx_state, recipient).code_hash
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            )
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            delegated_address = get_delegated_code_address(recipient_code)
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            if delegated_address is not None:
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                charge_gas(evm, GasCosts.COLD_ACCOUNT_ACCESS)
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                evm.accessed_addresses.add(delegated_address)
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        if message.should_transfer_value and message.value != 0:
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            move_ether(
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                tx_state,
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                message.caller,
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                message.current_target,
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                message.value,
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            )
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            if message.caller != message.current_target:
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                emit_transfer_log(
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                    evm,
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                    message.caller,
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                    message.current_target,
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                    message.value,
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                )
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        if evm.message.code_address in PRE_COMPILED_CONTRACTS:
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            if not message.disable_precompiles:
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                evm_trace(evm, PrecompileStart(evm.message.code_address))
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                PRE_COMPILED_CONTRACTS[evm.message.code_address](evm)
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                evm_trace(evm, PrecompileEnd())
348
        else:
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            while evm.running and evm.pc < ulen(evm.code):
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                try:
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                    op = Ops(evm.code[evm.pc])
352
                except ValueError as e:
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                    raise InvalidOpcode(evm.code[evm.pc]) from e
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                evm_trace(evm, OpStart(op))
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                op_implementation[op](evm)
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                evm_trace(evm, OpEnd())
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            evm_trace(evm, EvmStop(Ops.STOP))
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    except ExceptionalHalt as error:
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        evm_trace(evm, OpException(error))
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        refill_frame_state_gas(evm)
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        evm.regular_gas_used += evm.gas_left
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        evm.gas_left = Uint(0)
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        evm.output = b""
367
        evm.error = error
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    except Revert as error:
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        evm_trace(evm, OpException(error))
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        refill_frame_state_gas(evm)
371
        evm.error = error
372
373
    if evm.error:
374
        restore_tx_state(tx_state, snapshot)
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    return evm