ethereum.constantinople.vm.instructions.environment

Ethereum Virtual Machine (EVM) Environmental Instructions ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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

Introduction

Implementations of the EVM environment related instructions.

address

Pushes the address of the current executing account to the stack.

Parameters

evm : The current EVM frame.

def address(​evm: Evm​) -> None:
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    """
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    Pushes the address of the current executing account to the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_BASE)
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    # OPERATION
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    push(evm.stack, U256.from_be_bytes(evm.message.current_target))
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    # PROGRAM COUNTER
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    evm.pc += 1

balance

Pushes the balance of the given account onto the stack.

Parameters

evm : The current EVM frame.

def balance(​evm: Evm​) -> None:
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    """
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    Pushes the balance of the given account onto the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    address = to_address(pop(evm.stack))
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    # GAS
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    charge_gas(evm, GAS_BALANCE)
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    # OPERATION
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    # Non-existent accounts default to EMPTY_ACCOUNT, which has balance 0.
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    balance = get_account(evm.env.state, address).balance
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    push(evm.stack, balance)
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    # PROGRAM COUNTER
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    evm.pc += 1

origin

Pushes the address of the original transaction sender to the stack. The origin address can only be an EOA.

Parameters

evm : The current EVM frame.

def origin(​evm: Evm​) -> None:
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    """
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    Pushes the address of the original transaction sender to the stack.
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    The origin address can only be an EOA.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_BASE)
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    # OPERATION
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    push(evm.stack, U256.from_be_bytes(evm.env.origin))
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    # PROGRAM COUNTER
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    evm.pc += 1

caller

Pushes the address of the caller onto the stack.

Parameters

evm : The current EVM frame.

def caller(​evm: Evm​) -> None:
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    """
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    Pushes the address of the caller onto the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_BASE)
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    # OPERATION
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    push(evm.stack, U256.from_be_bytes(evm.message.caller))
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    # PROGRAM COUNTER
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    evm.pc += 1

callvalue

Push the value (in wei) sent with the call onto the stack.

Parameters

evm : The current EVM frame.

def callvalue(​evm: Evm​) -> None:
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    """
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    Push the value (in wei) sent with the call onto the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_BASE)
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    # OPERATION
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    push(evm.stack, evm.message.value)
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    # PROGRAM COUNTER
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    evm.pc += 1

calldataload

Push a word (32 bytes) of the input data belonging to the current environment onto the stack.

Parameters

evm : The current EVM frame.

def calldataload(​evm: Evm​) -> None:
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    """
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    Push a word (32 bytes) of the input data belonging to the current
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    environment onto the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    start_index = pop(evm.stack)
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    # GAS
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    charge_gas(evm, GAS_VERY_LOW)
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    # OPERATION
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    value = buffer_read(evm.message.data, start_index, U256(32))
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    push(evm.stack, U256.from_be_bytes(value))
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    # PROGRAM COUNTER
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    evm.pc += 1

calldatasize

Push the size of input data in current environment onto the stack.

Parameters

evm : The current EVM frame.

def calldatasize(​evm: Evm​) -> None:
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    """
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    Push the size of input data in current environment onto the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_BASE)
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    # OPERATION
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    push(evm.stack, U256(len(evm.message.data)))
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    # PROGRAM COUNTER
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    evm.pc += 1

calldatacopy

Copy a portion of the input data in current environment to memory.

This will also expand the memory, in case that the memory is insufficient to store the data.

Parameters

evm : The current EVM frame.

def calldatacopy(​evm: Evm​) -> None:
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    """
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    Copy a portion of the input data in current environment to memory.
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    This will also expand the memory, in case that the memory is insufficient
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    to store the data.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    memory_start_index = pop(evm.stack)
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    data_start_index = pop(evm.stack)
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    size = pop(evm.stack)
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    # GAS
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    words = ceil32(Uint(size)) // 32
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    copy_gas_cost = GAS_COPY * words
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    extend_memory = calculate_gas_extend_memory(
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        evm.memory, [(memory_start_index, size)]
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    )
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    charge_gas(evm, GAS_VERY_LOW + copy_gas_cost + extend_memory.cost)
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    # OPERATION
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    evm.memory += b"\x00" * extend_memory.expand_by
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    value = buffer_read(evm.message.data, data_start_index, size)
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    memory_write(evm.memory, memory_start_index, value)
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    # PROGRAM COUNTER
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    evm.pc += 1

codesize

Push the size of code running in current environment onto the stack.

Parameters

evm : The current EVM frame.

def codesize(​evm: Evm​) -> None:
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    """
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    Push the size of code running in current environment onto the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_BASE)
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    # OPERATION
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    push(evm.stack, U256(len(evm.code)))
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    # PROGRAM COUNTER
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    evm.pc += 1

codecopy

Copy a portion of the code in current environment to memory.

This will also expand the memory, in case that the memory is insufficient to store the data.

Parameters

evm : The current EVM frame.

def codecopy(​evm: Evm​) -> None:
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    """
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    Copy a portion of the code in current environment to memory.
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    This will also expand the memory, in case that the memory is insufficient
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    to store the data.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    memory_start_index = pop(evm.stack)
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    code_start_index = pop(evm.stack)
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    size = pop(evm.stack)
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    # GAS
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    words = ceil32(Uint(size)) // 32
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    copy_gas_cost = GAS_COPY * words
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    extend_memory = calculate_gas_extend_memory(
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        evm.memory, [(memory_start_index, size)]
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    )
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    charge_gas(evm, GAS_VERY_LOW + copy_gas_cost + extend_memory.cost)
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    # OPERATION
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    evm.memory += b"\x00" * extend_memory.expand_by
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    value = buffer_read(evm.code, code_start_index, size)
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    memory_write(evm.memory, memory_start_index, value)
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    # PROGRAM COUNTER
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    evm.pc += 1

gasprice

Push the gas price used in current environment onto the stack.

Parameters

evm : The current EVM frame.

def gasprice(​evm: Evm​) -> None:
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    """
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    Push the gas price used in current environment onto the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_BASE)
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    # OPERATION
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    push(evm.stack, U256(evm.env.gas_price))
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    # PROGRAM COUNTER
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    evm.pc += 1

extcodesize

Push the code size of a given account onto the stack.

Parameters

evm : The current EVM frame.

def extcodesize(​evm: Evm​) -> None:
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    """
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    Push the code size of a given account onto the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    address = to_address(pop(evm.stack))
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    # GAS
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    charge_gas(evm, GAS_EXTERNAL)
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    # OPERATION
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    # Non-existent accounts default to EMPTY_ACCOUNT, which has empty code.
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    codesize = U256(len(get_account(evm.env.state, address).code))
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    push(evm.stack, codesize)
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    # PROGRAM COUNTER
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    evm.pc += 1

extcodecopy

Copy a portion of an account's code to memory.

Parameters

evm : The current EVM frame.

def extcodecopy(​evm: Evm​) -> None:
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    """
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    Copy a portion of an account's code to memory.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    address = to_address(pop(evm.stack))
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    memory_start_index = pop(evm.stack)
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    code_start_index = pop(evm.stack)
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    size = pop(evm.stack)
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    # GAS
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    words = ceil32(Uint(size)) // 32
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    copy_gas_cost = GAS_COPY * words
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    extend_memory = calculate_gas_extend_memory(
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        evm.memory, [(memory_start_index, size)]
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    )
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    charge_gas(evm, GAS_EXTERNAL + copy_gas_cost + extend_memory.cost)
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    # OPERATION
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    evm.memory += b"\x00" * extend_memory.expand_by
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    code = get_account(evm.env.state, address).code
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    value = buffer_read(code, code_start_index, size)
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    memory_write(evm.memory, memory_start_index, value)
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    # PROGRAM COUNTER
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    evm.pc += 1

returndatasize

Pushes the size of the return data buffer onto the stack.

Parameters

evm : The current EVM frame.

def returndatasize(​evm: Evm​) -> None:
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    """
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    Pushes the size of the return data buffer onto the stack.
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    pass
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    # GAS
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    charge_gas(evm, GAS_BASE)
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    # OPERATION
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    push(evm.stack, U256(len(evm.return_data)))
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    # PROGRAM COUNTER
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    evm.pc += 1

returndatacopy

Copies data from the return data buffer code to memory

Parameters

evm : The current EVM frame.

def returndatacopy(​evm: Evm​) -> None:
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    """
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    Copies data from the return data buffer code to memory
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    memory_start_index = pop(evm.stack)
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    return_data_start_position = pop(evm.stack)
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    size = pop(evm.stack)
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    # GAS
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    words = ceil32(Uint(size)) // 32
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    copy_gas_cost = GAS_RETURN_DATA_COPY * words
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    extend_memory = calculate_gas_extend_memory(
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        evm.memory, [(memory_start_index, size)]
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    )
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    charge_gas(evm, GAS_VERY_LOW + copy_gas_cost + extend_memory.cost)
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    if Uint(return_data_start_position) + Uint(size) > len(evm.return_data):
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        raise OutOfBoundsRead
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    evm.memory += b"\x00" * extend_memory.expand_by
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    value = evm.return_data[
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        return_data_start_position : return_data_start_position + size
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    ]
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    memory_write(evm.memory, memory_start_index, value)
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    # PROGRAM COUNTER
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    evm.pc += 1

extcodehash

Returns the keccak256 hash of a contract’s bytecode Parameters

evm : The current EVM frame.

def extcodehash(​evm: Evm​) -> None:
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    """
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    Returns the keccak256 hash of a contract’s bytecode
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    Parameters
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    ----------
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    evm :
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        The current EVM frame.
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    """
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    # STACK
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    address = to_address(pop(evm.stack))
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    # GAS
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    charge_gas(evm, GAS_CODE_HASH)
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    # OPERATION
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    account = get_account(evm.env.state, address)
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    if account == EMPTY_ACCOUNT:
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        codehash = U256(0)
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    else:
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        codehash = U256.from_be_bytes(keccak256(account.code))
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    push(evm.stack, codehash)
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    # PROGRAM COUNTER
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    evm.pc += 1