Ethereum Virtual Machine (EVM) Gas

Table of Contents

Introduction

EVM gas constants and calculators.

Module Contents

Classes

`ExtendMemory`	Define the parameters for memory extension in opcodes
`MessageCallGas`	Define the gas cost and stipend for executing the call opcodes.

Functions

`charge_gas`	Subtracts amount from evm.gas_left.
`calculate_memory_gas_cost`	Calculates the gas cost for allocating memory
`calculate_gas_extend_memory`	Calculates the gas amount to extend memory
`calculate_message_call_gas`	Calculates the MessageCallGas (cost and stipend) for
`max_message_call_gas`	Calculates the maximum gas that is allowed for making a message call

Module Details

GAS_JUMPDEST

GAS_JUMPDEST

GAS_JUMPDEST = Uint(1)

GAS_BASE

GAS_BASE

GAS_BASE = Uint(2)

GAS_VERY_LOW

GAS_VERY_LOW

GAS_VERY_LOW = Uint(3)

GAS_SLOAD

GAS_SLOAD

GAS_SLOAD = Uint(200)

GAS_STORAGE_SET

GAS_STORAGE_SET

GAS_STORAGE_SET = Uint(20000)

GAS_STORAGE_UPDATE

GAS_STORAGE_UPDATE

GAS_STORAGE_UPDATE = Uint(5000)

GAS_STORAGE_CLEAR_REFUND

GAS_STORAGE_CLEAR_REFUND

GAS_STORAGE_CLEAR_REFUND = Uint(15000)

GAS_LOW

GAS_LOW

GAS_LOW = Uint(5)

GAS_MID

GAS_MID

GAS_MID = Uint(8)

GAS_HIGH

GAS_HIGH

GAS_HIGH = Uint(10)

GAS_EXPONENTIATION

GAS_EXPONENTIATION

GAS_EXPONENTIATION = Uint(10)

GAS_EXPONENTIATION_PER_BYTE

GAS_EXPONENTIATION_PER_BYTE

GAS_EXPONENTIATION_PER_BYTE = Uint(50)

GAS_MEMORY

GAS_MEMORY

GAS_MEMORY = Uint(3)

GAS_KECCAK256

GAS_KECCAK256

GAS_KECCAK256 = Uint(30)

GAS_KECCAK256_WORD

GAS_KECCAK256_WORD

GAS_KECCAK256_WORD = Uint(6)

GAS_COPY

GAS_COPY

GAS_COPY = Uint(3)

GAS_BLOCK_HASH

GAS_BLOCK_HASH

GAS_BLOCK_HASH = Uint(20)

GAS_EXTERNAL

GAS_EXTERNAL

GAS_EXTERNAL = Uint(700)

GAS_BALANCE

GAS_BALANCE

GAS_BALANCE = Uint(400)

GAS_LOG

GAS_LOG

GAS_LOG = Uint(375)

GAS_LOG_DATA

GAS_LOG_DATA

GAS_LOG_DATA = Uint(8)

GAS_LOG_TOPIC

GAS_LOG_TOPIC

GAS_LOG_TOPIC = Uint(375)

GAS_CREATE

GAS_CREATE

GAS_CREATE = Uint(32000)

GAS_CODE_DEPOSIT

GAS_CODE_DEPOSIT

GAS_CODE_DEPOSIT = Uint(200)

GAS_ZERO

GAS_ZERO

GAS_ZERO = Uint(0)

GAS_CALL

GAS_CALL

GAS_CALL = Uint(700)

GAS_NEW_ACCOUNT

GAS_NEW_ACCOUNT

GAS_NEW_ACCOUNT = Uint(25000)

GAS_CALL_VALUE

GAS_CALL_VALUE

GAS_CALL_VALUE = Uint(9000)

GAS_CALL_STIPEND

GAS_CALL_STIPEND

GAS_CALL_STIPEND = Uint(2300)

GAS_SELF_DESTRUCT

GAS_SELF_DESTRUCT

GAS_SELF_DESTRUCT = Uint(5000)

GAS_SELF_DESTRUCT_NEW_ACCOUNT

GAS_SELF_DESTRUCT_NEW_ACCOUNT

GAS_SELF_DESTRUCT_NEW_ACCOUNT = Uint(25000)

REFUND_SELF_DESTRUCT

REFUND_SELF_DESTRUCT

REFUND_SELF_DESTRUCT = Uint(24000)

GAS_ECRECOVER

GAS_ECRECOVER

GAS_ECRECOVER = Uint(3000)

GAS_SHA256

GAS_SHA256

GAS_SHA256 = Uint(60)

GAS_SHA256_WORD

GAS_SHA256_WORD

GAS_SHA256_WORD = Uint(12)

GAS_RIPEMD160

GAS_RIPEMD160

GAS_RIPEMD160 = Uint(600)

GAS_RIPEMD160_WORD

GAS_RIPEMD160_WORD

GAS_RIPEMD160_WORD = Uint(120)

GAS_IDENTITY

GAS_IDENTITY

GAS_IDENTITY = Uint(15)

GAS_IDENTITY_WORD

GAS_IDENTITY_WORD

GAS_IDENTITY_WORD = Uint(3)

GAS_RETURN_DATA_COPY

GAS_RETURN_DATA_COPY

GAS_RETURN_DATA_COPY = Uint(3)

ExtendMemory

Define the parameters for memory extension in opcodes

cost: ethereum.base_types.Uint: The gas required to perform the extension
expand_by: ethereum.base_types.Uint: The size by which the memory will be extended

class ExtendMemory

cost :ethereum.base_types.Uint

expand_by :ethereum.base_types.Uint

MessageCallGas

Define the gas cost and stipend for executing the call opcodes.

cost: ethereum.base_types.Uint: The non-refundable portion of gas reserved for executing the call opcode.
stipend: ethereum.base_types.Uint: The portion of gas available to sub-calls that is refundable if not consumed

class MessageCallGas

cost :ethereum.base_types.Uint

stipend :ethereum.base_types.Uint

charge_gas

charge_gas(evm, amount)

Subtracts amount from evm.gas_left.

Parameters

evm – The current EVM.
amount – The amount of gas the current operation requires.

def charge_gas(evm: Evm, amount: Uint) -> None:
    if evm.gas_left < amount:
        raise OutOfGasError
    else:
        evm.gas_left -= U256(amount)

calculate_memory_gas_cost

calculate_memory_gas_cost(size_in_bytes)

Calculates the gas cost for allocating memory to the smallest multiple of 32 bytes, such that the allocated size is at least as big as the given size.

Parameters: size_in_bytes – The size of the data in bytes.
Returns: total_gas_cost – The gas cost for storing data in memory.
Return type: ethereum.base_types.Uint

def calculate_memory_gas_cost(size_in_bytes: Uint) -> Uint:
    size_in_words = ceil32(size_in_bytes) // 32
    linear_cost = size_in_words * GAS_MEMORY
    quadratic_cost = size_in_words**2 // 512
    total_gas_cost = linear_cost + quadratic_cost
    try:
        return total_gas_cost
    except ValueError:
        raise OutOfGasError

calculate_gas_extend_memory

calculate_gas_extend_memory(memory, extensions)

Calculates the gas amount to extend memory

Parameters

memory – Memory contents of the EVM.
extensions – List of extensions to be made to the memory. Consists of a tuple of start position and size.

Returns

extend_memory

Return type

ExtendMemory

def calculate_gas_extend_memory(
    memory: bytearray, extensions: List[Tuple[U256, U256]]
) -> ExtendMemory:
    size_to_extend = Uint(0)
    to_be_paid = Uint(0)
    current_size = Uint(len(memory))
    for start_position, size in extensions:
        if size == 0:
            continue
        before_size = ceil32(current_size)
        after_size = ceil32(Uint(start_position) + Uint(size))
        if after_size <= before_size:
            continue

        size_to_extend += after_size - before_size
        already_paid = calculate_memory_gas_cost(before_size)
        total_cost = calculate_memory_gas_cost(after_size)
        to_be_paid += total_cost - already_paid

        current_size = after_size

    return ExtendMemory(to_be_paid, size_to_extend)

calculate_message_call_gas

calculate_message_call_gas(value, gas, gas_left, memory_cost, extra_gas, call_stipend=GAS_CALL_STIPEND)

Calculates the MessageCallGas (cost and stipend) for executing call Opcodes.

Parameters

value – The amount of ETH that needs to be transferred.
gas – The amount of gas provided to the message-call.
gas_left – The amount of gas left in the current frame.
memory_cost – The amount needed to extend the memory in the current frame.
extra_gas – The amount of gas needed for transferring value + creating a new account inside a message call.
call_stipend – The amount of stipend provided to a message call to execute code while transferring value(ETH).

Returns

message_call_gas

Return type

MessageCallGas

def calculate_message_call_gas(
    value: U256,
    gas: Uint,
    gas_left: Uint,
    memory_cost: Uint,
    extra_gas: Uint,
    call_stipend: Uint = GAS_CALL_STIPEND,
) -> MessageCallGas:
    call_stipend = Uint(0) if value == 0 else call_stipend
    if gas_left < extra_gas + memory_cost:
        return MessageCallGas(gas + extra_gas, gas + call_stipend)

    gas = min(gas, max_message_call_gas(gas_left - memory_cost - extra_gas))

    return MessageCallGas(gas + extra_gas, gas + call_stipend)

max_message_call_gas

max_message_call_gas(gas)

Calculates the maximum gas that is allowed for making a message call

Parameters: gas – The amount of gas provided to the message-call.
Returns: max_allowed_message_call_gas – The maximum gas allowed for making the message-call.
Return type: ethereum.base_types.Uint

def max_message_call_gas(gas: Uint) -> Uint:
    return gas - (gas // 64)

`GAS_JUMPDEST`
`GAS_BASE`
`GAS_VERY_LOW`
`GAS_SLOAD`
`GAS_STORAGE_SET`
`GAS_STORAGE_UPDATE`
`GAS_STORAGE_CLEAR_REFUND`
`GAS_LOW`
`GAS_MID`
`GAS_HIGH`
`GAS_EXPONENTIATION`
`GAS_EXPONENTIATION_PER_BYTE`
`GAS_MEMORY`
`GAS_KECCAK256`
`GAS_KECCAK256_WORD`
`GAS_COPY`
`GAS_BLOCK_HASH`
`GAS_EXTERNAL`
`GAS_BALANCE`
`GAS_LOG`
`GAS_LOG_DATA`
`GAS_LOG_TOPIC`
`GAS_CREATE`
`GAS_CODE_DEPOSIT`
`GAS_ZERO`
`GAS_CALL`
`GAS_NEW_ACCOUNT`
`GAS_CALL_VALUE`
`GAS_CALL_STIPEND`
`GAS_SELF_DESTRUCT`
`GAS_SELF_DESTRUCT_NEW_ACCOUNT`
`REFUND_SELF_DESTRUCT`
`GAS_ECRECOVER`
`GAS_SHA256`
`GAS_SHA256_WORD`
`GAS_RIPEMD160`
`GAS_RIPEMD160_WORD`
`GAS_IDENTITY`
`GAS_IDENTITY_WORD`
`GAS_RETURN_DATA_COPY`

Ethereum Virtual Machine (EVM) Gas

Introduction

Module Contents

Classes

Functions

Attributes

Module Details

GAS_JUMPDEST

GAS_BASE

GAS_VERY_LOW

GAS_SLOAD

GAS_STORAGE_SET

GAS_STORAGE_UPDATE

GAS_STORAGE_CLEAR_REFUND

GAS_LOW

GAS_MID

GAS_HIGH

GAS_EXPONENTIATION

GAS_EXPONENTIATION_PER_BYTE

GAS_MEMORY

GAS_KECCAK256

GAS_KECCAK256_WORD

GAS_COPY

GAS_BLOCK_HASH

GAS_EXTERNAL

GAS_BALANCE

GAS_LOG

GAS_LOG_DATA

GAS_LOG_TOPIC

GAS_CREATE

GAS_CODE_DEPOSIT

GAS_ZERO

GAS_CALL

GAS_NEW_ACCOUNT

GAS_CALL_VALUE

GAS_CALL_STIPEND

GAS_SELF_DESTRUCT

GAS_SELF_DESTRUCT_NEW_ACCOUNT

REFUND_SELF_DESTRUCT

GAS_ECRECOVER

GAS_SHA256

GAS_SHA256_WORD

GAS_RIPEMD160

GAS_RIPEMD160_WORD

GAS_IDENTITY

GAS_IDENTITY_WORD

GAS_RETURN_DATA_COPY

ExtendMemory

MessageCallGas

charge_gas

calculate_memory_gas_cost

calculate_gas_extend_memory

calculate_message_call_gas

max_message_call_gas