ethereum.paris.vm.gas

Ethereum Virtual Machine (EVM) Gas ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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

Introduction

EVM gas constants and calculators.

GAS_JUMPDEST

24
GAS_JUMPDEST = Uint(1)

GAS_BASE

25
GAS_BASE = Uint(2)

GAS_VERY_LOW

26
GAS_VERY_LOW = Uint(3)

GAS_STORAGE_SET

27
GAS_STORAGE_SET = Uint(20000)

GAS_STORAGE_UPDATE

28
GAS_STORAGE_UPDATE = Uint(5000)

GAS_STORAGE_CLEAR_REFUND

29
GAS_STORAGE_CLEAR_REFUND = Uint(4800)

GAS_LOW

30
GAS_LOW = Uint(5)

GAS_MID

31
GAS_MID = Uint(8)

GAS_HIGH

32
GAS_HIGH = Uint(10)

GAS_EXPONENTIATION

33
GAS_EXPONENTIATION = Uint(10)

GAS_EXPONENTIATION_PER_BYTE

34
GAS_EXPONENTIATION_PER_BYTE = Uint(50)

GAS_MEMORY

35
GAS_MEMORY = Uint(3)

GAS_KECCAK256

36
GAS_KECCAK256 = Uint(30)

GAS_KECCAK256_WORD

37
GAS_KECCAK256_WORD = Uint(6)

GAS_COPY

38
GAS_COPY = Uint(3)

GAS_BLOCK_HASH

39
GAS_BLOCK_HASH = Uint(20)

GAS_LOG

40
GAS_LOG = Uint(375)

GAS_LOG_DATA

41
GAS_LOG_DATA = Uint(8)

GAS_LOG_TOPIC

42
GAS_LOG_TOPIC = Uint(375)

GAS_CREATE

43
GAS_CREATE = Uint(32000)

GAS_CODE_DEPOSIT

44
GAS_CODE_DEPOSIT = Uint(200)

GAS_ZERO

45
GAS_ZERO = Uint(0)

GAS_NEW_ACCOUNT

46
GAS_NEW_ACCOUNT = Uint(25000)

GAS_CALL_VALUE

47
GAS_CALL_VALUE = Uint(9000)

GAS_CALL_STIPEND

48
GAS_CALL_STIPEND = Uint(2300)

GAS_SELF_DESTRUCT

49
GAS_SELF_DESTRUCT = Uint(5000)

GAS_SELF_DESTRUCT_NEW_ACCOUNT

50
GAS_SELF_DESTRUCT_NEW_ACCOUNT = Uint(25000)

GAS_ECRECOVER

51
GAS_ECRECOVER = Uint(3000)

GAS_SHA256

52
GAS_SHA256 = Uint(60)

GAS_SHA256_WORD

53
GAS_SHA256_WORD = Uint(12)

GAS_RIPEMD160

54
GAS_RIPEMD160 = Uint(600)

GAS_RIPEMD160_WORD

55
GAS_RIPEMD160_WORD = Uint(120)

GAS_IDENTITY

56
GAS_IDENTITY = Uint(15)

GAS_IDENTITY_WORD

57
GAS_IDENTITY_WORD = Uint(3)

GAS_RETURN_DATA_COPY

58
GAS_RETURN_DATA_COPY = Uint(3)

GAS_FAST_STEP

59
GAS_FAST_STEP = Uint(5)

GAS_BLAKE2_PER_ROUND

60
GAS_BLAKE2_PER_ROUND = Uint(1)

GAS_COLD_SLOAD

61
GAS_COLD_SLOAD = Uint(2100)

GAS_COLD_ACCOUNT_ACCESS

62
GAS_COLD_ACCOUNT_ACCESS = Uint(2600)

GAS_WARM_ACCESS

63
GAS_WARM_ACCESS = Uint(100)

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

66
@dataclass
class ExtendMemory:

cost

77
    cost: Uint

expand_by

78
    expand_by: 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

81
@dataclass
class MessageCallGas:

cost

94
    cost: Uint

stipend

95
    stipend: Uint

charge_gas

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:
99
    """
100
    Subtracts `amount` from `evm.gas_left`.
101
102
    Parameters
103
    ----------
104
    evm :
105
        The current EVM.
106
    amount :
107
        The amount of gas the current operation requires.
108
109
    """
110
    evm_trace(evm, GasAndRefund(amount))
111
112
    if evm.gas_left < amount:
113
        raise OutOfGasError
114
    else:
115
        evm.gas_left -= U256(amount)

calculate_memory_gas_cost

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 : ethereum.base_types.Uint The gas cost for storing data in memory.

def calculate_memory_gas_cost(​size_in_bytes: Uint​) -> Uint:
119
    """
120
    Calculates the gas cost for allocating memory
121
    to the smallest multiple of 32 bytes,
122
    such that the allocated size is at least as big as the given size.
123
124
    Parameters
125
    ----------
126
    size_in_bytes :
127
        The size of the data in bytes.
128
129
    Returns
130
    -------
131
    total_gas_cost : `ethereum.base_types.Uint`
132
        The gas cost for storing data in memory.
133
    """
134
    size_in_words = ceil32(size_in_bytes) // 32
135
    linear_cost = size_in_words * GAS_MEMORY
136
    quadratic_cost = size_in_words**2 // 512
137
    total_gas_cost = linear_cost + quadratic_cost
138
    try:
139
        return total_gas_cost
140
    except ValueError:
141
        raise OutOfGasError

calculate_gas_extend_memory

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: ExtendMemory

def calculate_gas_extend_memory(​memory: bytearray, ​​extensions: List[Tuple[U256, U256]]​) -> ExtendMemory:
147
    """
148
    Calculates the gas amount to extend memory
149
150
    Parameters
151
    ----------
152
    memory :
153
        Memory contents of the EVM.
154
    extensions:
155
        List of extensions to be made to the memory.
156
        Consists of a tuple of start position and size.
157
158
    Returns
159
    -------
160
    extend_memory: `ExtendMemory`
161
    """
162
    size_to_extend = Uint(0)
163
    to_be_paid = Uint(0)
164
    current_size = Uint(len(memory))
165
    for start_position, size in extensions:
166
        if size == 0:
167
            continue
168
        before_size = ceil32(current_size)
169
        after_size = ceil32(Uint(start_position) + Uint(size))
170
        if after_size <= before_size:
171
            continue
172
173
        size_to_extend += after_size - before_size
174
        already_paid = calculate_memory_gas_cost(before_size)
175
        total_cost = calculate_memory_gas_cost(after_size)
176
        to_be_paid += total_cost - already_paid
177
178
        current_size = after_size
179
180
    return ExtendMemory(to_be_paid, size_to_extend)

calculate_message_call_gas

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: MessageCallGas

def calculate_message_call_gas(​value: U256, ​​gas: Uint, ​​gas_left: Uint, ​​memory_cost: Uint, ​​extra_gas: Uint, ​​call_stipend: Uint​) -> MessageCallGas:
191
    """
192
    Calculates the MessageCallGas (cost and stipend) for
193
    executing call Opcodes.
194
195
    Parameters
196
    ----------
197
    value:
198
        The amount of `ETH` that needs to be transferred.
199
    gas :
200
        The amount of gas provided to the message-call.
201
    gas_left :
202
        The amount of gas left in the current frame.
203
    memory_cost :
204
        The amount needed to extend the memory in the current frame.
205
    extra_gas :
206
        The amount of gas needed for transferring value + creating a new
207
        account inside a message call.
208
    call_stipend :
209
        The amount of stipend provided to a message call to execute code while
210
        transferring value(ETH).
211
212
    Returns
213
    -------
214
    message_call_gas: `MessageCallGas`
215
    """
216
    call_stipend = Uint(0) if value == 0 else call_stipend
217
    if gas_left < extra_gas + memory_cost:
218
        return MessageCallGas(gas + extra_gas, gas + call_stipend)
219
220
    gas = min(gas, max_message_call_gas(gas_left - memory_cost - extra_gas))
221
222
    return MessageCallGas(gas + extra_gas, gas + call_stipend)

max_message_call_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: ethereum.base_types.Uint The maximum gas allowed for making the message-call.

def max_message_call_gas(​gas: Uint​) -> Uint:
226
    """
227
    Calculates the maximum gas that is allowed for making a message call
228
229
    Parameters
230
    ----------
231
    gas :
232
        The amount of gas provided to the message-call.
233
234
    Returns
235
    -------
236
    max_allowed_message_call_gas: `ethereum.base_types.Uint`
237
        The maximum gas allowed for making the message-call.
238
    """
239
    return gas - (gas // 64)