@spec call_forwarded_gas(
  non_neg_integer(),
  non_neg_integer(),
  EEVM.HardforkConfig.t()
) ::
  non_neg_integer()

Gas a CALL-family or CREATE opcode hands to its child frame. From Tangerine Whistle (EIP-150) the caller keeps 1/64 of what it has left and the request is capped at the rest; before, the full request is forwarded, and a request above the available gas is an out-of-gas error in the caller.

@spec call_new_account_cost(
  boolean(),
  boolean(),
  non_neg_integer(),
  EEVM.HardforkConfig.t()
) ::
  non_neg_integer()

25,000 when a CALL brings an account into existence. From Spurious Dragon (EIP-161) that is a value transfer to an empty account; before, a call to any account that does not exist.

@spec log_cost(non_neg_integer(), non_neg_integer()) :: non_neg_integer()

Dynamic part of LOG0–LOG4: 375 per topic plus 8 per data byte. The 375 base (G_log) is the opcode's static cost in EEVM.Gas.Static.

@spec selfdestruct_new_account_cost(
  boolean(),
  boolean(),
  non_neg_integer(),
  EEVM.HardforkConfig.t()
) :: non_neg_integer()

25,000 when SELFDESTRUCT brings its beneficiary into existence: from Tangerine Whistle (EIP-150) when the beneficiary does not exist, and from Spurious Dragon (EIP-161) only when a non-zero balance moves to an empty account. Nothing before Tangerine Whistle.

@spec selfdestruct_refund(boolean(), EEVM.HardforkConfig.t()) :: non_neg_integer()

Refund for a SELFDESTRUCT: 24,000 before London when the account has not already been destroyed in this transaction (destroyed?), 0 from London (EIP-3529).

@spec sstore_cost(
  non_neg_integer(),
  non_neg_integer(),
  non_neg_integer(),
  EEVM.HardforkConfig.t()
) ::
  {non_neg_integer(), integer()}

Returns {gas, refund_delta} for an SSTORE writing new_value over current, where original is the slot's value at the start of the transaction. The cold-slot charge (EIP-2929) is separate, in EEVM.Gas.Access.sstore_access_cost/3.

• Before Istanbul: 20,000 to set a zero slot, 5,000 for any other write, and a 15,000 refund for clearing one.
• Istanbul (EIP-2200) net metering: writes that leave the slot unchanged or touch an already-dirty slot cost SLOAD_GAS (800); refunds track whether the write clears the slot or restores its original value.
• Berlin (EIP-2929): SLOAD_GAS becomes 100 and the 5,000 reset cost 2,900.
• London (EIP-3529): the clearing refund drops to 4,800.

Examples

iex> EEVM.Gas.Dynamic.sstore_cost(7, 7, 0, EEVM.HardforkConfig.new(:byzantium))
{5000, 15000}

iex> EEVM.Gas.Dynamic.sstore_cost(7, 7, 0, EEVM.HardforkConfig.new(:istanbul))
{5000, 15000}

iex> EEVM.Gas.Dynamic.sstore_cost(7, 9, 9, EEVM.HardforkConfig.new(:istanbul))
{800, 0}

iex> EEVM.Gas.Dynamic.sstore_cost(7, 7, 0, EEVM.HardforkConfig.new(:london))
{2900, 4800}