ethereum.dao_fork.vm.instructions.storage
Ethereum Virtual Machine (EVM) Storage Instructions ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. contents:: Table of Contents :backlinks: none :local:
Introduction
Implementations of the EVM storage related instructions.
sload
Loads to the stack, the value corresponding to a certain key from the storage of the current account.
Parameters
evm : The current EVM frame.
def sload(evm: Evm) -> None:
28 | """ |
---|---|
29 | Loads to the stack, the value corresponding to a certain key from the |
30 | storage of the current account. |
31 |
|
32 | Parameters |
33 | ---------- |
34 | evm : |
35 | The current EVM frame. |
36 |
|
37 | """ |
38 | # STACK |
39 | key = pop(evm.stack).to_be_bytes32() |
40 | |
41 | # GAS |
42 | charge_gas(evm, GAS_SLOAD) |
43 | |
44 | # OPERATION |
45 | value = get_storage(evm.env.state, evm.message.current_target, key) |
46 | |
47 | push(evm.stack, value) |
48 | |
49 | # PROGRAM COUNTER |
50 | evm.pc += 1 |
sstore
Stores a value at a certain key in the current context's storage.
Parameters
evm : The current EVM frame.
def sstore(evm: Evm) -> None:
54 | """ |
---|---|
55 | Stores a value at a certain key in the current context's storage. |
56 |
|
57 | Parameters |
58 | ---------- |
59 | evm : |
60 | The current EVM frame. |
61 |
|
62 | """ |
63 | # STACK |
64 | key = pop(evm.stack).to_be_bytes32() |
65 | new_value = pop(evm.stack) |
66 | |
67 | # GAS |
68 | current_value = get_storage(evm.env.state, evm.message.current_target, key) |
69 | if new_value != 0 and current_value == 0: |
70 | gas_cost = GAS_STORAGE_SET |
71 | else: |
72 | gas_cost = GAS_STORAGE_UPDATE |
73 | |
74 | if new_value == 0 and current_value != 0: |
75 | evm.refund_counter += GAS_STORAGE_CLEAR_REFUND |
76 | |
77 | charge_gas(evm, gas_cost) |
78 | |
79 | # OPERATION |
80 | set_storage(evm.env.state, evm.message.current_target, key, new_value) |
81 | |
82 | # PROGRAM COUNTER |
83 | evm.pc += 1 |