ethereum.cancun.vm.instructions.log
Ethereum Virtual Machine (EVM) Logging Instructions ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
.. contents:: Table of Contents :backlinks: none :local:
Introduction
Implementations of the EVM logging instructions.
log_n
Appends a log entry, having num_topics
topics, to the evm logs.
This will also expand the memory if the data (required by the log entry) corresponding to the memory is not accessible.
Parameters
evm : The current EVM frame. num_topics : The number of topics to be included in the log entry.
def log_n(evm: Evm, num_topics: U256) -> None:
33 | """ |
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34 | Appends a log entry, having `num_topics` topics, to the evm logs. |
35 |
|
36 | This will also expand the memory if the data (required by the log entry) |
37 | corresponding to the memory is not accessible. |
38 |
|
39 | Parameters |
40 | ---------- |
41 | evm : |
42 | The current EVM frame. |
43 | num_topics : |
44 | The number of topics to be included in the log entry. |
45 |
|
46 | """ |
47 | # STACK |
48 | memory_start_index = pop(evm.stack) |
49 | size = pop(evm.stack) |
50 | |
51 | topics = [] |
52 | for _ in range(num_topics): |
53 | topic = pop(evm.stack).to_be_bytes32() |
54 | topics.append(topic) |
55 | |
56 | # GAS |
57 | extend_memory = calculate_gas_extend_memory( |
58 | evm.memory, [(memory_start_index, size)] |
59 | ) |
60 | charge_gas( |
61 | evm, |
62 | GAS_LOG |
63 | + GAS_LOG_DATA * Uint(size) |
64 | + GAS_LOG_TOPIC * Uint(num_topics) |
65 | + extend_memory.cost, |
66 | ) |
67 | |
68 | # OPERATION |
69 | evm.memory += b"\x00" * extend_memory.expand_by |
70 | if evm.message.is_static: |
71 | raise WriteInStaticContext |
72 | log_entry = Log( |
73 | address=evm.message.current_target, |
74 | topics=tuple(topics), |
75 | data=memory_read_bytes(evm.memory, memory_start_index, size), |
76 | ) |
77 | |
78 | evm.logs = evm.logs + (log_entry,) |
79 | |
80 | # PROGRAM COUNTER |
81 | evm.pc += Uint(1) |
log0
84 | log0 = partial(log_n, num_topics=0) |
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log1
85 | log1 = partial(log_n, num_topics=1) |
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log2
86 | log2 = partial(log_n, num_topics=2) |
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log3
87 | log3 = partial(log_n, num_topics=3) |
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log4
88 | log4 = partial(log_n, num_topics=4) |
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