test_worst_modexp()

Documentation for tests/zkevm/test_worst_compute.py::test_worst_modexp@44293f1e.

Generate fixtures for these test cases for Prague with:

fill -v tests/zkevm/test_worst_compute.py::test_worst_modexp --fork Prague

Test running a block with as many MODEXP calls as possible.

Source code in tests/zkevm/test_worst_compute.py

@pytest.mark.valid_from("Cancun")
def test_worst_modexp(
    blockchain_test: BlockchainTestFiller,
    pre: Alloc,
    fork: Fork,
):
    """Test running a block with as many MODEXP calls as possible."""
    env = Environment()

    base_mod_length = 32
    exp_length = 32

    base = 2 ** (8 * base_mod_length) - 1
    mod = 2 ** (8 * base_mod_length) - 2  # Prevents base == mod
    exp = 2 ** (8 * exp_length) - 1

    # MODEXP calldata
    calldata = (
        Op.MSTORE(0 * 32, base_mod_length)
        + Op.MSTORE(1 * 32, exp_length)
        + Op.MSTORE(2 * 32, base_mod_length)
        + Op.MSTORE(3 * 32, base)
        + Op.MSTORE(4 * 32, exp)
        + Op.MSTORE(5 * 32, mod)
    )

    # EIP-2565
    mul_complexity = math.ceil(base_mod_length / 8) ** 2
    iter_complexity = exp.bit_length() - 1
    gas_cost = math.floor((mul_complexity * iter_complexity) / 3)
    attack_block = Op.POP(Op.STATICCALL(gas_cost, 0x5, 0, 32 * 6, 0, 0))
    code = code_loop_precompile_call(calldata, attack_block)

    code_address = pre.deploy_contract(code=code)

    tx = Transaction(
        to=code_address,
        gas_limit=env.gas_limit,
        sender=pre.fund_eoa(),
    )

    blockchain_test(
        env=env,
        pre=pre,
        post={},
        blocks=[Block(txs=[tx])],
    )

Parametrized Test Cases

This test case is only parametrized by fork.

Fork All Forks Cancun Prague Osaka

Fixture Type All Fixture Types blockchain_test

Test ID (Abbreviated)
...fork_Cancun-blockchain_test
...fork_Prague-blockchain_test
...fork_Osaka-blockchain_test