ethereum.byzantium.vm.memoryethereum.constantinople.vm.memory

Ethereum Virtual Machine (EVM) Memory ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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

Introduction

EVM memory operations.

memory_write

Writes to memory.

Parameters

memory : Memory contents of the EVM. start_position : Starting pointer to the memory. value : Data to write to memory.

def memory_write(​memory: bytearray, ​​start_position: U256, ​​value: Bytes​) -> None:
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    """
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    Writes to memory.
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    Parameters
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    ----------
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    memory :
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        Memory contents of the EVM.
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    start_position :
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        Starting pointer to the memory.
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    value :
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        Data to write to memory.
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    """
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    memory[start_position : int(start_position) + len(value)] = value

memory_read_bytes

Read bytes from memory.

Parameters

memory : Memory contents of the EVM. start_position : Starting pointer to the memory. size : Size of the data that needs to be read from start_position.

Returns

data_bytes : Data read from memory.

def memory_read_bytes(​memory: bytearray, ​​start_position: U256, ​​size: U256​) -> bytearray:
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    """
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    Read bytes from memory.
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    Parameters
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    ----------
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    memory :
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        Memory contents of the EVM.
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    start_position :
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        Starting pointer to the memory.
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    size :
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        Size of the data that needs to be read from `start_position`.
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    Returns
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    -------
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    data_bytes :
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        Data read from memory.
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    """
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    return memory[start_position : Uint(start_position) + Uint(size)]

buffer_read

Read bytes from a buffer. Padding with zeros if necessary.

Parameters

buffer : Memory contents of the EVM. start_position : Starting pointer to the memory. size : Size of the data that needs to be read from start_position.

Returns

data_bytes : Data read from memory.

def buffer_read(​buffer: Bytes, ​​start_position: U256, ​​size: U256​) -> Bytes:
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    """
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    Read bytes from a buffer. Padding with zeros if necessary.
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    Parameters
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    ----------
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    buffer :
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        Memory contents of the EVM.
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    start_position :
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        Starting pointer to the memory.
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    size :
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        Size of the data that needs to be read from `start_position`.
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    Returns
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    -------
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    data_bytes :
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        Data read from memory.
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    """
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    return right_pad_zero_bytes(
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        buffer[start_position : Uint(start_position) + Uint(size)], size
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    )