Ethereum Virtual Machine (EVM) Memory

Table of Contents

Introduction
Module Contents
- Functions
Module Details

Introduction

EVM memory operations.

Module Contents

Functions

`memory_write`	Writes to memory.
`memory_read_bytes`	Read bytes from memory.
`buffer_read`	Read bytes from a buffer. Padding with zeros if neccesary.

Module Details

memory_write

memory_write(memory: bytearray, start_position: ethereum.base_types.U256, value: ethereum.base_types.Bytes) → None

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:
    memory[start_position : Uint(start_position) + len(value)] = value

memory_read_bytes

memory_read_bytes(memory: bytearray, start_position: ethereum.base_types.U256, size: ethereum.base_types.U256) → bytearray

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 read from memory.

Return type

data_bytes

def memory_read_bytes(
    memory: bytearray, start_position: U256, size: U256
) -> bytearray:
    return memory[start_position : Uint(start_position) + Uint(size)]

buffer_read

buffer_read(buffer: ethereum.base_types.Bytes, start_position: ethereum.base_types.U256, size: ethereum.base_types.U256) → ethereum.base_types.Bytes 

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

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 read from memory.

Return type

data_bytes

def buffer_read(buffer: Bytes, start_position: U256, size: U256) -> Bytes:
    return right_pad_zero_bytes(
        buffer[start_position : Uint(start_position) + Uint(size)], size
    )