MegaETH EVM

A specialized Ethereum Virtual Machine (EVM) implementation tailored for MegaETH specifications, built on top of revm and op-revm.

Overview

This repository contains a customized version of the revm EVM implementation specifically designed for MegaETH. The implementation extends the Optimism EVM (op-revm) with MegaETH-specific modifications and optimizations to support high-performance blockchain operations.

EVM Version

• Base EVM: revm v27.1.0 (v83)
• Optimism EVM: op-revm v8.1.0 (v83)
• Alloy EVM: alloy-evm v0.15.0

Terminology: Spec vs Hardfork

This codebase distinguishes between two related concepts:

• Spec (MegaSpecId): Defines EVM behavior - what the EVM does. Values: EQUIVALENCE, MINI_REX, REX
• Hardfork (MegaHardfork): Defines network upgrade events - when specs are activated. Values: MiniRex, MiniRex1, MiniRex2, Rex

Multiple hardforks can map to the same spec. For example, both MiniRex and MiniRex2 hardforks use the MINI_REX spec.

Key Features

EQUIVALENCE Spec

• Optimism Compatibility: Maintains full compatibility with Optimism Isthmus EVM
• Parallel Execution Support: Block environment access tracking for conflict detection

MINI_REX Spec

• Multidimensional Gas Model: Independent tracking for compute gas (1B), data size (3.125 MB), and KV updates (125K)
• Compute Gas Tracking: Separate limit for computational work with gas detention for volatile data access
• Dynamic Gas Costs: SALT bucket-based scaling preventing state bloat
• Split LOG Costs: Compute gas (standard) + storage gas (10× multiplier) for independent resource pricing
• SELFDESTRUCT Prohibition: Complete disabling for contract integrity
• Large Contract Support: 512 KB contracts (21x increase from 24 KB)
• Gas Detention: Volatile data access (block env, beneficiary, oracle) triggers gas limiting with refunds
• Enhanced Security: Comprehensive limit enforcement preserving remaining gas on limit violations

For complete MiniRex specification, see MiniRex.md.

REX Spec

• Refined Storage Gas Economics: Optimized storage gas formulas with gradual scaling (20K-32K base costs vs. MiniRex's 2M)
• Transaction Intrinsic Storage Gas: 39,000 storage gas baseline for all transactions (total 60K with compute gas)
• Zero Cost Fresh Storage: Storage operations in minimum-sized SALT buckets charge 0 storage gas
• Separate Contract Creation Cost: Distinct storage gas for contract creation (32K base) vs. account creation (25K base)
• Critical Security Fixes: DELEGATECALL, STATICCALL, and CALLCODE now properly enforce 98/100 gas forwarding and oracle access detection
• MiniRex Foundation: Inherits all MiniRex features including multidimensional gas model, compute gas detention, and enhanced security

For complete Rex specification, see Rex.md.

Quick Start

Basic Usage

use mega_evm::{Context, Evm, SpecId, Transaction};
use revm::{
    context::TxEnv,
    database::{CacheDB, EmptyDB},
    inspector::NoOpInspector,
    primitives::TxKind,
};

// Create EVM instance with MINI_REX spec
let mut db = CacheDB::<EmptyDB>::default();
let spec = SpecId::MINI_REX;
let mut context = Context::new(db, spec);
let mut evm = Evm::new(context, NoOpInspector);

// Execute transaction
let tx = Transaction {
    base: TxEnv {
        caller: address!("..."),
        kind: TxKind::Call(target_address),
        data: Bytes::default(),
        value: U256::ZERO,
        gas_limit: 1000000,
        ..Default::default()
    },
    ..Default::default()
};

let result = alloy_evm::Evm::transact_raw(&mut evm, tx)?;

Command Line Tool: mega-evme

The mega-evme binary provides a command-line interface for executing and debugging EVM transactions, similar to go-ethereum's evm tool.

Installation

cargo build --release -p mega-evme
# Binary will be at ./target/release/mega-evme

Commands

Command	Description
run	Execute arbitrary EVM bytecode directly
tx	Run a transaction with full transaction context
replay	Replay an existing transaction from RPC

Basic Usage

# Execute bytecode directly
mega-evme run 0x60016000526001601ff3

# Run a transaction with state forking
mega-evme tx --fork --fork.rpc https://rpc.example.com \
  --receiver 0x1234... --input 0x...

# Replay a transaction from RPC
mega-evme replay 0xTxHash --rpc https://rpc.example.com

Transaction Types

The tx command supports multiple transaction types with type-specific options:

Type	Name	Specific Options
0	Legacy	-
1	EIP-2930	--access ADDRESS:KEY1,KEY2,...
2	EIP-1559	--priority-fee, --access
4	EIP-7702	--auth AUTHORITY:NONCE->DELEGATION, --access
126	Deposit	--source-hash, --mint

For detailed documentation, see mega-evme README.

Development

Building

cargo build

Testing

cargo test

Running Examples

cargo run --example block_env_tracking

Documentation

• ARCH.md: Detailed implementation architecture and technical specifications

License

MIT OR Apache-2.0