eth_vm — Concise reference

A minimal Rust EVM prototype for experimentation. This file is intentionally short and points to the most relevant locations.

Purpose

• Small EVM core for learning and extension.
• Not production-ready: no gas metering, limited validation, and some panics (unwrap()).

Project layout (essential)

• crates/evm_core — VM core: Opcode enum, jump table, handlers.
• crates/primitives — runtime primitives: Memory, Stack, EvmStorage, Transaction, BlockEnv.
• bins/evm — example runner that creates an Evm instance.

Dispatch (runtime)

• Evm::step() reads a byte from memory[pc], converts it with Opcode::from_u8, looks up the handler in the 256-entry table from build_jump_table(), calls the handler (fn(&mut Evm)), then increments pc. Handlers that perform jumps must set evm.pc directly.

Short opcode snippet (Rust)

pub enum Opcode {
    STOP = 0x00,
    ADD = 0x01,
    MUL = 0x02,
    SUB = 0x03,
    DIV = 0x04,
    SDIV = 0x05,
    MOD = 0x06,
    SMOD = 0x07,
    ADDMOD = 0x08,
    MULMOD = 0x09,
    EXP = 0x0A,
    SIGNEXTEND = 0x0B,
    // ... remainder in file
}

How to add an opcode (3 steps)

1. Add/confirm enum entry and from_u8 mapping in crates/evm_core/src/opcodes.rs.
2. Implement handler fn(&mut Evm) in crates/evm_core/src/operations/.
3. Register it in crates/evm_core/src/jump_tables.rs:

jump_table[Opcode::MYOP as usize] = myop_handler;

Notes

• For exact semantics and gas rules consult https://www.evm.codes/.

• To run locally: from repo root use cargo build --workspace

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