PraneshASP / smol-evm-rs

☄️ A toy implementation of the EVM from scratch using Rust.

smol-evm-rs •

---

Warning

It is important to note that the code is not optimized and may contain bugs. It is primarily intended for educational purposes. So don't use any code from this repo for production.

smol-evm-rs is a toy implementation of the Ethereum Virtual Machine, inspired by the smol-evm project, originally implemented in Python by karmacoma. The primary goal of the project is to increase my Rust proficiency.

• Part 1: The execution context
• Part 2: Branching instructions
• Part 3: Calldata & comparison instructions

Getting started:

Prerequisites

• Rust

Build Instructions

1. Clone the repository:

   git clone https://github.com/PraneshASP/smol-evm-rs.git
   cd smol-evm-rs

2. Build the project:

   cargo build

3. Run the project:

   cargo run <BYTECODE>

Example:

Run: cargo run 60048060005b8160125760005360016000f35b8201906001900390600556

The above bytecode calculates 4.pow(2) (four-squared)

It should return0x10 as output along with the memory, stack and program counter values.

Opcode: 96
"PUSH1" @ pc=0
Stack: [4]
Memory: []
---------
Opcode: 128
"DUP1" @ pc=2
Stack: [4, 4]
Memory: []
---------
Opcode: 96
"PUSH1" @ pc=3
Stack: [4, 4, 0]
Memory: []
---------
Opcode: 3
"SUB" @ pc=25
Stack: [4, 8, 2]
Memory: []
---------
Opcode: 144
"SWAP1" @ pc=26
Stack: [4, 2, 8]
Memory: []
---------

...

...

...

---------
Opcode: 87
"JUMPI" @ pc=9
Stack: [4, 0, 16]
Memory: []
---------
Opcode: 96
"PUSH1" @ pc=10
Stack: [4, 0, 16, 0]
Memory: []
---------
"MSTORE8" @ pc=12
Stack: [4, 0]
Memory: [16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
---------
"PUSH1" @ pc=13
Stack: [4, 0, 1]
Memory: [16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
---------
"PUSH1" @ pc=15
Stack: [4, 0, 1, 0]
Memory: [16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
---------
"RETURN" @ pc=17
Stack: [4, 0]
Memory: [16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
---------
Output : 0x1000000000000000

Note

Supported Opcodes: ADD,SUB,MUL,PUSH1, MSTORE8, RETURN, STOP,JUMP, JUMPI,JUMPDEST,GT,LT,ISZERO,SHR,SHL,CALLDATALOAD, CALLDATASIZE, CALLVALUE,SWAP[1-16], PUSH[0-32]and DUP[1-16]

Improvement ideas:

• Make word size 32 instead of 16.
• Implement remaining opcodes like MSTORE, MLOAD, CALLDATACOPY
• Implement gas calculation.
• Add more tests.

Acknowledgments

• karmacoma-eth for the original Python implementation of smol-evm.