ERC-20 Token Contract (Yul Implementation)

This repository contains a minimalistic implementation of an ERC-20 token contract using Yul. The contract includes basic ERC-20 functionalities such as transferring tokens, approving allowances, and querying balances. It also has a minting function restricted to the contract owner.

Overview

The contract is written in Yul, an intermediate language for the Ethereum Virtual Machine (EVM). It leverages low-level operations to provide efficient and gas-optimized token functionality.

Features

• Token Transfers: Transfer tokens to other addresses.
• Allowance Mechanism: Approve third-party addresses to transfer tokens on behalf of the token holder.
• Minting: Mint new tokens to any address, restricted to the contract owner.
• Query Functions: Check balances and allowances.
• Event Emissions: Emits standard ERC-20 events (Transfer and Approval).

Functions

balanceOf(address)

Returns the balance of the specified address.

• Selector: 0x70a08231
• Parameters: address - the address to query the balance for.

totalSupply()

Returns the total supply of the token.

• Selector: 0x18160ddd
• Parameters: None

transfer(address to, uint256 amount)

Transfers amount tokens to the specified to address.

• Selector: 0xa9059cbb
• Parameters:
  • to - the recipient address.
  • amount - the amount of tokens to transfer.

transferFrom(address from, address to, uint256 amount)

Transfers amount tokens from the from address to the to address using the allowance mechanism.

• Selector: 0x23b872dd
• Parameters:
  • from - the address to transfer tokens from.
  • to - the recipient address.
  • amount - the amount of tokens to transfer.

approve(address spender, uint256 amount)

Approves the spender address to spend amount tokens on behalf of the caller.

• Selector: 0x095ea7b3
• Parameters:
  • spender - the address allowed to spend tokens.
  • amount - the amount of tokens to be approved for spending.

allowance(address owner, address spender)

Returns the remaining number of tokens that the spender will be allowed to spend on behalf of owner.

• Selector: 0xdd62ed3e
• Parameters:
  • owner - the address owning the tokens.
  • spender - the address allowed to spend tokens.

mint(address account, uint256 amount)

Mints amount tokens to the account address. Only callable by the contract owner.

• Selector: 0x40c10f19
• Parameters:
  • account - the address to receive the minted tokens.
  • amount - the amount of tokens to mint.

Deployment

To deploy the contract, use the following steps:

1. Compile the Yul code to bytecode.
2. Deploy the bytecode to the Ethereum network using a deployment tool (e.g., Remix, Hardhat, Truffle).

Events

Transfer

Emitted when tokens are transferred, including zero value transfers.

• Signature: 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef
• Indexed Parameters:
  • from - address sending the tokens.
  • to - address receiving the tokens.
• Non-Indexed Parameters:
  • amount - the amount of tokens transferred.

Approval

Emitted when the allowance of a spender for an owner is set by a call to approve.

• Signature: 0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925
• Indexed Parameters:
  • owner - address that owns the tokens.
  • spender - address allowed to spend the tokens.
• Non-Indexed Parameters:
  • amount - the amount of tokens approved.

Storage Layout

• Slot 0: Contract owner address.
• Slot 1: Total supply of tokens.
• Slot 0x1000 and above: Token balances of addresses.
• Keccak256 hash of account and spender addresses: Allowances for each owner-spender pair.

Security

• Ownership: The mint function is restricted to the contract owner.
• Zero Address Checks: Transfers to the zero address are disallowed.
• Safe Arithmetic: Uses safe addition and subtraction to prevent overflow and underflow.

License

This project is licensed under the MIT License. See the LICENSE file for details.