OneTwo

Experimental

0x72e6f1da97ca...851d05dba08f

FrontierContract #1,458Exact Bytecode MatchEdit this contract

Deployed September 22, 2015 (10 years ago)Block 271,722

A 115-byte contract with two functions, one() and two(), which write the constants 1 and 2 into the same storage slot.

Frontier EraVerified Source

Historical Significance

The smallest possible test of function dispatch. Two functions that differ only in a constant let a developer confirm that the four-byte selector routing worked and that each one reached its own body, which in 2015 was a real question rather than an assumption. It is a compiler test rather than a contract.

Context

Deployed 2015-09-22 by 0x5d1d36555752b215cfdb6a92995f5bf0e16f5ea6. One instance of this runtime is known. Source recovered by exact runtime bytecode match, verified on Sourcify and Etherscan.

Key Facts

Deployer

0x5d1d36...6f5ea6

Deployment Block

271,722

Deployment Date

Sep 22, 2015, 06:44 AM

Code Size

131.0 B

Gas at Deploy

50,527

Deployment Transaction: 0xb486f6c277f157e5...54d1e98404853c07

Description

The whole contract is a single uint in storage slot 0 and two argument-free setters. one() at selector 0x901717d1 writes 1, two() at 0x5fdf05d7 writes 2. There is no getter, no access control and no event, so the only way to observe the result is to read storage directly.

Source Verified

SolidityExact bytecode match(131 bytes)

Compiler: v0.1.3+

View verification proof

Heuristic Analysis

The following characteristics were detected through bytecode analysis and may not be accurate.

Detected Type: Experimental

Frontier Era

The initial release of Ethereum. A bare-bones implementation for technical users.

Block span: 0 — 1,149,999

July 30, 2015 — March 14, 2016

Bytecode Overview

Opcodes131

Unique Opcodes34

Jump Instructions10

Storage Operations4

Verified Source Available

Source verified through compiler archaeology and exact bytecode matching.

Verified on Etherscan Verified on Sourcify

View Verification Proof

Show source code (Solidity)

// Submitted by EthereumHistory (ethereumhistory.com)
contract OneTwo {
    uint x;
    function two() { x = 2; }
    function one() { x = 1; }
}

External Links

Etherscan Verified Source (if any)

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