EVM Precompiled Contracts

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This article explains useful precompiled smart contracts available in Plasm Network runtime.

Precompiles
A precompile means a common functionality for smart contracts which has been compiled, so that Ethereum nodes can run this efficiently. From a contract's perspective, this is just a single command like an opcode. The Frontier EVM used in Astar provides several useful precompiled contracts. These contracts are implemented in our ecosystem as a native implementation. The precompiled contracts 0x01 through 0x08 are the same as those in Ethereum (see list below). Astar additionally implements precompiled contracts start from 0x5001, and support new Astar features.
Ethereum Native Precompiles​​
Precompile
Address
ECRecover
0x0000000000000000000000000000000000000001
Sha256
0x0000000000000000000000000000000000000002
Ripemd160
0x0000000000000000000000000000000000000003
Identity
0x0000000000000000000000000000000000000004
Modexp
0x0000000000000000000000000000000000000005
Bn128Add
0x0000000000000000000000000000000000000006
Bn128Mul
0x0000000000000000000000000000000000000007
Bn128Pairing
0x0000000000000000000000000000000000000008
Blake2F
0x0000000000000000000000000000000000000009
Non-Ethereum Precompiles
Precompile
Address
Sha3FIPS256
0x0000000000000000000000000000000000001000
Dispatch
0x0000000000000000000000000000000000001001
ECRecoverPublicKey
0x0000000000000000000000000000000000001002
Ed25519Verify
0x0000000000000000000000000000000000001003
​
Astar Specific Precompiles​​
Precompile
Address
DappsStaking
0x0000000000000000000000000000000000005001
Sr25519
0x0000000000000000000000000000000000005002
SubstrateEcdsa
0x0000000000000000000000000000000000005003
The interface descriptions for these precompiles can be found in the precompiles folder: astar-frame repo.
The Addresses can be checked in the Astar repo for each runtime in precompile.rs files.
DappsStaking Precompile​​
DappsStaking Precompile enables EVM smart contract to access pallet-dapps-staking functionality. Example use of this precompile from Contract A:
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import "./DappsStaking.sol";contract A {    
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DappsStaking public constant DAPPS_STAKING = DappsStaking(0x0000000000000000000000000000000000005001);    
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/// @notice Check current era    
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function checkCurrentEra() public view {        
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    uint256 currentEra = DAPPS_STAKING.read_current_era();    
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}}
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Example use: check current era and total staked amount in the pallet-dapps-staking for Shiden Network. For this example, we will use Remix.
1.Copy DappsStaking.sol from astar-frame repo and create new contract in Remix: 
2. Compile the dAppStaking contract: 
3. The precompile does not need to be deployed since it is already on the network, but you need to tell Remix where to find it. After you connect your EVM wallet to Shiden Network (same applies for Astar Network and for Shibuya Testnet) follow these steps:
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Go to Deploy tab
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Use injected Web3 environment. It should point to Shiden Mainnet with `ChainId 336`
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Make sure you have the selected dAppStaking contract
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Provide the address of the precompiled contract `0x0000000000000000000000000000000000005001`
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The dAppStaking contract will appear under Deployed contracts
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4. Interact with the contract.
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Check the current era 
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Use the current era as input to check total staked amount on the network
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