Shardeum Opcodes

Blocks work differently in Shardeum because transactions are processed individually and not grouped into blocks. However, generating blocks at a specific interval is still required to support the existing smart contracts, which use block-related opcodes and comply with the JSON RPC specifications.

Shardeum uses a life cycle called cycle to schedule validator rotation and many other operations. For example, a cycle can take 60 seconds, producing a cycle record for each cycle. In Shardeum, block numbers are tied to the cycle production rate. Shardeum decided to generate 10 blocks in each cycle. If the cycle duration is 60 seconds, a new block will be generated every 6 seconds to produce 10 blocks in each cycle.

Transaction’s timestamp selects the appropriate block by deterministically mapping the timestamp to the block number. If the injected transaction does not have a timestamp, the network will determine a timestamp for the transaction and select the correct block. The block information will be fed into the EVM together with the transaction parameter.

Shardeum exposes block-related public API endpoints so JSON RPC servers can use the same block information as the network.

Block Related Opcodes

Stack	Name	Supported	Notes
40	BLOCKHASH	Supported	Hash of the specific block, only valid for the 256 most recent blocks, excluding the current one
41	COINBASE	Supported	Return network account address because there is no block miner in Shardeum
42	TIMESTAMP	Supported	Return network account address because there is no block miner in Shardeum
43	NUMBER	Supported	Current block's number
44	DIFFICULTY	Supported	Current block's difficulty. Since Shardeum does not use Proof of Work for transaction consensus the difficulty value is set to 0
45	GASLIMIT	Supported	Current block's gas limit
46	CHAINID	Supported	Current network's chain id: 8080
48	BASEFEE	EIP-1559	London hardfork, EIP-3198: Current block's base fee