EIP698 - OPCODE 0x46 BLOCKREWARD

# Simple Summary

This EIP adds an additional opcode to the EVM which will return a finalized blocks reward value.

# Abstract

In the EVM, the 0x40 opcodes are reserved for Block Information. Currently reserved opcodes are:

0X40 BLOCKHASH
0X41 COINBASE
0X42 TIMESTAMP
0X43 NUMBER
0X44 DIFFICULTY
0X45 GASLIMIT

This EIP would add an additional opcode, 0x46 BLOCKREWARD, which would return the block reward for any finalized block. The finalized block reward would include the base reward, uncle payments, and gas.

# Motivation

Per EIP-649 ( #669 ) periodic block reward reductions/variance are now planned in the roadmap, however, this EIP is consensus system agnostic and is most useful in decentralized pool operations and for any contract that benefits from knowing a block reward payout(i.e. Merge mined tokens)

# Specification

After block n all clients should process opcode 0x46 as follows:

Value: 0x46
Mnemonic: BLOCKREWARD
δ:0 nothing removed from stack
α:1 block reward added to stack
Description: Get the block's reward emission
GasCost: Gbase

Where:µ's[0] ≡ IHR

# Rationale

# Contract Mining Pools

For distributed consensus systems(staking pools and mining pools) ad hoc groups combine resources in order to reduce variance in payouts. Broadly, pool operations function by allowing a collective of miners / stakers to verify their contribution to solving PoW or staking share by periodically submitting solutions which are is representative of the miners probability of finding a true block.

In all these schemes B stands for a block reward minus pool fee and p is a probability of finding a block in a share attempt ( p=1/D, where D is current block difficulty).

Some common methods of mining pool payout are pay-per-share, R = B * p, proportional [R = B * (n/N) where n is amount of a miners shares, and N is amount of all shares in this round.], and pay-per-last-N-shares [R = B * (n/N) where miner's reward is calculated on a basis of N last shares, instead of all shares for the last round]. All of these methods are predicated on knowing the block reward paid for a given block. In order to provide a trust minimized solution, 0x46 can be used to call a blocks reward for computing payouts.

# Merge mined tokens

Contracts could create tokens which could be variably ‘minted’ as a function of block reward by calling 0x46

# Backwards Compatibility

# Currently deployed contracts

No impact

# Current clients

This EIP would be incompatible with currently deployed clients that are not able to handle 0x46 and would process all transactions and block containing the opcode as invalid.

Implementation should occur as part of a coordinated hardfork.

# Implementation

# Further reading

Mining Pools (opens new window)

The Yellow Paper Appendix H. Virtual Machine Specification section H.2