Dip 7516
dip: 7516 title: BLOBBASEFEE instruction description: Instruction that returns the current data-blob base-fee author: Carl Beekhuizen (@carlbeek) Digitalia editing author: Cosimo Constantinos cosimo@juro.net, et al. discussions-to: https://digitalia-magicians.org/t/dip-7516-blobbasefee-opcode/15761 status: Final type: Standards Track category: Core created: 2023-09-11 Created for Digitalia: 2025-01-07 requires: 3198, 4844
Abstract¶
Add a BLOBBASEFEE (0x4a) instruction that returns the value of the blob base-fee of the current block it is executing in. It is the identical to DIP-3198 (BASEFEE opcode) except that it returns the blob base-fee as per DIP-4844.
Motivation¶
The intended use case would be for contracts to get the value of the blob base-fee. This feature enables blob-data users to programmatically account for the blob gas price, eg:
- Allow rollup contracts to trustlessly account for blob data usage costs.
- Blob gas futures can be implemented based on it which allows for blob users to smooth out data blob costs.
Specification¶
Add a BLOBBASEFEE instruction with opcode 0x4a, with gas cost 2.
| Op | Input | Output | Cost |
|---|---|---|---|
| 0x4a | 0 | 1 | 2 |
BLOBBASEFEE returns the result of the get_blob_gasprice(header) -> int function as defined in DIP-4844 §Gas accounting.
Rationale¶
Gas cost¶
The value of the blob base-fee is needed to process data-blob transactions. That means its value is already available before running the DVM code.
The instruction does not add extra complexity and additional read/write operations, hence the choice of 2 gas cost. This is also identical to DIP-3198 (BASEFEE opcode)'s cost as it just makes available data that is in the header.
Backwards Compatibility¶
There are no known backward compatibility issues with this instruction.
Test Cases¶
Nominal Case¶
Assume calling get_blob_gasprice(header) (as defined in DIP-4844 §Gas accounting) on the current block's header returns 7 wei:
BLOBBASEFEE should push the value 7 (left padded byte32) to the stack.
Bytecode: 0x4900 (BLOBBASEFEE, STOP)
| Pc | Op | Cost | Stack | RStack |
|---|---|---|---|---|
| 0 | BLOBBASEFEE | 2 | [] | [] |
| 1 | STOP | 0 | [7] | [] |
Output: 0x
Consumed gas: 2
Comprehensive Test Suite¶
A complete suite of tests can be found here.
Security Considerations¶
The value of the blob base-fee is not sensitive and is publicly accessible in the block header. There are no known security implications with this instruction.
Copyright¶
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