EIP-7516: BLOBBASEFEE instruction


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      EIP-7516: BLOBBASEFEE instruction
    
    
      
        
      
    
    
      
        
      
    
  

  Instruction that returns the current data-blob base-fee

  	Authors	Carl Beekhuizen (@carlbeek)
	Created	2023-09-11
	Last Call Deadline	2024-02-15
	Requires	

  EIP-3198, 

  EIP-4844




  


  
    
      
      
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    Table of Contents

    	Abstract
	Motivation
	Specification
	Rationale
    	Gas cost


  
	Backwards Compatibility
	Test Cases
    	Nominal case


  
	Security Considerations
	Copyright



  


  
      
      
         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 EIP-3198 (BASEFEE opcode) except that it returns the blob base-fee as per EIP-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 EIP-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 EVM 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 EIP-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
      
      
    


Assuming calling get_blob_gasprice(header) (as defined in EIP-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

  
    
      
      
         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
      
      
    


Copyright and related rights waived via CC0.


  Citation

  Please cite this document as:

  
  Carl Beekhuizen (@carlbeek), "EIP-7516: BLOBBASEFEE instruction [DRAFT]," Ethereum Improvement Proposals, no. 7516, September 2023. [Online serial]. Available: https://eips.ethereum.org/EIPS/eip-7516.






      
    
  

  

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