forked from DecentralizedClimateFoundation/DCIPs
88 lines
3.7 KiB
Markdown
88 lines
3.7 KiB
Markdown
|
---
|
||
|
|
eip: 1109
|
||
|
|
title: PRECOMPILEDCALL opcode (Remove CALL costs for precompiled contracts)
|
||
|
|
author: Jordi Baylina (@jbaylina)
|
||
|
|
discussions-to: https://ethereum-magicians.org/t/eip-1109-remove-call-costs-for-precompiled-contracts/447
|
||
|
|
status: Stagnant
|
||
|
|
type: Standards Track
|
||
|
|
category: Core
|
||
|
|
created: 2018-05-22
|
||
|
|
---
|
||
|
|
|
||
|
|
## Simple Summary
|
||
|
|
|
||
|
|
This EIP creates a specific opcode named `PRECOMPILEDCALL` to call Precompiled contracts without the costs of a normal `CALL`.
|
||
|
|
|
||
|
|
## Abstract
|
||
|
|
|
||
|
|
This EIP tries to resolve the problem of high gas consumption when calling precompiled contracts with a small gas cost. Using this opcode for calling precompiled contracts allows to define precompiled contracts whose effective cost it is less than 700.
|
||
|
|
|
||
|
|
## Motivation
|
||
|
|
|
||
|
|
Each precompiled contract has an already defined cost for calling it. It does not make sense to add the implicit extra gas cost of the CALL opcode.
|
||
|
|
|
||
|
|
As an example, SHA256 precompiled contract costs 60 and ECADD costs 500 (proposed to costs only 50 in [EIP-1108](./eip-1108.md) . When a precompiled contract is called, 700 gas is consumed just for the CALL opcode besides the costs of the precompiled contract.
|
||
|
|
|
||
|
|
This makes no sense, and right now it's impossible to define a precompiled contract whose effective cost for using it, is less than 700.
|
||
|
|
|
||
|
|
## Specification
|
||
|
|
|
||
|
|
If `block.number >= XXXXX`, define a new opcode named `PRECOMPILEDCALL` with code value `0xfb`.
|
||
|
|
|
||
|
|
The gas cost of the OPCODE is 2 (Gbase) plus the Specific gas cost defined for each specific precompiled smart contract.
|
||
|
|
|
||
|
|
The OPCODE takes 5 words from the stack and returns 1 word to the stack.
|
||
|
|
|
||
|
|
The input stack values are:
|
||
|
|
|
||
|
|
mu_s[0] = The address of the precompiled smart contract that is called.
|
||
|
|
mu_s[1] = Pointer to memory for the input parameters.
|
||
|
|
mu_s[2] = Length of the input parameters in bytes.
|
||
|
|
mu_s[3] = Pointer to memory where the output is stored
|
||
|
|
mu_s[4] = Length of the output buffer.
|
||
|
|
|
||
|
|
|
||
|
|
The return will be 1 in case of success call and 0 in any of the next cases:
|
||
|
|
|
||
|
|
1.- mu_s[0] is an address of an undefined precompiled smart contract.
|
||
|
|
2.- The precompiled smart contract fails (as defined on each smart contract). Invalid input parameters for example.
|
||
|
|
|
||
|
|
Precompiled smart contracs, does not execute opcodes, so there is no need to pass a gas parameter as a normal `CALL` (`0xf1`). If the available gas is less that 2 plus the required gas required for the specific precompiled smart cotract, the context just STOPS executing with an "Out of Gas" error.
|
||
|
|
|
||
|
|
There is no stack check for this call.
|
||
|
|
|
||
|
|
The normal `CALL`s to the precompiled smart contracts continue to work with the exact same behavior.
|
||
|
|
|
||
|
|
A `PRECOMPILEDCALL` to a regular address or regular smart contract, is considered a call to an "undefined smart contract", so the VM MUST not execute it and the opcode must return 0x0 .
|
||
|
|
|
||
|
|
|
||
|
|
## Rationale
|
||
|
|
|
||
|
|
There was a first proposal for removing the gast consts for the `CALL`, but it looks that it's easier to implement and test a new opcode just for that.
|
||
|
|
|
||
|
|
The code is just the next opcode available after the `STATICCALL` opcode.
|
||
|
|
|
||
|
|
## Backwards Compatibility
|
||
|
|
|
||
|
|
This EIP is backwards compatible. Smart contracts that call precompiled contracts using this new opcode will cost less from now on.
|
||
|
|
|
||
|
|
Old contracts that call precompiled smart contracts with the `CALL` method, will continue working.
|
||
|
|
|
||
|
|
## Test Cases
|
||
|
|
|
||
|
|
- Normal call to a defined precompiled contract.
|
||
|
|
- Call to undefined precompiled contract.
|
||
|
|
- Call to a regular contract
|
||
|
|
- Call to a regular account
|
||
|
|
- Call to 0x0 smart contract (Does not exists).
|
||
|
|
- Call with large values for the offste pointers and lengths
|
||
|
|
- Call with the exact gas remaining needed to call smart contract.
|
||
|
|
- Call with the exact gas remaining minus one needed to call smart contract.
|
||
|
|
|
||
|
|
## Implementation
|
||
|
|
|
||
|
|
Not implemented yet.
|
||
|
|
|
||
|
|
## Copyright
|
||
|
|
Copyright and related rights waived via [CC0](../LICENSE.md).
|