Hardfork.hasEIP1153

Check if transient storage opcodes (TLOAD/TSTORE) are available

Try it Live

Run Hardfork examples in the interactive playground

EIP-1153 Features

Active Since: Cancun (March 13, 2024)

Transient Storage Opcodes

TLOAD (0x5C):

• Load from transient storage
• Gas cost: 100 gas (warm)

TSTORE (0x5D):

• Store to transient storage
• Gas cost: 100 gas

Storage Lifecycle

Transaction-Scoped:

• Storage cleared at end of transaction
• Not persisted to state
• Survives across internal calls within same transaction

Namespace:

• Same key space as regular storage
• Separate from permanent storage
• Per-contract transient storage

Usage Patterns

Reentrancy Locks

Implement cheap reentrancy guards:

import { Hardfork } from 'tevm'

function getReentrancyLockImplementation(fork: BrandedHardfork) {
  if (fork.hasEIP1153()) {
    // Solidity pseudocode:
    // uint256 locked;  // transient storage
    // modifier nonReentrant() {
    //   assembly { if tload(0) { revert(0, 0) } }
    //   assembly { tstore(0, 1) }
    //   _;
    //   assembly { tstore(0, 0) }
    // }
    return {
      type: "transient",
      gas: 200  // 100 TSTORE + 100 TLOAD
    }
  }

  return {
    type: "storage",
    gas: 20_200  // SSTORE + SLOAD (cold)
  }
}

// Transient storage saves ~20k gas per lock

Intermediate Calculations

Store temporary values:

import { Hardfork } from 'tevm'

function useTransientCache(fork: BrandedHardfork): boolean {
  // Use transient storage for intermediate calculations
  // that don't need to persist
  return fork.hasEIP1153()
}

Cross-Contract Communication

Pass data between contracts in same transaction:

import { Hardfork } from 'tevm'

function supportsTransientMessaging(fork: BrandedHardfork): boolean {
  // Enable contract-to-contract data passing
  // without permanent storage
  return fork.hasEIP1153()
}

Flash Accounting

Track temporary balances:

import { Hardfork } from 'tevm'

function getFlashLoanImplementation(fork: BrandedHardfork) {
  if (fork.hasEIP1153()) {
    return "transient"  // Track loan state in transient storage
  }

  return "storage"  // Must use expensive SSTORE/SLOAD
}

Gas Costs

Transient Storage (EIP-1153)

Operation	Gas Cost
TLOAD	100 gas
TSTORE	100 gas

Regular Storage (Comparison)

Operation	Gas Cost
SLOAD (warm)	100 gas
SLOAD (cold)	2,100 gas
SSTORE (warm, no change)	100 gas
SSTORE (cold, zero → non-zero)	20,000 gas
SSTORE (cold, non-zero → zero)	2,900 gas (with refund)

Savings Example

Reentrancy lock pattern:

import { Hardfork } from 'tevm'

function estimateReentrancyLockGas(fork: BrandedHardfork): number {
  if (fork.hasEIP1153()) {
    // TLOAD + TSTORE + TSTORE
    return 100 + 100 + 100  // 300 gas
  }

  // SLOAD (cold) + SSTORE (cold) + SSTORE (cold)
  return 2_100 + 20_000 + 2_900  // 25,000 gas
}

// Savings: ~24,700 gas per reentrancy lock

Network Configuration

Check transient storage support:

import { Hardfork, CANCUN } from 'tevm'

function validateTransientStorage(config: NetworkConfig) {
  const fork = Hardfork(config.hardfork)

  if (fork.hasEIP1153()) {
    console.log("Transient storage available - use for reentrancy locks")
  } else {
    console.log("Transient storage not available - using permanent storage")
  }
}

Compiler Integration

Enable transient storage in compiler:

import { Hardfork } from 'tevm'

function getSoliditySettings(fork: BrandedHardfork) {
  return {
    evmVersion: fork.hasEIP1153() ? "cancun" : "shanghai",
    viaIR: true  // Required for transient storage optimization
  }
}

EIP References

Primary:

• EIP-1153 - Transient storage opcodes

Impact

For Developers:

• Dramatically cheaper temporary storage (~100x cheaper)
• Ideal for reentrancy locks, flash loans, temporary state
• Must clear at transaction end (automatic)

For Smart Contracts:

• Typical savings: 15,000-25,000 gas per reentrancy lock
• Enables new patterns (cheap cross-contract communication)
• No persistence - not suitable for state that must survive transaction

For Security:

• Reentrancy locks become affordable
• Reduces incentive to skip security checks for gas savings
• Clearer separation of temporary vs permanent state

Common Use Cases

1. Reentrancy Guards: Save ~24k gas per lock
2. Flash Accounting: Track temporary balances (flash loans)
3. Cross-Contract Coordination: Pass data between contracts
4. Intermediate Calculations: Cache expensive computations within transaction
5. Access Control: Temporary permissions that expire at transaction end

See Also

• hasEIP4844 - Check blob transactions availability (Cancun)
• hasEIP1559 - Check EIP-1559 base fee availability (London)
• isAtLeast - General version comparison