This page is a placeholder. All examples on this page are currently AI-generated and are not correct. This documentation will be completed in the future with accurate, tested examples.
Overview
Opcode: 0x3a
Introduced: Frontier (EVM genesis)
GASPRICE pushes the gas price of the current transaction onto the stack, measured in wei per gas unit.
Specification
Stack Input:
Stack Output:
gasPrice (uint256, wei per gas)
stack.push(transaction.gasPrice)
Behavior
Returns the gas price specified in the transaction. For EIP-1559 transactions, this is the effective gas price (baseFee + priorityFee).
Key characteristics:
- Same value throughout transaction
- In wei per gas unit
- For EIP-1559: min(baseFee + maxPriorityFeePerGas, maxFeePerGas)
- For legacy: transaction’s gasPrice field
Examples
Basic Usage
import { gasprice } from '@tevm/voltaire/evm/context';
import { createFrame } from '@tevm/voltaire/evm/Frame';
const frame = createFrame({ stack: [] });
const txGasPrice = 20_000_000_000n; // 20 gwei
const err = gasprice(frame, txGasPrice);
console.log(frame.stack[0]); // 20000000000n
Gas Refunds
contract GasRefunder {
function expensiveOperation() public {
uint256 startGas = gasleft();
// ... expensive operations ...
uint256 gasUsed = startGas - gasleft();
uint256 refund = gasUsed * tx.gasprice;
payable(msg.sender).transfer(refund);
}
}
Gas Price Oracle
contract GasPriceTracker {
uint256[] public recentPrices;
function record() public {
recentPrices.push(tx.gasprice);
}
function averagePrice() public view returns (uint256) {
uint256 sum = 0;
for (uint i = 0; i < recentPrices.length; i++) {
sum += recentPrices[i];
}
return sum / recentPrices.length;
}
}
Gas Cost
Cost: 2 gas (GasQuickStep)
Common Usage
Transaction Cost Calculation
function estimateCost(uint256 gasEstimate) public view returns (uint256) {
return gasEstimate * tx.gasprice;
}
Minimum Gas Price
modifier minGasPrice(uint256 min) {
require(tx.gasprice >= min, "Gas price too low");
_;
}
function urgentOperation() public minGasPrice(50 gwei) {
// Only execute if gas price >= 50 gwei
}
Security
EIP-1559 Considerations
Post-EIP-1559, tx.gasprice is effective gas price, not maxFeePerGas:
// Block baseFee = 30 gwei
// maxPriorityFeePerGas = 2 gwei
// maxFeePerGas = 100 gwei
// tx.gasprice = 32 gwei (30 + 2)
Gas Price Manipulation
Don’t use tx.gasprice for critical logic - miners can manipulate it.
Implementation
import { consumeGas } from "../Frame/consumeGas.js";
import { pushStack } from "../Frame/pushStack.js";
/**
* GASPRICE opcode (0x3a) - Get transaction gas price
*
* Stack: [] => [gasPrice]
* Gas: 2 (GasQuickStep)
*/
export function gasprice(
frame: FrameType,
gasPrice: bigint
): EvmError | null {
const gasErr = consumeGas(frame, 2n);
if (gasErr) return gasErr;
const pushErr = pushStack(frame, gasPrice);
if (pushErr) return pushErr;
frame.pc += 1;
return null;
}
References
