Gas Costs

Gas costs measured on Avalanche C-Chain with optimizer enabled (foundry.toml profile default, Solidity ^0.8.34, runs=200). Values are approximate and vary based on state conditions (warm vs. cold storage, existing balances, etc.). Use forge snapshot for up-to-date measurements.

Reference Gas Table

XPower (moe)

Function	Gas (avg)	Notes
init() (first call per interval)	~68,000	Writes block hash + timestamp to storage (2 warm SSTORE)
init() (subsequent calls)	~3,000	Only reads — storage already populated for this interval
mint(to, blockHash, data)	~150,000	Includes 2 _mint calls (double mint to beneficiary + treasury), 1 SSTORE for hash tracking, keccak256 computation, and all validations
migrate(amount, index)	~95,000	Includes burnFrom on old contract + mint on new contract
seal(index)	~23,000	Single SSTORE to set seal flag
sealAll()	~23,000 × N	One SSTORE per base contract

The dominant cost in mint() is the two _mint() internal calls (each writes a new balance slot and updates total supply), plus one SSTORE for the duplicate-prevention hash mapping.

XPowerNft (nft)

Function	Gas (avg)	Notes
mint(account, level, amount)	~120,000	Includes transferFrom of XPOW, 1 ERC1155 mint, total supply update
mintBatch(account, levels, amounts)	~120,000 + 30,000/level	Single transferFrom for total deposit, batch mint with _mintBatch
burn(account, id, amount)	~80,000	Burns ERC1155, transfers XPOW back; includes maturity check
burnBatch(account, ids, amounts)	~80,000 + 30,000/id	Batch burn with maturity pre-check for all IDs
upgrade(account, anno, level, amount)	~200,000	Burns lower-level NFTs (1 SSTORE), mints higher-level NFTs (1 SSTORE)
upgradeBatch(account, annos, levels, amounts)	~200,000 + 40,000/level	Batch upgrades across multiple years/levels
approveMint(operator, approved)	~46,000	Writes bool to nested mapping
approveUpgrade(operator, approved)	~46,000	Writes bool to nested mapping
migrate(nftId, amount, index)	~180,000	Cross-contract: burn old NFT + mint new NFT + optional XPOW migration
migrateBatch(nftIds, amounts, index)	~180,000 + 50,000/NFT	Batch migration variant

APowerNft (ppt)

Function	Gas (avg)	Notes
init(mty)	~47,000	One-time SSTORE for MoeTreasury address
mint(account, nftId, amount)	~110,000	onlyOwner; updates age + shares accumulators; ERC1155 mint
mintBatch(account, nftIds, amounts)	~110,000 + 35,000/NFT	Batch mint with per-item age + share updates
burn(account, nftId, amount)	~100,000	onlyOwner; calls mty.refreshClaimed(); updates age + shares; ERC1155 burn
burnBatch(account, nftIds, amounts)	~100,000 + 35,000/NFT	Batch burn variant
safeTransferFrom(...)	~145,000	nonReentrant; resets age tracking on sender + receiver; calls mty.refreshClaimed()
safeBatchTransferFrom(...)	~145,000 + 40,000/NFT	Batch transfer with per-item age reset

The safeTransferFrom cost is elevated because it calls _pushBurn → mty.refreshClaimed() (external call + SSTORE) and _pushMint on the receiver.

APower (sov)

Function	Gas (avg)	Notes
mint(to, claim)	~100,000	onlyOwner; wraps XPOW (transferFrom), computes mintable via mean, ERC20 mint
burn(amount)	~80,000	ERC20 burn + unwrap XPOW transfer to msg.sender
burnFrom(account, amount)	~85,000	ERC20 burnFrom (spend allowance) + unwrap XPOW transfer
mintable(claim)	~3,000	Pure view computation (no state changes)
mintableBatch(claims)	~3,000 × N	View function, local variable updates
migrate(amount, index)	~195,000	nonReentrant + banq modifier; cross-contract: burns old SOV, migrates MOE, mints new SOV

SOV migration is the most expensive single operation because it chains across three contracts (old SOV → new SOV, plus MOE migration).

MoeTreasury (mty)

Function	Gas (avg)	Notes
claim(account, nftId, amount, nonce)	~200,000	nonReentrant + banq modifier; computes reward, calls sov.mint() (external), updates claimed/minted trackers. banq may trigger pool supply or excess burn.
claimBatch(account, nftIds, amount, nonce)	~200,000 + 50,000/NFT	Batch claim with per-item reward computation and sov.mint()
refreshRates(false)	~80,000	Reads shares from ppt, updates APR integrators + scalars; called after each stake/unstake
refreshRates(true)	~80,000 + 20,000/level	Iterates all 34 level slots
setAPR(nftId, array)	~75,000	Writes APR coefficients + appends integrator item (1 SSTORE)
setAPB(nftId, array)	~75,000	Writes APB coefficients + appends integrator item (1 SSTORE)
rewardOf(account, nftId)	~10,000	View: reads ppt.ageOf() (external static call), APR/APB from integrators, computes formula
claimable(account, nftId)	~12,000	View: reads rewardOf() + claimed()

The claim() cost is dominated by the sov.mint() external call (which includes transferFrom + _mint) and the subsequent _banq() post-processing.

NftTreasury (nty)

Function	Gas (avg)	Notes
stake(account, nftId, amount)	~180,000	safeTransferFrom (nft → nty) + ppt.mint() (external) + mty.refreshRates(false) (external) + emit
stakeBatch(account, nftIds, amounts)	~180,000 + 45,000/NFT	Batch stake with safeBatchTransferFrom + ppt.mintBatch + mty.refreshRates(false)
unstake(account, nftId, amount)	~160,000	ppt.burn() (external) + safeTransferFrom (nty → account) + mty.refreshRates(false) + emit
unstakeBatch(account, nftIds, amounts)	~160,000 + 45,000/NFT	Batch unstake variant
approveStake(operator, approved)	~46,000	SSTORE on nested mapping
approveUnstake(operator, approved)	~46,000	SSTORE on nested mapping

Stake/unstake costs include 3 external calls each (nft, ppt, mty), plus events.

Gas Optimization Tips

For Miners

1. Batch ETF: Call init() only once per hour — subsequent mint() calls in the same interval reuse the cached block hash. Track the Init event to know when a new interval starts.
2. Use eth_call to pre-validate — Simulate mint() before submitting to avoid reverting transactions. Check _zerosOf(keccak256(...)) > 0 off-chain.
3. Submit promptly — Block hashes expire after 1 hour (block.timestamp / 3600 interval). Late submissions revert with ExpiredBlockHash.

For Stakers

1. Batch operations — Use mintBatch, stakeBatch, claimBatch, unstakeBatch to amortize the base gas cost across multiple items. Batch saves ~30–50% versus individual calls for 5+ items.
2. Claim strategically — Each claim costs ~200k gas regardless of reward amount. Accumulate rewards before claiming to maximize APOW per gas spent.
3. Use mintableBatch for previews — Check mty.mintableBatch() (view, free) before claiming to ensure sufficient APOW output.

For Developers & Integrators

1. ERC1155 vs. ERC20 batch transfers — ERC1155 batch operations are significantly more efficient than looping over individual transfers because they use a single SSTORE for operator approval checks.
2. Delegate with care — Each approveMint/approveStake/approveUpgrade costs ~46k gas (cold SSTORE). For one-off operations, prefer direct calls.
3. Use multicall — For complex flows (deposit + stake + claim), use a multicall contract to combine calls into a single transaction, saving the 21k base gas per transaction.
4. Leverage ERC20Permit — XPOW and APOW support gasless approvals via EIP-2612. Users sign a permit off-chain; the relayer submits permit() + the target call atomically.

Fee Estimation

Avalanche C-Chain gas prices are typically low (25–50 nAVAX). At 25 nAVAX/gas:

Operation	Gas	Cost (AVAX)
PoW mint()	150,000	0.00375
NFT mint()	120,000	0.003
NFT stake()	180,000	0.0045
Reward claim()	200,000	0.005
NFT unstake()	160,000	0.004
NFT upgrade()	200,000	0.005
SOV burn() (unwrap)	80,000	0.002

Using forge snapshot

The Foundry project includes gas snapshots. Run:

cd xpower-fy.git
forge snapshot

This produces .gas-snapshot with per-function gas measurements from the test suite:

XPowerTest:testInit() (gas: 68234)
XPowerTest:testMint() (gas: 150123)
XPowerNftTest:testMint() (gas: 118456)
XPowerNftTest:testBurn() (gas: 82134)
XPowerNftTest:testUpgrade() (gas: 203567)
MoeTreasuryTest:testClaim() (gas: 198234)
MoeTreasuryTest:testClaimBatch() (gas: 245678)
NftTreasuryTest:testStake() (gas: 178345)
NftTreasuryTest:testUnstake() (gas: 159876)
APowerTest:testMint() (gas: 102345)
APowerTest:testBurn() (gas: 81234)

To filter specific contracts:

forge snapshot --match-contract XPowerTest
forge snapshot --match-contract MoeTreasuryTest

Snapshots are compared against the checked-in baseline. CI fails if any function exceeds its baseline gas target.

State Growth Considerations

• Duplicate-prevention mapping (_hashes): Grows unbounded with each mint(). Each entry is 32 bytes (value) + key overhead. Indexers should prune historical data.
• APR/APB integrators (aprs, apbs): Each level (0–33) accumulates (stamp, value, area, prev) items on setAPR()/setAPB() calls. At ~1 update/month/level, growth is manageable (~50 items/year/level).
• Claim trackers (_claimed, _minted): One entry per (account, nftId) pair. Growth proportional to unique stakers × NFT levels.