TremorMarketEngine

TremorMarketEngine is the Extruction target for all three legs. It is where every executable price in Tremor comes from.

function extrude(
    uint256 pc,
    bytes calldata args,        // immutable program arguments
    bytes calldata takerArgs,   // unused: v1 consumes no taker bytes
    SwapQuery calldata query,
    SwapRegisters memory swap,
    bool isStaticContext
) external returns (uint256 nextPC, uint256 takerArgsConsumed, SwapRegisters memory);

The arguments select the leg

[version:1][mode:1][seriesId:8]        10 bytes

version  1
mode     1 ISSUE · 2 EXIT · 3 SETTLE

Anything else reverts: an unknown version, a wrong length, a mode outside 1–3.

What it validates before it prices

The engine is called by the router with an order it did not choose, so it re-derives everything rather than trusting the arguments:

The order-hash check is the important one: it means a Tremor program cannot be lifted into somebody else's order and pointed at somebody else's vault.

What each mode does

ISSUE — USDC → receipts. Exact-in and exact-out. Units are clamped by the inventory still shipped, by the cap, and by the vault's free collateral; the premium is the integral of the rising ask over the size that actually fills. On a swap it calls onIssue, which reserves collateral at the cap and raises the skew.

EXIT — receipts → USDC, exact-in only. Units are clamped by the units outstanding and by the point where the falling bid reaches zero; proceeds are additionally clamped by the collateral this burn releases and by the leg's Aqua balance. On a swap it calls onExit, which lowers the skew.

SETTLE — receipts → USDC, exact-in only, at the fixed payoutPerUnit. Clamped the same way.

The reservation itself is released by the receipt, not by the engine: the maker hook burns the units and calls onBurn, which is the single place a liability decreases. That is why the two burn legs can share one real balance.

Quote and swap are the same arithmetic

There is exactly one difference between a quote and a swap, and it is guarded on SwapVM's isStaticContext: a swap writes state (the new skew, the new reservation) and a quote does not. The numbers are computed by identical code paths, so the price in a ticket and the price in a block cannot diverge within a block.

Views for the app

function market(uint256 seriesId)      returns (MarketQuote memory);
function quoteIssueExactIn(uint256 seriesId, uint256 amountIn)   returns (...);
function quoteIssueExactOut(uint256 seriesId, uint256 units)     returns (...);
function quoteExit(uint256 seriesId, uint256 units)              returns (...);
function quoteSettle(uint256 seriesId, uint256 units)            returns (...);

Each runs the same clamps as the corresponding fill, so a quote that returns a partial fill tells you so before you sign. TremorLens bundles market() into its per-series read; the trade tickets use the quote* views for the exact size in the box.