$$ \newcommand \EC {\mathrm{EC}} $$

Evaluation Context

An Evaluation Context \( \EC \) is a core runtime structure used during AVM program execution. It maintains all the state and metadata required to evaluate a program within a transaction (group) scope.

Below is a simplified interface example for the Evaluation Context, inspired by the go-algorand reference implementation.

Static Properties

These \( \EC \) methods expose context information that remains fixed throughout the execution of a specific transaction within the group:

• RunMode() -> {SmartSignature, Application}
  Returns whether the context is for a stateless LogicSig or a stateful Application.

• GroupIndex() -> int
  Returns the index of the current transaction within its group.

• PastScratch(past_group_index int) -> map[int, StackValue]
  Retrieves the final scratch space of a previous transaction in the same group, by index.

• GetProgram() -> []byte
  Returns the bytecode of the currently executing program \( \EC_P \).

Additional program-related accessors:

• getCreatorAddress() -> []byte — Gets the Creator address of the Application.

• AppID() -> uint64 — Returns the ID of the current Application.

• ProgramVersion() -> uint64 — AVM version for the executing program.

• GetOpSpec() -> OpSpec — Returns the Opcode Specification for the current opcode.

• begin(program []byte) -> bool — Verifies whether the given program version is supported and executable in the current context.

Dynamic Properties

These \( \EC \) reflect the evolving state of execution, may change as the transaction executes.

• PC() -> int
  Returns the current program counter of the executed application \( \EC_{pc} \).

Budget and Cost Tracking

The opcode budget limits the AVM program execution.

• Cost() -> int
  Returns the total opcode execution cost so far.

• remainingBudget() -> int
  Returns the remaining opcode budget available for execution.

Inner Transactions

• InnerTxnPending() -> []Transaction
  Returns inner transactions that are queued but not yet submitted.

• addInnerTxn() Adds an inner transaction to the group. Validates constraints such as group size, fees, and sender address. Used by the itxn_begin and itxn_next opcodes.

Program Evaluation

• step() The core transition function that advances execution one opcode at a time. See the dedicated non-normative section for further details.

Ledger Interaction

These functions expose the current Ledger context to the AVM:

• getRound() -> uint64 Returns the current round from the Ledger.

• getLatestTimestamp() -> uint64 Returns the latest timestamp of the most recently committed block.

Prefetched Ledger Accessors

• accountRetrieval(), assetRetrieval(), boxRetrieval(), applicationRetrieval()
  Provide runtime access to prefetched Ledger data (e.g., foreign accounts, apps, boxes, and assets) as declared in the transaction’s foreign arrays.