wasm_base_spec.md

WebAssembly Binary Base Specification

This is the base specification for a Primea WebAssembly module. All binaries must conform to these rules. The base spec is not meant to be used as standalone. Other interfaces should be used to add functionality.

This specification defines:

• Entry Points
• Memory export
• Table of Callbacks export

Entry Points

The following functions with the speficied signatures MUST be exported by a valid wasm binary.

onCreation(messageRef: i32) -> i32

This function runs once when the container is initially created. It receives a message reference that is used to initailize the container. This message MAY contain ports, but doesn't contain any data payload.

onMessage(messageRef: i32) -> i32

This function runs on every message the container receives.

Memory export

If any interface needs to read or write to memory then the memory MUST be exported with the string "memory".

Table of Callbacks export

A WebAssembly container should provide functionality for asynchronous functions with callback functions. All functions that a WebAssembly binary intends to use MUST be indexed in the callback table. The callback table MUST be exported with the string "callbacks".