This repository contains a structured reference of the WebAssembly instruction set and its opcodes, formatted as a TOML file.
The instructions.toml file lists all instructions as an array-of-tables under the key [[instructions]].
Each entry represents a single instruction (or more precisely, a single opcode) and includes details such as its name, category, binary opcode, immediate arguments, and stack signature.
| Key | Type | Value |
|---|---|---|
name |
string | The name of the instruction. |
variant |
string (optional) | A unique identifier for a specific variant of the instruction, if needed. |
opcode |
number or array | The binary opcode for the instruction. |
category |
string | The category of the instruction as defined in the spec. |
immediates |
array (optional) | The immediate arguments, if any. |
stack-type |
table (optional) | The instruction type, describing stack input and output types. |
feature |
string (optional) | The feature proposal to which the instruction belongs, if any. |
since |
string (optional) | The first major version of WebAssembly that includes the instruction. |
[[instructions]]
name = "i32.add"
opcode = 0x6A
category = "numeric"
stack-type = { from = [ { type = "i32" }, { type = "i32" } ], to = [ { type = "i32" } ] }
since = "1"[[instructions]]
name = "table.fill"
opcode = [0xFC, 17]
category = "table"
immediates = [ { type = "tableidx", name = "x" } ]
stack-type = { from = [ { type = "i32" }, { type-of = "x" }, { type = "i32" } ], to = [] }
feature = "reference-types"
since = "2"