# ISA Definition

Formal, machine-readable specification of the instruction set.

## Structure

- `encoding/`   — Instruction encoding bitfield definitions (JSON/YAML tables)
- `opcodes/`    — Opcode mnemonics, values, operand types
- `extensions/` — Optional ISA extensions (e.g. float, vector, crypto)
- `privileged/` — Privileged architecture: CSRs, traps, memory management

This directory is the **source of truth** consumed by the generators in `gen/`.