WASURO

A WebAssembly virtual machine for the Asuro operating system, written in Standard Pascal.

WASURO parses and executes WASM binaries directly in a bare-metal kernel environment — no runtime library, no classes, no heap manager beyond what the OS provides.

Architecture

src/
├── emu/               # OS emulation layer (types, console, memory, LEB128)
├── wasm/              # WASM Virtual Machine
│   ├── parser/        # WASM binary parser
│   │   └── sections/  # Section-specific parsers (type, function, export,
│   │                  #   code, global, memory, start, data, etc.)
│   ├── types/         # WASM type system, stack, and linear memory (heap)
│   ├── vm/            # VM tick loop and opcode jump table
│   └── test/          # Test suite
│       ├── infra/     # Stack, heap, LEB128 tests
│       ├── opcodes/   # Per-opcode test units
│       └── parsers/   # Per-section parser tests
└── project/           # Lazarus project files

Key components

• VM (wasm.vm) — Tick-based execution loop dispatching opcodes through a 256-entry jump table.
• Parser (wasm.parser) — Validates the WASM magic/version header, then routes each binary section to its handler.
• Stack (wasm.types.stack) — Operand and control stacks supporting i32, i64, f32, f64 push/pop.
• Heap (wasm.types.heap) — Paged linear memory with read/write at 8/16/32/64-bit widths.
• Emulation layer (src/emu/) — Provides the same types, console, lmemorymanager, and leb128 interfaces that exist in the real Asuro kernel, allowing development and testing on a host OS.

Implemented opcodes

Category	Opcodes
Control	nop, unreachable, drop, select, return
Variables	local.get/set/tee, global.get/set
Constants	i32.const, i64.const, f32.const, f64.const
i32 Arithmetic	add, sub, mul, div_s/u, rem_s/u, clz, ctz, popcnt
i32 Bitwise	and, or, xor, shl, shr_s/u, rotl, rotr
i32 Comparison	eqz, eq, ne, lt_s/u, gt_s/u, le_s/u, ge_s/u
i64 Arithmetic	add, sub, mul, div_s/u, rem_s/u, clz, ctz, popcnt
i64 Bitwise	and, or, xor, shl, shr_s/u, rotl, rotr
i64 Comparison	eqz, eq, ne, lt_s/u, gt_s/u, le_s/u, ge_s/u
f32/f64 Comparison	eq, ne, lt, gt, le, ge
Memory Loads	i32/i64/f32/f64.load, sign/zero-extending variants (8/16/32-bit)
Memory Stores	i32/i64/f32/f64.store, narrowing variants (8/16/32-bit)
Memory Mgmt	memory.size, memory.grow

Parsed sections

Type, Function, Export, Code, Global, Memory, Start, Data, Import (stub), Table (stub), Element (stub), Custom (stub).

Constraints

• Standard Pascal only — no runtime library, no classes.
• Kernel-compatible — all arithmetic (including shr_s) uses manual implementations, no RTL intrinsics.
• Emulation layer — src/emu/ mirrors the real Asuro kernel API; only these interfaces are available.

Requirements

• Free Pascal Compiler 3.2.2+ (x86_64-win64)
• Windows (build script is a .bat file)

Building

# Normal build
build.bat

# Build with test suite
build.bat test

Output: bin\WASURO.exe

Testing

build.bat test
bin\WASURO.exe

Runs 374 tests across 108 test units. Exit code equals the number of failed tests (0 on success), making it CI/CD-friendly.

License

See repository for license details.