wasd 0.0.1

WASD: Wasm And Dart System / WebAssembly System for Dart.

WASD

WASD (Wasm And Dart System / WebAssembly System for Dart) is a pure Dart WebAssembly runtime inspired by zwasm's layered design, implemented as a cross-target interpreter that works on Dart native, JS, and Wasm compile targets.

Current coverage

• Binary module decoding
  • sections: type, import, function, table, memory, global, export, start, element, code, data, data_count
  • custom sections are skipped safely during decode
• Runtime features
  • function/table/memory/global imports
  • global initialization with const-expression evaluation
  • active element initialization
  • active data initialization
  • start function execution
  • pre-instantiation static validation phase (WasmValidator)
• Control flow
  • block, loop, if, else, br, br_if, br_table, return
• Calls
  • call, call_indirect + signature checking
  • tail-call opcodes: return_call, return_call_indirect
• Variable and memory access
  • local.get/set/tee, global.get/set
  • full MVP load/store family (i32/i64/f32/f64 + 8/16/32 signed/unsigned variants)
  • memory.size, memory.grow
  • table instructions: table.get/set
• Numeric execution
  • i32 full core arithmetic/bit/compare ops
  • i64 core arithmetic/bit/compare ops
  • f32/f64 core arithmetic and compare ops
  • conversions/reinterpret/sign-extension/trunc-sat families
• Bulk memory/table
  • memory.init, data.drop, memory.copy, memory.fill
  • table.init, elem.drop, table.copy, table.grow, table.size, table.fill
• Multi-value
  • multi-result functions (including import/export call paths)
• WASI Preview1 (phase-2 baseline)
  • fd_write, fd_read, fd_pread, fd_pwrite
  • fd_seek, fd_tell, fd_advise, fd_allocate
  • fd_datasync, fd_sync
  • fd_filestat_get, fd_filestat_set_size, fd_filestat_set_times
  • fd_fdstat_get, fd_fdstat_set_flags, fd_fdstat_set_rights
  • fd_prestat_get, fd_prestat_dir_name, fd_readdir
  • fd_renumber
  • fd_close, path_open, path_rename, path_unlink_file
  • path_create_directory, path_remove_directory
  • path_filestat_get, path_filestat_set_times
  • path_link, path_symlink, path_readlink
  • args_sizes_get, args_get
  • environ_sizes_get, environ_get
  • clock_time_get, clock_res_get, random_get
  • poll_oneoff, sched_yield, proc_exit
  • proc_raise (stub: ENOSYS)
  • sock_accept, sock_recv, sock_send, sock_shutdown (stubs: ENOSYS)
  • filesystem backend auto-selection via conditional import:
    • supports dart:io: use host-backed filesystem
    • no dart:io: fallback to WasiInMemoryFileSystem
  • can force in-memory backend: WasiPreview1(preferHostIo: false)
  • host-io path sandbox checks (canonical root boundary enforcement)
  • proposal feature gates: WasmFeatureSet(simd/threads/exceptionHandling/gc/componentModel)
  • helper runner: WasiRunner (instantiate + bind memory + invoke _start)
  • runtime adapter: lib/src/wasi_preview1.dart
  • filesystem abstractions: lib/src/wasi_filesystem.dart
  • conditional backend selector: lib/src/wasi_fs_auto.dart

Not implemented yet

• SIMD execution semantics
• threads/atomics/shared memory semantics
• exception handling semantics
• GC/reference-subtyping semantics
• component model semantics
• remaining WASI Preview1 semantics (fd_prestat_set_flags, fd_filestat_set_times full flag semantics, path_open symlink-follow semantics, full sock_* behavior, etc.)

Examples

• Basic invocation: example/invoke.dart
• Load various wasm modules: example/load_various_wasm.dart
• Load .wasm from file: example/load_from_file.dart
• Batch-load all .wasm files under a directory: example/load_wasm_suite.dart
• Minimal WASI hello example: example/wasi_hello.dart
• WASI file-write example (via in-memory FS): example/wasi_write_file.dart
• WASI seek/stat example: example/wasi_seek_stat.dart
• WASI runner example (_start + proc_exit): example/wasi_runner.dart
• Doom wasm headless runner: example/run_doom_wasm.dart
• Doom wasm terminal playable runner: example/play_doom_terminal.dart
• Doom asset bootstrap script: example/doom/setup_assets.sh

Run:

dart run example/invoke.dart
dart run example/load_various_wasm.dart
dart run example/load_from_file.dart ./path/to/module.wasm exported_fn 1 2
dart run example/load_wasm_suite.dart ./path/to/wasm_dir
dart run example/wasi_hello.dart
dart run example/wasi_write_file.dart
dart run example/wasi_seek_stat.dart
dart run example/wasi_runner.dart
example/doom/setup_assets.sh
dart run example/run_doom_wasm.dart
dart run example/play_doom_terminal.dart

Doom quick run (headless, 120 frames, dump first frame as PPM):

example/doom/setup_assets.sh
dart run example/run_doom_wasm.dart example/doom/doom.wasm example/doom/doom1.wad 120 example/doom/frame_0001.ppm

Doom terminal playable mode (interactive):

example/doom/setup_assets.sh
dart run example/play_doom_terminal.dart

If your terminal shows a black screen, use monochrome fallback:

dart run example/play_doom_terminal.dart --mono

Doom desktop window mode (Flutter):

cd doom_window
tool/sync_assets.sh
flutter pub get
flutter run -d macos

On Linux/Windows, replace -d macos with your desktop target. doom_window now loads doom.wasm + doom1.wad from Flutter assets (doom_window/assets/doom/*) instead of external filesystem paths. Controls in window mode: arrows/WASD move, Ctrl (and Space) fire, Alt strafe, Shift run, Enter use, Esc menu.

zwasm WAT samples

Copied from zwasm/examples/wat into:

• example/wat

These are source .wat samples for reference and conversion workflows.

Why WASD

No FFI, no native code, and no runtime-specific APIs. This keeps the runtime portable across all Dart compile targets.