Spec Coverage

zwasm targets full WebAssembly 3.0 compliance. All spec tests pass on macOS ARM64 and Linux x86_64.

Test results: 62,158 / 62,158 (100.0%)

Core specification

All 9 Wasm 3.0 proposals are fully implemented:

Proposal	Opcodes	Spec tests	Status
Memory64	extends existing	Pass	Complete
Tail calls	2	Pass	Complete
Extended const	extends existing	Pass	Complete
Branch hinting	metadata section	Pass	Complete
Multi-memory	extends existing	Pass	Complete
Relaxed SIMD	20	85/85	Complete
Exception handling	3	Pass	Complete
Function references	5	104/106	Complete
GC	31	Pass	Complete

46 / 46 syscalls implemented (100%):

Category	Count	Functions
args	2	args_get, args_sizes_get
environ	2	environ_get, environ_sizes_get
clock	2	clock_time_get, clock_res_get
fd	14	read, write, close, seek, stat, prestat, readdir, …
path	8	open, create_directory, remove, rename, symlink, …
proc	2	exit, raise
random	1	random_get
poll	1	poll_oneoff
sock	4	NOSYS stubs

121 Component Model tests pass.

The text format parser supports:

All value types including v128
Named locals, globals, functions, types
Inline exports and imports
S-expression and flat syntax
Data and element sections
All prefix opcodes: 0xFC (bulk memory, trunc_sat), 0xFD (SIMD + lane ops), 0xFE (atomics)
Wasm 3.0 opcodes: try_table, call_ref, br_on_null, throw_ref, etc.
GC prefix (0xFB): GC type annotations and struct/array encoding
100% WAT roundtrip: 62,156/62,156 spec test modules parse and re-encode correctly