Roadmap

What has shipped and what is planned.

v2.0 shipped on 2026-07-25. The compliance matrix gives the status of each IEEE 1800-2023 clause.

Shipped

Everything below is in the current release. The Since column marks what came with v1 and what v2.0 added.

Capability	Since	Status
4-state simulation (0, 1, X, Z)	v1	Shipped
Synthesizable SystemVerilog (modules, generate, packages, interfaces, parameters)	v1	Shipped
VPI, used by cocotb testbenches	v1	Shipped
Code coverage (line, branch, toggle) with LCOV output	v1	Shipped
VCD / FST waveform generation	v1	Shipped
IEEE 1735 IP encryption / decryption	v1	Shipped
DPI	v1	Shipped (partial; see the matrix)
Linux builds for Ubuntu, Debian, Rocky and Fedora (supported versions)	v1	Shipped
Stratified region scheduler (cl. 4) with suspendable processes	v2.0	Shipped
Behavioral timing: `#` delays (incl. intra-assignment), mid-procedure `@`, `wait`, timing in tasks (cl. 9, 10, 13)	v2.0	Shipped
Native output: `$display`/`$write`/`$monitor`/`$strobe` and the `$random` family run in the design; v1 ran them over VPI only (cl. 20, 21)	v2.0	Shipped
`fork`/`join`/`join_any`/`join_none`, `disable`, `wait fork`, the `process` class (cl. 9)	v2.0	Shipped
IPC: named `event`, `semaphore`, `mailbox` (cl. 15)	v2.0	Shipped
Dynamic data: queues, dynamic and associative arrays, array manipulation methods, string methods, packed multi-dimensional arrays (cl. 6, 7)	v2.0	Shipped (partial; see the matrix)
Classes and OOP: inheritance, virtual methods, `$cast`, parameterized and interface classes, virtual interfaces (cl. 8, 25)	v2.0	Shipped
Randomization and constraints: `rand`/`randc`, constraint blocks, `randomize() with`, `randcase`/`randsequence` (cl. 18)	v2.0	Shipped
Functional coverage: covergroups, coverpoints, bins, crosses, coverage computation (cl. 19)	v2.0	Shipped (partial; see the matrix)
Clocking blocks, `program` blocks, `final`, `$exit` (cl. 14, 24)	v2.0	Shipped
Assertions: immediate and concurrent SVA, sampled-value functions, sequence local variables, recursive properties, `expect`, `let`, assertion control (cl. 16)	v2.0	Shipped
Checkers (cl. 17)	v2.0	Shipped
DPI completion and the remaining system tasks: UVM DPI helpers, file I/O, `$dist_*` (cl. 20, 21, 35)	v2.0	Shipped (partial; see the matrix)
UVM: `uvm_pkg` compiles and runs; SystemVerilog testbenches run without VPI	v2.0	Shipped
Design-true VCD / FST timescales (cl. 22)	v2.0	Shipped
Multi-core RTL evaluation (`--threads`), per-host `-march` detection, SIMD runtime dispatch	v2.0	Shipped

Planned for v2.x

RyuSim does not yet implement the items below. A design that uses one of the constructs marked rejected fails to compile with an unsupported construct error. Some of the others compile without a diagnostic and have no effect; the compliance matrix lists which under Accepted without a diagnostic.

Gate-level and switch-level modeling, including strengths and gate delays (clause 28). Gate instances compute logic values today.
Delays on continuous assignments and net declarations (clause 10).
Covergroup variables declared inside a procedural block (clause 19). Today they stop the compile with an internal error.
The DPI limits listed in the DPI guide (clause 35).
Nine VPI routines from clause 38, among them vpi_get64, vpi_get_data and vpi_put_data.
User-defined primitives, UDPs (clause 29). Rejected.
Specify blocks (clause 30).
Timing checks (clause 31).
SDF back-annotation (clause 32).
Design configurations (clause 33).
VPI assertion API (clause 39), coverage control API (clause 40) and data read API (clause 41).
interconnect, trireg and user-defined nettypes (clause 6). Rejected.
Tagged unions and tagged-union expressions (clauses 7, 11.9). Rejected.
Assignments used as expressions (11.3.6) and streaming operators with a with clause (11.4.14.4). Rejected.
Pattern matching: case … matches and if … matches (12.6). Rejected.
The rest of the optional system tasks and compiler directives (Annex D/E).

Not on the roadmap

GPU offload is parked. The GPU path is not carried forward in v2. The --gpu flag still parses, prints a deprecation warning, and has no effect (exit status is unchanged).
ARM and macOS are a future product decision. Portability is preserved (no hard x86 dependencies; SIMD kernels sit behind an abstraction with a scalar fallback), but there is no deliberate ARM tuning and macOS support is not committed. Released builds are Linux x86-64.

Version support

v2 is the active line. The v1 maintenance branch is sunset as of the v2.0 release: v1 downloads stay hosted indefinitely, but no further v1 releases are planned. See Downloads for installing a specific version or channel.