STARC

Data-parallel programming for hypercubes

A C-like language for programming thousand-core supercomputers. Designed for a Connection Machine-inspired architecture with TDMA message passing.

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KEY FEATURES

SPMD EXECUTION

Single Program, Multiple Data. All 4,096 processors run the same code with different data. Write once, execute massively parallel.

EXPLICIT COMMUNICATION

No hidden costs. All communication happens in exchange blocks with bounded latency and zero collisions.

HYPERCUBE TOPOLOGY

12-dimensional hypercube with deterministic routing. Neighbor exchanges, reductions, and scans map directly to hardware.

MASKED EXECUTION

Use where() blocks to run code on a subset of processors. Divergent control flow without branches.

TYPE SAFETY

Distinct types for per-processor (pvar) and shared variables. Catches parallelism bugs at compile time.

DETERMINISTIC

No race conditions. No deadlocks. TDMA scheduling makes every operation predictable and repeatable.

WHY STARC?

THIS ISN'T A GPU. GPUs have thousands of threads with shared memory. StarC has thousands of processors with explicit communication. You don't hide latency—you design algorithms that use the hypercube topology.

THIS ISN'T MPI. There's no send(dest, msg). Communication is symmetric (everyone exchanges with neighbors) and deterministic (bounded latency, no collisions).

THIS IS DATA-PARALLEL COMPUTING. Inspired by the Connection Machine CM-1, StarC brings 1980s supercomputer thinking to modern hardware. Write topology-aware code, and the machine executes it predictably.

EXAMPLE CODE

hello_4096.starc

void main() {
  // Each processor has its own copy of 'x'
  pvar<int> x = pid();  // 0, 1, 2, ..., 4095

  // Exchange with neighbor in dimension 0
  exchange {
    pvar<int> neighbor = nbr(0, x);
  }

  // Sum across all processors
  exchange {
    int total = reduce_sum(x);  // 8,386,560
  }

  // Only some processors execute this
  where (x < 64) {
    led_set(255);  // Light up first 64 LEDs
  }
}

PROGRAM YOUR SUPERCOMPUTER

Ready to get started? Try the interactive playground to see 4,096 processors in action, grab the tools to build your own StarC programs, or dive into the documentation to learn the language.

Launch Playground Read The Docs Get The Tools