C & POSIX Code Generation

While VHDL generation targets spatial execution on reconfigurable hardware, the C & POSIX Code Generation backend lowers Invocation Language AST nodes into portable, deterministic ANSI C/POSIX software constructs. This allows space-time graph definitions to execute on conventional host operating systems and embedded processors.

Architectural Mapping

The software backend translates spatial-temporal graph semantics into low-overhead POSIX primitives without modifying the core IPL syntax:

• Resolutions → Threads / Tasks: Top-level resolutions map directly to POSIX threads (pthread_create) or task routines.
• Streams & Places → File Descriptors & Pipes: Data paths between processing nodes are emitted as POSIX byte streams, non-blocking FIFOs (mkfifo), or Unix domain sockets.
• Tokens & Signals → POSIX Synchronization: Token passage across graph edges lowers to POSIX semaphores (sem_t), mutexes, or poll/select readiness checks to enforce deterministic signal flow.

+------------------------+        +---------------------------+
|    IPL AST Node        |        |    C / POSIX Target       |
+------------------------+        +---------------------------+
|  Resolution Node       |  --->  |  void* task_thread(void*) |
|  Stream / Data Place   |  --->  |  int pipe_fd[2]           |
|  Token / Signal Edge   |  --->  |  sem_t token_sem          |
+------------------------+        +---------------------------+

Compilation Pipeline Steps

1. AST lowering: Flatten resolution graphs into explicit execution frames and state transitions.
2. Buffer Allocation: Bind data channels to fixed-size ring buffers or file descriptor handles to prevent runtime dynamic memory allocations (malloc).
3. Thread Instantiation: Synthesize main entry loops and initialize POSIX synchronization primitives (pthread_mutex_init, sem_init).
4. Target Emission: Output clean, dependency-free ANSI C code suitable for compilation via gcc, clang, or target cross-compilers.

Target Attributes & Configuration

Low-level OS parameters that fall outside core language logic are specified directly via target attributes attached to nodes:

$sensor_node() : [
    @target(posix, path="/dev/ttyS0", priority=100)
    dev< stream_in >
]

This ensures full portability across environments while allowing explicit control over OS resources, scheduling priorities, and file paths when compiling for standard Linux or embedded POSIX runtimes.

Drafting in progress…