Function write_engine_program 

pub fn write_engine_program(
    machine: &Machine,
    map: &PhysicalMap,
    dir: &Path,
) -> Result<EngineProgram>

Write the program machine — as super::machine::Machine::new left it, its regions empty — runs on the engine build over map, a flat map (super::physical::PhysicalMap::flat: the reference engine reads its weights a line at a time through the card port), into dir: engine.txt, table<k>.bin for the engine’s static tables (0 the step’s jobs after the host’s embedding, 2 the slots, 3 the tensors, 4 the rotary tables, 5 the blocks), a 64-byte line an entry, jobs.txt the step’s job listing (job_listing), channel<k>.bin the memory image, and embed.bin, every token’s embedding as f32.