pub fn emit_gpu_simt_testbench(
name: &str,
eng: &SimtEngine,
n_vectors: usize,
) -> StringExpand description
A self-checking iverilog testbench: for each of n_vectors vectors, reset the load counter,
stream the load slots from gpu_{name}_in.hex, pulse go (all lanes compute in one cycle),
then read back every lane output + the reduced scalar via raddr and compare against the VM
oracle in gpu_{name}_out.hex. Prints PASS/FAIL. Layout matches write_gpu_hex.