Function run_soft_core 

pub fn run_soft_core(imem: &[u32], max_cycles: usize) -> Vec<i64>

The integer-differential view of run_soft_core_typed: the Show sequence as raw i64 values. The pure integer programs (the hand-assembled ≡VM differential, the testbench emitter, the silicon demo) never emit a float Show, so at the 32-bit width this stays value-identical to the pre-FPU model (a 32-bit result carried in the low bits of an i64). A float program uses run_soft_core_typed + ShowVal::fmt instead (panics loudly here if one leaks a float).