walk_core

The loop a walk kernel runs for one walker: load its state (up to 8 floats, held as two vec4), call the step hooks for each of steps steps (stopping when the stop hook says so), write the state after every step to the walker's path rows, and write the end state and the number of steps that ran. The includer defines zero_walk_lo, zero_walk_hi and zero_walk_stop, and calls zero_walk_run from its entry point; the module header lists the bindings and params the includer declares.