initcache_noise.va

// Enhancement-326: the NUMERIC guard for the mis-typed init cache slot.
//
// Same ingredients as `initcache.va` -- a noise source whose power is an
// op-independent NON-parameter expression (so it is routed through an init CACHE
// SLOT, which is exactly the slot whose recorded type was wrong), plus an `idt`
// implicit equation under a parameter-only non-constant condition -- but here the
// noise is left observable at the terminals so its magnitude can be checked
// against the closed form.
//
// If the slot is typed `Bool` (i8) instead of `Real`, the power is read back as a
// raw i8 and the noise magnitude is garbage; with the fix it matches
// white_noise(p) exactly.
`include "disciplines.vams"
module initcache_noise(a, b);
    inout a, b;
    electrical a, b;
    parameter real p = 4.0e-18;
    parameter integer s = 1;
    real n, q, d;
    analog begin
        d = d + V(a, b) * 1.0;
        d = d + V(a, b) * 2.0;
        n = white_noise(abs(p));          // power routed through a cache slot
        if (s) q = idt(V(a, b));          // implicit equation -> collapse flag
        I(a, b) <+ 1.0e-3 * V(a, b) + n + 1.0e-30 * (d + q);
    end
endmodule