FA-89288 / Digital logic simulation / Member archive

Capture evaluates next state from partially updated flops · case 03

Flops later in the chain capture values computed from already-updated earlier flops.

Member previewVariant 3 · 3 implementations · 6 checks per implementation

Case contract

Input [chain, logic, state, ops]: chain lists flops from scan-in to scan-out. 'shift' with bit b: scan-out observes the last flop before the edge, then every flop takes its predecessor's old value and the first takes b. 'capture': every flop loads its functional next state logic[f] = [op, inputs] (and/xor/not) computed from the old state of all flops simultaneously. Return [scan-out bits, final chain values].

Why this case matters

Scan-based test simulation must shift and capture as simultaneous register updates.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
capture then unload	`[[1, 0, 1, 1], [0, 0, 0, 0]]`	`[[0, 0, 1, 1], [0, 0, 0, 0]]`	Failed

MEMBER ARCHIVE

The complete case is available to members.

This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

Member access is invitation-based. Sign in with your invited account to inspect the sources.